Interface engineering to construct BN@SiO2 multilayer structure for thermal interface materials with high thermal conductivity and low dielectric loss

Electric insulation, high thermal conductivity, and ultra-high EMI shielding composite films with a Janus structure

First - Principles investigation of electronic structures and thermoelectric properties of GaX (X = N, P, Sb, As) III-V compounds.

Purpose This paper aims to systematically review the directional transfer and low-temperature interconnect packaging of nano metal materials, analyze their sintering mechanism, transfer methods and interconnection performance, overcome the reliability bottleneck of traditional interconnection materials in high-temperature and high-power environments and promote their application in three-dimensional integrated packaging and high-density packaging. Design/methodology/approach Through literature review and analysis, the sintering mechanism of nanometal materials is sorted out, and the reported transfer technologies, including magnetron sputtering, pulsed laser deposition, liquid bridge transfer, micro-contact printing, selective wetting and electrohydrodynamic jet printing, are compared and investigated in terms of transfer accuracy, pattern resolution and interconnection performance. Findings Nano metal can be sintered at low temperature to form high-strength interconnection structures with high electrical and thermal conductivity and high-temperature resistance due to the small size effect and high surface activity. Different transfer techniques exhibit different performance in terms of resolution, uniformity and alignment accuracy, among which magnetron sputtering and pulsed laser deposition are suitable for high-coverage deposition, while liquid bridge transfer and selective wetting are suitable for patterned transfer. Originality/value This review provides a systematic comparison and performance evaluation of directional transfer and low-temperature interconnect packaging of nano metal materials, points out the limitations of current transfer technologies in terms of precision, efficiency and reliability and proposes that future research should focus on process optimization, defect control and the study of multi-physical field coupling mechanisms, providing theoretical support and technical references for high-density interconnect packaging.

Charging and discharging electric vehicle (EV) batteries generate heat, which impacts their longevity and operational efficiency over time. This study evaluates the thermal performance of various cooling fluids in a battery thermal management system (BTMS). N-Octadecane, hybrid nanofluid, ternary hybrid nanofluid, synthetic ester oil, and water are compared across heat transfer coefficients of 5, 10, and 20 W/m2K. N-Octadecane demonstrates superior thermal regulation, maintaining a low maximum cell temperature of 304.987 K with a minimal temperature difference of 0.684°C. Hybrid and ternary hybrid nanofluids exhibit enhanced heat transfer efficiency, while water shows effective heat distribution due to its high specific heat capacity and thermal conductivity. Synthetic ester oil, despite its strong electrical insulation, lags in thermal performance. N-Octadecane outperforms other fluids by 35–40%, surpassing synthetic ester oil by 66.5% under non-flow conditions. Moreover, varying the heat transfer coefficient has minimal influence on n-octadecane's liquid fraction (60–62% of total volume). This research emphasizes the significance of thermal properties in BTMS, advocating for the integration of PCMs and nanofluids to optimize thermal control in batteries.

CuAgSe-based materials are attractive for low-temperature thermoelectric (TE) applications but are limited by bipolar conduction and relatively high thermal conductivity. Herein, we report a ligand-free aqueous synthesis of Te-doped CuAgSe (CuAgSe1-xTex), where structural and electronic modulation improve carrier transport and suppress phonon propagation. Ex-situ time-resolved X-ray diffraction reveals a spontaneous growth mechanism, while density functional theory calculations show that Te-5s and 5p orbitals hybridization generates localized states and an asymmetric density of states, thereby enhancing the Seebeck coefficient. Electron microscopy and strain analyses confirm that Te-doping introduces a high density of lattice dislocations and grain boundaries, leading to a reduced lattice thermal conductivity of 0.11W m-1K-1 at 443 K. These synergistic effects translate into device-level performance-the first integrated CuAgSe thermoelectric modules, exhibit a maximum cooling temperature difference of 27.3 K, and power density of 0.34W cm-2 with a conversion efficiency of 3.6% at a modest temperature gradient of 136 K. These results demonstrate that CuAgSe1-xTex enables efficient energy harvesting and localized cooling under small temperature gradient, underscoring the importance of structural and electronic design beyond conventional zT benchmarks.

