Yttrium and lanthanum hydride films with switchable optical properties
Yttrium and lanthanum hydride films with switchable optical properties
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DOI：
10.1038/380231a0
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发表时间：
1996-03-21
期刊：
影响因子：
64.8
通讯作者：
Koeman, NJ
中科院分区：
文献类型：
--
作者：
Huiberts, JN;Griessen, R;Koeman, NJ
在许多物质中，化学成分、压力或温度的变化会引起金属到绝缘体的转变（1）。虽然光学和电学性质的急剧变化伴随着这种转变，但它们的解释往往因晶体结构的伴随变化而复杂化（2）。钇、镧和三价稀土元素形成的氧化物也表现出金属-绝缘体转变（3-5），但这些材料的极端反应性和脆弱性阻碍了实验研究（5，6）。为了克服这些困难，我们在钇和镧的薄膜上涂上了一层钯，氢可以通过钯扩散。从金属的实时过渡（YH 2或LaH 2）到半导体在连续吸氢过程中，这些薄膜会发生（YH_3或LaH_3）行为，并伴随着其光学性质的显著变化，尽管这种转变发生的时间尺度目前相当缓慢（几秒钟），似乎有相当大的改进余地，通过选择罕见的-由于氢化钇的光学性质发生了惊人的变化，例如，从闪亮的镜子到黄色透明的窗口金属的变化可能会找到重要的技术应用。
IN many substances, changes in chemical composition, pressure or temperature can induce metal-to-insulator transitions(1). Although dramatic changes in optical and electrical properties accompany such transitions, their interpretation is often complicated by attendant changes in crystallographic structure(2). Yttrium, lanthanum and the trivalent rare-earth elements form hydrides that also exhibit metal-insulator transitions(3-5), but the extreme reactivity and fragility of these materials hinder experimental studies(5,6). To overcome these difficulties, we have coated thin films of yttrium and lanthanum with a layer of palladium through which hydrogen can diffuse. Real-time transitions from metallic (YH2 or LaH2) to semiconducting (YH3 or LaH3) behaviour occur in these films during continuous absorption of hydrogen, accompanied by pronounced changes in their optical properties, Although the timescale on which this transition occurs is at present rather slow (a few seconds), there appears to be considerable scope for improvement through the choice of rare-earth element and by adopting electrochemical means for driving the transition, In view of the spectacular changes in optical properties-yttrium hydride, for example, changes from a shiny mirror to a yellow, transparent window-metal hydrides might find important technological applications.