LAT4 is a broadly expressed uniporter selective for essential branched chain amino acids, methionine and phenylalanine, which are involved in epithelial transport.Its global deletion leads to an early malnutrition‐like phenotype and death within 10 days after birth.Here, we tested the impact of deleting LAT4 selectively in the mouse intestine. This affected slightly the absorption of amino acids (AAs) and delayed gastrointestinal motility; however, it had no major phenotypic effect, even when combined with aromatic AA uniporter TAT1 knockout (KO).Conversely, kidney tubule‐selective deletion of LAT4 led to a substantial aminoaciduria that strongly increased under a high protein diet. Combining a partial tubular LAT4 deletion with TAT1 KO implicated their synergistic action on AA reabsorption.These results show that LAT4 plays an important role for kidney AA reabsorption, but that its functional role in intestinal AA absorption is largely dispensable.in vivo, the functional co‐operation of these two transporters. The major role played by basolateral uniporters in the kidney was further supported by the observation that, in mice lacking TAT1, another neutral AA uniporter, a partial LAT4 KO led to a synergistic increase of urinary AA loss. Surprisingly in the SI, the same combined KO induced no major effect, suggesting yet unknown compensatory mechanisms. Taken together, the lethal malnutrition‐like phenotype observed previously in LAT4 global KO pups is suggested to be the consequence of a combinatorial effect of LAT4 deletion in the SI, kidney and presumably other tissues.Amino acid (AA) transporter LAT4 (Slc43a2) functions as facilitated diffusion uniporter for essential neutral AAs and is highly expressed at the basolateral membrane of small intestine (SI) and kidney tubule epithelia. Previously, we showed that LAT4 global knockout (KO) mice were born at the expected Mendelian ratio but died within 10 days. Their failure to gain weight and a severe malnutrition‐like phenotype contrasted with apparently normal feeding, suggesting a severe intestinal AA absorption defect. In the present study, using conditional global and tissue‐specific LAT4 KO mouse models, we nullified this hypothesis, demonstrating that the selective lack of intestinal LAT4 does not impair postnatal development, although it leads to an absorption defect accompanied by delayed gastrointestinal motility. Kidney tubule‐specific LAT4 KO led to a substantial aminoaciduria as a result of a reabsorption defect of AAs transported by LAT4 and of other AAs that are substrates of the antiporter LAT2, demonstrating,  LAT4 is a broadly expressed uniporter selective for essential branched chain amino acids, methionine and phenylalanine, which are involved in epithelial transport.Its global deletion leads to an early malnutrition‐like phenotype and death within 10 days after birth.Here, we tested the impact of deleting LAT4 selectively in the mouse intestine. This affected slightly the absorption of amino acids (AAs) and delayed gastrointestinal motility; however, it had no major phenotypic effect, even when combined with aromatic AA uniporter TAT1 knockout (KO).Conversely, kidney tubule‐selective deletion of LAT4 led to a substantial aminoaciduria that strongly increased under a high protein diet. Combining a partial tubular LAT4 deletion with TAT1 KO implicated their synergistic action on AA reabsorption.These results show that LAT4 plays an important role for kidney AA reabsorption, but that its functional role in intestinal AA absorption is largely dispensable. AAs are crucial metabolites that are not only used as building blocks of proteins, but also as substrates for energy metabolism, precursors of biologically important molecules and neurotransmitters, as well as for many other functions  for most neutral AAs, and the H+ symporter PEPT1 (Slc15A1) for di‐ and tripeptides. One of the active luminal AA transporters is an antiporter (exchanger), b0,+AT‐rBAT (Slc7a9‐Slc3a1), which was mentioned above in the context of cystinuria   to cross the two lipid membranes of the polarized epithelial cell barrier. The luminal transport into the epithelial cells is mediated by active transporters, mostly by symporters (cotransporters), such as Naet al. et al. −1)  across the membrane . LAT4 is highly expressed in various tissues such as the placenta, SI enterocytes, kidney epithelium and peripheral blood leukocytes, and, to a lesser extent, in the brain, white adipose tissue and heart  is a facilitated diffusion uniporter originally identified by Bodoy et al. . It funcSlc43a2 (Lat4) KO mouse model . Analysis of the amniotic fluid showed a strong decrease in AA levels that was not limited to LAT4 substrates, indicating a broader defect at the level of placental AA transport. After birth, these mice did not grow normally and displayed a starvation‐like phenotype with increased plasma acylcarnitines, reduced plasma non‐essential AA levels and low fasting plasma glucose levels. Although they appeared to feed normally as suggested by the milk‐spot in their belly, they did not gain much weight and died before day 10  of LAT4 were responsible for the postnatal malnutrition phenotype and death of the global KO mice. Was it a result of the lack of LAT4 in the intestine and kidney and the consecutive defective AA (re)absorption? Or was it a result of the lack of LAT4 function in other tissues? And would a deletion of LAT4 induced only past the postnatal phase result in a lethal phenotype as well? To address these questions, we generated and studied a number of conditional LAT4 KO mouse models. Additionally, by knocking out both LAT4 and TAT1 in the SI and kidney, we addressed the question of whether together these two major AA uniporters expressed at the basolateral membrane might be a requisite for the basolateral efflux of AAs and thus AA transport across (re)absorbing epithelia.The Journal of Physiology.All animal experiments were carried out according to the Swiss animal welfare laws and approved by the Cantonal Veterinary Office of Zürich . The study was conducted in compliance with the ethical principles and standards of f/fLAT4 were produced by PolyGene Transgenetics . The targeting vector containing exon 5 of the Slc43a2 gene floxed with LoxP sites and a FRT flanked neomycin cassette  was transfected into C57Bl/6N‐derived embryonic stem cells by electroporation. Positive clones containing the correct homologous recombination were further identified by PCR analysis and injected into blastocysts from grey C57Bl/6 mice, which were then transferred into CD‐1 foster mice. Resulting chimeric mice were mated with grey Flp‐deleter mice (C57Bl/6N derived) to remove the neomycin cassette.Lat4 (Slc43a2) floxed mice, f/fLAT4 mice with mice containing T2+Rosa26‐CreER (B6.129‐Gt(ROSA)26Sortm1(cre/ERT2)Tyj/J)  23Syr/J)  1Koes/J)  997Gum/J]  .Inducible global, intestine‐ and kidney tubule‐specific LAT4 KO mouse models were generated by breeding −/−TAT) mice  and TAT1  dKO mouse models were generated by breeding TAT1 null  in 8‐week‐old mice of both genders unless otherwise specified. We did not observe any gender‐specific differences in our results.All animals were bred in the LASC husbandry of the University of Zurich under standard conditions and had Genomic DNA was isolated from ear biopsies by adding 20 μL of microLYSIS‐Plus buffer  followed by placing in a thermal cycler  in accordance with the manufacturer's instructions.All genes were amplified using conventional PCR in the thermal cycler. The primers  used in each reaction are summarized in Table f/f Rosa26‐CreERT2+LAT4 and f/f Villin‐CreERT2+LAT4) and control littermates (f/f Rosa26‐CreERT2‐LAT4 and f/f Villin‐CreERT2−LAT4) were treated similarly with tamoxifen   for 1 h at RT. Primary antibodies were also diluted in the blocking solution  and membranes were incubated overnight on a shaker at 4°C. Membranes were then washed in TBS‐Tween for 3 × 10 min and incubated for 1 h at RT in secondary antibodies also diluted 1:5000 in the blocking solution. β‐actin was used as loading control, and both primary and secondary antibodies were diluted 1:5000 in blocking solution and incubated 1 h at RT. Antibody binding was detected using Luminata Classico Western Chemiluminescent HRP substrate  or CDP‐Star substrate . Blots were then imaged with a ImageQuant LAS 4000 camera  and further densitometric analysis was performed using ImageJ .Scraped intestinal mucosa, villi fractions or kidney  were homogenized in 400 μL of mannitol resuspension buffer (200 mR = 2−[Ct(test RNA)‐Ct(18S rRNA)], where Ct is the cycle number observed at the threshold for the tested mRNAs.Total RNA was extracted using RNeasy Mini Kit  in accordance with the manufacturer's instructions, with the exception that the frozen samples were lysed with 1 mL of Trizol  (instead of RLT buffer) using MagNa Lyser Green Beads  in a Precellys 24 homogenizer . The quality and quantity of the extracted RNA were assessed using a RNA 600 Nano kit  and a Nanodrop ND‐1000 UV‐spectrophotometer , respectively. Reverse transcription was then performed with qScript cDNA synthesis kit  using 500 ng of RNA as template. For real‐time PCR, TaqMan Universal PCR Mastermix , 75 ng cDNA and other reaction components were mixed in accordance with the manufacturer's instructions. The primers and probes  used in the study are provided in Table –1 mouse) containing all the proteinogenic AAs in 1 × PBS (pH 7.4) at a concentration 10× higher than the plasma AA concentration of wild‐type mice ‐dextran 4 kDa . Blood samples were collected 10 min before and at several time points  after the oral gavage from the tip of the tail into heparin coated capillaries. One hour (or 20 min) after the gavage, mice were killed as described above and blood was collected by cardiac puncture. The SI was divided into four equal parts and the intestinal tissue and its contents (washed with 1 mL of 1 × PBS pH 7.4 at room temperature) collected separately. Volume (10 μL g–1 body weight) and osmolality of the gavage fluid (∼350 mosmol kg–1) were the same as in previous experiments in which no deleterious effects had been observed  were food deprived for 11 h (22.00 h to 09.00 h the next day) before giving an oral gavage of an AA mix (10 μL gce Table  (Singer 2O2 (200 μL) for 1 h at RT on a shaker. Radioactivity in the blood plasma and the bleached intestinal tissue and contents were then measured by liquid scintillation counting in Ultima Gold solution  using a ß‐counter . The radiolabelled AA tracers used in the present study