Abstract
Continuous breakthroughs of photoelectric conversion efficiency (PCE) in perovskitesolar cells are achieved, but the inherent instability caused by residualtensile strain and interfacial defects remains a major obstacle to their application.In this study, a polydentate ligand-regulated dual-surface stress managementstrategy for perovskite (PVK) is introduced to eliminate tensile strain andinterface defects via multidentate anchoring. 3-amino-5-bromopicolinaldehyde(BD) is employed on the lower surface of PVK, while its −C=O, −NH_2, andpyridine functional groups facilitate the bridging of SnO_2 with PVK, alleviatingtensile stress and lowering interfacial energy barriers. For the upper surface,the bis−SO_2, pyridine, and bis−CF_3 functional groups ofN-(5-Chloro-2-pyridyl)bis(trifluoromethanesulfonimide) (FC) are utilized to increase the ion migrationenergy barrier through anchoring, which effectively diminishes tensile stressand defects. Besides, −CF_3 also constructs a hydrophobic barrier on the uppersurface. Notably, tensile stress successfully transforms into compressive stressbased on the dual-surface stress regulation, significantly improving the frameworkstability of PVK. Consequently, the devices treated with BD and FC achievean elevated open-circuit voltage of 1.24 V and PCE of 24.70%. The modifieddevice (unencapsulated) maintains 92% of initial PCE after 2000 h in the atmosphereand 91% after 500 h under 85% RH, showcasing enhanced stability.
NETL
NSTL
Wiley