Improved fill factors in solution-processed ZnO/Cu2O photovoltaics

Abstract The influence of semiconductor layer morphology on the performance of solution-processed ZnO/Cu2O photovoltaics has been examined. ZnO films were prepared using three highly scalable, cost-effective methods: electrodeposition, zinc acetate decomposition, and diethyl zinc decomposition. To optimize device performance, it is found that a low density of nano-scale pores in the ZnO layer and large grains in the Cu2O is necessary. Through optimizing the ZnO morphology, one of the highest fill factors observed to date (up to 54%) in solution-processed ZnO/Cu2O was achieved. This value is comparable with the fill factor of the record-efficiency ZnO/Cu2O device, which was prepared with much larger energy inputs.