Exploring Cu-Doping for Performance Improvement in Sb(2)Se(3) Photovoltaic Solar Cells

Copper-doped antimony selenide (Cu-doped Sb(2)Se(3)) thin films were deposited as absorber layers in photovoltaic solar cells using the low-temperature pulsed electron deposition (LT-PED) technique, starting from Sb(2)Se(3) targets where part of the Sb was replaced with Cu. From a crystalline point of view, the best results were achieved for thin films with about Sb(1.75)Cu(0.25)Se(3) composition. In order to compare the results with those previously obtained on undoped thin films, Cu-doped Sb(2)Se(3) films were deposited both on Mo- and Fluorine-doped Tin Oxide (FTO) substrates, which have different influences on the film crystallization and grain orientation. From the current-voltage analysis it was determined that the introduction of Cu in the Sb(2)Se(3) absorber enhanced the open circuit voltage (V(OC)) up to remarkable values higher than 500 mV, while the free carrier density became two orders of magnitude higher than in pure Sb(2)Se(3)-based solar cells.