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Suppressed Ion Migration in Reduced-Dimensional Perovskites Improves Operating Stability

2019; American Chemical Society; Volume: 4; Issue: 7 Linguagem: Inglês

10.1021/acsenergylett.9b00892

2380-8195

Ziru Huang, Andrew H. Proppe, Hairen Tan, Makhsud I. Saidaminov, Furui Tan, Anyi Mei, Chih‐Shan Tan, Mingyang Wei, Yi Hou, Hongwei Han, Shana O. Kelley, Edward H. Sargent,

Chalcogenide Semiconductor Thin Films

Impressive progress in halide perovskite solar cells motivates further work to improve operating stability. It is known that ion-migration-driven decomposition represents a degradation pathway in perovskite solar cells and that it can occur within the perovskite material even in well-encapsulated devices. Here we find that quasi-two-dimensional (2.5D) perovskites suppress this ion-migration-induced degradation. Using TOF-SIMS, we confirm that iodide migration occurs in bulk perovskite photovoltaic devices operating at their maximum power point (MPP). We observe that iodine ions migrate across the spiro-OMeTAD layer to the spiro/gold contact interface, oxidizing and deteriorating the gold at the interface. In contrast, we find that large ⟨n⟩ 2.5D perovskites exhibit a significantly reduced rate of ion migration compared to 3D devices and exhibit less than 1% relative PCE loss in over 80 h of continuous operation at MPP, whereas the PCE of 3D devices diminishes by more than 50% within the first 24 h.