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Highly Emissive 9-Borafluorene Derivatives: Synthesis, Photophysical Properties and Device Fabrication.

Xing ChenGuoyun MengGuanming LiaoFlorian RauchJiang HeAlexandra FriedrichTodd B MarderNan WangPangkuan ChenSuning WangXiaodong Yin
Published in: Chemistry (Weinheim an der Bergstrasse, Germany) (2021)
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.
Keyphrases
  • light emitting
  • solid state
  • public health
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  • climate change
  • room temperature
  • low cost
  • water soluble