| Abstract Scope |
The low-temperature WO3 polymorph, ε-WO3, has been shown to function as a highly sensitive and selective gas sensor for the detection of acetone, an important biomarker for metabolic disorders, and as the foundational material for various chromic devices. Unfortunately, the kinetic and thermodynamic characteristics of the phase transformation between the room-temperature γ-WO3 and ε-WO3 phase as well as the thermostability of the ε polymorph is limited. Here, the low temperature phase transformation from γ-WO3 into ε-WO3 is studied by using in-situ Raman spectroscopy. The results provide insight into the size dependency nature of this phase transformation. Specifically, the transformation onset temperature between γ-WO3 and ε-WO3 is confirmed to be linearly proportional to reciprocal of average crystallite radius, which can be explained by several published thermodynamic models. [1] [1] O.O. Abe, Z. Qiu, Z. Chen, J.R. Jinschek, P.-I. Gouma, Ceramics International 2021 |