Interfacial Molecular Lock Enables Highly Efficient Tin Perovskite Solar Cells

• DOI: 10.1021/acsami.3c10146
• Publication Date: 2023-11-09T19:32:35Z
• Authors: Yu Zhang; Bin Zhao; Lang Liu; Ning Wang
• Keywords: SN2 reaction; Triiodide

Tin perovskite solar cells (TPSCs) have been facing challenges in power conversion efficiency (PCE) and long-term stability due to the easy oxidation of Sn2+ migration iodine ions, which create populated trap states cause detrimental recombination photogenerated carriers. In this work, we design a novel "molecular lock" suppress tin perovskites by introducing F-type pseudohalide tetrafluoroborate (BF4-) natural multifunctional antioxidant myricetin (C15H10O8). We find that incorporation BF4- releases lattice strain enhances structural perovskites. Furthermore, it is confirmed molecules are anchored on surface grain boundaries layers via hydrogen bonding interactions, reducing Sn4+ stabilizing octahedrons. The resultant TPSC with molecular lock based (MA0.25FA0.75)0.98EDA0.01SnI2.99(BF4)0.01 achieves high PCE 14.08%. Moreover, target device shows negligible change under 1000 h storage dark retains 89.9% initial after continuous irradiation for 200 h.