Site-Selective Ion Intercalation Controls Spectral Response in Electrochromic Hexagonal Tungsten Oxide Nanocrystals
Site-Selective Ion Intercalation Controls Spectral Response in Electrochromic Hexagonal Tungsten Oxide Nanocrystals
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DOI：
10.1021/acs.jpcc.2c02865
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发表时间：
2022-08
期刊：
影响因子：
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通讯作者：
Benjamin Z. Zydlewski;Hsin-Che Lu;H. Celio;D. Milliron
中科院分区：
文献类型：
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作者：
Benjamin Z. Zydlewski;Hsin-Che Lu;H. Celio;D. Milliron
氧化钨的电致变色通过电化学还原发生，为智能窗提供主动的阳光控制，但对光谱响应的控制是有限的，主要是经验性的。为了确定特定的化学变化如何导致负责着色的光吸收过程，我们将结构明确的电致变色纳米晶体（NC）与不同离子半径的阳离子配对，以限制嵌入特定的晶体学位点。六方晶系铯掺杂氧化钨（Cs：WO 3）纳米晶的局域表面等离子体吸收增强，并出现新的吸收特征，这取决于阳离子如何嵌入到各种间隙空隙中。这些差异是合理的，使用X-射线光电子和拉曼光谱，以揭示化学和结构的变化，导致所观察到的电化学诱导吸收光谱的变化。较小的阳离子Na +和Li +可以进入额外的间隙位点，导致电致变色的次级极化机制，从而增强可见光吸收。
The electrochromism of tungsten oxide occurs through electrochemical reduction, providing active solar control to smart windows, but control over the spectral response is limited and largely empirical. To determine how specific chemical changes result in the optical absorption processes responsible for coloration, we pair structurally well-defined electrochromic nanocrystals (NCs) with cations of varying ionic radii to limit intercalation into specific crystallographic sites. The localized surface plasmon absorption of hexagonal cesium-doped tungsten oxide (Cs:WO 3 ) NCs is enhanced, and new absorption features appear, depending on how the cations intercalate into various interstitial voids. These differences were rationalized using X-ray photoelectron and Raman spectroscopies to reveal the chemical and structural changes leading to the observed variations in the electrochemically induced absorption spectra. Smaller cations, Na + and Li + , can access additional interstitial sites, leading to a secondary, polaronic mechanism of electrochromism, accounting for enhanced visible light absorption.