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Construction of Luminogen Exhibiting Multicolored Emission Switching through Combination of Twisted Conjugation Core
Haiyan Tian1, Xi Tang2, Yong Qiang Dong3
1Beijing Key Laboratory of Energy Conversion and Storage Materials, Department of Chemistry, Beijing Normal University, Beijing 100875, China. 201431150053@mail.bnu.edu.cn.
Abstract:
Stimuli responsive luminescent materials, especially those exhibiting multicolor emission switching, have potential application in sensor, optical recording, security ink, and anti-counterfeit label. Through combination of twisted conjugation core and donor and acceptor units, a luminogen (2-(bis(4-(carbazol-9-yl)phenyl)methylene)malononitrile (1) was synthesized. Luminogen 1 can form three kinds of crystals emitting green (1GC, λem = 506 nm, ΦF = 19.8%), yellow-green (1YC, λem = 537 nm, ΦF = 17.8%), and orange (1OC, λem = 585 nm, ΦF = 30.0%) light upon 365 nm UV illumination. The emission of amorphous solid of 1 (1Am) overlaps with that of 1OC (λem = 585 nm), with quantum yield of 13.9%, which is seldom reported. Emission of 1 can be switched among green, yellow-green, and orange through morphology modulation upon exposure to thermal, solvent vapor, or mechanical stimuli. Finally, its potential application in optical recording was also investigated.
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