Improving the stability and scalability of all-inorganic inverted CsPbI2Br perovskite solar cell

Abstract All-inorganic perovskite solar cells (PSCs) have potential to pass the stability international standard of IEC61215:2016 but cannot deliver high performance and stability due to the poor interface contact. In this paper, Sn-doped TiO2 (Ti1−xSnxO2) ultrathin nanoparticles are prepared for electron transport layer (ETL) by solution process. The ultrathin Ti0.9Sn0.1O2 nanocrystals have greatly improved interface contact due to the facile film formation, good conductivity and high work function. The all-inorganic inverted NiOx/CsPbI2Br/Ti0.9Sn0.1O2 p-i-n device shows a power conversion efficiency (PCE) of 14.0%. We test the heat stability, light stability and light-heat stability. After stored in 85 °C for 65 days, the inverted PSCs still retains 98% of initial efficiency. Under continuous standard one-sun illumination for 600 h, there is no efficiency decay, and under continuous illumination at 85 °C for 200 h, the device still retains 85% of initial efficiency. The 1.0 cm2 device of inverted structure shows a PCE of up to 11.2%. The ultrathin Ti1−xSnxO2 is promising to improve the scalability and stability and thus increase the commercial prospect.