Geometry, Phase Stability, and Electronic Properties of Isolated Selenium Chains Incorporated in a Nanoporous Matrix
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- 作者：Irene Ling Li ; Jian Pang Zhai ; Pascale Launois ; Shuang Chen Ruan ; and Zi Kang Tang
- 刊名：Journal of the American Chemical Society
- 出版年：2005
- 出版时间：November 23, 2005
- 年：2005
- 卷：127
- 期：46
- 页码：16111 - 16119
- 全文大小：417K
- 年卷期：v.127,no.46(November 23, 2005)
- ISSN：1520-5126
文摘
We report the fabrication process of isolated one-dimensional Se chains incorporated in thematrix of AlPO4-5 single crystals and the experimental investigation of the geometry, phase stability,electronic properties, and electron-phonon coupling effect of these Se chains. The structure of the helicalSe chains inside the channels is discussed on the basis of X-ray scattering measurements. Thermal analysisand temperature-dependent micro-Raman measurements show that Se single chains are flexible and canconvert from a weak distorted phase into another phase with strongly disordered structure ("melting" state)around 340 K. Since the electrons are confined in the one-dimensional channels, the absorption band ofthe Se chain is obviously blue shifted compared with that of trigonal Se. With increasing temperature, thisband shifts linearly to the lower energy side, in sharp contrast to the nonlinear temperature coefficient oftrigonal Se, which is attributed to the greatly diminished interchain interaction and the weakening of theelectron-optical phonon coupling in a low-dimensional system. In the vicinity of the absorption band, bothfirst-order and second-order Raman signals for the Se chain are enhanced, due to the strong electron-phonon coupling when the excitation laser energy matches the electronic transition in isolated Se chains.