High‐Performance Organic Dyes with Electron‐Deficient Quinoxalinoid Heterocycles for Dye‐Sensitized Solar Cells under One Sun and Indoor Light

Abstract

Abstract A series of Y‐shaped sensitizers incorporating quinoxaline or quinoxalinoid moieties were prepared and applied in dye‐sensitized solar cells (DSSCs). By the introduction of quinoxalinoid functionalities, the absorption extinction coefficients could be enhanced. The molecular structures were modified by introducing an extra acceptor group (A) between a donor (D) and a π‐bridge (D–A–π–A) and also by incorporating electron‐donating substituents at various positions of the quinoxalinoid moiety. Some of the dyes and mixtures thereof were found to exhibit good light‐harvesting efficiencies under both sunlight and indoor light, with efficiencies up to 7.92 % under one sun (AM 1.5G). When operated under indoor light, the efficiency could be boosted to 27.76, 28.74, and 30.45 % under 600, 1000, 2500 lux illumination, respectively. The best performance could be ascribed partly to an improved dye coverage on the TiO 2 surface.