Interface and grain boundary defect passivation of perovskite solar cells by incorporation of crystalline carbon nitride

Abstract

Metal halide perovskite solar cells are attracting attention as a next-generation solar cell material with a low manufacturing cost through a solution process and a high efficiency of 25.5% recently. However, due to the characteristics of the fast crystallization rate of perovskite, sandwiched structure, and the complex composition ratio, the film is fabricated as polycrystalline form, inevitable interfacial defect formation, and various intrinsic defects. The defects in perovskite layer act as a factor that degrades the performance and stability of perovskite solar cells. Therefore, for a high-efficiency perovskite solar cell, research is needed to passivate defects at the interface and grain boundaries of perovskite. In this paper, crystalline carbon nitride was introduced to control defects in perovskite. Crystalline carbon nitride contains various electron-donating functional groups, has excellent stability in operating conditions of solar cells such as high temperature and light, and can form stable dispersion in perovskite precursor. Crystalline carbon nitrite is used as a defect control material in perovskite to reduce the activated defects in perovskite and improve efficiency by 8.9% compared to existing solar cell devices.