Origin of photoluminescence from antimony selenide

Abstract Antimony selenide (Sb2Se3) absorber material has great potential for low-cost photovoltaics due to its excellent optoelectronic properties and low processing temperatures. This study presents detailed temperature and excitation power dependent photoluminescence (PL) analysis of Sb2Se3 polycrystals revealing the dominating radiative recombination mechanisms and related defects in the studied material. The low-temperature (T = 10 K) PL spectrum consisted of three bands at 0.94 eV, 1.10 eV and 1.24 eV, the last one located close to the low-temperature band gap of Sb2Se3 1.32 eV. The PL bands at 1.24 eV and 0.94 eV were found to originate from the donor-acceptor pair recombination, the first one at 1.24 eV involving more distant pairs while the second one at 0.94 eV resulting from the deep acceptor – deep donor pair recombination. Third PL band at 1.10 eV is proposed to be related to the grain boundaries.