85 °C/85%-Stable n-i-p Perovskite Photovoltaics with NiO Hole Transport Layers Promoted By Perovskite Quantum Dots.

Power conversion efficiency (PCE) and long-term stability are two vital issues for perovskite solar cells (PSCs). However, there is still a lack of suitable hole transport layers (HTLs) to endow PSCs with both high efficiency and stability. Here, NiO nanoparticles are promoted as an efficient and 85 °C/85%-stable inorganic HTL for high-performance n-i-p PSCs, with the introduction of perovskite quantum dots (QDs) between perovskite and NiO as systematic interfacial engineering. The QD intercalation enhances film morphology and assembly regulation of NiO HTLs . Due to structure-function correlations, hole mobility within NiO HTL is improved. And the hole extraction from perovskite to NiO is also facilitated, resulting from reduced trap states and optimized energy level alignments. Hence, the promoted NiO -based n-i-p PSCs exhibit high PCE (21.59%) and excellent stability (sustaining 85 °C aging in air without encapsulation). Furthermore, encapsulated solar modules with QDs-promoted NiO HTLs show impressive stability during 85 °C/85% aging test for 1000 hours. With high transparency, QDs-promoted NiO is also demonstrated to be an advanced HTL for semitransparent PSCs. This work develops promising NiO inorganic HTL in n-i-p PSCs for manufacturing next-generation photovoltaic devices.