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 (VOC) 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 VOC of 695 mV, corresponding to a remarkably low voltage deficit. This work establishes a universal physical passivation paradigm for interface quality optimization and VOC loss mitigation in high-performance Sb2(S,Se)3 photovoltaics. The inferior heterojunction quality and misaligned energy levels at the buffer/absorber layer hinders development of antimony selenosulfide solar cells. Here, authors introduce low-work-function tantalum pentoxide dielectric layer for field-effect passivation, achieving device efficiency of 10.95%.