Transparent p–n Junction in Cu2O/ZnS/ZnO Core–Shell Nanoarrays via In Situ Sulfuration for Enhanced Photovoltaic Stability

A Cu2O/ZnS/ZnO core–shell orderly nanoarray transparent p–n junction was prepared using a hydrothermal in situ sulfuration–sputtering method. Compared with Cu2O/ZnO, Cu2O/ZnS/ZnO exhibited a higher transmittance of ∼85%, photovoltaic enhancement by ∼1.2 × 103-fold (a photovoltaic conversion efficiency of ∼1.28%), and stable output during a 6 month cycle. This can be primarily attributed to the in situ dual functional ZnS transition layer, which exhibits an appropriate Fermi level and high quantum yield, thereby efficiently optimizing the carrier equilibrium while sustaining higher transparency. Furthermore, the ZnS/ZnO core–shell nanoarrays with a better carrier transport pathway and increased solar efficiency can optimize the carrier kinetic equilibrium. In addition, the ZnS/ZnO nanoarrays with higher physical stability and in situ ZnS shell with higher chemical stability can efficiently increase the photovoltaic stability.