A synchronous reduction and assembly strategy is designed to fabricate large-area graphene films and patterns with tunable transmittance and conductivity. Through an oxidation-reduction reaction between the metal substrate and graphene oxide, graphene oxide is reduced to chemically converted graphene and is organized into highly ordered films in situ. This work will form the precedent for industrial-scale production of graphene materials for future applications in electronics and optoelectronics.

We report the intrinsic room-temperature ferromagnetism in undoped ZnO nanoparticles with different sizes synthesized by a wet chemical method at different temperatures. Electron paramagnetic resonance, X-ray photoelectron spectroscopy, and photoluminescence measurements demonstrate clearly the singly charged oxygen vacancies are the main defects, and the relative occupancy of that decreases with increasing sizes and annealing temperatures. Importantly, a direct correlation between the ferromagnetism and the relative concentration of the singly charged oxygen vacancies is established, which suggests that the singly charged oxygen vacancies play a crucial role in modulating ferromagnetic behaviors. Moreover, the size-dependent ferromagnetism can be manipulated conveniently by changing of the surface–volume ratio, which is in favor of future electronic and spintronic application.

This paper reports the temperature-dependent tailoring of acceptor defects in oxygen rich ZnO thin films, for enhanced p-type conductivity. The oxygen rich p-type ZnO thin films were successfully grown by pulsed laser deposition on silicon substrate at different postdeposition annealing temperatures (500-800 C). The oxygen rich ZnO powder was synthesized by wet chemical method using zinc acetate dihydrate [Zn(CH 3 COO) 2 Á2H 2 O] and potassium hydroxide (KOH) as precursors. The powder was then compressed and sintered to make pellets for pulsed laser deposition system. The x-ray diffraction analysis exhibits an improved crystallinity in thin films annealed at elevated temperatures with a temperature-dependent variation in lattice constants. An analysis of Auger Zn L 3 M 4,5 M 4,5 peak reveals a consistent decrease in interstitial zinc (Zn i) exhibiting its temperaturedependent reversion to zinc lattice sites. Room temperature photoluminescence of the p-type ZnO shows a dominant deep level emission peak at $3.12 eV related to oxygen interstitials (acceptors). The relative concentration of oxygen interstitials (O i) increases with increase in annealing temperature, resulting in enhanced hole carrier concentration. The maximum hole carrier concentration of 6.8 Â 10 14 cm À3 (indicating p-type conductivity) was estimated using Hall probe measurements for the thin film sample annealed at 700 C. V

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Carbon-SnO(2) core-shell hybrid nanofibers were prepared via single-spinneret electrospinning and subsequent heat treatment. The Kirkendall effect during the heat treatment is found to be responsible for the formation of core-shell morphology. The route is proven to be generic for fabrication of carbon-metal oxide or carbon-metal core-shell nanofibers, and corresponding nanotubes.