Suppressing Morphological and Energetic Disorder in Copper Antimony Sulfide‐based Hole‐Transporting Materials via Ligand–Precursor Engineering for Efficient and Stable Perovskite Solar Cells
Ibrahimhan Dilci, Savas SonmezogluABSTRACT
Dopant‐free inorganic hole‐transport layers (HTLs) are promising for improving the efficiency and stability of perovskite solar cells (PSCs). Here, CuSbS 2 nanocrystals are engineered through sulfur‐precursor and ligand‐coordination chemistry using hexamethyldisilathiane (TMS) and thiourea (ThU) combined with oleylamine/oleic acid (OAm/OAc) ligands. While the TMS route reduces platelet dimensions, the ThU precursor with an optimized OAm: OAc ratio of 3:7 suppresses excessive anisotropic growth and induces mixed plate‐like/quasi‐spherical nanostructures, leading to denser particle packing and improved interfacial coverage. Structural and electronic analyses reveal that sulfur‐release kinetics and ligand coordination govern morphology evolution, energetic disorder, and interfacial charge‐transfer behavior. As a result, PSCs employing ThU‐derived CuSbS 2 HTLs achieve a champion power conversion efficiency of 22.72% with 0.82 for fill factor, outperforming TMS‐derived (20.00%) and ES‐derived (17.31%) counterparts. The optimized devices also exhibit enhanced operational stability under illumination and thermal aging conditions. These findings establish sulfur‐precursor and ligand engineering as an effective strategy for high‐performance inorganic HTLs in PSCs.