Antimony doped CsPbI₂Br for high-stability all-inorganic perovskite solar cells

All-inorganic perovskites, adopting cesium (Cs⁺) cation to completely replace the organic component of A-sites of hybrid organic–inorganic halide perovskites, have attracted much attention owing to the excellent thermal stability. However, all-inorganic iodine-based perovskites generally exhibit poor phase stability in ambient conditions. Herein, we propose an efficient strategy to introduce antimony (Sb³⁺) into the crystalline lattices of CsPbI₂Br perovskite, which can effectively regulate the growth of perovskite crystals to obtain a more stable perovskite phase. Due to the much smaller ionic radius and lower electronegativity of trivalent Sb³⁺ than those of Pb²⁺, the Sb³⁺ doping can decrease surface defects and suppress charge recombination, resulting in longer carrier lifetime and negligible hysteresis. As a result, the all-inorganic perovskite solar cells (PSCs) based on 0.25% Sb³⁺ doped CsPbI₂Br light absorber and screen-printable nanocarbon counter electrode achieved a power conversion efficiency of 11.06%, which is 16% higher than that of the control devices without Sb³⁺ doping. Moreover, the Sb³⁺ doped all-inorganic PSCs also exhibited greatly improved endurance against heat and moisture. Due to the use of low-cost and easy-to-process nanocarbon counter electrodes, the manufacturing process of the all-inorganic PSCs is very convenient and highly repeatable, and the manufacturing cost can be greatly reduced. This work offers a promising approach to constructing high-stability all-inorganic PSCs by introducing appropriate lattice doping.