include: 3H‐Leu , 3H‐Mannitol ; 14C‐Lys , 14C‐Trp  and 14C‐Met . The concentration of the AAs was calculated and the results are expressed as pmol mg–1 wet segment weight for intestinal tissue, as concentration (nmol μL–1) for luminal contents and as pmol μL–1 for plasma.Isolated intestinal tissue and its flushed contents were then digested with 1 mL of Solvable  overnight at 50°C followed by destaining with 30% HThe appearance of FITC‐dextran in the blood was determined by measuring the fluorescence intensity (excitation 490/emission 530) of plasma collected at different time points using a plate reader .f/f Pax8‐rtTA+/LC1+LAT4) were housed under standard laboratory conditions and had ad libitum access to food and water until 3 days before the urine and blood sample collection. Starting from 3 days before sample collection, animals were time restrictedly fed only for 16 h from ZT12 to ZT4 (18.00 h to 10.00 h the next day). On the day of sample collection, mice were restrained before feeding (18.00 h) in an attempt to make them empty the bladder. Two hours after feeding (20.00 h), mice were restrained on parafilm to collect spot urine followed by blood collection from the tail vein into heparin coated capillaries .Kidney tubule‐specific LAT4 KO mice TAT1 were time restrictedly fed for 3 days as described above and were also acclimatized to the cages for ∼3 h during their inactive phase (from 13.00 h to 16.00 h). Two days after the training, mice were again transferred to the metabolic cages (at 18.00 h). Standard chow or a HPD was ground as a feed for the mice in metabolic cages. All animals had ad libitum access to water. Urine samples were then collected overnight (from 18.00 h until 10.00 h the next day) and water consumption was recorded. Mice were then anaesthetized with Attane Isolfurane  and killed by cardiac incision followed by blood collection using heparin coated syringes. Plasma separation and sample storage was performed as described above.In experiments involving metabolic cages, mice  using the Mass Track AA Analysis Application Solution and ACQUITY ultra performance liquid chromatography  in accordance with the manufacturer's instructions. Plasma and urine samples were deproteinized by sulphosalicylic acid (10%) precipitation prior to UPLC.t test, as well as one‐way or two‐way ANOVA followed by a Bonferroni multiple comparison test, as indicated where appropriate. P < 0.05 was considered statistically significant. Data are shown as individual values with the mean ± SD. Exact numerical values for the mean ± SD and P values for each dataset are provided in the Supporting information .Data were plotted and analysed using Prism, versions 5.0 and 6.0 . Differences between the mean values of groups were assessed with an unpaired Student's et al. f/f Rosa26‐CreERT2+LAT4) by crossing f/fLAT4 mice with T2+Rosa26‐CreER mice  and negligible at the protein level . By contrast, KO of LAT4 was ∼98% efficient in the SI at both mRNA  and protein levels . This LAT4 deletion induced in adult intestine remained stable even after 1 month post tamoxifen treatment (data not shown). Interestingly, this deletion of LAT4 in the SI induced past the postnatal phase did not lead to any change in body weight gain, fasting plasma AA or glucose levels , nor did it lead to any visible phenotype.Constitutional LAT4 global KO in mice lead to a severe phenotype with early postnatal death  which, at the level of the intestine, was found to be very similar to the global inducible model described above .To investigate the impact of LAT4 deletion in adult mouse SI in more detail, we additionally generated an intestine‐specific inducible LAT4 KO mouse model  and apical (B0AT1 and SGLT1) membrane AA and glucose transporters revealed no significant compensatory changes at the mRNA level in the SI of LAT4 KOs at both ZT12  and ZT0 (data not shown). Taken together, our data clearly suggest that the KO of LAT4 in SI induced past the postnatal phase did not lead to any obvious phenotype, nor to a significant compensation at the level of the mRNA of other studied nutrient transporters.To challenge the intestinal AA absorption in adult mice lacking intestinal LAT4, we subjected animals to diets containing different amounts of proteins, namely low protein (8% = LPD), normal (18% = NPD) and high protein (40% = HPD) diets. Based on previous observations that the expression of various nutrient transporters are more responsive to food entrainment than just central circadian rhythm entrained by light, we subjected mice to TRF with access to food only for 8 h during the active phase from ZT12 to ZT20) and killed them either at the start of their active phase (ZT12) or at the start of their inactive phase (ZT0) (Hatori  to ZT20 f/f Villin‐Cre+LAT4) mice by crossing the f/fLAT4 mice with mice constitutively expressing Cre recombinase in the intestine: +Villin‐Cre , body composition  or general behaviour was detected between the genotypes even up to 2 months after birth. Mice were then killed and the efficiency of LAT4 KO was studied. LAT4 KO was found to be 85–95% efficient in the SI at both mRNA and protein levels . LAT4 KO efficiency was also validated in 5‐day‐old pups and gave identical results (data not shown).Although the KO of LAT4 in the SI past the postnatal phase did not affect the general well‐being of mice, we could not completely nullify the hypothesis that LAT4 KO in the SI could have led to the lethal phenotype of LAT4 global KO pups, unless we confirm the role of LAT4 in the SI during pre‐ and postnatal development. Accordingly, we generated constitutional intestine‐specific LAT4 KO  and 14C‐Lys (not a LAT4 substrate) as tracers. Blood was collected from the tail vein at six different time points: 10 min before, 2, 5, 10, 20 and 60 min after gavage, after which mice were killed and the distribution of radiolabelled AAs in the luminal content of the intestine, in the intestinal tissue and in the blood plasma was analysed.Using 8‐week‐old mice, we further analysed the impact of LAT4 deletion on AA transport along the intestine by gavaging them with an AA mix containing radioactively labelled A, B and N). In addition, LAT4 KOs displayed higher levels of both Leu and Lys remaining in the luminal content of the third (late jejunum) segment SI3, whereas, in wild‐type mice, they were higher in the last segment SI4, denoting a delay in the overall bolus movement in the KOs . Killing the mice at 20 minutes after the oral gavage also revealed a similar absorption defect of 3H‐Leu in SI1  with a delayed bolus movement, which, in this case, was still in segments SI1 and SI2 instead of SI3 and SI4, respectively . When we gavaged mice with radiolabelled 14C‐Met (another LAT4 substrate), we observed results similar to those obtained with 3H‐Leu, further confirming the observations made with 3H‐Leu .LAT4 KO mice displayed a strong accumulation of the LAT4 substrate Leu but not of Lys in the initial segment (SI1) of the small intestinal tissue harvested 60 min after the gavage  and 14C‐Lys (not a LAT4 substrate)] in tissue and luminal content of the SI of LAT4 KO (grey triangles) (f/f Villin‐Cre+LAT4) and control (black dots) (f/f Villin‐Cre−LAT4) mice 60 min after they were given by gavage as tracers in an AA mix. E–H, distribution of radiolabelled AAs [3H‐Leu and 14C‐Met (both LAT4 substrates)] as for (A) to (D), but measured 20 min after gavage. The amount of gavaged AAs found in intestinal tissue  is indicated relative to the tissue weight and AAs measured in the luminal content as nmol per segment of the small intestine (SI). I–K, time course analysis of the appearance in blood plasma of radiolabelled AAs  and (L and M) of paracellularly transported molecules (3H‐mannitol and fluorescence labelled FITC‐dextran) given by oral gavage. Values are given as pmol μL–1 plasma (I–L) or as arbitrary fluorescence units (M). N, schematic representation of intestinal absorption defect and delayed bolus movement in LAT4 KO mice. Data are shown as the mean ± SD (n = 5–6). Two‐way ANOVA with a Bonferroni post hoc test, *P < 0.05; **P < 0.01; ***P < 0.001.I–K). At later time points, Leu (after 10 min) and Met (after 30 min) were abundant in the blood plasma of LAT4 KOs to a similar extent as in the controls, indicating that they were absorbed anyway, suggesting a possible compensatory (or redundant) role of other basolateral transporters and/or of a paracellular leak. Assessing a possible paracellular leak in the intestine of these mice using the relatively high molecular weight marker FITC‐dextran (4 kDa) and smaller molecules such as 3H‐Mannitol (182 Da) did not reveal a significant difference between the KO and the control group, although it demonstrated that such a leak is present and suggested a general increase in intestinal paracellular permeability with time, irrespective of genotype .Time course measurements of the appearance of labelled AAs in the blood after gavage showed that LAT4 substrates Leu and Met but not Lys (which is not a LAT4 substrate) appeared with a small delay in the blood of LAT4 KOs compared to control littermates , by crossing the global constitutional TAT1 null mice (−/−TAT1) with inducible intestine‐specific LAT4 KO mice (f/f Villin‐CreERT2+LAT4). LAT4 KO in this model was induced by giving i.p. injections of tamoxifen for 5 consecutive days and allowing for a minimum recovery period of 10 days after the first injection. The induced LAT4 KO was almost 100% efficient in the SI and negligible in the kidney at both mRNA and protein levels . The KO efficiency of TAT1 in the TAT1−/− mice has been described previously  of these mice compared to their control littermates.We hypothesized that deletion of TAT1 , in addition to that of LAT4, would potentially interrupt the directional transport of AAs through the basolateral membrane and would eliminate the potential compensatory/redundant role of TAT1. Hence, we generated an intestine‐specific dKO for LAT4 and TAT1, f/f Villin‐Cre+LAT4). We gavaged an AA mix containing radiolabelled 14C‐Trp (a TAT1 substrate) and 3H‐Leu (a LAT4 substrate) to TAT1‐LAT4 dKO, TAT1 KO and wild‐type like LAT4f/f (WT) mice. In the case of TAT1 substrate, 14C‐Trp, we observed its significant accumulation in the distal small intestinal tissue (SI4) in TAT1 KO mice, although there were no significant changes in the TAT1‐LAT4 dKO mice, which showed only a mild trend towards Trp accumulation in SI2 . In addition, TAT1 KO mice displayed a stronger early appearance of gavaged Trp in the plasma, which was absent in the