High Efficiency Semiconductor-Liquid Junction Solar Cells based on Cu/Cu2O

Cu/Cu2O photoelectrodes are synthesized by a simple electrodepositing process at low temperature. The values of the electrolyte pH have great influence on the morphology and the compositions of the obtained films, and thus affect the performance of the electrodes. The best device based on Cu/Cu2O and I−/I3− electrolyte gives a high conversion efficiency of 3.13% under simulated AM1.5G illumination. To the best of our knowledge, this is the highest efficiency reported for solar cells based on electrodeposited Cu2O. For comparison purposes, pure Cu2O films are also synthesized. The performance of the solar cells based on pure Cu2O is very poor, as low as 0.013%. In addition, the Cu/Cu2O films are perfectly compatible with the lightweight plastic substrates and yielded a power conversion efficiency of 1.44%. The abundance and nontoxicity of Cu2O, as well as the good solar spectral absorption, allows for the possibility of constructing efficient solar cells with Cu2O. Cu/Cu2O is prepared by a low‐cost and easily scalable solution processing technique; the solar cells based on the obtained Cu/Cu2O have a best conversion efficiency of 3.13% under simulated AM1.5G. The efficiency of the flexible cell based on Cu/Cu2O films is 1.44%.