Investigation of the Hydrolysis of Perovskite Organometallic Halide CH(3)NH(3)PbI(3) in Humidity Environment

Instability of emerging perovskite organometallic halide in humidity environment is the biggest obstacle for its potential applications in solar energy harvest and electroluminescent display. Understanding the detailed decay mechanism of these materials in moisture is a critical step towards the final appropriate solutions. As a model study presented in this work, in situ synchrotron radiation x-ray diffraction was combined with microscopy and gravimetric analysis to study the degradation process of CH(3)NH(3)PbI(3) in moisture, and the results reveal that: 1) intermediate monohydrated CH(3)NH(3)PbI(3)·H(2)O is detected in the degradation process of CH(3)NH(3)PbI(3) and the final decomposition products are PbI(2) and aqueous CH(3)NH(3)I; 2) the aqueous CH(3)NH(3)I could hardly further decompose into volatile CH(3)NH(2), HI or I(2); 3) the moisture disintegrate CH(3)NH(3)PbI(3) and then alter the distribution of the decomposition products, which leads to an incompletely-reversible reaction of CH(3)NH(3)PbI(3) hydrolysis and degrades the photoelectric properties. These findings further elucidate the picture of hydrolysis process of perovskite organometallic halide in humidity environment.