Sahu Subhashree, Debnath Tushar, Sahu Kalyanasis
Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India.
Nano Physical Spectroscopy Group, Department of Chemistry, School of Natural Sciences, Shiv Nadar Institution of Eminence, Delhi NCR, Uttar Pradesh 201314, India.
J Phys Chem Lett. 2024 Apr 4;15(13):3677-3682. doi: 10.1021/acs.jpclett.4c00451. Epub 2024 Mar 27.
Lead halide perovskites suffer from water and moisture instability due to the highly ionic nature of the crystal structures, though a few groups took advantage of it for chemical transformation via water-assisted strategy. However, direct exposure of the perovskite to bulk water leads to uncontrolled chemical transformation. Here, we report a controlled chemical transformation of CsPbBr to CsPbBr triggered by nanoconfined water by placing CsPbBr in the nonpolar phase within a reverse micelle. The chemical transformation reaction is probed by using steady-state and time-resolved optical spectroscopy. We observe absorption and photoluminescence in the UV region stemming clearly from the CsPbBr phase upon interaction with the reverse micellar aqueous solution. Transmission electron microscopy and X-ray diffraction measurements further provided the structure and morphology. Our results direct the formation of CsPbBr-CsPbBr nanocomposite under dry conditions while the chemically transformed CsPbBr phase exists only in moist conditions, which we explain via the CsBr-stripping mechanism.
由于晶体结构具有高度离子性，卤化铅钙钛矿会受到水和湿气的影响而不稳定，尽管有少数研究小组利用水辅助策略将其用于化学转化。然而，将钙钛矿直接暴露于大量水中会导致无法控制的化学转化。在此，我们报告了通过将CsPbBr置于反胶束的非极性相中，利用纳米限域水引发CsPbBr向CsPbBr的可控化学转化。通过稳态和时间分辨光谱对化学转化反应进行了探究。我们观察到，在与反胶束水溶液相互作用时，紫外区域的吸收和光致发光明显源于CsPbBr相。透射电子显微镜和X射线衍射测量进一步提供了结构和形态信息。我们的结果表明，在干燥条件下会形成CsPbBr-CsPbBr纳米复合材料，而化学转化后的CsPbBr相仅在潮湿条件下存在，我们通过CsBr剥离机制对此进行了解释。
