Synthesis of a carbazole-substituted diphenylethylene hole transporting material and application in perovskite solar cells

Abstract In this work, a carbazole-substituted stilbene derivatives hole transporting material, 9,9’-(ethene-1,1-diylbis(4,1-phenylene))bis(3,6-dimethoxy-9H-carbazole) (EPC) was designed and synthesized. The structure was characterized by FT-IR spectroscopy, 1 H NMR, 13 C NMR and MS. The glass transition temperature is 95.09°C and the 5% weight loss temperature is 423.37°C by DSC/TG analysis. Through the UV-Vis absorption spectrum combined with cyclic voltammetry, the energy level of the highest occupied molecular orbital (HOMO) of EPC and the lowest unoccupied orbital (LUMO) energy level were obtained (-5.38 eV, -2.19 eV). The energy level is well matched with methylamine lead iodine crystals. A mesoporous structure perovskite solar cell was fabricated based on the undoped EPC, and photoelectric conversion efficiency of 13.11% was obtained. After 600 hours of storage in a dark environment at 25°C and 60% relative humidity, 82% of the initial efficiency was obtained. This work provides new ideas for the development of undoped hole transporting materials.