TAT1‐LAT4 dKOs that closely resembled WT controls . In the case of LAT4 substrate Leu, TAT1 KO but not TAT1‐LAT4 dKO mice displayed a strong accumulation in the small intestinal tissue of SI4, although Leu is not a substrate of the aromatic AA transporter TAT1 . The appearance, and thus the absorption, of Leu into blood was also shortly delayed in TAT1 KOs , and this effect was also present in the TAT1‐LAT4 dKOs . At later time points, the dKOs behaved very similarly to the WT controls. Taken together with the results obtained from intestine‐specific LAT4 KO mice described above, single deletions of LAT4 or TAT1 led to stronger defects in Leu absorption than the double deletion of TAT1 and LAT4, suggesting a possible compensatory mechanism via another AA transporter or a paracellular leak that is turned on specifically in the absence of both uniporters. However, probing for a compensatory increase in paracellular leak (using paracellularly transported molecules such as mannitol and FITC‐dextran)  or investigating the gene expression of other known AA transporters  revealed no significant difference between the genotypes.To precisely investigate the functional impact of double deletion of LAT4 and TAT1 on SI AA absorption, we used a gavage protocol similar to that described above for constitutional intestine‐specific LAT4 KO mice  Fig. I or invers Fig. J revealf/fLAT4 mice with an inducible kidney tubule‐specific Cre mouse: +/LC‐1+Pax8‐rtTA  was induced by administering 2 mg mL–1 doxycycline in 2% sucrose via drinking water for 10 days to 8‐ or 4‐week‐old mice. To optimize the LAT4 KO induction procedure and test for its efficiency, we killed one set of mice at 2 weeks post induction (wpi). The second set of mice received an additional short doxycycline treatment from day 28 to 30 and was killed at 5 wpi. Inducing LAT4 KO in 8‐week‐old mice resulted in almost 90% efficient LAT4 mRNA deletion already at 2 wpi . However, at 2 wpi, KO of LAT4 protein was only ∼30% and 60% efficient in the cortex and medulla, respectively. At 5 wpi, LAT4 protein deletion reached almost 90% and 80% in cortex and medulla, respectively . Attempts to improve LAT4 KO efficiency by inducing it immediately after weaning did not lead to a marked increase in the KO efficiency at the protein level at 2 wpi, but only at 4–5 wpi, suggesting that LAT4 protein is indeed very stable in the kidney, especially in the cortex . IF on kidney sections for LAT4 and B0AT1 , also showed an efficient KO of LAT4, especially in the PTs only after 4–5 wpi .To investigate the specific role of LAT4 in the kidney tubular reabsorption of AAs, we crossed our wpi Fig. A. HowevA, analysing AA concentrations in the urine of these mice revealed an almost three‐fold increase in the urinary excretion of the LAT4 substrate Met  under NPD (LAT4 KO induced at 8 weeks of age). However, subjecting mice to a HPD (LAT4 KO induced at 4 weeks of age) to challenge LAT4's maximal transport capacity, led to a more obvious phenotype with marked increase in the urinary excretion of not only LAT4 substrates , but also LAT2 substrates  and, additionally, of Pro and Asp (by three‐ to seven‐fold) . We also observed a corresponding increase in LAT2 mRNA levels in LAT4 KO mice , although we did not detect a concordant increase in LAT2 protein . By contrast to urinary AA levels, we observed no significant differences in plasma AA concentrations between the KOs and controls both under NPD and HPD conditions (data not shown). Performing similar studies and maintaining mice in metabolic cages overnight to collect urine and plasma samples led to similar results. In accordance to the increased aminoaciduria, urinary volume and water consumption rate was also increased in LAT4 KO mice . Overall, our observations clearly demonstrate an important role for LAT4 in the tubular reabsorption of AAs in the kidney .Given the highly efficient KO of LAT4 protein in kidney PTs, the region where most AAs are known to be reabsorbed, we tested for a possible defect in tubular AA reabsorption by collecting spot urine and plasma samples from mice during the absorptive phase at ZT14–16. Mice were subjected to TRF for 3 days before the sample collection to ensure that they start feeding only at ZT12. As shown in Fig. ld) Fig. B. We alice Fig. C, althoein Fig. D. By coice Fig. E and F.ney Fig. G.T2Rosa26‐CreER‐mediated global LAT4 KO in the constitutional global TAT1 KO mouse, −/− LAT4f/f Rosa26‐CreERT2+TAT1  . With this procedure, LAT4 KO efficiency in the kidney reached almost 85% at the mRNA level  and ∼60% at the protein level .To investigate whether simultaneous deletion of LAT4 and TAT1 in the kidney would act synergistically on aminoaciduria or lead (as observed in the SI) to no major effect on AA transport Fig. , we geneC), despite the fact that the plasma concentration of most of the AAs  was reduced by around one‐half . These observations show that a partial global deletion of LAT4 [60% reduction in the kidney  and ∼98% in the intestine ], together with complete global TAT1 deletion, leads to profound changes in body AA homeostasis even under NPD and, specifically, to a synergistic decrease of renal AA reabsorption.Kidney tubular AA reabsorption was tested in this model by measuring AAs in urine samples collected over a 16 h period from ZT12 to ZT4) from mice subjected to NPD. Kidney AA reabsorption was more strongly affected in these partial global dKO mice as revealed by a 1.5‐ to three‐fold increase in the urinary excretion of almost all AAs  compared to the TAT1 KO littermates Fig. C, despialf Fig. D. Theseney Fig. B and C  to ZT4 ff/f Rosa26‐CreERT2+LAT4). Induced LAT4 KO was very efficient and stable in the SI at the mRNA and protein levels   and other organs such as the brain, adrenal glands and adipose tissue (data not shown) was poor.To investigate the role of LAT4 past the postnatal phase, we used an inducible global LAT4 KO mouse model (0%) Fig. . By contf/f Rosa26‐CreERT2+LAT4 mice suggested an AA absorption defect because the LAT4 substrate Leu was found to be accumulated within the initial segments of the SI (duodenum) (data not shown), similar to the observation made previously by Guetg et al. , which was also almost 100% efficient in knocking out LAT4 in the SI without affecting the kidney, unlike other Villin promoter constructs that are also active in the kidney   revealed no changes in body weight gain, body composition or general behaviour, despite a highly efficient KO of LAT4 in the SI. As a result of the length and larger surface area of the SI, it was technically difficult to measure the levels of non‐absorbed amino acids (which is comparatively easier to measure in the kidney with the low background of AAs excreted in the urine). Therefore, we followed the fate of gavaged radioactive amino acids in the intestinal content, the mucosal cells and the blood. Constitutional intestine‐specific LAT4 KO mice displayed a strong accumulation of Leu and Met (LAT4 substrates) but not Lys (not LAT4 substrate) within the cells of the initial segments of the SI . This accumulation also led to the retention of LAT4 substrates within the lumen of the intestine that presumably caused the delay of intestinal bolus movement observed in the KOs   but does not have an impact on growth or survival of mice.Further analysis of the role of LAT4 in intestine during early development  using a constitutional intestine‐specific LAT4 KO mouse model  would, in dKO conditions, switch to an alternative kinetic mode of non‐obligatory exchange and function as efflux pathway  Fig. . Given tet al. et al. f/f Rosa26‐CreERT2+LAT4) turned out to be inefficient in knocking out LAT4 in the kidney, we generated an inducible kidney tubule‐specific LAT4 KO mouse model (f/f Pax8‐rtTA+ LC1+LAT4) using a system known to have a higher penetrance and specificity for the entire kidney tubular epithelium  suggesting that LAT4 KO in the kidney is not a major contributor to the overall altered AA homeostasis in LAT4 global KO pups. Taken together, our observations demonstrate that LAT4 plays a prominent role in the kidney PTs for the reabsorption of neutral AAs from the primary urine. Understanding the role of LAT4 in other kidney tubules such as the distal renal tubules, connecting tubules and collecting ducts still needs further investigation.As shown in previous studies, LAT4 is quite highly expressed in different kidney tubule segments . Because the half‐life of LAT4 protein is relatively high in the kidney, our attempts to induce its KO immediately after weaning and for longer time periods led to a significant reduction of LAT4 expression. Our observations show that knocking out both the uniporters in the kidney leads to a substantial aminoaciduria even under NPD, which included not only substrates of LAT4 and TAT1, but also other neutral AAs that are LAT2 substrates. This aminoaciduria, although quantitatively not impressive (1.5‐ to three‐fold for 11 AAs) is clearly more pronounced and broader than that observed for the global TAT1 single KO   mice described above. We hypothesize that this reduction of plasma AA levels observed under NPD was largely caused by the synergistic effect of the lack of TAT1 and LAT4 in other tissues and not only by the amino acid loss as a result of the relatively mild intestinal and kidney (re)absorption defects.In addition, these TAT1 LAT4 global dKO mice also displayed about a two‐fold reduction in the level of many plasma AAs, including most neutral and cationic ones, compared to the TAT1 KO mice that were used as controls in this experiment, which is an effect that is not observed in the partial LAT4 KO (Collectively, our results demonstrate that LAT4 is necessary for an optimal absorption of its substrate AAs in the SI, where it also plays a role in altering gastrointestinal transit (Table The authors declare that they have no competing interests.All of the experiments were carried out at the University of Zurich in Zurich, Switzerland. AR, NP, LO and FV designed the study and all of the necessary experiments. AR, NP, LO and BH carried out the experiments. AR and FV analysed and interpreted the data. AR and FV wrote and critically revised the article. All authors approved the final version of the article submitted for publication and agree to be held accountable for all aspects of this study. All persons qualifying for authorship are listed as such.This study was supported by the Swiss National Science Foundation grant #31_166430/1.Statistical Summary DocumentClick here for additional data file.


