Synergistic Modulation of SnO2 and Perovskite Improving the Performance of n–i–p Wide-Band-Gap Perovskite Solar Cells

Tin dioxide (SnO2) has emerged as a highly promising candidate for electron transport layers in perovskite solar cells. However, defects in the SnO2 film and at the interface between SnO2 and perovskite often cause serious nonradiative recombination, resulting in the deterioration of the performance of perovskite solar cells. Herein, a synergistic passivation strategy is employed through the introduction of amphiphilic fluorosurfactants (FS-31) into the SnO2 precursor solution, enabling the passivation of defects present both in the SnO2 film and at the interface between SnO2 and perovskite. Moreover, FS-31 is capable of modulating the energy level of the SnO2 film and enhancing the crystalline quality of the wide-band-gap perovskite, thereby minimizing residual lead iodide. Thanks to the positive effects of FS-31, the n–i–p type wide-band-gap perovskite (1.68 eV) solar cells achieve a champion power conversion efficiency (PCE) of 20.92%, an open circuit voltage (VOC) of 1.24 V, and a minimal VOC deficit of 0.44 V. Furthermore, this simple strategy provides strong support for the preparation of high-efficiency n–i–p perovskite/silicon tandem solar cells.