Rational Design of Phenothiazine-Based Organic Dyes for Dye-Sensitized Solar Cells: The Influence of π-Spacers and Intermolecular Aggregation on Their Photovoltaic Performances
Lemin Mao, Yaxu Wu, Jiamin Jiang, Xugeng Guo, Panpan Heng, Li Wang, Jinglai Zhang
Abstract
Power conversion efficiency (PCE) is one of the important factors in influencing the overall performance of dye-sensitized solar cells (DSSCs), and precise prediction of PCE is a feasible strategy for preparing highly efficient DSSCs devices. In this work, we designed a series of phenothiazine-based organic dyes by introducing different π-spacers including the 4-isopropyl-4H-dithieno[3,2-b:2′,3′-d]pyrrole (DTP) and 2,7-dihydronaphtho[1,2-d:5,6-d′]diimidazole (NDI) to tune their photovoltaic properties. The present studies reveal that the PCE value of the DTP-based dye is estimated to be 8.55%, in excellent agreement with the experimentally available value (8.19%) observed in the reported analogue. In comparison to DTP, the strong electron-deficiency NDI group induces a remarkable red-shifting of maximum absorption band, broadening the optical absorption into the near-infrared region. As a consequence, the NDI-based dye achieves an impressive PCE value of 15.51%, which is expected to be a potential organic dye applied in DSSCs.