Qiang Wang

The miniaturization and high-frequency development of electronic devices demand advanced packaging materials that simultaneously possess improved thermal conductivity, notable electromagnetic interference shielding effectiveness, and reliable electrical insulation. Although liquid metals exhibit superior thermal and electrical conductivity, their potential leakage may cause environmental contamination and corrosion of electronic components. Aiming at this dilemma, we designed novel liquid metal microcapsule composites. The composite features Ga-In alloy droplets encapsulated within poly(urea-formaldehyde) shells, which effectively harness the advantageous properties of liquid metals while preventing leakage risks and providing electrical insulation through the polymeric coating. Four microcapsules with different particle sizes (10.6, 9.8, 8.6, and 7.6 μm) were prepared, and LMMCS were synthesized. Comprehensive characterization revealed that, the composite containing 60 wt% of 9.8 μm microcapsules exhibited optimal thermal conductivity (0.527 W·m⁻¹·K⁻¹). The 60 wt% 7.6 μm composite demonstrated the highest volume resistivity (8.99 × 10¹¹ Ω·cm). EMI shielding effectiveness increased with microcapsule loading, while showing non-monotonic diameter dependence at a fixed 60 wt% concentration. Beyond conventional shielding mechanisms, we developed a microcapacitor model that elucidates the size-dependent interfacial polarization and multiple reflection phenomena. This study provides insights for the design of advanced electronic packaging materials, although further reliability and durability tests are needed to validate practical applicability.

MXene (Ti3C2Tx) is a highly conductive two-dimensional material with significant potential for use in flexible electronics; however, its practical application is hindered by its self-stacking behavior and mechanical brittleness. To address these challenges, a sandwich-structured composite film was designed and fabricated. The outer MXene layers function as highly efficient in-plane electron transport highways. Critically, the intermediate PANI@ANFs layer acts as a vertical conductive bridge, connecting the top and bottom MXene layers through its intertwined nanofiber network and the intrinsic conductivity of PANI. This architecture establishes a bicontinuous conductive network, enabling rapid electron transfer both laterally and across the film thickness, which is essential for maximizing the utilization of active materials. This interlayer not only provided abundant electrochemical active sites but also significantly enhanced mechanical robustness. The obtained MXene/PANI@ANFs/MXene (M/PA/M) film exhibited an elongation at break of 11.11% and a toughness of 95.32 MJ cm–2. Electrochemically, the film delivered an outstanding areal capacitance of 1213.82 mF cm–2 at 2 mV s–1 in a three-electrode configuration. A flexible symmetric supercapacitor based on this electrode demonstrated a specific capacitance of 918.38 mF cm–2 at the same scan rate and retained 77.77% of its capacitance after 10,000 cycles at 20 mA cm–2. Furthermore, this device achieved an energy density of 56.95 μWh cm–2 and a power density of 700 μW cm–2 at 2 mA cm–2, while maintaining stable performance under bending up to 90°. Overall, this work provides a new material platform that combines high mechanical flexibility and excellent electrochemical properties for advanced flexible energy storage devices.

Diamond–copper composites, due to their exceptional thermal conductivity, hold significant potential in the field of electronic device thermal management. Hot-press sintering is a promising fabrication technique with industrial application prospects; however, the thermal conductivity of composites prepared by this method has yet to reach optimal levels. In this study, tungsten was deposited on the surface of diamond particles by magnetron sputtering as an interfacial transition layer, and hot-press sintering was employed to fabricate the composites. The findings reveal that with prolonged annealing time, tungsten gradually transformed into W₂C and WC, significantly enhancing interfacial bonding strength. When the diamond volume content was 50% and the interfacial coating consisted of 2 wt.% W, 92 wt.% WC, and 6 wt.% W₂C, the composite exhibited a thermal conductivity of 640 W/(m·K), the highest value reported among hot-press sintered composites with diamond content below 50%. Additionally, the AMM (Acoustic Mismatch Model) and DMM (Diffusion Mismatch Model) models were utilized to calculate the interfacial thermal conductance between different phases, identifying the optimal interfacial structure as diamond/W₂C/WC/W₂C/Cu. This composite material shows potential for application in high-power electronic device cooling, thermal management systems, and thermoelectric conversion, providing a more efficient thermal dissipation solution for related devices.

This study examined the effects of gadolinium (Gd) doping and the resulting oxygen vacancies on the microstructure and phase-transition characteristics of VO₂ thin films.

Applying an appropriate bias voltage during direct current magnetron sputtering can optimize the valence state, facilitate phase transition, and improve the performance of deposited VO ₂ film.

In this study, three different substrate holder shapes—trapezoidal, circular frustum, and adjustable cyclic—were designed and optimized to enhance the quality of polycrystalline diamond films grown using microwave plasma chemical vapor deposition (MPCVD). Simulation results indicate that altering the shape of the substrate holder leads to a uniform distribution of the electric field on the surface, significantly suppressing the formation of secondary plasma. This design ensures a more even distribution of the temperature field and plasma environment on the substrate holder, resulting in a heart-shaped distribution. Polycrystalline diamond films were synthesized under these three different substrate holder conditions, and their morphology and crystal quality were characterized using optical microscopy, Raman spectroscopy, and high-resolution X-ray diffraction. Under conditions of 5 kW power and 90 Torr pressure, the adjustable cyclic substrate holder produced high-quality 3-inch diamond films with low stress and narrow Raman full width at half maximum (FWHM). The results confirm the reliability of the simulations and the effectiveness of the adjustable cyclic substrate holder. This approach provides a viable method for scaling up the size and improving the quality of polycrystalline diamond films for future applications.

Carbon nanomaterials are in high demand owing to their exceptional physical and chemical properties. This study employed a mixture of CH₄, H₂, and N₂ to create carbon nanostructures on a single-crystal diamond using microwave plasma chemical vapor deposition (MPCVD) under high-power conditions. By controlling the substrate surface and nitrogen flow rate, carbon nanowires, carbon nanotubes, and carbon pompons could be selectively deposited. The results obtained from OES, SEM, TEM, and Raman spectroscopy revealed that the nitrogen flow rate and substrate surface conditions were crucial for the growth of carbon nanostructures. The changes in the plasma shape enhanced the etching effect, promoting the growth of carbon pompons. The CN and C₂ groups play vital catalytic roles in the formation of carbon nanotubes and nanowires, guiding the precipitation and composite growth of carbon atoms at the interface between the Mo metal catalysts and diamond. This study demonstrated that heterostructures of diamond–carbon nanomaterials could be produced under high-power conditions, offering a new approach to integrating diamond and carbon nanomaterials.

A capacitance-soaring phenomenon induced by CuO electrode reconstruction with metastable Cu(OH)₂ nanowires after 10 000 charge and discharge cycles.