超细0.4nm直径单壁碳管的光学特性

由于纳米碳管的优异机械特性及其丰富多采的光学和电学特性，它自1991年被发现以来一直受到科学家的青睐，纳米碳管研究已成为当今世界上发展最迅速，竞争最激烈的科学前沿领域之一。怎样才能把纳米碳管做得更细小，尺寸更均匀以及如何使众多的纳米碳管排列规整，一直是纳米碳管研究中的难题。我们利用多孔的沸石晶体作为载体，首次成功地研制出了尺寸均一，排列规整的超细单壁纳米碳管，这些超细纳米碳管具有独特的性能，低温下（＜20K）甚至呈现出前所未有的一维超导现象。详细介绍了这些超细单壁纳米碳管的制备过程，并着重介绍其在可见光区的光吸收，光发射以及二次谱波的倍频特性。

Optical Properties of 0.4nm Single-walled Carbon Nanotubes

We report the polarized optical absorption and photoluminescence spectra of single-walled 0.4nm carbon nanotubes (SWNTs) arrayed in the channels of an A1PO4-5(AFI)single crystal.When the light electric field(E) is polarized parallel to the tube direction(c),the absorption spectrum display a sharp peak at 1.37eV with two broad bands at 2.eV and 3.1eV.The intensities of these absorption bands gradually decrease as the polarization angle is varied from 0?(E\\c)to 90?(E/c configuration ,the tube is nearly transparent in the measured energy region of 0.5-4.1eV.The photoluminescence observed around 700nm also shows strong polarization dependence.Under high power excitation using the rundamental frequency of a YAG laser ,the sample shows strong strong nonlinear up-conversion emission around 700nm and high efficeint second-harmonic generation.The mechanism of the nonliner photoluminescence and SHG is not clear yet.