Improving the properties of Cu2O/ZnO heterojunction for photovoltaic application by graphene oxide

A p-Cu2O/n-ZnO heterojunction grown on fluorine-doped tin oxide (FTO) substrate is reported by a combined low-cost approach employing tape-casting of ZnO layer and subsequent electrochemical deposition of Cu2O layer. Graphene oxide (GO) nanosheets were employed as nanofiller for the ZnO matrix. Moreover, a ZnO buffer layer was inserted at the interface between the Cu2O and ZnO layers. The morphological, structural and photoelectrical characteristics of these heterojunction layers were investigated by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Raman spectroscopy and photoelectrical current-voltage measurements. The results confirmed that the morphology and structure of ZnO layer were affected by the incorporation of GO nanosheets while the presence of buffer layer influenced the growth of Cu2O layer. This work shows the addition of GO and the use of ZnO buffer layer represent a viable approach towards improving the photoelectrical properties of the Cu2O/ZnO heterojunction cell.