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Multi‐Stimuli Responsive and Multicolor Adjustable Pure Organic Room Temperature Fluorescence‐Phosphorescent Dual‐Emission Materials
Author(s) -
Bi Xingqi,
Shi Yonggang,
Peng Tai,
Yue Shiwen,
Wang Feng,
Zheng Liyan,
Cao QiuE
Publication year - 2021
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202101312
Subject(s) - phosphorescence , materials science , fluorescence , luminescence , intermolecular force , carbazole , photochemistry , exciton , quenching (fluorescence) , thermochromism , molecule , optoelectronics , optics , chemistry , physics , organic chemistry , quantum mechanics
A simple bromine and cyanogen substituents positional isomeric 9‐phenyl‐9H‐carbazole (PhCz) donor–acceptor system (namely p ‐NN‐Br and m ‐NN‐Br) displays ultralong organic phosphorescence, and exhibits unique dual emission properties (fluorescence and phosphorescence). These molecules are found to display distinct responses toward multiple external stimuli including temperature ( T ), excitation light intensity ( I ) and pressure ( P ), and show multicolor tunable behaviors (including the white light, the Commission Internationale d'Eclairage (CIE) = 0.33, 0.34). The unique stimuli‐triggered proportion between singlet and triplet excitons for p ‐NN‐Br and m ‐NN‐Br is demonstrated systematically by investigating the photophysical spectrum, scanning electron microscope (SEM) imaging and X‐ray analysis, coupled with theoretical calculations. They reveal that the simultaneous introduction of halogens (Br) and pseudohalogens (CN) to the PhCz skeleton can improve the intermolecular interaction and thermal stability. Single crystal analysis shows that there are many more types of dimers and J ‐aggregates, thereby stabilizing the excitation of triplet states. Moreover, these isomers have “latent” fingerprint recognition and anti‐background interference performance, which is expected to provide a new method for fingerprint identification. All in all, this strategy paves the way to a multifunctional platform for the development of multi‐stimuli responsive, multicolor regulation and smart luminescent materials with long‐lived emission at room temperature.