10.1021/acsami.8b08658.s001 Fayin Zhang Fayin Zhang Shanyi Guang Shanyi Guang Meidan Ye Meidan Ye Kaibing Xu Kaibing Xu Wenxi Guo Wenxi Guo Xiangyang Liu Xiangyang Liu Hongyao Xu Hongyao Xu Chemical Decoration of Perovskites by Nickel Oxide Doping for Efficient and Stable Perovskite Solar Cells American Chemical Society 2018 p-type charge transport material decoration method PbI NiO x power conversion efficiency PCE Nickel Oxide Doping perovskite films photo-generated carrier lifetime NH Stable Perovskite Solar Cells Crystal engineering CH Cl photo-generated charge transport crystal chemical p-type semiconductor materials 2018-10-09 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Chemical_Decoration_of_Perovskites_by_Nickel_Oxide_Doping_for_Efficient_and_Stable_Perovskite_Solar_Cells/7215212 Crystal engineering of CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3–<i>x</i></sub>Cl<i><sub>x</sub></i> perovskite films through modification by decoration with p-type semiconductor materials was proposed as an efficient method for obtaining good-quality crystalline films. A simple method is demonstrated to improve the quality of perovskite films by adding nickel oxide (NiO<i><sub>x</sub></i>) nanoparticles into the precursor solution. The addition of NiO<i><sub>x</sub></i> brings about high-quality crystals and convenient photo-generated charge transport with reduced defect density owing to efficient control of the preferred nucleation and crystal growth. The sufficient contact between CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3–<i>x</i></sub>Cl<i><sub>x</sub></i>–NiO<i><sub>x</sub></i> and the electron-transport layer can contribute to photo-generated carrier lifetime and transport through the optimized interface. Moreover, it is demonstrated that a strong chemical bonding interaction between MAPbI<sub>3–<i>x</i></sub>Cl<i><sub>x</sub></i> and NiO<i><sub>x</sub></i> could protect perovskite materials from oxygen and humidity corrosion, showing remarkable stability holding ∼81% of the initial power conversion efficiency (PCE) after 50 days. The device with the best PCE of 19.34% is achieved because of the improved short-circuit current from 22.23 to 23.01 mA cm<sup>–2</sup> and fill factor from 68.97 to 75.06%. The results certify that this p-type charge transport material decoration method for the optimization of perovskite films is an efficient way to optimize the performance.