Large-Area Organic-Free Perovskite Solar Cells with High Thermal Stability

Organic-free perovskite solar cells (PSCs) have been considered as the most promising candidate for achieving long-term stability. Here, we demonstrate an organic-free PSC consisting of inorganic CsPbI2Br perovskite, nickel oxide hole transport layer, and niobium oxide electron transport layer. A maximum power conversion efficiency (PCE) of 11.20% is achieved with an active area of 5 cm2, and it increases to 14.11% with smaller area. More importantly, the organic-free PSCs show excellent thermal stability with PCE remaining above 98% of its initial value when heated at 100 °C for 150 min. Postannealing at a proper temperature further increases its maximum PCE to 14.45%, which is the highest among any reported all-inorganic PSCs with a p-i-n structure. The enhanced performance of the postannealed device is ascribed to the decreased trap-state density and improved interface charge-transfer properties. These results demonstrated that this novel organic-free device architecture can be employed to fabricate efficient and stable PSCs for large-scale manufacturing.