采用金刚石对顶砧装置对直径分布在1. 3nm左右的单壁碳纳米管进行了高压拉曼光谱研究。实验结果表明随压力的增加碳管的截面形状发生了由圆到椭圆再到扁平的变化, 这和我们之前的研究结果一致。从31 GPa卸压至常压后碳管的结构得到了较好的保持, 这个压力值明显高于传统的SP2键结构的碳材料所能稳定存在的压力范围(20 GPa以下)。通过对碳管G-band半峰宽的详细分析, 我们认为在较高的压力下碳管之间发生了成键, 形成了一种更为稳定的结构。这种结构对高压下的碳管起到了保护作用, 从而使碳管表现出了较好的可逆性。

High pressure Raman measurements on single-wall carbon nanotubes (SWNTs) with diameters around 1. 3nm have been carried out in a diamond anvil cell. The results show that the changes of nanotube cross-section follow the sequences from circular to elliptical and then to a flattened type structure, which is consistent with our earlier studies. Upon decompression from a high pressure cycle of 31 GPa, the SWNTs are almost recovered to ambient pressure, apressure well beyond the stability field of traditional sp2 C＝C bonds below ～20GPa. Through the detailed analysis of the linewidth of G-band, we proposed that at a critical pressure the inter-linked configuration is formed among the SWNTs, which can be taken as a more stable structure. This configuration can protect nanotubes experiencing very high pressure compression, so that the nanotubes are still reversible even after such high pressure cycle.