This outlines one way to carry out the practical using copper(II) oxide powder and dilute sulfuric acid. Eye protection must be worn. 1. Add some dilute sulfuric acid to a small beaker.

The record efficiency was achieved by engineering the cell with reduced copper(II) oxide (CuO) and copper (Cu) impurities in the thin-film deposition. It showed an open-circuit voltage of 1.13 V ...