Inorganic cesium lead mixed halide based perovskite solar materials modified with functional silver iodide

Inorganic CsPbIBr2 perovskites have recently attracted enormous attention as a viable alternative material for optoelectronic applications due to their higher efficiency, thermal stability, suitable bandgap, and proper optical absorption. However, the CsPbIBr2 perovskite films fabricated using a one-step deposition technique is usually comprised of small grain size with a large number of grain boundaries and compositional defects. In this work, silver iodide (AgI) will be incorporated as an additive into the CsPbIBr2 perovskite precursor solution to prepare the unique perovskite CsI(PbBr2)(1-x)(AgI)(x.) The AgI additive in the precursor solution works as a nucleation promoter which will help the perovskite to grow and merge into a continuous film with reduced defects. With detailed characterizations, we found that incorporating AgI additive resulted in a uniform perovskite film with fewer grain boundaries, increased grain size, crystallinity, optical absorption while decreasing carrier recombination and trap density. Using the AgI in an optimum amount, we fabricated CsPbIBr2 perovskite solar cells (PSCs) with a simple structure and achieved a power conversion efficiency (PCE) of 7.2% with a reduced hysteresis index. This work offers an alternative approach towards preparing high-quality CsPbIBr2 perovskite films for solar cells with higher stability and other optoelectronic applications.

Automated summary

Inorganic CsPbIBr2 perovskites have attracted great attention as alternative materials for optoelectronic applications due to their higher efficiency, thermal stability, suitable bandgap, and proper optical absorption. However, the one-step deposition technique often results in CsPbIBr2 perovskite films with small grain size and compositional defects. In this study, silver iodide (AgI) was added as an additive to the CsPbIBr2 perovskite precursor solution to improve the film quality. The addition of AgI resulted in a uniform perovskite film with increased grain size, crystallinity, and optical absorption, while reducing carrier recombination and trap density. By incorporating an optimum amount of AgI, CsPbIBr2 perovskite solar cells were fabricated with a simplified structure and achieved a higher power conversion efficiency (PCE) of 7.2% and reduced hysteresis index. This work offers a promising approach for preparing high-quality CsPbIBr2 perovskite films for solar cells and other optoelectronic applications.