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

Herein, the CuI/BaSnO3 quantum dot (QD)/ZnSnO3 perovskite-based transparent p–n junction was prepared using a hybrid approach involving sol–gel, freeze-drying, annealing, and sputtering. The resulting CuI/BaSnO3 QD/ZnSnO3 p–n junction exhibited a transmittance of ∼85% and a photovoltaic enhancement of ∼2.6 × 103 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 BaSnO3 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 BaSnO3 QD and ZnSnO3 could improve intrinsic stability.