As an inorganic hole transport material (HTM), nickel oxide (NiOx) is widely used in perovskite solar cells (PSCs) due to its low cost and intrinsic stability. However, on account of its poor film formation on perovskite, the low power conversion efficiency (PCE) and stability of regular NiOx‐based PSCs is a main obstacle for commercialization. Here, a solution‐processed inorganic/organic hybrid hole transporting system is developed to resolve this issue, thereby improving the PCE from 16.0% to 21.2%. Poly(3‐hexylthiophene) (P3HT) is studied as the typical case, revealing that the performance improvement mainly lies in the synergistic interaction between NiOx and P3HT: 1) the introduction of P3HT improves assembly regularity and film uniformity of NiOx; 2) electron redistribution between P3HT and NiOx increases the Ni3+/Ni2+ ratio for higher hole mobility; 3) the feed‐back impact of NiOx on P3HT enhances molecular orientation of polymer chains in P3HT for better hole transport through polymer framework. Finally, the encapsulated solar cell modules with P3HT‐promoted NiOx maintains 91% of the initial efficiency after 1000 h aging at a harsh 85 °C/85% relative humidity condition. This finding provides a feasible approach for using NiOx‐based HTMs to realize high‐performance regular PSCs, paving the way for their commercialization.

α-FAPbI3-based perovskite solar cells have recently attracted increasing attention as a result of an ideal bandgap and longer exciton lifetime of FAPbI3 compared to perovskites with other compositions. However, in a traditional fabrication method, the α-FAPbI3 films were usually obtained by a direct phase transition from δ to α phase at a high annealing temperature, leading to low quality with poor crystallinity and numerous defects. The formation and stabilization of phase-pure, material-pure, high-quality α-FAPbI3 films remain challenging. In this work, a FA vapor-assisted cation-exchange pathway from low-dimensional perovskites to three-dimensional α-FAPbI3 was built, through which phase-pure and material-pure α-FAPbI3 films were achieved at 100 °C below the temperature of thermodynamic δ-to-α phase transition (∼150 °C). Through an in-depth study, the cation-exchange pathway was found to have a low reaction barrier directly toward α-FAPbI3 and suppress the formation of δ-FAPbI3, leading to high-quality α-FAPbI3 with high orientation and few trap states at a low annealing temperature. Consequently, small-area devices and large-area modules with as-prepared α-FAPbI3 films were achieved with improved performance, showing great potential for further study and application.

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, NiOx 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 NiOx as systematic interfacial engineering. The QD intercalation enhances film morphology and assembly regulation of NiOx HTLs . Due to structure–function correlations, hole mobility within NiOx HTL is improved. And the hole extraction from perovskite to NiOx is also facilitated, resulting from reduced trap states and optimized energy level alignments. Hence, the promoted NiOx‐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 NiOx HTLs show impressive stability during 85 °C/85% aging test for 1000 hours. With high transparency, QDs‐promoted NiOx is also demonstrated to be an advanced HTL for semitransparent PSCs. This work develops promising NiOx inorganic HTL in n‐i‐p PSCs for manufacturing next‐generation photovoltaic devices.