[Show abstract][Hide abstract] ABSTRACT: We demonstrate a simple approach to grow graphene films on polycrystalline nickel (Ni) foils, in which polycrystalline carbon hybrid materials (CHMs) were used in sandwich structures (molybdenum-CHMs-Ni-molybdenum) as a carbon source for graphene, and pressure was then applied to the sandwich. The CHMs were transformed into single as well as few layer graphene by a segregation-precipitation process. The applied pressure not only increased the density of the graphene films but also reduced the vaporization of dissociated carbon molecules of the CHMs. We have explored the possibility to grow graphene films in low vacuum (5 x 10-1 Pa) at relatively low temperatures (≤750 ºC). The formation of the graphene films at 750 °C is simple and cost effective and can be scaled up.
No preview · Article · Jun 2013 · ACS Applied Materials & Interfaces
[Show abstract][Hide abstract] ABSTRACT: We established a cost-effective, scalable, and sustainable process to form single layer graphene from an inexpensive and common polymer at partially low temperature. The generated pressure and the metal capping layer on the polymer may control the evaporation rate and assist the transformation into graphene. This approach will have great advantages because of its simple, inexpensive, and nontoxic process.
[Show abstract][Hide abstract] ABSTRACT: Here we demonstrate a facile approach to grow uniform and large area single layer graphene directly over polycrystalline metal foil from nanoporous carbon (NC) material. The NC is synthesized by using the adamantane (C10H16) flame method. The flame-annealing of adamantane resulted in the conversion of adamantane to NC. The size of NC is 80 to 100 nm. The prepared sandwich structures (Mo–NC–Ni–dielectric–Mo) were annealed at 850 to 950 °C, where NC was used as a carbon source material. The NC material was successfully transformed into single layer graphene. We have explored the possibility of using our approach to grow graphene in low vacuum (1 × 10−10 Pa) air instead of inert Ar atmosphere. The generated pressure on sandwich structures has enhanced the density/scalability as well as the quality of graphene. We observed the sheet resistance of graphene was 929 Ω per sq at 91.8% transparency. Our work expands the possibility of synthesizing single-layer graphene from various carbon source materials. Moreover, the synthesized graphene films can be applied for future electronics applications.
No preview · Article · Jul 2012 · Journal of Materials Chemistry
[Show abstract][Hide abstract] ABSTRACT: Here we demonstrate a facile approach to grow uniform and large area single layer graphene directly over polycrystalline metal foil from fullerene, where fullerene molecules formed rod-like polycrystals in the toluene solvent. The generated pressure on sandwich structures has enhanced the density (scalable) as well as quality of graphene at partially low temperatures.
No preview · Article · Feb 2012 · Chemical Communications