Nanocarbon phase transformations controlled by solubility of carbon species in gold nanoparticles

The hybrid structures of carbon nanomaterials reveal the excellent properties and open new windows for the applications of carbon-based nanomaterials. However, the structural transformation of carbon nanomaterials should be better understood to design the new hybrid carbon nanomaterials. For this reason, we explore the growth of carbon nanorods composed of nanocrystalline graphite sheets and amorphous carbon nanoparticles by plasma enhanced hot filament chemical vapor deposition using Au film as the catalyst. The results indicate that the carbon nanorods are a hybrid structure of nanocrystalline graphite sheets and amorphous carbon nano particles formed via the large Au nanoparticles. The studies of transformation mechanism indicate that the solubility of C-2 and C-3 carbon species in the Au nanoparticles plays an important role in the conversion between graphite carbon and amorphous carbon. Moreover, the solubility of C, C-2 and C-3 carbon species in the Au nanoparticles can control the graphitic nanostructure and morphology. Furthermore, the study on the photoluminescence of carbon nanorods indicates the synthesized carbon nanorods emit the ultraviolet and green light at room temperature, which originates from the hydrocarbon radicals on the carbon nanorods and the transition between pi* and pi bands of sp(2) carbon clusters in the carbon nanorods, respectively. The results enable us not only to control the structure of carbon nanomaterials but also develop the next-generation optoelectronic devices based on carbon nanomaterials.