Consequently, the highly mobile TBs or GBs are inversely pinned by the relatively immobile dislocations. Due to the strong in‐plane covalent bonding, the GBs in high‐symmetry 2D materials such as graphene which consists of defects are immobile at room temperature. In contrast, in monoclinic 2D ReS2 several types of GBs (including TBs) can be readily generated and driven by mechanical loading. A complete library of the GBs in 2D ReS2 is established by the (in situ) atomic‐scale transmission electron microscopy (TEM) characterizations and density functional theory (DFT) calculations. The twinning (shear) stresses for 2D ReS2 are estimated as low as 4–30 MPa, one or two orders of magnitude lower than the traditional bulk materials. Full elucidation on the GB structures and especially the intriguing GB kinetics in such anisotropic 2D materials are of fundamental importance to understand the structure–property relationships and develop strain‐tunable applications for 2D materials in future.In bulk crystals, the kinetics of dislocations is usually hindered by the twining boundaries (TB) or grain boundaries (GB), rendering the well‐known grain boundary strengthening effects. Nevertheless, here it is found that in 2D rhenium disulfide  or grain boundaries (GBs) can be inversely pinned by the relatively immobile dislocations. Very recently, monoclinic 2D materials such as rhenium disulfide (ReS2) and rhenium diselenide (ReSe2) with the ever lowest symmetry in 2D have been fabricated and drawn much attentions for their outstanding anisotropic properties. On the other hand, it has been shown that the grain boundaries (GBs) prevalently existed in many 2D materials especially synthesized by chemical vapor deposition (CVD) growth. The remarkable electrical and mechanical effects from these GBs on 2D materials have been highlighted. Regarding the atomic structures, the GBs in high‐symmetry 2D materials, such as graphene and molybdenum disulfide (MoS2) have been well documented. The GBs in these high symmetry 2D materials consist of in‐plane dislocations or atomic defects; therefore, a relatively high energy barrier are requested to trigger the GB movement. Herein, through the high resolution atomic‐scale transmission electron microscopy (TEM) characterizations and atomistic density functional theory (DFT) simulations, the GBs in 2D materials with lowest symmetry—the monoclinic 2D ReS2, have been fully understood. Apparently, the GB types are greatly enriched by the low‐symmetry structure, in particular the twinning boundaries (TB). Meanwhile, the distinct GB kinetics is also unusual and endows larger mechanical deformability to 2D ReS2.The structures and novel properties of emergent 2D materials have been unveiled over the last decade.1 From In 2D monolayer (1L) MoS2 or other similar hexagonal phase transition metal dichalcogenides (TMD), except for the LA twin GBs and HA GBs above, the break of inversion symmetry additionally introduces the 180° mirror GBs (or inversion GB). Moreover, all the GBs in 2D MoS2 can be subdivided into two categories (“up” and “down”) due to lack of inversion symmetry. Different dislocation core structures belong to two respective categories have been observed by us. Generally, all these GBs observed in 2D materials are formed during the sample growth stages (viz. via thermodynamics), specifically, by the stitching of single‐crystalline flakes grown from different nuclei. Apart from growth, defect creation by electron irradiation and annealing could also generate new GBs within the pristine single‐crystalline graphene. However, the generation, movement and annihilation of dislocations usually require high energies in most of the defect‐less 2D materials. Besides, owning to the high energy of in‐plane stacking fault (SF), the mechanical twinning process is normally not allowed in high‐symmetry 2D materials. As a result, the presence of GBs and lack of dislocation/twinning dynamics in 2D materials lead to poor ductility in polycrystalline 2D materials.The GBs in graphene can be classified into low‐angle (LA) twinning GBs made of piled‐up  dislocations and high angle (HA) irregular GBs.18 In 22 has monoclinic atomic structure  in 2D ReS2 have been observed. In this connection, the twinning and TBs can be rendered by the lattice orientation switching in 2D ReS2. Basically, like the standard mechanical TBs, the TBs here can be nucleated and driven by mechanical straining in 2D ReS2. Here we classify all the GBs in ReS2 into four subgroups, by high/low‐index and coherent/incoherent, respectively  can be originated from two different mechanisms, viz., by direct growth and mechanical strain  atoms may have two types, named as type I and II, which are in mirror symmetry  (PMMA) method, and then characterized by the probe aberration‐corrected scanning TEM (STEM) at the atomic scale . However, GBs from direct growth form with the gaseous kinetic process and multiple chemical phases, which increase the complexity to control them. It is suggested the nucleation sites and growing rate can be controlled by the flow rate of the vapor sources and seeds density (in Au‐quantum‐dots‐assisted vapor‐phase growth). A high flow rate allows more monolayer TMDs with decent sizes of flakes. During transfer, wrinkles, cracks, and other defects can be created in the sample . For taking the GB images, the free‐standing membranes without such defects were chosen, and in the relatively flat area close to the edge of the flake where contains less strain. All the ReS2 GB atomic structures have been simulated by DFT method and directly matched with the experimental STEM‐annular dark field (ADF) images. First, we take a look at the coherent GBs (mainly twin GBs) with the least mismatch and internal strain. The coherent twin GBs can be sub‐divided into high‐index coherent GB (misorientation angle 0°—30°)  method,33 and) Figure . The for2 involves a synergistic bonding rearrangement between Re and S atoms. If we focus on the S atom positions, actually three types of TBs  in 1L ReS2. As we said, the S lattices are less likely to change the symmetry parity (switch between I and II types) under mechanical loading. This gives rise to a kind of special SF GB in 1L ReS2  process in 2D ReSs Figure  are exacs Figure  are TBs s Figure . It is o2 Figure . Both gr2, incoherent GBs have much higher misfit strain at the GBs. The typical incoherent high angle (HA) (30°—180°) GBs (namely incoherent high‐index GB) in 2D ReS2 are shown in Figure Compared to the coherent GBs in 2D ReSConversely, the incoherent low‐index GBs Figure  are usua2 are summarized in Table Due to the intrinsic lattice shearing at TBs and lattice mismatch at the incoherent low‐index GBs, they inherently tend to be pinned by the dislocations, more precisely, by the strain field of dislocations. One example can be found in Figure Figure  According to the Peierls framework for twinning, the critical stress for twinning can be estimated byτ is the shear stress along the slip planes, Δx is the share displacement of central pair of planes, Ψ is the energy of sheared configurations. The relationship of stress and energy is an integral in Peierls concepts which turns to linear during the calculation between two different orientations. Using the DFT obtained energies and lattice distortions, the critical twinning stresses in 2D ReS2 are estimated between 4 and 30 MPa. These values are much lower than the conventional twinning stresses for metals or inorganic bulks,  pinning can be found in Figure By using in situ STEM technique , the mobile GBs have been real‐time observed, which nucleated and moved close to the free edges of 2D ReS2 Figure 4a–c. Dur2 Figure ,e, an in2, irrespective of the GB types, are thermodynamically stable. Kinetics of GBs will be either triggered by the reduction of local curvatures in GBs (driven by GB tensions), or by the external mechanical stresses. Furthermore, these mobile GBs can be pinned by the relatively immobile dislocations, which is opposite to the cases in traditional metals. Usually in bulk metals, the dislocation dynamics (slip) are slowed down by the relatively immobile GBs or TBs. Therefore, the introduction of GBs or TBs intentionally can be utilized for material strengthening. However, in 2D ReS2 here, the inversed sequence for twinning (or lattice reconstruction which produce the incoherent low‐index GBs) and the dislocation slip under mechanical deformation have eventually led to the abnormal defect dynamics as we observed.Disregarding the surface (edge) effect, all of the straight GBs inside the 2D ReSs or TBs.41 TheFigure We have further investigated the electronic structures by spin‐polarized DFT calculations  for the coherent low‐index, coherent high‐index and incoherent‐low index GBs, respectively  will not only be passively impacted by the GBs, in turn, the GBs in 2D ReS2 can be created and changed under exterior straining, thereby extending rich possibilities for strain engineering on the electrical, electronic, and magnetic properties in such 2D monoclinic materials.In conclusion, we have established a complete library for the GBs in monoclinic 2D ReS42 was grown by method of atmospheric CVD on a c‐face sapphire substrate with a size of 1 cm × 1 cm. The precursor for the two quartz boats were ammonium perrhenate (NH4ReO4)  and sulfur powder , with 1:50 of the weight ratio. The temperature of sulfur and substrate were precisely controlled by a two‐zone splitting tube furnace. The sulfur zone temperature rose to 200 °C, while the substrate temperature was held for 10 min at 850 °C. Argon gas was used as carrier gas to deliver the sulfur vapor to substrate during deposition process.2D 1L ReS2 was transferred to the TEM grid. Using spin coating, a thin layer of PMMA formed on the grown sapphire substrate at 3000 rpm for 50 s. Supported by PMMA, 1L ReS2 was immersed in deionized water at 75 °C for two hours and fell off the substrate. The PMMA/ReS2 layer was then transferred to a Quantifoil TEM grid and dried at ambient temperature. In the end, the PMMA film was gently removed by acetone vapor.Through the well‐known PMMA‐assisted technology, CVD‐grown ReS−7 mbar, and the electron beam current was 13 µA. The size of the scanning probe is ≈1.5 Å. For image acquisition, the camera length on STEM was 120 mm. With a defocus of −4 nm, the acquisition time of HAADF images is 19 µs per pixel to minimize damage and obtain graphics with lower drift. Images of 512 × 512 pixels were obtained with a CL aperture of 40 µm, and the collection angle ranged from 45 to 180 mrad, to make atomic images with appropriate contrast be obtained. Wiener filtering was applied to HAADF images to reduce noise.The STEM JEM‐ARM200F with aberration correction at an acceleration voltage of 60 kV was used which equipped with a CEOS spherical (Cs) aberration corrector. The vacuum during the measurement was kept at 1.3 × 102 under the ultrahigh beam intensity more than 0.3 pA nm−2 for 15–30 min can create controlled circle area with diameter about 100 nm. After that, microscope was quickly changed into STEM mode. Due to the crack dynamics outside the exposed area of the beam, the length of these newly generated crack edges extended. Under the in‐plane mechanical loading, the shear stress caused the lattice reconstruction in 1L‐ReS2. With the in situ STEM serial capture , the GB dynamics under shear stress can be recorded.Exposing 2D ReS The high voltage of simulation was 60 kV, with −4 nm of defocus. The spherical aberration was 1 µm, Cc is 1 mm, and the temperature was 300 K. Angle of detectors was set from 45 mrad to 180 mrad, meanwhile the convergence angle was 15 mrad. The TDS runs 30 rounds for each simulated image, exhibited under the brightness of 10 × 108 A (cm2sr)−1.The STEM simulation was conducted in QSTEM.42 The within the projector augmented wave (PAW) to explore geometries and electronic properties of ReS2. The exchange‐correlation interactions are described with the generalized gradient approximation (GGA) in the form of the Perdew, Burke, and Ernzernhof (PBE) functional. This kinetic energy cut‐off of 450 eV was utilized in all calculations, and the distance of vacuum layer was set to be more than 20 Å, which was sufficiently large to avoid interlayer interactions. The electronic SCF tolerance was set to 10−4 eV. Fully relaxed geometries and lattice constant were obtained by optimizing all atomic positions until the Hellmann–Feynman forces were less than 0.02 eV Å−1. The k‐points samplings with a gamma‐centered Monkhorst–Pack scheme were 3 × 5 × 1 and 5 × 9 × 1 for structural optimizations and electronic properties, respectively .The first‐principles calculations were performed with spin‐unrestricted manner by using the Vienna ab initio Simulation Package (VASP) program package44 witThe authors declare no conflict of interest.Supporting InformationClick here for additional data file.


