Force-driven moisture-mediated CsPbBr3 nanocrystallization from amorphous glass

Abstract

While the “amorphous to crystalline” transformation process, which has significant potential for application, has been widely studied, the microscopic mechanism on the nanometer scale is not fully understood. In contrast to common heat-driven phase transformations, the present study demonstrated the force-driven moisture-mediated nanocrystallization of perovskite CsPbBr₃ precipitated from a glass matrix. In the present case, the breakage of the glass network under shearing force produces high-energy sites to absorb H₂O molecules/clusters from ambient moisture, and the hydration process promotes the crystallization process. Microscratch analysis combined with confocal laser scanning microscopy revealed that the distribution of CsPbBr₃ nanocrystals almost reproduced that of the localized stress field and clearly reflected the crack propagation pathways. The potential applications of perovskite glass in the optical sensing of force and moisture are also explored. Our findings provide insight into crystal nucleation/growth in glass, as well as understanding the dynamics of crack propagation during the brittle fracture process.