Phenyl-triggered photophysical switching between normal fluorescence and delayed fluorescence in phthalonitrile-based luminophores  

作　　者：In Seob Park Hyukgi Min Takuma Yasuda 

机构地区：[1]INAMORI Frontier Research Center(IFRC),Kyushu University,Fukuoka,Japan [2]Department of Applied Chemistry,Graduate School of Engineering,Kyushu University,Fukuoka,Japan

出　　处：《Aggregate》2021年第1期145-150,共6页聚集体（英文）

摘　　要：Herein,a facile strategy for switching luminescent properties between normal fluorescence and thermally activated delayed fluorescence(TADF)is presented.Two luminophoric molecules,VPN-Ph and VPN-H,combining phthalonitrile as an electron-accepting core and triphenylamines as electron-donating peripheries with and without two phenyl groups,are newly developed.A comparative study on their structural and photophysical properties is conducted.While non-phenyl VPN-H does not exhibit TADF but normal fluorescence,phenyl-introduced VPNPh exhibits TADF with a high photoluminescence quantum yield as a consequence of the phenyl-triggered steric congestion.By virtue of the TADF feature,an organic light-emitting diode(OLED)incorporating VPN-Ph as an emitter achieves a maximum external electroluminescence(EL)quantum efficiency as high as 28.0%,which is five times higher than that of the VPN-H-based OLED.Thus,phenyl-triggered geometric modulation has a drastic impact on the resulting photophysical and EL properties,leading to TADF on/off switching.

关 键 词：intramolecular charge transfer molecular orientation organic light-emitting diodes photophysical switching PHTHALONITRILE thermally activated delayed fluorescence 

分 类 号：O62[理学—有机化学]