Engineering crystal orientation of p-Cu2O on heterojunction solar cells

The Cu2O/AZO heterojunction solar cells were successfully constructed by synthesising p-Cu2O layer upon AZO using the electrochemical deposition method. The p-Cu2O nanostructures with different grain shape and preferred crystal orientation, including (100), (110) and (111) indicated by SEM and XRD, were obtained by controlling electrodeposition bath pH. The J-V characteristic shows that the performance of the Cu2O/AZO heterojunction solar cells is found to be dependent on the crystal orientation of p-Cu2O. Only the solar cell with Cu2O (111) exhibits well-defined rectifying behaviour and good photoelectric conversion efficiency, which may due to the optimised energy band structure of Cu2O (111)/AZO heterojunction solar cells. Furthermore, VOC and JSC were sharply increased by further optimising energy band structure through inserting the intrinsic ZnO layer between the Cu2O (111) and AZO. Therefore, the results illustrated above may offer a helpful guidance to design and construct the high performance solar cell.