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Tetra‐substituted Dipolar Carbazoles: Tuning Optical and Electroluminescence Properties by Linkage Variation
Author(s) -
Joseph Vellaichamy,
Justin Thomas K. R.,
Yang Wan Yun,
Kumar Yadav Rohit Ashok,
Kumar Dubey Deepak,
Jou JwoHuei
Publication year - 2018
Publication title -
asian journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.846
H-Index - 44
eISSN - 2193-5815
pISSN - 2193-5807
DOI - 10.1002/ajoc.201800248
Subject(s) - carbazole , triphenylamine , solvatochromism , chemistry , photochemistry , chromophore , excited state , electroluminescence , absorption (acoustics) , phosphorescence , acceptor , thermal stability , fluorescence , solvent , organic chemistry , materials science , physics , layer (electronics) , quantum mechanics , nuclear physics , composite material , condensed matter physics
Six isomeric carbazole derivatives featuring donors such as triphenylamine and carbazole and cyano acceptor are synthesized and characterized. Triphenylamine substituted compounds displayed longer wavelength absorption and emission and improved thermal stability when compared to their carbazole congeners. The compounds containing donors at 2,7‐position of carbazole core displayed negative solvatochromism in absorption while the other isomers showed solvent independent absorption profiles. Except the dye containing carbazole at 1,8‐positions, all the dyes exhibited solvatochromism in excited state. Within a series dyes containing donors at 1,8‐positions exhibited shorter wavelength absorption and emission due to the significant twisting of chromophores at 1,8‐positions. The dyes possessing donor at 2,7‐positions and cyano groups at 3,6‐positions showed best electroluminescence performance (external quantum efficiency, 4.1 %) in the series owing to their ability to utilize triplet excitons via hybridized local and charge transfer excited state.