The obtained 125I‐TiO2 nanoparticles first construct superficial Ti3+ active sites via the reaction between Ti4+ and AEs. Then Ti3+ stretches and weakens the O—H bond of the absorbed H2O, thus enhancing the radiolysis of H2O molecules and generating hydroxyl radicals (•OH). All in vitro and in vivo results demonstrate a good CIRT performance. These findings will broaden the application of radionuclides and introduce new perspectives to nanomedicine.Excess electrons play important roles for the construction of superficial active sites on nanocatalysts. However, providing excess electrons to nanocatalysts in vivo is still a challenge, which limits the applications of nanocatalysts in biomedicine. Herein, auger electrons (AEs) emitted from radionuclide 125  is developed by  Many published reports have shown that excess electrons  play an important role in the surface chemical activity of nanocatalysts. Generally, excess electrons are captured by superficial metal atoms to form active sites with localized charge imbalance. Then, these active sites can deform certain molecules, stretch chemical bonds, and reduce the energy barriers of chemical reactions. Hence, providing excess electrons to the surface of nanocatalysts is important for improving the nanocatalyst performance. However, hardly few methods exist for the generation of excess electrons in biological tissue, which inhibits the application of nanocatalysts in tumor treatment.Nanocatalysts have been widely used in the area of biomedicine, such as cancer therapy, antibacterial treatment, and biomolecules detection, because of their high surface activity.2, 3 Some radionuclides, such as 90Y, 125I, 131I, and 188Re, can emit electrons in situ and are thus usually implanted into tumors for IRT. Among these radionuclides, 125I can emit low‐energy (100–103 eV) auger electrons (AEs) via internal conversion with a production of 24.9 AEs per decay, which can be deposited on nanocatalysts more easily than the high‐energy (≈106 eV) β‐rays emitted from other radionuclides. Hence, 125I has the potential to inject excess electrons onto nanocatalysts surface and construct active sites for further applications in vivo. On the other hand, in IRT, ionizing radiation (primarily β‐ and γ‐rays) emitted from radionuclides induces radiolysis of H2O to generate hydroxyl radicals (•OH), which can efficiently kill cancer cells. However, the strong O—H bond of H2O molecule limits the yield of •OH induced by radionuclides, and especially for 125I, which emits low‐energy AEs and γ‐rays (35 keV). Fortunately, as mentioned above, the combination of nanocatalysts and AEs emitted from 125I will construct superficial active sites, which can stretch molecules and decrease the bond energy for H2O activation, thus facilitating the occurring of H2O radiolysis. Hence, 125I‐labeled nanocatalysts have the potential to increase the yield of •OH for enhanced IRT.Internal radiotherapy (IRT) is a common treatment method for suppressing tumor growth.7, 82) is a traditional and typical nanocatalyst with high stability and low toxicity, which is suitable for applications in vivo. Herein, we developed a method of injecting AEs to nanocatalysts by synthesizing 125I‐labeled TiO2 nanoparticles (125I‐TiO2 NPs) and explored the performance of 125I‐TiO2 NPs for cancer catalytic internal radiotherapy (CIRT), as illustrated in Scheme125I arrive on the surface of TiO2 and induce the formation of Ti3+. Then, Ti3+ absorbs and deforms H2O, resulting in the decreased O—H bond energy. Finally, upon irradiation by the γ‐rays emitted from 125I, the activated H2O is more easily converted to •OH compared to the unabsorbed H2O, leading to an enhanced effect of IRT. This strategy as CIRT will bring more chances for cancer therapy. Moreover, the method of constructing active sites by 125I will also widen the applications of radionuclides and nanocatalysts and introduce new perspectives to the area of nanocatalytic medicine.Titanium dioxide  were synthesized according to a typical solvothermal method. In Figure 2‐OA were in good uniformity with rhombus‐shaped morphology, and the average particle diameter was 11.78 ± 2.23 nm in length and 3.91 ± 0.56 nm in width. High‐resolution TEM (HRTEM) image revealed a lattice fringe width of 0.35 nm, corresponding to the anatase (confirmed by X‐ray diffraction (XRD) patterns in Figure 2‐OA were modified with citric acid (TiO2‐COOH) for well water solubility and to prepare for subsequent modification. Finally, TiO2‐COOH were conjugated with tyramine (TiO2‐tyr) for labeling of 125I. Successful synthesis of TiO2‐COOH and TiO2‐tyr was confirmed by the presence of characteristic peaks  in Fourier transform infrared spectroscopy (FT‐IR) spectra  spectra , indicating that TiO2 remained stable after modification. Obviously, compared with TiO2‐COOH, the conjugated tyramine restrained the ionization of carboxyls, leading to a decreased Zeta potential  and an increased hydrodynamic size  showed that the binding energy of Ti 2p orbitals of 125I‐TiO2 decreased by 0.2 eV compared with that of TiO2‐tyr, indicating the existence of Ti3+ in 125I‐TiO2  was used to simulate the O—H bond length under the influence of Ti4+ or Ti3+. Figure4+. In contrast, Ti3+ stretched the O—H bond to 1.48 Å  cells for all experiments in vitro. First, as sufficient intracellular accumulation of NPs is a prerequisite for an effective treatment, the cellular uptake and intracellular distribution of TiO2‐tyr was visualized via biological TEM (bio‐TEM). As exhibited in Figure S4 in the Supporting Information, the amount of endocytosed TiO2‐tyr increased as the incubation time prolonged from 0.5 to 5 h. Next, we investigated the appropriate dosage of 125I and 125I‐TiO2 via the Cell Counting Kit 8 Assay. As illustrated in Figure S5 in the Supporting Information, 125I exhibited a negligible detrimental effect especially when the dosage was below 600 µCi mL−1. Compared to 600 µCi mL−1 of 125I , 125I‐TiO2 with the equal dose  presented obvious cytotoxicity . Similar trends also appeared under other doses of radiation. As 125I or TiO2‐tyr alone exhibited little cytotoxicity to SW1990 cells , the cell killing effect of 125I‐TiO2 should be attributed to the reaction between 125I and TiO2‐tyr. To fully explore the effect of 125I‐TiO2, the control group, 125I group (600 µCi mL−1), and 125I‐TiO2 group  were adopted in this study for the following experiments.Pancreatic cancer usually induced a poor prognosis and short survival time for patients. Many clinical researches have reported that IRT was suitable for the treatment of pancreatic cancer.34 Hen Therefore, cell apoptosis was detected by terminal‐deoxynucleoitidyl Transferase Mediated Nick End Labeling (TUNEL) assays. As shown in Figure125I‐TiO2 triggered the most severe cell apoptosis , which was 13.82 and 37.62 times that of the 125I group and control group, respectively. Proliferative injury was first evaluated by the expression level of proliferating cell nuclear antigen (PCNA), which is a representative protein directly involved with the DNA replication. The expression of PCNA in 125I‐TiO2 group decreased by 61.05% and 73.78% compared to that in 125I group and control group, respectively . These data proved that 125I‐TiO2 can enhance the generation of •OH, thereby exacerbating DNA DSBs, and ultimately cause cell apoptosis and proliferative injury.Cytotoxicity of radiation is usually attributed to the •OH‐induced DNA double‐strand breaks (DSBs).41 As 125I (600 µCi of 125I per mouse) and 125I‐TiO2 (600 µCi of 125I corresponding to 144 µg of TiO2 per mouse), respectively. First, single‐photon emission computed tomography/computed tomography (SPECT/CT) scanning was performed. As shown in Figure125I was excreted through the urinary system with only minor residuals drawn in the thyroid. In a sharp contrast, 125I‐TiO2 exhibited remarkably prolonged retention time in the tumor for more than 12 d, which indicated an excellent labeling stability and intratumoral retention ability of 125I‐TiO2 in vivo, thus benefiting for a long‐lasting irradiation for tumor.Encouraged by these in vitro experiments, we tested the effect of CIRT in SW1990 tumor‐xenografted mice. Three groups were divided with intratumoral injection of dulbecco's modified eagle medium , free 125I‐TiO2 in vivo. As shown in Figure 125I groups progressed to 7.58 ± 0.54 and 6.71 ± 0.55 times that of the original volumes, whereas tumors treated by 125I‐TiO2 were distinctly controlled with the relative volume percentages of 59.49% (for control group) and 54.21% (for 125I group), respectively. Correspondingly, the survival rate within a 60 d observation was significantly improved in 125I‐TiO2 group, during which all mice in 125I and control groups died out  was downregulated in 125I‐TiO2 group compared to that in 125I or control groups , while the TNF‐α (a tumor necrosis factor) expressed the highest in 125I‐TiO2 group . All these data proved the highly efficient anticancer ability of 125I‐TiO2.We further examined the curative effect of t Figure . Moreovet Figure  and TUNEt Figure  revealed125I to inject electrons to TiO2 NPs for constructing active sites in vivo, and investigated its application for cancer CIRT. The obtained 125I‐TiO2 initially constructed Ti3+ species via the reaction between Ti4+ and AEs from 125I. Consequently, Ti3+ stretched the O—H bond of the absorbed H2O to decrease its bond energy. Finally, upon irradiation of γ‐rays emitted by 125I, the radiolysis of activated H2O will occur more easily, leading to an enhanced generation of •OH. Material characterization and DFT simulation confirmed the existence and function of the constructed active sites. In vitro and in vivo data further verified an enhanced curative effect of CIRT induced by the active sites. Compared with previous researches on nanocatalysts, this paper presented two major differences. First, the mechanism of the generation of ·OH in this research is different. In previous researches, ·OH is usually generated from the reaction between H2O and photoinduced holes. While in this research, ·OH comes from the reaction between γ‐rays and H2O that is activated by AEs‐constructed active sites. Second, the excitation source of nanocatalysts in this research is different. Previous researches usually use an external excitation source like UV or vis, of which the penetration depth in biological tissue is only millimeter‐sized. In this research, we solve this problem by using 125I as an internal excitation source. Hence, our strategy by using radionuclides to construct active sites in nanocatalysts will bring more ideas and chances for the applications of nanocatalysts. Moreover, we believe that this research will introduce new perspectives to the design of biomaterials and provide more opportunities for cancer therapy.In summary, we used searches,43 ·OHThe authors declare no conflict of interest.Supporting InformationClick here for additional data file.


