Control of the shell structure for the core-shell metal nano-particles using the supercritical CO2 fluid.

用超临界CO2对浸泡在甲苯中的银片进行了激光烧蚀实验。研究发现，激光烧蚀过程中形成了银纳米颗粒，并证实了银纳米颗粒表面覆盖了碳膜。为了进一步探讨激光烧蚀甲苯所形成的碳膜的来源，对激光辐照后的液体进行了GC-MS分析。观察到，芘是主要产物之一。由此得出结论：甲苯激光热解生成的Py是碳膜的来源。研究还发现，激光照射其他溶剂后，这些溶剂中也有芘的生成。在超临界CO2条件下对铜板进行了激光烧蚀实验，对铜板上沉积的薄膜进行了拉曼信号分析，证实了石墨烯的生成。

Laser ablation experiments toward the silver plate immersed in toluene, which were solvented with supercritical CO2, were performed. It was found that silver nanoparticles were formed by the laser ablation processes and it was also confirmed that silver nanoparticles were covered with carbon film. To investigate further the origin of the carbon film formed by the laser ablation into toluene, GC-MS analysis were carried out to the liquid after the laser irradiation. Pyrene was observed as one of the major products. And thus it was concluded that pyrene formed by the laser pyrolysis of toluene was the origin of the carbon film. It was also found that pyrene was also formed using the other solvents after the laser irradiation to those solvents. Laser ablation of Cu plate under the supercritical CO2 condition was also performed and the graphene formation was convinced by the Raman signal analysis of the deposited film on Cu plate.