Impact of Humidity in Triple Cation Perovskite Solar Cells : Interface Analysis

Perovskite (PVSK) is widely used in the absorber layer of solar cells due to its excellent conversion efficiency; however, these devices are highly susceptible to humidity. Furthermore, the mechanism underlying the moisture-induced performance degradation in triple cation PVSK has yet to be elucidated. In the current study, we used the anti-solvent method to prepare triple cation PVSK films in order to study the growth mechanism and influence of moisture on conversion performance. We determined that an appropriate quantity of moisture in PVSK films can improve crystallinity and passivate grain boundaries, thereby facilitating the transport of carriers across grain boundaries to extend the carrier lifespan. Excess moisture entering PVSK thin films leads to degradation of the PVSK absorber layer, resulting in the formation of PbI2, PbBr2, HI, FAI, and MABr, while leaving holes in the surface, which can compromise the stability of the crystals and efficiency of the solar cell. In the current study, the optimal humidity level PVSK thin film solar cells was 19.05%, which resulted in photoelectric characteristics and device efficiency on par with the results obtained under a pure nitrogen environment