Sun, T.; Zuo, S.; He, B.; Yuan, X.; Li, G.; Zhou, J.; Weigand, M.; Abate, A; Wang, J,: Ionic liquid functionalized tin halide perovskite investigated by STXM and spectro-ptychography. Journal of Electron Spectroscopy and Related Phenomena 265 (2023), p. 147330/1-7
10.1016/j.elspec.2023.147330
Open Access Version
Abstract:
The structural and compositional properties of tin halide perovskites (CH(NH2)2SnI3, FASnI3) with and without an ionic liquid of 1-Ethyl-3-methylimidazolium bis(trifluormethylsulfonyl) imide (EMITFSI) were investigated using the scanning transmission soft X-ray microscopy (STXM) and spectro-ptychography techniques at the Sn M5,4-edge, I M5,4-edge, O K-edge, C K-edge, and N K-edge. The study offers a comprehensive interpretation of the spectral characteristics of main components (C, N, Sn, and I) in Sn-based perovskites through STXM-based techniques and further reveals differences between the perovskite samples with and without adding EMITFSI ionic liquid. The chemical imaging of Sn and I shows that the perovskite sample without ionic liquid has Sn-rich regions in iodine cavities, while the ionic liquid-treated sample exhibits a more homogeneous perovskite phase. Furthermore, the C and N K-edge XANES resonance features support the interaction between the non-volatile ionic liquid and FA+, thus playing a protective role in the formation and stabilization of perovskite phase.