Highly Emissive 9-Borafluorene Derivatives: Synthesis, Photophysical Properties and Device Fabrication.
A series of 9-borafluorene derivatives, functionalised with electron-donating groups, have been prepared. Some of these 9-borafluorene compounds exhibit strong yellowish emission in solution and in the solid state with relatively high quantum yields (up to 73.6 % for FMesB-Cz as a neat film). The results suggest that the highly twisted donor groups suppress charge transfer, but the intrinsic photophysical properties of the 9-borafluorene systems remain. The new compounds showed enhanced stability towards the atmosphere, and exhibited excellent thermal stability, revealing their potential for application in materials science. Organic light-emitting diode (OLED) devices were fabricated with two of the highly emissive compounds, and they exhibited strong yellow-greenish electroluminescence, with a maximum luminance intensity of >22 000 cd m-2 . These are the first two examples of 9-borafluorene derivatives being used as light-emitting materials in OLED devices, and they have enabled us to achieve a balance between maintaining their intrinsic properties while improving their stability.
['Chen|Xing|X|', 'Meng|Guoyun|G|', 'Liao|Guanming|G|', 'Rauch|Florian|F|', 'He|Jiang|J|http://orcid.org/0000-0003-3586-0417', 'Friedrich|Alexandra|A|http://orcid.org/0000-0002-1411-7336', 'Marder|Todd B|TB|http://orcid.org/0000-0002-9990-0169', 'Wang|Nan|N|', 'Chen|Pangkuan|P|', 'Wang|Suning|S|', 'Yin|Xiaodong|X|http://orcid.org/0000-0001-7644-6744']
photophysics organic light-emitting diodes boron heterocycles density functional calculations luminescence