Apr 12, 2011
ALD cycling fine-tunes graphene-based nanocomposites
Metal oxides such as TiO2 and SnO2 are important candidates for many applications including fuel cells, lithium-ion batteries, solar cells, water splitting and gas sensing. By combining these materials with graphene, researchers from the Nanomaterials and Energy group at the University of Western Ontario, Canada, hope to create structures with exceptional properties. A recent success is the controlled synthesis of graphene-based TiO2 nanocompsites with tunable structures by atomic layer deposition (ALD).
As shown in the figure, graphene-based crystalline anatase TiO2 nanocomposites have been formed in a precise and well controlled manner by the group. The synthesized graphene displays a porous structure with very thin wrinkles. After several tens of ALD-cycles, TiO2 nanoparticles of around 5 nm were uniformly deposited on both sides of the host material. Further ALD-cycles led to the formation of homogenous films.
Additionally, the team reported that the as-synthesized TiO2–graphene nanocomposites could be tuned in morphology as well as structure. A lower temperature (150 °C) contributed to amorphous TiO2 while a higher temperature (250 °C) produced crystalline anatase TiO2. Thus, ALD as a deposition technique offers an elegant way of fine-tuning the synthesis of graphene-based nanocomposites.
Further details can be found in the journal Nanotechnology.
About the author
Xiangbo Meng, PhD, is a research fellow in the Nanomaterials and Energy group at the University of Western Ontario, Canada. Currently he is using an ALD system to develop various advanced functional nanomaterials for energy-related applications. Prof. Xueliang (Andy) Sun is group leader and Canada Research Chair in Nanomaterials and Clean Energy. His research interests are associated with the synthesis of various nanomaterials for energy-related applications such as fuel cells and lithium-ion batteries.