Cu2O Homojunction Solar Cells: F‑Doped N‑type Thin Film and Highly Improved Efficiency

Herein, F-doped Cu2O thin films with different F content are first synthesized on the ITO glass via a simple electrochemical deposition method. The prepared F-doped Cu2O thin films present n-type semiconductor character and show significantly high electronic and optical properties, especially for the one with preparation molar ratio of F/Cu = 1:2. This sample owns a unique net microstructure for a best absorption of visible-light and its electron concentration is more than ten times as that of pure Cu2O. Additionally, it has a lowest resistivity, which is beneficial for photogenerated charge transfer and the decrease of electron–hole pair recombination. The F-doped Cu2O films are utilized to fabricate Cu2O homojunction solar cells by consecutive electrochemical depositions. The conversion efficiency of the best homojunction solar cell with the F-doped Cu2O as n-type layer is nearly eight times as that with pure Cu2O as n-type layer. Hence, this study provides a strategy to improve the properties of Cu2O thin films through F ion doping. The application of F-doped Cu2O to homojunction solar cell will shed light on the development of another cheap and environmentally friendly solar cell.