A massive Dirac cone (DC) with a gap of 40–75 meV at 16 K is observed. By tracing the temperature evolution, this gap is shown to gradually decrease with increasing temperature and a blunt transition from a massive to a massless DC occurs around 200–250 K. Structural analysis shows that the samples also contain MnBi2Te4/Bi2Te3. Magnetic measurements show that there are two distinct Mn components in the system that corresponds to the two heterostructures; MnBi2Te4/Bi2Te3 is paramagnetic at 6 K while Mn4Bi2Te7/Bi2Te3 is ferromagnetic with a negative hysteresis . This novel heterostructure is potentially important for future device applications.Materials that possess nontrivial topology and magnetism is known to exhibit exotic quantum phenomena such as the quantum anomalous Hall effect. Here, we fabricate a novel magnetic topological heterostructure Mn Magnetic topological heterostructures are promising devices to manipulate emergent quantum effects. Here, Hirahara et al. fabricate a novel magnetic topological heterostructure with a massive Dirac cone which becomes a massless one tuned by temperature. In terms of the electronic structure, the surface Dirac cone (DC) of TI will be gapped due to the time-reversal symmetry breaking. So far most efforts to incorporate magnetism into TI have been performed by doping magnetic impurities inside the TI crystals. However, this approach induces inhomogeneity to the samples and the formation of impurity states. This has led to the unfortunate situation that the experimental observation of the quantum effects is limited to very low temperatures6. Furthermore, it has been reported that a DC gap can arise due to nonmagnetic origins7.Inducing magnetism in topological insulators (TI) leads to exotic quantum phenomena9. The idea is to place a magnetic monolayer inside the topmost quintuple layer (QL) of the TI. This was experimentally realized by self-organized incorporation of a Mn monolayer inside Bi2Se3, resulting in the formation of a MnBi2Se4/Bi2Se3 heterostructure10. This method was further extended and complicated heterostructures composed of MnBi2Se4 and Bi2Se3, or MnBi2Te4 and Bi2Te3, were experimentally fabricated12. Furthermore, MnBi2Te4 and MnBi4Te7 called “intrinsic magnetic TIs” were realized as bulk single crystals23.Recently, a novel method to combine magnetism with TI has been proposed, which is called magnetic extensionTC) but closes above it, indicating that the magnetic order and DC gap are correlated with each other12. On the other hand, there is a work reporting that the DC gap persists above the Néel temperature (TN) up to 300 K and this was explained by the formation of an instantaneous out-of-plane field generated by strongly anisotropic spin fluctuations13. Similar explanation was employed for the presence of the massive DC above TN in refs. 22. On the other hand, it was claimed that the DC is massless even at temperatures lower than TN21. The origin was described as a result of the neutralization of the net magnetic moments due to the presence of different magnetic domains within the sample21, or the weak hybridization between the local moments and the Dirac electrons18. There is another work that insists that the DC was massless at 25 K, which is above TN, but no comment was made on the behavior below TN in ref. 15.Concerning the surface DC of these systems, there is a debate about the presence/absence of the gap itself as well as its relation with the magnetic properties of the system. It has been shown that the DC gap is observed below the Curie temperature  of  ~20 K and showed a negative hysteresis likely due to the antiferromagnetic coupling between the Mn magnetic moments of the two heterostructures. Thus, our results show for the first time that the Dirac point gap of the interface topological state of the magnetic topological heterostructure eventually closes, albeit at a temperature well above the magnetic Tc.In the present work, we report on the successful experimental fabrication of such an exotic magnetic topological heterostructure. By co-depositing Mn and Te on BiEF) of the Bi2Te3 film. The surface DC, as well as the bulk conduction band, is observed. When the heterostructure is formed after Mn and Te deposition, the features change drastically as can be seen in Fig. EF at k = 0.1 – 0.2 Å−1 in Fig. hν = 8–21 eV  surface system13. The peak positions for each spectrum have been determined by the analyses described in Supplementary Fig. hν = 9 eV as shown in Fig. To investigate the origin of the DC gap formation, we have performed temperature-dependent angle-resolved photoemission spectroscopy (ARPES) measurements. Figure mentclass2pt{minimmentclass2pt{minimmentclass2pt{minim2Te4/Bi2Te3 heterostructure8. When one compares the dispersion shown in Fig. 2Te3 layer. However, the topmost layer seems to be composed of seven atomic layers in b, whereas it seems to be a 13 layer block in c.Otrokov et al., theoretically proposed that a massive DC with a gap of 77 meV will form for the MnBi2Te4/[7QL Bi2Te3] structure with the abcabca-bacba stacking, while Fig. 4Bi2Te7/[6QL Bi2Te3] with the abcabacabcabc stacking. To say it simply, the septuple layer block has only one Mn–Te bilayer whereas the 13 layer block is a structure with four Mn–Te layers incorporated into Bi2Te3. The NaCl-type hexagonal stacking (abcabcabc...) is somehow disturbed in the former heterostructure whereas the latter is a hybrid of the NaCl (top three Te–Bi–Te layers) and NiAs-type stacking . In ref. 24, it was reported that the NiAs-type stacking is energetically favored compared to the NaCl-type in the Mn–Te multilayers and is consistent with the experimental observation. The consequence of the realization of this interesting stacking for the magnetic order of the heterostructure will be discussed later.To gain further insight, we have performed high-resolution high-angle annular dark field STEM (HAADF-STEM) observation from the [110] direction as shown in the insets of Fig. 2Te3 QL, but the possibility to find them was very small. We think that when the Mn and Te deposition exceeds the mono-bilayer, the quadruple-bilayer will be formed since the system tends to maintain similar height as the sum of the topmost septuple and the QL so that the two structures can connect with a smooth interface. Such a growth allows minimizing the surface energy owing to the disappearance of the steps initially presented on Bi2Te3 surface as schematically shown in Supplementary Fig. 2Te413. This may be one of the reasons for the scattering of the measured DC gap size in ARPES.We should mention that there were some regions which showed the incorporation of two or three Mn–Te bilayers in the topmost Bi4Bi2Te7/Bi2Te3 shown in Fig. 2Te4/Bi2Te3 phase is not so different from the Bi2Te3 substrate and there is no gap opening at 16 K for this sample. This dispersion is quite similar to the additional feature observed outside of the massive DC in Fig. 2Te4/Bi2Te3. Since in ref. 12, the DC of the heterostructure consisting of MnBi2Te4 and Bi2Te3 showed a gap closing at 20 K with a Curie temperature of 10 K, it is most likely that the DC of our MnBi2Te4/Bi2Te3 heterostructure remains massless because the Curie temperature is not reached at 16 K. As such, we can say that the massive DC extensively studied in Fig. 4Bi2Te7/Bi2Te3 heterostructure.Now that the atomic structure has been resolved, the band dispersion for the two structures in Fig. L edge. μ+ and μ− correspond to the spectrum obtained with left and right-handed circularly polarized photons, respectively. The corresponding X-ray magnetic circular dichroism (XMCD) spectrum is also shown together and a clear signal is detected. Figure L3 peak for the fields smaller than 1 T. One can notice that at 0 T, the sign of the L3 peak reverses and becomes positive. This means that the remanent magnetization is opposite to the applied field (negative remanence). Moreover, we can find that the peak position changed by decreasing the field. Namely, the peak position was 639.9 eV for the fields larger than 0.5 T (peak A), but at 0.2 T a shoulder structure can be found at 639.5 eV which becomes dominant at 0.1 T and 0 T (peak B). Thus this clearly reveals that there are two different Mn components involved in the magnetization of this system.Finally, we have performed magnetic measurements to verify the relationship between the Dirac-cone gap opening/closing and the magnetic property of the system. Figure M–H curves). In order to display the magnetization change near zero-field clearly, we show the close-up for −0.2 to 0.2 T. Peak B shows a clear hysteresis although it is clockwise reflecting the negative remanence which is called an inverted hysteresis or proteresis26. For peak A, the signal intensity is nearly proportional to the field strength although it also shows some anomaly near zero-field albeit not a clear hysteresis. While it is difficult to make a definite conclusion, this is most likely to be caused by the finite peak width of peak B. Figure M–T curves). For peak B, the signal drops to nearly zero at  ~20 K. On the other hand, the XMCD intensity of peak A decreases for higher temperature but is still finite up to 60 K. Taking into account all these facts, peak A corresponds to the Mn component that is paramagnetic down to 6 K while peak B seem to be reflecting the ferromagnetic Mn components of the system.To gain further insight into the intricate magnetism of this system, we have performed detailed field dependent XMCD measurements for peaks A and B as shown in Fig. 2Te4 and Mn4Bi2Te7 blocks. It is natural to interpret that peaks A and B correspond to the Mn components in these two different heterostructures. Since the clear DC gap was only observed for Mn4Bi2Te7  However, the experimentally determined Curie temperature of  ~20 K for Mn B is much lower than the temperature that the DC gap gradually closes and seems to become massless (200–250 K). In fact, we have performed temperature-dependent SQUID measurements from 4 K to 350 K and found that there is no anomaly in the sample magnetization above 20 K, which is consistent with the XMCD data . Thus, our results show for the first time that the Dirac point gap of the interface topological state of a magnetic topological heterostructure eventually closes, albeit at a temperature well above the magnetic Tc.In conclusion, we fabricated a novel magnetic topological heterostructures by depositing Mn and Te on Bin-type substrate by a cycle of resistive heat treatments. Then Bi was deposited on the 7 × 7 substrate at  ~250 °C in a Te-rich condition. Such a procedure is reported to result in a smooth epitaxial film formation with the stoichiometric ratio of Bi:Te = 2:3. The grown Bi2Te3 films were annealed at  ~250 °C for 5 min. The thickness of the Bi2Te3 films in this work is  ~8 QL. Finally, Mn was deposited on Bi2Te3 in a Te-rich condition at  ~260 °C. The 1 × 1 periodicity with the same lattice constant is maintained during this process for the samples we have fabricated.The heterostructure samples were prepared by molecular beam epitaxy in ultrahigh vacuum (UHV) chambers equipped with a