Interfacial Sulfur Functionalization Anchoring SnO₂ and CH₃NH₃PbI₃ for Enhanced Stability and Trap Passivation in Perovskite Solar Cells

Abstract

Trap states at the interface or in bulk perovskite materials critically influence perovskite solar cells performance and long-term stability. Here, a strategy for efficiently passivating charge traps and mitigating interfacial recombination by SnO surface sulfur functionalization is reported, which utilizes xanthate decomposition on the SnO surface at low temperature. The results show that functionalized sulfur atoms can coordinate with under-coordinated Pb ions near the interface. After device fabrication under more than 60 % humidity in ambient air, the efficiency of methylammonium lead iodide (MAPbI ) perovskite solar cells based on sulfur-functionalized SnO increased from 16.56 % to 18.41 % with suppressed hysteresis, which resulted from the accelerated interfacial charge transport kinetics and decreased traps in bulk perovskite by interfacial sulfur functionalization. Additionally, thermally stimulated current studies show the decreased trap density in the shallow trap area after interfacial sulfur functionalization. The interfacial sulfur functionalized solar cells without sealing also exhibited considerable retardation of solar cell degradation with only 10 % degradation after 70 days air storage. This work demonstrates a facile sulfur functionalization strategy by using xanthate decomposition on SnO surfaces to obtain highly efficient perovskite solar cells.

Surfactant Sodium Dodecyl Benzene Sulfonate Improves the Efficiency and Stability of Air‐Processed Perovskite Solar Cells with Negligible Hysteresis

“…[ 12,13 ] For example, the defects associated with uncoordinated Pb 2+ can induce the deep‐level traps and low built‐in potential, leading to unefficient charge extraction and charge recombination. [ 14–17 ] Furthermore, some crystal defects can drive ion or vacancy to easily migrate in perovskite structures. [ 18 ] Recent study demonstrated the mobile iodine ions (I − ) in the hole‐transporting layer (HTL) and electron‐transporting layer (ETL).…”

Room-temperature multiple ligands-tailored SnO2 quantum dots endow in situ dual-interface binding for upscaling efficient perovskite photovoltaics with high VOC

“…S12B ) appears obviously in comparison with the c-SnO 2 and SnO 2 NPs film, which can be located at roughly 165.2 eV. This is generally assigned to the C–S–C (sulfide) or C–S–H (thiol) 57 , 58 , indicating the presence of sulfur species functionalities on SnO 2 QDs. Besides, we also detected the characteristic signals of Br 3 d core level located at a binding energy of 68.3 eV from SnO 2 QDs (Fig.…”

CsPbBr3 Nanocrystal Induced Bilateral Interface Modification for Efficient Planar Perovskite Solar Cells

“…[ 69 , 70 ] The lattice in these positions is extremely fragile and effortlessly destroyed by moisture and heat, thus the decomposition of perovskite film generally begins at the interface. [ 71 , 72 ] As shown in Figure S27 , Supporting Information, the moisture resistance of perovskite film has been reinforced by CN top modification. Except for passivating the defects at the surface, the incorporation of Cs + and Br − with smaller radii in the lattice also strengthens the ionic and covalent bonding of perovskite.…”