All-inorganic CsPbI2Br perovskite solar cells with thermal stability at 250 8C and moisture-resilience via polymeric protection layers

Abstract

All-inorganic perovskites, such as CsPbI2Br, have emerged as promising compositions due to their enhanced thermal stability. However, they face significant challenges due to their susceptibility to humidity. In this work, CsPbI2Br perovskite is treated with poly(3-hexylthiophen-2,5-diyl) (P3HT) during the crystallization resulting in significant stability improvements against thermal, moisture and steady-state operation stressors. The perovskite solar cell retains similar to 90% of the initial efficiency under relative humidity (RH) at similar to 60% for 30 min, which is among the most stable all-inorganic perovskite devices to date under such harsh conditions. Furthermore, the P3HT treatment ensures high thermal stress tolerance at 250 degrees C for over 5 h. In addition to the stability enhancements, the champion P3HT-treated device shows a higher power conversion efficiency (PCE) of 13.5% compared to 12.7% (reference) with the stabilized power output (SPO) for 300 s. In addition, the P3HT-protected perovskite layer in ambient conditions shows similar to 75% of the initial efficiency compared to the unprotected devices with similar to 28% of their initial efficiency after 7 days of shelf life.