Lanthanide Ions Doped CsPbBr3 Halides for HTM‐Free 10.14%‐Efficiency Inorganic Perovskite Solar Cell with an Ultrahigh Open‐Circuit Voltage of 1.594 V.

All‐inorganic cesium lead bromide (CsPbBr3) perovskite solar cells have attracted enormous attention owing to their outstanding stability in comparison with organic–inorganic hybrid devices. The greatest weakness for inorganic CsPbBr3 solar cells is their lower power conversion efficiencies, mainly arising from inferior light‐absorbance range and serious charge recombination at interfaces or within perovskite films. To address this issue, the lattice doping of lanthanide ions (Ln3+ = La3+, Ce3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Ho3+, Er3+, Yb3+, and Lu3+) into CsPbBr3 films for all‐inorganic solar cells free of hole‐transporting materials and precious metal electrodes is presented. Arising from the enlarged grain size and prolonged carrier lifetimes upon incorporating Ln3+ ions into perovskite lattice, the performances of these inorganic CsPbBr3 solar cell devices are significantly enhanced, achieving a champion efficiency as high as 10.14% and an ultrahigh open‐circuit voltage of 1.594 V under one sun illumination. Meanwhile, the nearly unchanged efficiency upon persistent attack by 80% RH in air atmosphere over 110 d and enhanced thermal stability at 80 °C over 60 d provide new opportunities of promoting commercialization of all‐inorganic CsPbBr3 perovskite solar cells. Lanthanide ions are doped into CsPbBr3 films to modulate crystal lattice for high‐performance all‐inorganic perovskite solar cells. Arising from the improved grain size and carrier lifetime, the solar cell achieves a champion power conversion efficiency of 10.14%, an ultrahigh Voc of 1.594 V, and excellent stability. [ABSTRACT FROM AUTHOR]