Stabilizing Top Interface by Molecular Locking Strategy with Polydentate Chelating Biomaterials towards Efficient and Stable Perovskite Solar Cells in Ambient Air.

The instability of top interface induced by interfacial defects and residual tensile strain hinders the realization of long-term stable n-i-p regular perovskite solar cells (PSCs). Herein, we report one molecular locking strategy to stabilize top interface by adopting polydentate ligand green biomaterial 2-deoxy-2,2-difluoro-D-erythro-pentafuranous-1-ulose-3,5-dibenzoate (DDPUD) to manipulate the surface and grain boundaries of perovskite films. Both experimental and theoretical evidences collectively uncover that the uncoordinated Pb 2+ ions, halide vacancy and/or I-Pb anti-site defects can be effectively healed and locked by firm chemical anchoring on the surface of perovskite films. The ingenious polydentate ligand chelating is translated into reduced interfacial defects, increased carrier lifetimes, released interfacial stress and enhanced moisture resistance, which should be liable for strengthened top interface stability and inhibited interfacial nonradiative recombination. The universality of the molecular locking strategy is certified by employing different perovskite compositions. The DDPUD modification achieves an enhanced power conversion efficiency (PCE) from 23.17% to 24.47%, which is one of the highest PCEs ever reported for the devices prepared in ambient air. The unsealed DDPUD-modified devices maintain 98.18% and 88.10%of their initial PCEs after more than 3000 h under a relative humidity of 10-20% and after 1728 h at 65°C, respectively. This article is protected by copyright. All rights reserved.