The status of CdS/Cu2S solar cell development

A photovoltaic effect in the junction between Cu
2
S and CdS was reported almost twenty-five years ago. Subsequent efforts to develop a CdS/Cu
2
S solar cell, first for space applications and then for terrestrial purposes, were generally unsuccessful. The major problems were low conversion efficiency, poor production reproducibility and limited cell durability. A cell development program based on a loss minimization technique has now resulted in major advances in each of these three areas. Energy conversion efficiencies of about 9% have been achieved and the condition governing long usable lifetimes defined. The limiting achievable efficiency for a CdS/Cu
2
S cell is above 10% and a modified cell using (CdZn)S/Cu
2
S should be capable of about 15% efficiency.