We investigate the formation of wrinkles and bulging in single-layer graphene sheets using an equivalent atomistic continuum nonlinear hyperelastic theory for nanoindentation and nanopressurization. We show that nonlinear geometrical effects play a key role in the development of wrinkles. Without abandoning the classical tension field membrane theory, we develop an enhanced model based upon the...

Pd-metal graphite (Pd-MG) has a layered structure, where each Pd sheet is sandwiched between adjacent graphene sheets. DC magnetization and AC magnetic susceptibility of Pd-MG have been measured using a SQUID magnetometer. Pd-MG undergoes a superconducting transition at Tc (= 3.63±0.04 K). The superconductivity occurs in Pd sheets. The relaxation of MZFC (aging), which is common to spin glass s...

Zn2GeO4 nanorod/graphene composites (ZGCs) were yielded by a two-step hydrothermal processing. Crystalline and amorphous regions were found to coexist in a single Zn2GeO4 nanorod. The surface of the Zn2GeO4 nanorod was compactly covered and anchored by graphene sheets. The ZGCs were then utilized as anodes for lithium ion batteries (LIBs). Intriguingly, partially crystalline ZGC containing 10.2...

We report that copper thin films deposited on top of graphene oxide (GO) serve as an effective catalyst to reduce GO sheets in a diluted hydrogen environment at high temperature. The reduced GO (rGO) sheets exhibit higher effective field-effect hole mobility, up to 80 cm(2) V(-1) s(-1), and lower sheet resistance (13 kΩ □(-1)) compared with those reduced by reported methods such as hydrazine an...

Tunnel effect is a possible mechanism to explain the apparent large electric conductivity and nonlinear electric behavior of graphene-reinforced nanocomposites with polymer matrix. In this work, a numerical modeling framework is proposed to evaluate the effective electric conductivity in polymer composites reinforced with graphene sheets, taking into account the electrical tunneling effect, whi...

We use first-principles calculations to investigate the geometric, electronic and magnetic properties of metal adatoms on two typical graphene substrates (monolayer and bilayer). Firstly, we study the adsorption behaviors and the doping effects of metal atoms on pristine and defective bilayer graphene sheets (PBG and DBG). It is found that the metal doping in DBG sheets is more stable than that...

The buckling of graphene sheets on substrates can significantly degrade their performance in materials and devices. Therefore, a systematic investigation on the buckling behavior of monolayer graphene sheet/substrate systems is carried out in this paper by both molecular mechanics simulations and theoretical analysis. From 70 simulation cases of simple-supported graphene sheets with different s...

There are numerous studies on the growth of planar films on sp(2)-bonded two-dimensional (2D) layered materials. However, it has been challenging to grow single-crystalline films on 2D materials due to the extremely low surface energy. Recently, buffer-assisted growth of crystalline films on 2D layered materials has been introduced, but the crystalline quality is not comparable with the films g...

The graphene (GR) has attracted intensive interest due to its two-dimensional and unique physical properties. In the present study, the graphene sheets were synthesized by electrochemical exfoliation of graphite in sulfuric acid solution. The polybithiophene-graphene (PbTh-GR) composite films deposited onto indium tin oxide substrate (ITO/PbTh-GR) have been prepared by the incorporation of ...