ABSTRACT
Composite structures integrated with metasurfaces and nonlinear films have emerged as alternative candidates to enhance nonlinear response. The cooperative interaction between the two components is complicated. Herein, a split-ring resonator (SRR)-type metasurface was fabricated on a free-standing nanocrystal diamond (NCD) film utilizing electron beam lithography, electron beam evaporation, and a lift-off process. The terahertz (THz) radiation from the SRR-NCD under normal incidence originates from the high-order magnetic resonance of SRR because the NCD film cannot produce detectable THz radiation at this incident angle. As increasing the incident angle, the contribution of the THz radiation from the NCD film gradually increases until reaching 40° incident angle limitation. The results indicate that this angular-dependent THz radiation is induced by the interplay between the NCD film and SRR. This study offers a new approach to investigate nonlinear processes in composite structures.
ABSTRACT
The implementation of passive cooling strategies is crucial for transitioning from the current high-power- and energy-intensive thermal management practices to more environmentally friendly and carbon-neutral alternatives. Among the various approaches, developing thermal management materials with high thermal conductivity and emissivity for effective cooling of personal and wearable devices in both indoor and outdoor settings poses significant challenges. In this study, we successfully fabricated a cooling patch by combining biodegradable silk fibroin with boron nitride nanosheets. This patch exhibits consistent heat dissipation capabilities under different ambient conditions. Leveraging its excellent radiative cooling efficiency (Rsolar = 0.89 and εLWIR = 0.84) and high thermal conductivity (in-plane 27.58 W m-1 K-1 and out-plane 1.77 W m-1 K-1), the cooling patch achieves significant simulated skin temperature reductions of approximately 2.5 and 8.2 °C in outdoor and indoor conditions, respectively. Furthermore, the film demonstrates excellent biosafety and can be recycled and reused for at least three months. This innovative BNNS/SF film holds great potential for advancing the field of personal thermal management materials.
ABSTRACT
The rapid development of chip technology has all put forward higher requirements for highly thermally conductive materials. In this work, a new type of material of Fishbone-like silicon carbide (SiC) material was used as the filler in a polyvinylidene fluoride (PVDF) matrix. The silicon carbide/polyvinylidene fluoride (SiC/PVDF) composites were successfully prepared with different loading by a simple mixing method. The thermal conductivity of SiC/PVDF composite reached 0.92 W m-1 K-1, which is 470% higher than that of pure polymer. The results show that using the filler with a new structure to construct thermal conductivity networks is an effective way to improve the thermal conductivity of PVDF. This work provides a new idea for the further application in the field of electronic packaging.
