CsPbIBr₂ Perovskite Solar Cell by Spray-Assisted Deposition

In this work, an inorganic halide perovskite solar cell using a spray-assisted solution-processed CsPbIBr 2 film is demonstrated. The process allows sequential solution processing of the CsPbIBr 2 film, overcoming the solubility problem of the bromide ion in the precursor solution that would otherwise occur in a single-step solution process. The spraying of CsI in air is demonstrated to be successful, and the annealing of the CsPbIBr 2 film in air is also successful in producing a CsPbIBr 2 film with an optical band gap of 2.05 eV and is thermally stable at 300 °C. The effects of the substrate temperature during spraying and the annealing temperature on film quality and device performance are studied. The substrate temperature during spraying is found to be the most critical parameter. The best-performing device fabricated using these conditions achieves a stabilized conversion efficiency of 6.3% with negligible hysteresis. Cesium metal halide perovskites remain viable alternatives to organic metal halide perovskites as the cesium-containing perovskites can withstand higher temperature.