Herein, we have synthesized four indolo[2,3-b]quinoxalin-2-yl)(phenyl)methanone derivatives by cyclocondensation. The photophysical studies of dyes in various solvents and neat solid film exhibit typical electronic spectra with inbuilt intramolecular charge transfer (ICT) (λ_max: 397–490 nm) confirming donor–acceptor architecture. Herein, dyes fluoresce in the blue-orange region (λ_Emax: 435–614) on excitation at their ICT maxima in toluene, ethyl acetate, chloroform, DMSO, and neat solid film. Two dyes, which exhibit good emission intensity in all mediums, were studied for aggregation-induced emission (AIE) effect. Electrochemical studies indicate the dyes possess relatively low lying LUMO (− 3.65 to − 3.98 eV) comparable to reported n-type/electron-transporting materials. The HOMO and LUMO energy levels were evaluated by DFT and TD-DFT calculations. TGA analysis shows the dyes exhibit good thermal stability. The characteristic optoelectronic properties and thermal stability signify these dyes are potential candidates for their application in optoelectronics.

Graphical abstract

中文翻译：

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荧光 indolo[2,3-b]quinoxalin-2-yl(phenyl)methanone 染料：光物理、AIE 活性、电化学和理论研究

在此，我们通过环缩合合成了四种吲哚[2,3 - b ]喹喔啉-2-基）（苯基）甲酮衍生物。染料在各种溶剂和纯固体薄膜中的光物理研究显示出典型的电子光谱，具有内置的分子内电荷转移 (ICT) ( λ _max : 397–490 nm)，证实了供体-受体结构。在此，染料在蓝橙色区域发出荧光（λ _Emax: 435–614) 在甲苯、乙酸乙酯、氯仿、DMSO 和纯固体薄膜中以 ICT 最大值激发。研究了两种在所有介质中都表现出良好发射强度的染料的聚集诱导发射 (AIE) 效应。电化学研究表明，与报道的 n 型/电子传输材料相比，染料具有相对较低的 LUMO（- 3.65 至 - 3.98 eV）。通过 DFT 和 TD-DFT 计算评估 HOMO 和 LUMO 能级。TGA 分析表明染料表现出良好的热稳定性。特有的光电特性和热稳定性表明这些染料是其在光电应用中的潜在候选者。

图形概要