reflection-high-energy electron diffraction (RHEED) system. First, a clean Si(111)-7 × 7 surface was prepared on an For the X-ray magnetic circular dichroism (XMCD), superconducting quantum interference device (SQUID) and scanning transmission emission microscopy (STEM) measurements, the fabricated samples were first characterized with ARPES at room temperature. After confirming that the desired band dispersion is obtained  and spin-resolved ARPES (SARPES) measurements were performed in situ after the sample preparation. The ARPES measurements were performed at BL-7U of UVSOR-III using The SQUID measurements were conducted with a commercial MPMS-52 system (Quantum Design).31 and BL-16A of KEK-PF32 with circularly polarized X-ray radiation. The total-electron yield mode was employed in both cases. The Te-capped samples were annealed at ~250 °C to remove the capping layers prior to the measurements.The X-ray absorption spectroscopy (XAS) and XMCD measurements were performed at BL-23SU of SPring-8Electron transparent specimens for STEM observations were prepared by the standard lift-out technique using an FEI Helios G4-UX dual-beam system. Probe abberation corrected STEM, FEI TitanG2 80–200 microscope, was used. Chemical compositions were measured by energy-dispersive X-ray spectroscopy (EDS).33 as implemented in the VASP code36. The exchange-correlation energy was treated using the generalized gradient approximation37. The Hamiltonian contained scalar relativistic corrections and the SOC was taken into account by the second variation method38. In order to describe the van der Waals interactions, we made use of the DFT-D340 approach. The energy cutoff for the plane-wave expansion was set to 270 eV. All structural optimizations were performed using a conjugate-gradient algorithm and a force tolerance criterion for convergence of 0.01 eV/Å. SOC was always included when performing relaxations. The Mn 3d-states were treated employing the GGA+U approach41 within the Dudarev scheme42. The Ueff = U − J value for the Mn 3d-states was chosen to be equal to 5.34 eV, as in previous works on similar systems24.Electronic structure calculations were carried out within the density functional theory using the projector augmented-wave (PAW) methodSupplementary Information


Scientific Reports 10.1038/s41598-020-75764-5, published online 02 November 2020Correction to: The original version of this Article contained errors, where values of light power were incorrect due to miscalculation. The light power values were underestimated by 4 times, where the correct values of light power are 4 times larger than the stated values of light power. As a result, also the responsivity and detectivity values contained errors. Specifically, the intensity of light was calculated by dividing the total light power of the laser by the beam size of the incident light, where accidentally the diameter instead of the radius to calculate the beam size was used.As a result, in the Abstract,3 photodetectors prepared by flash evaporation which exhibited the responsivity of 0.2 A/W and detectivity of 3.82 × 1011 Jones.”“Finally, the excellent large-area uniformity of the physical properties of the deposited thin films can be transferred to the uniformity in the device performance of MAPbInow reads:3 photodetectors prepared by flash evaporation which exhibited the responsivity of 51 mA/W and detectivity of 9.55 × 1010 Jones.”“Finally, the excellent large-area uniformity of the physical properties of the deposited thin films can be transferred to the uniformity in the device performance of MAPbIIn the Results section,“The estimated responsivity is 0.20 A/W for the photodetector with the flash evaporated film and 0.55 A/W for the photodetector with the spin-coated film at a bias of 20 V and light power of 0.21 uW.”now reads:“The estimated responsivity is 51 mA/W for the photodetector with the flash evaporated film and 137 mA/W for the photodetector with the spin-coated film at a bias of 20 V and light power of 0.84 μW.”Additionally,11 Jones within the measured range for the photodetector with the flash evaporated film. This is a comparable value to the detectivity of 6.14 × 1011 Jones for the device with the spin-coated film.”“The highest value of detectivity was found to be 3.82 × 10now reads:10 Jones within the measured range for the photodetector with the flash evaporated film. This is a comparable value to the detectivity of 1.53 × 1011 Jones for the device with the spin-coated film.”“The highest value of detectivity was found to be 9.55 × 10In the Conclusion section,11 Jones which are comparable to the previously reported MAPbI3-based photodetectors.”“The fabricated devices showed the responsivity of 0.2 A/W and detectivity of 3.82 × 10now reads:10 Jones which are comparable to the previously reported MAPbI3-based photodetectors.”“The fabricated devices showed the responsivity of 51 mA/W and detectivity of 9.55 × 10Consequently, Figure 6 of the main article, as well as Figure S5 and Figure S6 of the Supplementary Information file that accompanies this Article, contained errors, where the light power was displayed incorrectly. The original Figure 6 appears below as Figure These errors have now been corrected in the PDF and HTML versions of the Article, and in the Supplementary Information file that accompanies the Article.


Accompanied with the first dimethyl sulfoxide sublimation process, the subsequent sublimation of GA before 150 °C in the FA0.85MA0.15PbI3 perovskite film can artfully regulate the perovskite crystallinity without any residual after annealing. The improved film formation upon GA modification induced by the strong interaction between GA and Pb2+ delivers a champion power conversion efficiency (PCE) as high as 21.32%. In order to investigate the role of volatility in perovskite solar cells (PSCs), nonvolatile thioglycolic acid  with a similar structure to GA is utilized as an additive reference. Large perovskite grains are obtained by TGA modification but with obvious pinholes, which directly leads to an increased defect density accompanied by a decline in PCE. Encouragingly, the champion PCE achieved for GA‐based PSC device (21.32%) is almost 13% or 20% higher than those of the control device or TGA‐based device. In addition, GA‐modified PSCs exhibit the best stability in light‐, thermal‐, and humidity‐based tests due to the improved film formation.A strategy for efficaciously regulating perovskite crystallinity is proposed by using a volatile solid glycolic acid  against nonvolatile thioglycolic acid (TGA) following dimethyl sulfoxide sublimation, resulting in enhanced device performance. A champion power conversion efficiency as high as 21.32% is achieved for the GA‐based device, which is almost 13% or 20% higher than those of the control device or TGA‐based device. The latter effect would retard the crystallization rate of the organic–inorganic hybrid perovskite material due to the formation of an intermediate phase, thus promoting the growth of uniform films.Important for the performance of PSCs is a uniform and pinhole‐free surface morphology, good crystallinity, and large grain size throughout the perovskite film, all of which are strongly influenced by the nucleation and crystal growth process.0.85MA0.15PbI3 (FA: HC(NH2)2; MA: CH3NH3) (150 °C). It should only have a delaying impact on the nucleation and crystal growth behavior of the perovskite and vanish without a trace during the final annealing process. Such novel design strategy is required for the commercial large‐scale PSC production as it can substantially reduce the defect density of the perovskite films instead of the passivation methods like the common additive approaches.However, the residual of the unwanted phases is probably formed for the above common additive approaches. Another option to induce large grained perovskite formation with improved crystallographic orientation is to design perovskite precursor solutions with higher boiling points. Such processing will allow for higher tolerance regarding the delay time during the nucleation and crystal growth process of perovskite. The sublimation of DMSO from a perovskite film appears at less than 100 °C,2COOH, GA) which is solid at room temperature and has a moderate boiling point in an FA0.85MA0.15PbI3 perovskite precursor solution. GA as a polar molecule contains one carboxyl group in one side and one hydroxyl group in the other side. Thus, GA solid is facilely guaranteed to be dissolved in DMF/DMSO solvent. Compared with the other reported additives, one highlight of GA is the low boiling point less than 150 °C, there can be no residual of the unwanted phases expect perovskite after annealing. The interesting role of GA solid here plays more like a solvent rather than a common passivation additive. Before GA leaves the perovskite film, GA also can be utilized as a Lewis acid due to the relatively strong interaction between GA and perovskite including FA+ and PbI2. Due to this strong interaction, large perovskite grains can be obtained by GA modification. Finally, a champion PCE of 21.32% with outstanding stability was achieved for GA‐modified PSC due to the superior quality of the perovskite film that contained a lower number of defects. In order to investigate the effect of volatile versus nonvolatile molecules in perovskite solar cells, thioglycolic acid  with a similar molecular structure to GA is utilized as an additive reference.In this work, we introduce the volatile molecule glycolic acid  solution. The film formation was completed by a 150 °C annealing step for 30 min. Figure As shown in Figure2 is observed for the pristine film3) is observed for TGA‐modified perovskite film.Jsc). Next, steady‐state photoluminescence (PL) and time‐resolved photoluminescence (TRPL) decay measurements were performed to investigate the charge recombination dynamics in the different perovskite films as shown in Figure 1) and a faster (τ2) time constant.2/perovskite/PCBM/Ag. The trap‐state density (ntrap) can be calculated based on the equation ntrap = (2εε0VTFL)/(eL2),0 represent the relative dielectric constant of the perovskite film and the vacuum permittivity (8.854 × 10−14 F cm−1),VTFL can be extracted from the kink point between the ohmic and the trap‐filled limit region, e is the elementary charge, and L is the thickness of the perovskite layer obtained from the cross‐sectional SEM image. The extracted trap densities are 1.06  ×  1016, 1.80 ×  1016, and 0.48 ×  1016 cm−3 for the pristine, TGA‐modified, and GA‐modified perovskite films, respectively. The observed trend is consistent with the PL and TRPL results. We suggest that GA‐modified perovskite layers exhibit the smallest trap‐state density due to a reduction in Pb‐I antisite defects (induced by the undercoordinated Pb atoms), while the larger trap state density in TGA‐modified perovskite likely originates from the TGA residue and the numerous of pinholes.The effect of GA or TGA on the crystallinity of perovskite films is investigated by thin film X‐ray diffraction (XRD) and the measurement results are shown in 2/FA+. The PbI2/FA+ can either interact with the oxygen on