Chemo-thermal surface dedoping for high-performance tin perovskite solar cells

Removing the lead (Pb) from state-of-the-art perovskite solar cells (PSCs) while maintaining high power conversion efficiencies (PCEs) is a prominent step toward full commercialization. The field has identified tin (Sn) PSCs as a promising alternative, but the performance of these Sn PSCs are limited primarily by detrimental Sn(IV) self-doping. Herein, we demonstrate Sn PSCs with PCEs up to 14.7% via a surface-dedoping approach. This method features the chemo-thermal removal of Sn(IV) self-dopants that are found mainly accumulated on the surface of Sn perovskite thin films, and its optimization can avoid negative effects on film morphology. Using this method, we show about a 3-fold enhancement in carrier lifetime and a 2-fold reduction in trap density, underpinning the device's efficiency improvement. The Sn PSCs are also stable, with a 92% PCE retention after 1,000 h of storage in a nitrogen-filled glovebox. This work paves a way for PSCs to achieve their technological potential without Pb involvement.

Automated summary

In this study, a surface-dedoping approach is used to enhance the efficiency of tin perovskite solar cells. By optimizing the film morphology, negative effects are avoided. The method also improves carrier lifetime and reduces trap density, resulting in higher device efficiency. Furthermore, the tin perovskite solar cells exhibit stability even after long-term storage.