Cheng Lv

Fabrication of Carbon Nanoscrolls from Monolayer Graphene

A simple way of synthesizing carbon nanotube (CNT)/graphene (GN) nanoscroll core/shell nanostructures is demonstrated using molecular dynamics (MD) simulations. The simulations show that GN sheets can fully self-scroll onto CNTs when the CNT radius is larger than a threshold of about 10 A, forming a stable core/shell structure. Increasing the length of the GN sheet results in multilayered carbon nanoscroll (CNS) shells that exhibit a tubular structure similar to that of multiwall CNTs. The distances between the CNT and the GN wall or adjacent GN walls are about 3.4 A. It is found that the van der Waals force plays an important role in the formation of the CNT/GN nanoscroll core/shell-composite nanostructures. However, the chirality of the CNT and the GN sheet does not affect the self-scrolling process, which thus provides a simple way of controlling the chirality and physical properties of the resulting core/shell structure. It is expected that this preparation method of CNT/GN nanoscroll core/shell composites will lead to further development of a broad new class of carbon/carbon core/shell composites with enhanced properties and even introduce new functionalities to composite materials.

Photovoltaic characteristics of Pd doped amorphous carbon film/SiO2/Si

The Pd doped amorphous carbon (a-C:Pd) films were deposited on n-Si substrates with or without a native SiO2 layer using magnetron sputtering. The photovoltaic characteristics of the a-C:Pd/SiO2/Si and a-C:Pd/Si junctions were studied. It is found that under light illumination of 15 mW/cm2 at room temperature, the a-C:Pd/SiO2/Si solar cell fabricated at 350 °C has a high power conversion efficiency of 4.7%, which is much better than the a-C/Si junctions reported before. The enhanced conversion efficiency is ascribed to the Pd doping and the increase in sp2-bonded carbon clusters in the carbon film caused by the high temperature deposition.