Field-effect passivation for minimized voltage loss in highly efficient antimony selenosulfide solar cells

The inferior heterojunction quality and misaligned energy levels at the buffer/absorber interface cause severe interface recombination and large open-circuit voltage (V_OC) loss, limiting the power conversion efficiency (PCE) of antimony selenosulfide (Sb₂(S,Se)₃) solar cells. Here, we develop a field-effect passivation strategy by introducing a low-work-function Ta₂O₅ dielectric layer between the CdS and Sb₂(S,Se)₃ layers. This Ta₂O₅ layer serves as an optimal substrate for growing highly crystalline Sb₂(S,Se)₃ films while also enhancing interfacial charge transport. The positive fixed charges in Ta₂O₅ strengthen the built-in electric field and promotes electrons extraction while suppressing holes accumulation at the interface, thereby substantially suppressing non-radiative recombination probabilities. Implementing this passivation strategy yields a record PCE of 10.95% (10.65% certified) an V_OC of 695 mV, corresponding to a remarkably low voltage deficit. This work establishes a universal physical passivation paradigm for interface quality optimization and V_OC loss mitigation in high-performance Sb₂(S,Se)₃ photovoltaics.