Enhancement of short-circuit current density in Cu2O/ZnO heterojunction solar cells

Abstract

This study reports the achievement of a high short-circuit current density (Jsc) of 9.53 mA/cm2 for low-cost electrodeposited (ED) semi-transparent Cu2O/ZnO nanorod (NR) solar cells. High-quality chemical-bath-deposited ZnO NRs that align with the carrier collection path were used to replace the traditional sputtered ZnO film. An almost four-fold increase (from 1.63 to 6.41 mA/cm2) in Jsc was obtained with the NRs compared to the level obtained with a sputtered ZnO thin film cell. Decreased the ED Cu2O absorber film thickness is able to compensate for the recombination loss that results from Cu2O's short minority carrier drift and diffusion length (both on the order of 100 nm), further boosting Jsc to 7.77 mA/cm2. Additional photo-generated carriers were created for the semi-transparent solar cells when a silver mirror was deposited on the backside of the glass; this further enhanced absorption and improved Jsc to 9.53 mA/cm2. This is the highest Jsc value reported to date for a low-cost ED Cu2O/ZnO solar cell.