Isolating the Oxygen Adsorption Defects on Sputtered Tin Oxide for Efficient Perovskite Solar Cells

Tin oxide (SnO₂) is the most commonly used electron transport material for perovskite solar cells (PSCs). Various techniques have been applied to deposit tin dioxide, including spin-coating, chemical bath deposition, and magnetron sputtering. Among them, magnetron sputtering is one of the most mature industrial deposition techniques. However, PSCs based on magnetron-sputtered tin oxide (sp-SnO₂) have a lower open-circuit voltage (V_oc) and power conversion efficiency (PCE) than those prepared by the mainstream solution method. This is mainly due to the oxygen-related defects at the sp-SnO₂/perovskite interface, and traditional passivation strategies usually have little effect on them. Herein, we successfully isolate the oxygen adsorption (O_ads) defects located on the surface of sp-SnO₂ from the perovskite layer using a PCBM double-electron transport layer. This isolation strategy effectively suppresses the Shockley-Read-Hall recombination at the sp-SnO₂/perovskite interface, which results in an increase in the V_oc from 0.93 to 1.15 V and an increase in PCE from 16.66 to 21.65%. To our knowledge, this is the highest PCE achieved using a magnetron-sputtered charge transport layer to date. The unencapsulated devices maintain 92% of their initial PCE after storage in air with a relative humidity of 30-50% after 750 h. We further use the solar cell capacitance simulator (1D-SCAPS) to confirm the effectiveness of the isolation strategy. This work highlights the application prospect of magnetron sputtering in the field of perovskite solar cells and provides a simple yet effective way to tackle the interfacial defect issue.