Unravelling Optical and Electrical Degradation of Perovskite Solar Cells and Impact on Perovskite/Silicon Monolithic Tandem Modules

Perovskite materials have emerged as promising candidates for high-efficiency silicon based tandem solar cells. Critically, the different degradation rates of perovskite and silicon cells can affect the lifetime performance of tandem modules. In this paper we design and conduct experiments to investigate the impact of electrical and optical degradation of perovskite cells. Experiment results indicate that degradation dominated by fill factor and current reduction can change the optical transmittance of the perovskite cells. The long-term module performance is then simulated accordingly. A maximum permissible perovskite cell degradation rate of 0.9%/year is calculated to meet the current industry warranty requirements, while a minimum required tandem cell efficiency of 28.7% is estimated for a two-terminal tandem module to be economically superior to a silicon module.