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.

中文翻译：

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四取代偶极咔唑：通过链接变化来调节光学和电致发光性质

合成并表征了以供体如三苯胺和咔唑为特征的六种异构咔唑衍生物和氰基受体。与咔唑同类物相比，三苯胺取代的化合物表现出更长的波长吸收和发射并改善了热稳定性。在咔唑核心的2,7位上含供体的化合物在吸收中显示出负溶剂溶变色，而其他异构体则显示出与溶剂无关的吸收曲线。除了在1,8位上含有咔唑的染料外，所有染料均在激发态下表现出溶剂化变色现象。在一系列包含供体1,8位的供体的染料中，由于发色团在1,8位的显着扭曲，显示出较短的波长吸收和发射。染料在2,7位具有给体，在3位具有氰基，