Phase change materials (PCMs) have exhibited significant application potential in thermal management and thermal energy storage, owing to their high latent heat and low cost. However, inherent drawbacks of certain PCMs (e.g., paraffin (PA)), such as low thermal conductivity (0.2 W·m-1·K-1) and liquid leakage during phase transition, lead to delayed thermal response and reliability issues, restricting their utilization in high-precision thermal control scenarios. Herein, we propose an "interface enhancement" design strategy: constructing a composite system with graphene-skinned alumina micropowder (G-Al2O3) as the cross-scale thermal bridges to enhance the 3D thermally conductive skeleton of expanded graphite in PA phase change matrix. The high-thermal-conductivity network is synergistically coupled with the phase change medium during vacuum impregnation due to the well-wetting behavior. The composite material achieves a thermal conductivity of 6.1 W·m-1·K-1, representing a 2033% increase compared to pure PA, while retaining a high phase change latent heat of 210 J·g-1. After 200 thermal cycles, the composite material exhibits a leakage rate of <5% and a latent heat attenuation rate of <2%. This study provides a novel approach for designing high-efficiency thermal control materials, with potential applications in temperature stabilization of high-power electronic devices and thermal storage systems for aerospace satellites.

Purpose At the same temperature, the thermal conductivity of adhesive with epoxy was higher. However, the common material of thermal conductive adhesive was silicone in the industry. There was very little introduction to the application of thermal conductivity adhesives for epoxy and silicone. The purpose of this study was to explore high-efficiency thermal adhesive solutions and meet the heat dissipation requirements of high-end electronic components. Design/methodology/approach Heat dissipation was one of the core problems in system in package (SiP). It directly determined the application environment of SiP. In this paper, the authors built a data processing of SiP and a temperature measuring point was set up inside the chip, which could observe the maximum working temperature. The heat of SiP transferred outward through the following components in turn: chip, heat sink, thermal conductive adhesive and metal plate. There were two materials of thermal conductivity adhesive: silicone and epoxy. Findings Adhesives did not play an obvious role in SiP, and this related to its thermal conductivity and thickness. Interestingly, the operating temperature of SiP had a linear relationship with the substrate temperature and current. Silicone-based thermal conductive adhesive demonstrated excellent heat dissipation performance. After replacing glue with solder paste, the working temperature of SiP dropped by 17°C, and the metal interconnection effectively improved the heat dissipation efficiency. Originality/value Although epoxy had a high thermal conductivity, the adhesive detached at high temperature. The simulation results showed that at an ambient temperature of 90°C, the SiP’s temperature of adhesive-free, epoxy and silicone were 121°C, 119°C and 117°C, respectively. The maximum error between actual temperature and simulation result was 4.2%.

The double perovskite Sr₂MgWO₆ exhibits outstanding mechanical, electronic, and optical properties, making it a potential candidate for high-performance optical and optoelectronic applications. In this regard, we investigated the electronic, magnetic, optical, elastic, and structural properties of the double perovskite Sr₂MgWO₆ using the Quantum ESPRESSO code. Structural stability has been confirmed through calculations of formation energy and the tolerance factor. The material exhibited a wide-band-gap (3.18 eV) semiconductor with intense polarization (ε₁(ω) = 12.46) and a decreasing ε₂(ω) peak with photon energy. Elastic parameters, including elastic constants, bulk modulus, shear modulus, and Young's modulus, were determined using the stress-strain method. The calculated elastic constants satisfied Born-Huang criteria for mechanical stability. Calculated high value of bulk modulus (B), and Young's modulus (E) indicated the material's high resistance to volumetric deformation and stiffness, with a moderate shear modulus. A G/B ratio greater than 0.57, a negative Cauchy constant, and a low Poisson's ratio collectively indicated brittle behavior. The calculated Debye temperature of 492.34 K and specific heat capacity (Cᵥ) of 373.4 J/mol-K further emphasized the mechanical strength, thermal stability, and high thermal conductivity of the material. These findings suggest that Sr₂MgWO₆ could be an excellent material for optical waveguides, light-emitting devices, and other optoelectronic technologies.

