Mitigation of Self-p-Doping and Off-Centering Effect in Tin Perovskite via Strontium Doping
Chiara Frasca, Paola Alippi, René Schwiddessen, Karunanantharajah Prashanthan, Giuseppe Nasti, Shengnan Zuo, Muhammad Okash Ur Rehman, Mahmoud H. Aldamasy, Noor Titan Putri Hartono, Artem Musiienko, Antonio Abate
Abstract
Tin-based perovskite solar cells offer a less toxic alternative to their lead-based counterparts. Despite their promising optoelectronic properties, their performances still lag behind, with the highest power conversion efficiencies reaching around 15%. This efficiency limitation arises primarily from electronic defects leading to self-p-doping and stereochemical activity of the Sn(II) ion, which distorts the atomic arrangement in the material. In this study, we investigate the effect of strontium doping in tin-based perovskite on the distortion of the material's structure and its optoelectronic properties. Using a combination of Density Functional Theory calculations and experiments, we demonstrate that strontium doping reduces p-doping and structural strain. This approach improves the efficiency from 6.3% in undoped devices to 7.5% in doped devices without relying on dimethyl sulfoxide, a harmful solvent for tin-based perovskites. This method could enable precise control of tin off-centering and self-p-doping, advancing the development of efficient and stable tin perovskite solar cells.