Quantum Dots Mediated Crystallization Enhancement in Two-Step Processed Perovskite Solar Cells.

Hybrid organic-inorganic lead halide perovskites have emerged as a promising material for high-efficiency solar cells, yet challenges related to crystallization and defects limit their performance and stability. This study investigates the use of perovskite quantum dots (QDs) as crystallization seeds to enhance the quality of FAPbI perovskite films and improve the performance of perovskite solar cells (PSCs). We demonstrate that CsPbI and CsPbBr QDs effectively guide the crystallization process, leading to the formation of larger crystals with preferential orientations, particularly the (001) and (002) planes, which are associated with reduced defect densities. This seed-mediated growth strategy resulted in PSCs with power conversion efficiencies (PCEs) of 24.75% and 24.11%, respectively, compared to the baseline efficiency of 22.05% for control devices. Furthermore, devices incorporating QD-treated perovskite films exhibited remarkable stability, maintaining over 80% of their initial PCE after 1000 h of simulated sunlight exposure, a significant improvement over the control. Detailed optoelectronic characterization revealed reduced non-radiative recombination and enhanced charge transport in QD-treated devices. These findings highlight the potential of QDs as a powerful tool to improve perovskite crystallization, facet orientation, and overall device performance, offering a promising route to enhance both efficiency and stability in PSCs.