Interface engineering of low temperature processed all-inorganic CsPbI2Br perovskite solar cells toward PCE exceeding 14%

摘要

All-inorganic perovskite CsPbI2Br has received much attention recently due to its suitable bandgap and excellent thermal stability. Herein, we demonstrated a low temperature solution process to obtain high quality CsPbI2Br films and fabricate devices with a facile n-i-p structure (ITO/SnO2/CsPbI2Br/Spiro-OMeTAD/MoO3/Ag), in which MoO3 was introduced as interfacial layer that led to high efficient charge extraction and suppressed carrier recombination. As a result, the champion cells exhibited a relatively high power conversion efficiency of 14.05% and superb fill factor of 81.5%. More importantly, unencapsulated PSCs with MoO3 interfacial layers showed outstanding stabilities with retaining 80% of initial PCE with thermal treatment at 85 degrees C for 140 min in ambient air, 80% of initial PCE under continuous illumination for 120 min in ambient air, and 89% of initial PCE after being stored in N-2 glove-box over 60 days. Meantime, it should be mentioned that all interlayers and active layer were processed at temperature below 160 degrees C, and hence, this fabrication technique is promising for flexible energy devices and future commercialization.