Imidazo[1,2-a]pyridine based deep-blue emitter: effect of donor on the optoelectronic properties

• Published in: Journal of materials science. Materials in electronics 2021-11, Vol.32 (22), p.26838-26850
• Main Authors: Anupriya, Thomas, K. R. Justin, Nagar, Mangey Ram, Shahnawaz, Jou, Jwo-Huei
• Format: Article
• Language: English
• Subjects: Carbazoles; Characterization and Evaluation of Materials; Charge transfer; Chemistry and Materials Science; Chromophores; Dyes; Electrochemical analysis; Electroluminescence; Emitters; Materials Science; Optical and Electronic Materials; Optical properties; Optoelectronics; Pyridines; Thermal stability; Topology
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-021-07060-5

Isomeric materials featuring triphenylamine and carbazole as a donor and 2-phenylimidazo[1,2- a ]pyridine electron deficient unit as the core moiety were designed, synthesized, and studied as blue-emitting materials. As expected, their optical and electrochemical properties are prominently dependent on the nature of chromophore loading and their linking topology to the 2-phenylimidazo[1,2- a ]pyridine unit. C2 substituted dyes exhibit red-shifted absorption and emission compared to their positional analogues containing donors in the C6-position of imidazopyridine. Interestingly, positive solvatochromism is exhibited by triphenylamine containing dyes, which suggests the intramolecular charge transfer from triphenylamine donor to imidazopyridine acceptor in the excited state. All the compounds revealed excellent thermal stability surpassing 355 °C. The dye possessing triphenylamine on both C2 and C6 positions of imidazopyridine showed the comparatively better electroluminescence performance in the series and achieved blue colour with CIE coordinate (0.18, 0.11).