Cu(In,Ga)Se2-based solar cells prepared from Se-containing precursors

In this paper, we prepared the CIGS thin films with various [Cu]/[In + Ga] ratios by selenization of Cu0.8Ga0.2 and In2Se3 precursor films. The properties of Cu(In,Ga)Se2 film and related solar cell were investigated. Raman spectra confirm that the secondary Cu2−xSe phase tends to segregate at film surface. SEM results show that the grain-size improves noticeably with the increase of the [Cu]/[In + Ga] ratios. For Cu-rich CIGS films, the performances of the related solar cells were damaged greatly and good photovoltaic characteristics cannot be obtained. For near-stoichiometric and Cu-poor films, the mean conversion efficiency close to 10% was achieved over a wide range of composition.