Graphene composite phase change materials (PCMs) show great application potential in solar energy conversion and storage due to their strong light absorption and high thermal conductivity. To further enhance the photothermal conversion and leakage prevention performance of graphene composite PCMs. This article adopts a “point‐surface” modification strategy. Through a hydrothermal reduction self‐assembly method, nanocopper particles are doped into polyvinyl alcohol (PVA) cross‐linked graphene nanosheets to construct a novel graphene nanosheet‐nanosized Cu particle/polyethylene glycol (PEG) composite PCMs. The random distribution of nanocopper particles significantly enhances the spectrum absorption capacity and interfacial heat transfer efficiency of the graphene skeleton. The results show that the thermal conductivity of PEG/PG–Cu 0.06 reaches 0.793 W/m −1 k −1 , which is 317.4% of pure PEG. Its latent heat enthalpy value reaches 185.7 J g −1 , and the enthalpy value attenuation rate after 200 thermal cycles is less than 0.21%. Moreover, when the simulated light intensity was 120 mW cm −2 , the PEG/PG–Cu 0.06 photothermal conversion efficiency is 86.2%. Meanwhile, the cross‐linked network formed by PVA and graphene can effectively inhibit PEG leakage, and the leakage rate of PEG/PG–Cu 0.06 is 21.6%. Additionally, the 3D graphene‐PVA matrix modified by nano‐Cu particles is used to improve the thermal conductivity and the spectrum adsorption capacity of composite PCMs, which have excellent photothermal conversion performance and thermal stability and have great application prospects in solar energy heat storage.

Engineering amorphous dielectric films with tunable thermal conductivity is advantageous for the thermal management of semiconductor devices and thermal insulation of aerospace applications. Here, we demonstrate that incorporating dense dispersed amorphous Al(Ti)N (~1 nm or above) nanoparticles having phase volume fractions from 6 to 70 %, has a negligible effect on the intrinsic thermal conductivity of the amorphous Si3N4 matrix (~2 W m-1K-1), in which the wave-like 'propagons' in Allen-Feldmann theory are believed to be unsupressed and non-tuned. By contrast, incorporating (5-15 nm) crystalline TiN phases significantly increases the thermal conductivity (up to 15 W m-1K-1). Critically, the micrometre-thick Si3N4/AlN and Si3N4/TiN amorphous matrix dual-phase nanocomposite coatings exhibit excellent thermal stability upon exposure to ambient air at 1000 °C for 50 h. These findings shed light on the phonon transport mechanism regarding the effects of the second phase and pave a design pathway for engineering amorphous coatings displaying unprecedented high thermal conductivity and excellent thermal stability.

Copper is widely used in two-phase devices for electronic cooling due to its ease of manufacture and high thermal conductivity. However, such high-heat conduction can limit the performance of pulsating heat pipes (PHPs) through transverse heat leakage. The use of lower-conductivity materials such as stainless steel enhances phase-change heat transfer by promoting stronger flow oscillations and reducing parasitic heat leakage, but it may be overall detrimental due to its poor thermal linkage between evaporator and condenser sections. Therefore, in this study, two main objectives are addressed: (i) experimentally characterizing the thermal behavior of a mini flat-plate PHP made of stainless steel (AISI 316L), and (ii) benchmarking its performance against a copper counterpart. Both devices were manufactured by diffusion bonding and tested under different orientations to evaluate operational robustness. The stainless steel PHP initiated oscillations at lower heat loads and showed larger temperature oscillations compared to the copper PHP, demonstrating effective phase-change heat transfer despite its lower thermal conductivity. A filling ratio of 71% of water provided the most stable operation, while orientation affected startup conditions and oscillation amplitude. Overall, stainless steel achieved comparable thermal performance to copper at low-to-moderate heat loads from 2.6 to 13.0 W/cm2, with additional benefits including reduced mass (~11% lighter), higher mechanical strength, and corrosion resistance. These results indicate that stainless steel is a viable alternative to copper at least for miniature flat-plate PHPs, offering a balance between thermal efficiency, mechanical robustness, and operational reliability.

Al–Zn–Ca alloys are good candidates for industrial electronics and electric vehicles due to their high thermal conductivity, castability, and corrosion resistance, but their strength requires improvement. This study investigates how Sc and Zr additions affect the microstructure, thermal, mechanical, and corrosion properties of an Al–3 wt% Zn–3 wt% Ca base alloy. