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Issue 25, 2011
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Formation of AgI/TiO2 nanocomposite leads to excellent thermochromic reversibility and photostability

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Abstract

AgI/TiO2 nanocomposite was prepared and characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and diffusive reflectance UV-vis (DRUV-vis) absorption spectra at different temperatures. The AgI/TiO2 nanocomposite exhibits thermochromic switching phenomena at the phase β–α transition temperature of AgI with the evolution of its color from light yellow at ambient temperature to dark khaki at 150 °C. It was found for the first time that the formation of the AgI/TiO2 nanocomposite not only results in a considerable reduction of thermochromic transition temperature of AgI as well as excellent thermochromic reversibility, but also leads to excellent photostability under illumination with an indoor fluorescent lamp. Based on the characterization results by photoluminescence, transient photocurrent decay and positron annihilation spectra, it is concluded that large surface defects, such as I vacancy clusters (e.g.Ag+–IV–Ag+–IV–Ag+) on the surface of AgI as deep electron traps, are responsible for the photodecomposition of pure AgI. The excellent photostability of the AgI/TiO2 nanocomposite is due to the following reason: the surface I vacancy clusters as deep electron traps in pure AgI are replaced by Ag+–O2−–Ti4+ bonds on the interface of AgI/TiO2, thus Agncluster formation through the surface migration of photogenerated Ag atoms is completely inhibited, resulting in the inhibition of photodecomposition of AgI.

Graphical abstract: Formation of AgI/TiO2 nanocomposite leads to excellent thermochromic reversibility and photostability

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Publication details

The article was received on 11 Jan 2011, accepted on 13 Apr 2011 and first published on 25 May 2011


Article type: Paper
DOI: 10.1039/C1JM10155B
Citation: J. Mater. Chem., 2011,21, 9263-9270
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    Formation of AgI/TiO2 nanocomposite leads to excellent thermochromic reversibility and photostability

    W. Sun, Y. Li, W. Shi, X. Zhao and P. Fang, J. Mater. Chem., 2011, 21, 9263
    DOI: 10.1039/C1JM10155B

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