Stability Testing and Rapid Environmental Stress Simulation for Perovskite Photovoltaics

forthcoming

To reach net zero by 2050 a 30-fold expansion in solar energy capacity is required, necessitating cheaper alternatives to Si semiconductors. Perovskite solar cells have power conversion efficiencies (PCEs) equivalent to the best Si cells and are inherently defect tolerant, meaning they are cheaper to manufacture than Si. Early perovskite technology was restricted by short operating lifetimes with most cells lasting only a few weeks rather than the 25 years required for commercial application. Recent advances have produced perovskite cells with negligible degradation after a year in the field, however. Thus researchers are turning to accelerated testing to quantify lifetimes and speed up stability improvements. Current accelerated testing uses 1-sun illumination and increased temperature to estimate lifetimes under normal conditions. Even under extreme temperatures this procedure requires several months to approximate 5 years in the field. To further speed up this process and expedite stability improvements I shall combine accelerated thermal degradation with accelerated photodegradation to reduce testing timescales to a matter of days. To achieve this, I will describe the decay modes of illumination based on spectral intensity and shape, and derive from them acceleration factors which relate back to outdoor testing results, thus deriving a protocol which mimics a decade of operation in only one week. Not only will this work expedite stability testing, but it will also explain how cells are damaged by light and which wavelengths. I will use these photo/thermal degradation insights to advance techniques for improved stability under light and heat. The project will conclude with an accelerated aging protocol used to demonstrate reproducible fabrication of > 20% PCE perovskite solar cells with estimated lifetimes of 10 years.