The state of the art of Sb₂(S, Se)₃thin film solar cells: Current progress and future prospect

In this work, a review focused on the recent development of antimony sulfide selenide (Sb2(S,Se)3) solar cells is presented. In particular, experimental and theoretical results are discussed to understand the current limiting factors of this technology, as well as possible routes for device promotion. The Sb2(S,Se)3 compound is introduced as an attractive compound for single junction and multijunction solar cells since it is described by a band-gap that can be tailored in the range of 1.1-1.8 eV. Furthermore, improved transport properties are observed in solar cells when SnO2:F is used as substrate due to better ribbons orientation. In addition, defect energy levels in the range of 0.49-0.52 eV and 0.69-0.81 eV associated to VSb and SeSb (or SSb), respectively result in carrier lifetime values in the range of 0.1-67 ns. It is demonstrated that, unlike other semiconductor compounds, temperatures lower than 450 °C are required for Sb2(S,Se)3 processing. Moreover, the highest solar cell efficiency of 10.7% has been reported by the hydrothermal method. Although Sb2(S,Se)3 is a stable compound, it is found that there are some instability problems concerning solar cells due to the use of the Spiro-OMeTAD as the hole transport layer. Finally, theoretical results show that interface defects are the main reason for low experimental efficiencies. In particular, losses at the CdS/Sb2(S,Se)3 interface are introduced as dominant. In this sense, the introduction of Zn to the CdS compound is presented as a potential solution, which can result in higher solar cell efficiencies along with the reduction of Cd concentration.