Band Gap and Defect Engineering for High‐Performance Cadmium‐free Sb₂(S,Se)₃ Solar Cells and Modules

Abstract

High‐efficiency antimony selenosulfide (Sb2(S,Se)3) solar cells are often fabricated by hydrothermal deposition and also comprise a CdS buffer layer. Whereas the use of toxic materials such as cadmium compounds should be avoided, both of these issues hinder scaling up to large areas and market access. For this reason, co‐sublimation is studied as a manufacturing process for the active layer as well as the use of Cd‐free buffer layers. To further improve the power conversion efficiency (PCE), a graded bandgap profile is designed for the absorber layer. A V‐shaped graded bandgap in the Sb2(S,Se)3 absorber layer is produced on a TiO2 substrate by co‐sublimation of a controlled varying molar ratio of Sb2Se3 and Sb2S3. Moreover, increasing the Se/S ratio improves the grain size and favorable (hk1) orientations, reduces the detrimental bulk defects in Sb2(S,Se)3 films. Consequently, the optimized Sb2(S,Se)3 solar cells reach a PCE of 9.02%, which is a record value for Cd‐free Sb‐based solar cells. A PCE of 7.15% is further demonstrated for a Sb2(S,Se)3 monolithically interconnected minimodule with an active area of 12.32 cm2. This co‐sublimation graded bandgap technique provides a useful guidance for the optimization of a range of solar cells based on alloy compounds.

Tellurium Doping Inducing Defect Passivation for Highly Effective Antimony Selenide Thin Film Solar Cell

“…Antimony selenide (Sb 2 Se 3 ) has become a promising light-harvesting material, thanks to the advantages of high earth abundance, low toxicity, superior photoelectric properties, and a high light absorption coefficient [ 1 , 2 , 3 , 4 , 5 ]. Sb 2 Se 3 as a binary compound has high stability and fixed stoichiometry.…”

Heterostructured CdS Buffer Layer for Sb2Se3 Thin Film Solar Cell

“…To date, the low toxic and earth‐abundant antimony selenide (Sb 2 Se 3 ) has been considered a very promising light absorber material with theoretical high‐efficiency solar cell due to its excellent optoelectronic property with an appropriate bandgap of 1.10–1.30 eV, anisotropic charge transport, high light absorption coefficient (>10 5 cm −1 ), and stable orthorhombic phase. [ 2–5 ]…”

Solvent‐Assisted Hydrothermal Deposition Approach for Highly‐Efficient Sb2(S,Se)3 Thin‐Film Solar Cells

“…As the quality of Sb 2 (S,Se) 3 films is largely determined by the manufacturing method, deposition recipes, and posttreatment, continuous efforts have been made to upgrade the fabrication technologies and new understandings of this material. [13][14][15][16] In the past 2 years, we developed an effective deposition strategy for high-quality Sb-based thin films as well as final solar devices, namely the hydrothermal deposition (HD) method. [17,18] Although the highest-performance devices are achieved by this method, its disadvantages cannot be ignored.…”