No abstract

High-quality intrinsic graphene can be prepared by a simple triggered microwave reduction method under air conditions, which provides a simple and low-cost route for large-scale production of high-quality graphene.

Thermal management plays an important role in miniaturized and integrated nanoelectronic devices, where finding ways to enable efficient heat‐dissipation can be critical. 2D materials, especially graphene and hexagonal boron nitride (h‐BN), are generally regarded as ideal materials for thermal management due to their high inherent thermal conductivity. In this paper, a new method is reported, which can be used to characterize thermal transport in 2D materials. The separation of pumping from detection can obtain the temperature at different distances from the heat source, which makes it possible to study the heat distribution of 2D materials. Using this method, the thermal conductivity of graphene and molybdenum disulfide is measured, and the thermal diffusion for different shapes of graphene is explored. It is found that thermal transport in graphene changes when the surrounding environment changes. In addition, thermal transport is restricted at the boundary. These processes are accurately simulated using the finite element method, and the simulated results agree well with the experiment. Furthermore, by depositing a layer of h‐BN on graphene, the heat‐dissipation characteristics of graphene become tunable. This study introduces and describes a new method to investigate and optimize thermal management in 2D materials.

Tuning the thermal properties of materials is considered to be of crucial significance for improving the performance of electronic devices. Along these lines, the development of van der Waals (vdW) heterostructures becomes an effective solution to affect the thermal transport mechanisms. However, vdW interactions usually block phonon transport, which leads to a reduction in thermal conductivity. In this work, we experimentally demonstrate a large enhancement in the thermal conductivity of a vdW heterostructure composed of few-layer hexagonal boron nitride (h-BN) and reduced graphene oxide (RGO). By controlling the reduction temperature of RGO and changing the thickness of h-BN, the thermal conductivity of the RGO is increased by nearly 18 times, namely, from 91 to 1685 W m–1 K–1. Photothermal scanning imaging is used to reveal the changes in the heat transfer and temperature distribution of the h-BN/RGO heterostructure. Both photothermal scanning and Raman spectroscopy experiments show that the vdW interaction between h-BN and RGO can greatly increase the thermal conductivity of RGO, which is in contrast to the conventional understanding that vdW interaction reduces thermal conductivity. Our work paves the way for the manipulation of the thermal conductivity of two-dimensional (2D) heterostructures, which could be of great significance for future nanoelectronic circuits.

Protein-protein interactions play an important role in the investigation of biomolecules. In this paper, we reported on the use of a reduced graphene oxide microshell (RGOM)-based optical biosensor for the determination of goat anti-rabbit IgG. The biosensor was prepared through a self-assembly of monolayers of monodisperse polystyrene microspheres, combined with a high-temperature reduction, in order to decorate the RGOM with rabbit IgG. The periodic microshells allowed a simpler functionalization and modification of RGOM with bioreceptor units, than reduced graphene oxide (RGO). With additional antibody-antigen binding, the RGOM-based biosensor achieved better real-time and label-free detection. The RGOM-based biosensor presented a more satisfactory response to goat anti-rabbit IgG than the RGO-based biosensor. This method is promising for immobilizing biomolecules on graphene surfaces and for the fabrication of biosensors with enhanced sensitivity.