Hexagonal boron nitride (BN) is often used as filler to improve the thermal conductivity of polymer matrix due to its high thermal conductivity. However, previously reported BN-based composites always have a high in-plane thermal conductivity, which is not beneficial for vertical heat dissipation. In addition, high BN content results in the deterioration of the mechanical properties. Here, we report a feasible method to prepare a BN/silicone rubber (SiR) composite with oriented BN in organosilicon matrix via a vacuum-assisted self-assembly technique. The BN/SiR composite displays a 1270% higher (2.74 W/(m·K)) thermal conductivity than that of neat organosilicon matrix (0.20 W/(m·K)). The oriented BN nanosheets increase the polymer's adhesive force and exhibit excellent compression cycle performance. In turn, these features support its superiority as thermal interface material in the light-emitting diode chips heat dissipation application.

A novel terahertz modulator based on graphene is proposed and designed. The device consists of a silicon ridge covered by a graphene sheet. The transmission properties of the proposed structure demonstrate that the introduction of graphene can improve the switching and filtering performance of modulators, and enhance its field confinement capability. In the case of the number of layers, a blue shift can be observed in the center wavelength with increase of graphene layers. Meanwhile, the relationship between the number of layers and the peak of reflection spectra is an inverse proportion function. In addition, we find that the center wavelength is almost unchanged with respect to the different chemical potential, thus the effective refractive indices of the cross section of light propagation direction can be well preserved. These findings will contribute to the research and development of graphene based THz waveguide modulators.

In this paper, the heat transfer performance of the multi-chip (MC) LED module is investigated numerically by using a general analytical solution. The configuration of the module is optimized with genetic algorithm (GA) combined with a response surface methodology. The space between chips, the thickness of the metal core printed circuit board (MCPCB), and the thickness of the base plate are considered as three optimal parameters, while the total thermal resistance (R_tot) is considered as a single objective function. After optimizing objectives with GA, the optimal design parameters of three types of MC LED modules are determined. The results show that the thickness of MCPCB has a stronger influence on the total thermal resistance than other parameters. In addition, the sensitivity analysis is performed based on the optimum data. It reveals thatR_tot increases with the increased thickness of MCPCB, and reduces as the space between chips increases. The effect of the thickness of base plate is far less than that of the thickness of MCPCB. After optimization, three types of MC LED modules obtain lower T_j andR_tot. Moreover, the optimized modules can emit large luminous energy under high-power input conditions. Therefore, the optimization results are of great significance in the selection of configuration parameters to improve the performance of the MC LED module.

The sensing properties of pristine, B-, Al-, Si-, and S-doped blue phosphorus (BP) monolayer to nitric oxide (NO) are theoretically investigated using density functional theory and non-equilibrium Green's function method. We systematically discuss the concentration effect, sensing mechanism, and current-voltage (I-V) response of BP adsorbing NO molecule. Our results show that the pristine BP exhibits a weak sensitivity for NO molecule, while B-, Al-, and Si-doped BP strongly adsorb NO via robust chemical bonds, meaning a good potential in metal-free catalysts, but unsuitable as NO sensors. Interestingly, S-doped BP is recommended as a desirable material for NO detection due to moderate adsorption energy and large charge transfer. Besides, the flowing current in S-doped BP can be significantly improved after NO adsorption under the same bias voltage. Therefore, S-doped BP could be a good candidate as an NO sensor.