Generic Water-Based Spray-Assisted Growth for Scalable, High-Efficiency Carbon-Electrode, All-Inorganic Perovskite Solar Cells

Abstract

A water-based spray-assisted growth strategy is proposed for the first time to prepare large-area all-inorganic perovskite films for perovskite solar cells (PSCs), which involves the direct spraying of cesium halide water solution onto lead halide films under ambient air, followed by thermal annealing. With CsPbBr3 as an example, we show that the proposed growth strategy yields the films with uniform surface, full coverage, pure phase, large grains, and high crystallinity, which primarily benefit from the controllable CsBr loading quantity and the use of water as the CsBr solvent makes the reaction between CsBr and PbBr2 immune to the underlying PbBr2 film microstructure. As a result, the small-area (0.09 cm2) and large-area (1.00 cm2) carbon-electrode CsPbBr3 PSCs without any interface modification yield record-high power conversion efficiencies (PCEs) of 10.22% and 8.21%, coupled with excellent operational stability in ambient air. We also illustrate that the water-based spray-assisted deposition strategy is suitable to prepare CsPbCl3, CsPbIBr2, and CsPbI2Br films with outstanding PCEs of 1.27%, 10.44%, and 13.30% for carbon-electrode, all-inorganic PSCs.