Transparent CuGaO2/BaTiO3 nanoarray pn junction with high-entropy perovskite quantum dots for enhanced photoelectric response

A transparent pn junction in CuGaO2/La(Ni0.2Fe0.2Co0.2Cr0.2Zn0.2)O3 QDs/BaTiO3 is prepared via the hydrothermal-sol-gel approach. The obtained CuGaO2/LaCrHEO QDs/BaTiO3 pn junction achieves a high transmittance of ∼85%–90%, a remarkable photoelectric enhancement of ∼3.1 × 103-fold compared to intrinsic CuGaO2/BaTiO3, and a good stability in 6 months. In this system, the interfacial modification of LaCrHEO QDs is deemed as the core issue, because besides appropriate Fermi level/high QY, it owns the charge inducing/injecting/driving via B-site Ni–Fe–Co–Cr–Zn polymetallic ionic metastable state coupling can heighten the carrier kinetics transportation to maintain PCE-transparency balance, including Cu+/Cu2+ hole inducing. Additionally, the CuGaO2 nanoarray can improve interfacial contact and maintain good physical/mechanical stability in practical applications, while enhancing solar utilization.