University of Oulu

Joseph, N., Varghese, J., Teirikangas, M., & Jantunen, H. (2019). A Temperature-Responsive Copper Molybdate Polymorph Mixture near to Water Boiling Point by a Simple Cryogenic Quenching Route. ACS Applied Materials & Interfaces, 12(1), 1046–1053.

A temperature-responsive copper molybdate polymorph mixture near to water boiling point by a simple cryogenic quenching route

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Author: Joseph, Nina1; Varghese, Jobin1; Teirikangas, Merja1;
Organizations: 1Microelectronics Research Unit, Faculty of Information Technology and Electrical Engineering, University of Oulu, P. O. Box 4500,Oulu FI-90014, Finland
Format: article
Version: accepted version
Access: embargoed
Persistent link:
Language: English
Published: American Chemical Society, 2020
Publish Date: 2020-12-13


Smart temperature-responsive inorganic materials in accessible temperature ranges open up new positions in the technology. Herein, we present for the first time a CuMoO₄ polymorph mixture prepared by a simple cryogenic quenching approach, which offers a fast temperature response close to water boiling temperature for use as a permanent temperature recorder. The new cryogenic quenching technique initiates the formation of a unique polymorph mixture of a deep brown color with a nonuniform combination of γ- and α-CuMoO₄, with the γ phase being confined to the outer region of α-CuMoO₄, which has been prepared by conventional solid-state synthesis. In situ structural analysis and refinement results confirm the presence of CuMoO₄ α and γ polymorphs in which the amount of γ polymorph decreases and that of the α phase increases with temperature, accounting for the irreversible thermochromic behavior. The thermal analysis reveals that the polymorph mixture exhibits a fast response with the color changing from deep brown to bright green with intermediate colors of light brown, yellowish green, and light green depending on the exposure temperature as observed from reflectance measurements.

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Series: ACS applied materials & interfaces
ISSN: 1944-8244
ISSN-E: 1944-8252
ISSN-L: 1944-8244
Volume: 12
Issue: 1
Pages: 1046 - 1053
DOI: 10.1021/acsami.9b17300
Type of Publication: A1 Journal article – refereed
Field of Science: 213 Electronic, automation and communications engineering, electronics
216 Materials engineering
Funding: The authors are thankful to European Research Council (ERC) Project No 24001893 and ERC POC No 812837 for the financial support.
EU Grant Number: (812837) FUNCOMP - Fabricating Functional Components in Room Temperature
(640887) LTCeramics - Low Temperature Ceramics Applications
Dataset Reference: The Supporting Information is available free of charge at
Copyright information: This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Materials & Interfaces, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see