the carboxyl groups (referred to as “−1” below) or with the oxygen or sulfur on the hydroxyl or thiol group . The optimized molecular structures of PbI2⋅DMSO, PbI2⋅GA‐1 and PbI2⋅TGA‐1 are plotted in Figure 2⋅DMSO, PbI2⋅GA‐2, and PbI2⋅TGA‐2 are shown in Figure S2 (Supporting Information). For the first case, the interaction energies of the bonds are calculated to be −0.955 eV for PbI2⋅GA‐1, and −0.989 eV for PbI2⋅TGA‐1. For the second case, these values are smaller . Thus, PbI2 prefers to react with the oxygen on the carboxyl groups in either GA or TGA. Further, the interaction energy between PbI2 and the oxygen in DMSO was calculated to be −0.840 eV. Overall, PbI2 can interact with either DMSO, GA, or TGA however a slightly stronger interaction of PbI2 with GA and TGA is found. To consider also the other components of the precursor solution, the binding energies of FA+⋅DMSO, FA+⋅ GA, and FA+⋅TGA were analyzed, yielding values of −1.347 eV (FA+⋅DMSO), −1.286 eV (FA+⋅GA‐1 or FA+⋅GA‐2), and −1.214 eV (FA+⋅TGA‐1) or −1.254 eV (FA+⋅TGA‐2). The optimized molecular structures of FA+⋅DMSO, FA+⋅TGA, and FA+⋅GA with the largest binding energy are shown in Figure S3 (Supporting Information). Intriguingly, this trend is different from the PbI2 adducts. FA+ preferentially interacts with DMSO, whereas PbI2 preferentially interacts with GA or TGA molecule. To probe such interactions between FA+ and GA/TGA experimentally, the three deuterated dimethylsulfoxide (DMSO) perovskite precursor solutions were probed by 1H NMR measurements as shown in Figures S4–S6 (Supporting Information). Upon the addition of GA or TGA, the 1H NMR signals of FA+ at 8.56 and 7.79 ppm split while the 1H NMR signals from the carboxyl groups in GA (12.37) or TGA (12.67) are in also displaced upfield, which strongly indicates the interaction of FA+ with GA or TGA.To better understand the interaction between GA/TGA and the perovskite on a molecular scale, we performed theoretical calculations regarding their binding energy. The corresponding results are listed in Table S2 (Supporting Information). Due to the asymmetric structure of the modifiers, there are two possible conformations between GA/TGA and PbIFigure2⋅DMSO, PbI2⋅DMSO⋅GA, and PbI2⋅DMSO⋅TGA powder. The asymmetrical stretching vibrations related to the C=O bond in the pure GA and TGA, as shown in Figure −1, respectively. The vibrations is shifted to 1630 cm−1 for the mixture of PbI2⋅DMSO⋅GA and even to 1655 cm−1 for PbI2⋅DMSO⋅TGA. This indicates that TGA or GA molecules are successfully introduced into the corresponding powder. Next, Figure 2, PbI2⋅DMSO, PbI2⋅DMSO⋅GA, and PbI2⋅DMSO⋅TGA films, respectively. For the as‐prepared films , there is a strong peak at 26.0° attributed to the (015) plane of PbI2,2⋅DMSO, to 25.9° for PbI2⋅DMSO⋅GA, and it splits into two peaks at 25.6° and 25.9° for PbI2⋅DMSO⋅TGA. Upon annealing, the PbI2 lattice can be recovered via the release of DMSO and GA after a temperature of 150 °C for PbI2⋅DMSO⋅GA. The similar crystalline structure of PbI2 but with lower crystallinity was achieved for annealed PbI2⋅DMSO after a temperature of 150 °C compared with PbI2⋅DMSO⋅GA as shown in Figure S8 (Supporting Information), which demonstrated that GA modifier could improve the crystalline of PbI2 and would be beneficial to the perovskite crystalline. The annealing process is also supported by thermo gravimetric analysis (TG) on the PbI2⋅DMSO, PbI2⋅DMSO⋅GA, and PbI2⋅DMSO⋅TGA powders presented in Figure S9 (Supporting Information). Both PbI2⋅DMSO and PbI2⋅DMSO⋅GA show a single step loss at 127 and 136 °C, respectively. The PbI2⋅DMSO⋅GA complex exhibits a wider endotherm peak as the weight loss of both DMSO and GA appear during this process. PbI2⋅DMSO⋅TGA exhibits a more complicated weight loss possess with four different characteristic temperatures. The first three of these  are attributed to the loss of DMSO while the fourth (≈220 °C) corresponds to the loss of TGA. This is a clear evidence that TGA remains in the film even after 150 °C annealing although annealed PbI2⋅DMSO⋅TGA exhibits the similar XRD patterns as annealed PbI2⋅DMSO⋅GA.We further studied the influence of GA and TGA using Fourier transform infrared spectroscopy (FTIR). s Figure , new XRD2⋅DMSO, FAI⋅PbI2⋅DMSO⋅GA, and FAI⋅PbI2⋅DMSO⋅TGA are shown in Figure S10a (Supporting Information). Again, distinct differences are found, showing the incorporation of the solvent and the modifiers in the perovskite film at room temperature. Exemplarily, the sample of FAI⋅PbI2⋅DMSO⋅GA is stepwise annealed as shown in Figure S10b (Supporting Information). Here, FAPbI3 is successfully formed after a heating at 150 °C for 30 min. The TG analysis on the as‐prepared powders of FAI⋅PbI2⋅DMSO, FAI⋅PbI2⋅DMSO⋅GA, and FAI⋅PbI2⋅DMSO⋅TGA are shown in Figure S10d–f (Supporting Information). Here, the weight loss of pure GA is at about 100 °C as shown in Figure S10c (Supporting Information) while for the pristine FAI⋅PbI2⋅DMSO perovskite powder  there are three main weight loss processes at approximately 90, 300, and 480 °C. These correspond to the loss of DMSO, FAI, and PbI2, respectively. For the GA or TGA incorporated perovskite powders, the loss temperature of FAI and PbI2 are higher than that of the pure FAI⋅PbI2⋅DMSO mixture, which demonstrates the strong interaction between the GA or TGA and perovskite precursor. There are two endotherm peaks at 86 °C (the weight loss of DMSO) and 212 °C (the weight loss of TGA) as shown in Figure S10e (Supporting Information) and two endotherm peaks at 92 °C (the weight loss of DMSO) and 139 °C (the weight loss of GA) as shown in Figure S10f (Supporting Information), which confirms of our previous findings that GA can disappear before 150 °C, while TGA still exists in the as‐annealed powder due to its high boiling point over 150 °C. This presence of TGA in the annealed film was further proven by energy‐dispersive X‐ray spectrometry (EDX). As the sulfur is specific to this modifier, one can analyze the film composition as shown in Figure S11 (Supporting Information). By comparing two different areas on the sample, we can conclude that TGA remains at the perovskite grain boundaries after such a moderate annealing step.Also for the complete FAI perovskite adduct powders, these investigations were performed. The XRD patterns of as‐prepared FAI⋅PbI2/perovskite/spiro‐OMeTAD/Au. In order to find the optimal concentration of the modifier, we prepared a series of perovskite precursors with different amounts of GA  as well as TGA . The corresponding device parameters are summarized in Table S3 (Supporting Information). When increasing the amount of GA from 0 to 5 mg mL−1, the PSC parameters including the short‐circuit current (Jsc), fill factor (FF), open‐circuit voltage (Voc), and efficiency first increase and then decrease. The best device performance is found for 3 mg mL−1 GA incorporation. In contrast, when increasing the concentration of TGA from 1 to 20 µL mL−1 the PSC device performance gradually decreases, so there is no optimal concentration. This can be ascribed to the rough and pinhole rich surface of perovskite films. The champion and average photovoltaic performance parameters of pristine and GA‐ or TGA‐modified PSC devices are summarized in Table S4 (Supporting Information).The J–V curves of the champion solar cell devices based on GA‐and TGA‐modified perovskites were measured in reverse scan direction under an AM 1.5G solar simulator with an intensity of 100 mW cm−2 as shown in FigureJsc: 24.30 mA cm−2; Voc: 1.07 V; FF: 72.7%). Upon 3 mg mL−1 GA addition, a PCE of 21.32%  is achieved. Judging from the TRPL results, the enhanced Jsc, Voc, and FF originate from the decreased trap density upon GA incorporation. The calculated Jsc values  obtained from integrating over the external quantum efficiency (EQE) spectra shown in Figure Jsc values. The PCE distribution for a batch of 40 individual perovskite solar cell devices is shown in Figure J–V scans are shown in Figure S12 (Supporting Information). The data are summarized in Table S5 (Supporting Information). Hysteresis indices of 13.3 for the control device, 16.6 for the TGA‐modified PSC, and 6.5 for the GA‐modified PSC are obtained. Therefore, the reduction in trap density by GA is also beneficial for lowering the hysteresis in PSC devices,To assess the effectiveness of GA modification and test it against the TGA treatment, we fabricated and optimized PSC devices based on the n‐i‐p planar architecture of glass/FTO/TiOcurrent Jsc, fill FigureRs) and a recombination resistance (Rrec) in parallel with a chemical capacitance (Cµ) at the TiO2/perovskite/HTL interface.Rrec (363 Ω) compared to the control device (277 Ω) and TGA‐modified PSC device (172 Ω). Additionally, the Nyquist plots of these PSC devices at different bias voltages  were also carried out in the dark and the dependence of the fitted Rrec on these bias potentials is illustrated in Figure Rrec values significantly decrease. For the same bias voltage, the Rrec value varies in the order of TGA < control < GA, which is in good agreement with the Voc trend of the PSC devices as shown in Table S4 (Supporting Information). The series resistance of GA‐modified PSC device, as shown in Figure In order to investigate the effects of perovskite modification on the device stability under external stress, we tested the effects of light soaking, thermal degradation, and moisture30.85MA0.15PbI3 perovskite. This material is solid at room temperature, but leaves the perovskite film upon annealing to 150 °C after DMSO sublimation, which is totally different from the common additive approaches. During processing, the molecule slows down the perovskite crystal growth process and simultaneously facilitates the generation of large grained and smooth perovskite films due to the strong interaction between GA and Pb2+. The improved film formation reduces the defect density in the perovskite and for the champion solar cell device a PCE as high as 21.32% is achieved. To understand the role of volatility, the less‐volatile molecule thioglycolic acid (TGA) with a similar chemical structure was investigated as an additive. This compound also increased the grain sizes in the perovskite film, however TGA remained in the film after annealing, leading to the formation of pinholes. Overall the perovskite surface was rougher and an increased defect density was found accompanied by a decline in PCE. This shows that the low evaporation point of GA is an essential feature. Furthermore, due to the superior film formation, GA can effectively enhance the light, thermal, and moisture stability of the PSC compared with a pristine or TGA‐modified film. In a word, we demonstrate a novel strategy for efficacious regulating perovskite crystallinity using volatile solid GA against nonvolatile TGA additive following DMSO sublimation in FA0.85MA0.15PbI3 PSCs, resulting in reduced defect density, enhanced device performance, and superior long‐term stability.In this work, we presented the use of glycolic acid (GA) in the precursor solution of FAThe authors declare no conflict of interest.Supporting InformationClick here for additional data file.