Sb2Se3: a possible future for thin-film photovoltaics?

Antimony selenide (Sb2Se3) is today one of the most promising alternative materials for p-type absorbers in thin-film photovoltaics, with an optimal band-gap and a very high absorption coefficient. However, its crystal structure is extremely anisotropic and its natural carrier density is generally very low. Sb2Se3 thin films have been deposited by two different high-energy techniques: magnetron RF-sputtering (MS) and low-temperature pulsed electron deposition (LT-PED). Their dominant crystallographic orientations have been studied as a function of deposition parameters and of the different used substrates, while complete solar cells have been subsequently made with the obtained samples to confirm the dependence of conversion efficiencies on the observed (Sb4Se6)n ribbon orientation. Cu-doped Sb2Se3 thin-films have been also preliminary prepared in order to evaluate a possible route to further improve the free charge-carrier density and the cell performance.