Acceleration effect of chlorine in the gas-phase growth process of CH3NH3PbI3(Cl) films for efficient perovskite solar cells
Abstract
To date, the fundamental question still remains regarding the role of chlorine (Cl) in the gas-phase growth process of CH3NH3PbI3(Cl) perovskites. Herein, we report an NH4Cl-assisted chemical vapor deposition (CVD) method for fabricating efficient perovskite solar cells (PSCs). It was found that the elaborately introduced Cl has an obvious acceleration influence on the formation of perovskites through forming intermediate phase CH3NH3PbCl3 and volatile NH3 and HI, which may effectively reduce the reaction time from 2–4 hours to 50 minutes, and drastically decrease the reaction temperature from above 150 °C to 120 °C. As such, the average power conversion efficiency (PCE) of perovskites was significantly enhanced from 10.86% to 12.2%, and an impressive 13.3% champion efficiency was successfully achieved in this study. Therefore, our finding readily overcame the bottleneck of common CVD approaches and was also helpful to understand the PbI2–CH3NH3PbCl3–CH3NH3PbI3 gas-phase growth kinetics of perovskites, which shows high potential for application in flexible PV devices.