Electron-withdrawing molecules as efficient antioxidants of tin-perovskite solar cells

All-perovskite tandem solar cells offer promising avenues for increased photovoltaic efficiency. However, the inherent oxidation of tin limits the actual performance of narrow-band-gap Sn–Pb mixed subcells, thereby diminishing the efficiency and stability of tandem solar cells. A significant step forward was made by the group of Ning, 1 Yu D. Pan M. Liu G. Jiang X. Wen X. Li W. Chen S. Zhou W. Wang H. Lu Y. et al. Electron-withdrawing organic ligand for high-efficiency all-perovskite tandem solar cells. Nat. Energy. 2024; 9: 298-307https://doi.org/10.1038/s41560-023-01441-2 Crossref Scopus (13) Google Scholar as outlined in Nature Energy, in which they proposed an electron-withdrawing chloromethyl phosphonic acid (CMP) ligand additive, based on the electron-withdrawing substituent effect of Cl, designed to reduce Sn2+ oxidation. This electron-withdrawing CMP molecule lowered the HOMO energy level of the formed tin adduct, yielding a more stable and better-performing tandem solar cell (26.96% certified efficiency). This approach provides a new strategy for antioxidant additives in Sn-based perovskite solar cells. All-perovskite tandem solar cells offer promising avenues for increased photovoltaic efficiency. However, the inherent oxidation of tin limits the actual performance of narrow-band-gap Sn–Pb mixed subcells, thereby diminishing the efficiency and stability of tandem solar cells. A significant step forward was made by the group of Ning, 1 Yu D. Pan M. Liu G. Jiang X. Wen X. Li W. Chen S. Zhou W. Wang H. Lu Y. et al. Electron-withdrawing organic ligand for high-efficiency all-perovskite tandem solar cells. Nat. Energy. 2024; 9: 298-307https://doi.org/10.1038/s41560-023-01441-2 Crossref Scopus (13) Google Scholar as outlined in Nature Energy, in which they proposed an electron-withdrawing chloromethyl phosphonic acid (CMP) ligand additive, based on the electron-withdrawing substituent effect of Cl, designed to reduce Sn2+ oxidation. This electron-withdrawing CMP molecule lowered the HOMO energy level of the formed tin adduct, yielding a more stable and better-performing tandem solar cell (26.96% certified efficiency). This approach provides a new strategy for antioxidant additives in Sn-based perovskite solar cells.