The Saga of Water and Halide Perovskites: Evidence of Water in Methylammonium Lead Tri‐Iodide. (21st August 2022)

• Record Type: Journal Article
• Authors: Jasti, Naga Prathibha; Shter, Gennady E.; Feldman, Yishay (Isai); Ceratti, Davide Raffaele; Kama, Adi; Buchine, Isaac; Grader, Gideon S.; Cahen, David
• Is Part Of: Advanced functional materials. Volume 32:Number 43(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-08-21
• Subjects: humidity -- MAPbI 3 -- monohydrate -- single crystal quality; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202204283
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: The environment humidity effects on performance of halide perovskites (HaPs), especially MAPbI3, are known. Nevertheless, it is hard to find direct experimental evidence of H2 O in the bulk materials at the levels lower than that of Monohydrate (MAPbI3 .H2 O). Here, for the first time, direct experimental evidence of water being released from bulk (µm‐s deep) of MAPbI3 single crystal is reported. The thermogravimetric analysis coupled with mass spectrometry (TGA‐MS) of evolved gases is used to detect the MS signal of H2 O from the penetrable depth and correlate it with the TGA mass loss due to H2 O leaving the material. These measurements yield an estimate of the average H2 O content of 1 H2 O molecule per three MAPbI3 formula units (MAPbI3 .0.33H2 O). Under the relatively low temperature conditions no other evolved gases that can correspond to MAPbI3 decomposition products, are observed in the MS. In addition to being direct evidence that there is H2 O inside MAPbI3, the data show that H2 O diffuses into it. With this article, a solid basis is proved for further studies on the mechanisms through which water modifies the properties of MAPbI3 and all the other halide perovskites. Abstract : Direct evidence of release of H2 O from bulk MAPbI3, under the conditions where the MAPbI3 crystal structure is intact and with an indication of a H2 O gradient of MAPbI3 .xH2 O with x =1 at the surface to x =0 in the bulk.