Homogroup Bi/Sb Lattice Substitution to Enhance the Photoelectric Properties of Sb2Se3 Crystals

International audienceAntimony selenide (Sb2Se3) is currently considered as a kind of promising candidate material for photovoltaic and photoelectric devices, but there is still a large practical application challenge due to its low electrical conductivity and low charge carrier density. To overcome such problems, we adopt a homogroup Bi/Sb strategy to prepare Bi-doped Sb2Se3 semiconductors. According to the XRD, XPS, and TEM results, the Bi/ Sb lattice substitution was evidenced in the grown (BixSb1-x)2Se3 crystals. Moreover, the doped crystals have a direct band gap from 1.07 to 1.14 eV with different Bi contents, which allows a strong absorption of the solar spectrum. Hall test results and DFT calculation then witness the semiconductive-type alternation from p-type (at a low Bi concentration with Sb vacancies as acceptors) to n-type (at a high Bi concentration with Se vacancies as donors). With the increased carrier concentration under Bi doping, the electrical conductivity and photoresponse have been greatly improved. The (BixSb1-x)2Se3 crystals then presented enhanced photocurrent density with fast response/recovery time (0.05 s/0.03 s) as well as long-term durability. The (BixSb1-x)2Se3-based FTO/CdS/(BixSb1-x)2Se3/Au solar cell eventually achieved a 62% improvement in device efficiency compared with the pure Sb2Se3based one. It thus demonstrated an efficient homogroup Bi/Sb substitution strategy to enhance the performance of Sb2Se3-based photoelectric devices