Transparent CuAlO2/Ba0.5Sr0.5TiO3 perovskite pn junction for enhanced photoelectric response via interfacial homogeneous perovskite La:BiFeO3 quantum dots

The transparent pn junction in CuAlO2/La:BiFeO3 quantum dots (QDs)/Ba0.5Sr0.5TiO3 is synthesized via an approach of multiple sol–gel-annealing method. The obtained CuAlO2/La:BiFeO3 QDs/Ba0.5Sr0.5TiO3 show a high transmittance of ∼85%–90%, an obvious photoelectric conversion enhancement of ∼2.5 × 103-folds than that of intrinsic CuAlO2/Ba0.5Sr0.5TiO3, and good stability over 6 months. The La:BiFeO3 QDs are regarded as the core issue because, besides a Fermi level transition and a high quantum yield, their carrier inducing/injecting/driving via La-doping and Fe2+/Fe3+ synergism can heighten carrier dynamic transportation to power conversion efficiency-transparency, including Cu+/Cu2+-interstitial oxygen-induced holes. Moreover, the CuAlO2/Ba0.5Sr0.5TiO3 pn junction with a high-quality interface and La:BiFeO3 QDs with interface filling are beneficial for structural stability.