CuI/BaSnO₃ Quantum Dot/ZnSnO₃ Perovskite-based Transparent p–n Junction for Photovoltaic Enhancement

Herein, the CuI/BaSnO 3 quantum dot (QD)/ZnSnO 3 perovskite-based transparent p–n junction was prepared using a hybrid approach involving sol–gel, freeze-drying, annealing, and sputtering. The resulting CuI/BaSnO 3 QD/ZnSnO 3 p–n junction exhibited a transmittance of ∼85% and a photovoltaic enhancement of ∼2.6 × 10 3 folds, resulting in a photovoltaic conversion efficiency of ∼1.13%. The p–n junction also demonstrated stable output over a 5-month cycle. This remarkable performance can be mainly attributed to the homologous perovskite BaSnO 3 QD, which facilitated the attainment of an appropriate Fermi level and high quantum yield, optimizing carrier equilibrium while maintaining high transparency and providing better lattice matching. Furthermore, the presence of additional hole-related carriers caused by Cu vacancy allowed the effective utilization of defects to optimize kinetic equilibrium. Additionally, the intrinsic high physical and chemical stability of the inorganic perovskites BaSnO 3 QD and ZnSnO 3 could improve intrinsic stability.