A water-based spray-assisted growth strategy is proposed to prepare large-area all-inorganic perovskite films for perovskite solar cells (PSCs), which involves in spraying of cesium halide water solution onto spin-coating-deposited lead halide films, followed by thermal annealing. With CsPbBr 3 as an example, we show that as-proposed growth strategy can enable the films with uniform surface, full coverage, pure phase, large grains, and high crystallinity, which primarily benefits from the controllable CsBr loading quantity, and the use of water as CsBr solvent makes the reaction between CsBr and PbBr 2 immune to PbBr 2 film microstructure. As a result, the small-area (0.09 cm 2 ) and large-area (1.00 cm 2 ) carbon-electrode CsPbBr 3 PSCs yield the record-high efficiencies of 10.22% and 8.21%, respectively, coupled with excellent operational stability. We also illustrate that the water-based spray-assisted deposition strategy is suitable to prepare CsPbCl 3 , CsPbIBr 2 , and CsPbI 2 Br films with outstanding efficiencies of 1.27%, 10.44%, and 13.30%, respectively, for carbon-electrode PSCs.

Inorganic lead halide perovskite CsPbCl 3 with an absorption edge of ∼420 nm and exceptional optoelectronic properties is promising for selective ultraviolet (UV)harvesting visibly transparent photovoltaics. However, the low solubilities of CsCl and PbCl 2 precursor materials in common solvents make it difficult to prepare high-quality CsPbCl 3 films with the desired thickness. Herein, we demonstrate a water-assisted two-step spin coating growth strategy for CsPbCl 3 films. Because of the high solubility of CsCl but the low solubility of PbCl 2 in water, it becomes possible to produce CsPbCl 3 films by direct spin coating of CsCl/H 2 O solution onto a PbCl 2 film without damaging it. After optimizing the dose of CsCl/H 2 O solution, CsPbCl 3 films with a full surface coverage, pure perovskite phase, high crystallinity, large average grain size of 620 nm, and thickness of ∼310 nm are obtained. Consequently, the selective UV-harvesting visibly transparent PSCs with the CsPbCl 3 films yield an optimized efficiency of 1.19%, an average visible transparency of 53.1%, and a color rendering index of 91.1. The findings of our study make it clear that the water-assisted twostep spin coating growth strategy is highly feasible to prepare CsPbCl 3 films with desired characters, and thus, it has a great potential in the future development of CsPbCl 3 optoelectronic devices.

As the necessary precursor of emerging lead‐halide perovskite materials, PbI2 is also promising for optoelectronic devices, such as photodetectors (PDs). Herein, the novel Ruddlesden-Popper (RP) perovskite Cs2PbI2Cl2 nanowires is grown...

All-inorganic perovskites, with their low-cost, simple processes and superior heat stability, have become potential candidate materials for photodetectors (PDs). However, they have no representative responsivity in the deep-ultraviolet (UV) wavelength region. As a new-generation semiconductor, gallium oxide (Ga2O3), which has an ultrawide bandgap, is appropriate for solar-blind (200 nm–280 nm) deep-UV detection. In this work, ultrawide-bandgap Ga2O3 was introduced into an inorganic perovskite device with a structure of sapphire/β-Ga2O3/Indium Zinc Oxide (IZO)/CsPbBr3. The performance of this perovskite PD was obviously enhanced in the deep UV region. A low-cost, vacuum-free Mist-CVD was used to realize the epitaxial growth of β-Ga2O3 film on sapphire. By introducing the Ga2O3 layer, the light current of this heterojunction PD was obviously enhanced from 10−8 to 10−7, which leds its detectivity (D*) to reach 1.04 × 1012 Jones under a 254 nm light illumination with an intensity of 500 μW/cm2 at a 5 V bias.

Photodetectors with excellent high-temperature performance and facile fabrication are desired for harsh environment applications. Herein, we report the high-temperature, self-powered PDs by adopting 0D-3D mixed-dimensionality perovskite Cs4Pb(BrCl)6-CsPbBr2-xCl1+x films and simple...