Allochroic thermally activated delayed fluorescence diodes through field-induced solvatochromic effect

作者：Han, Chunmiao; Duan, Chunbo; Yang, Weibo; Xie, Mingchen; Xu, Hui^*

来源：Science Advances, 2017, 3(9): e1700904.

DOI：10.1126/sciadv.1700904

• LIGHT-EMITTING-DIODES
• COLOR-VARIABLE ELECTROLUMINESCENCE
• PHOSPHINE OXIDE
• EFFICIENT
• DEVICES
• HOSTS
• EMISSION
• DENSITY
• PHOLEDS

Allochroic organic light-emitting devices (AOLEDs) characterized by field-dependent emissive color variation are promising as visible signal response units for intelligent applications. Most of the AOLEDs were realized by changing their recombination zones or inter-and intramolecular energy transfer, rendering the limited repeatability, stability, and electroluminescence (EL) performance. We report a novel thermally activated delayed fluorescence (TADF) diode that featured a successive and irreversible emission color change frombluish green to deep blue during voltage increase, which uses the significant influence of host polarity on the emission color of TADF dyes, namely, solvatochromic effect. Its host 3,6-di-tert-butyl-1,8-bis(diphenylphosphoryl)-9H-carbazole (tBCzHDPO) was designed with remarkable field-dependent polarity reduction from 7.9 to 3.3 D by virtue of hydrogen bond-induced conformational isomerization. This TADF device achieves the best EL performance among AOLEDs, to date, with, for example, an external quantum efficiency beyond 15%, aswell as the unique irreversible allochroic characteristic for visible data storage and information security.

• 出版日期2017-9
• 单位黑龙江大学