Cuprous oxide is a semiconductor, just like doped silicon, and was one of the first materials experimented with as a solar cell. But its efficiency was found to be so low, around 1%, that researchers stopped trying, though the occasional set of experiments are still done in research labs and papers published.
How to make solar cells (DIY/homemade solar cell
Cuprous oxide is a semiconductor, just like doped silicon, and was one of the first materials experimented with as a solar cell. But its efficiency was found to be so low, around 1%, that researchers stopped trying, though the occasional set of experiments are still done in research labs and papers published.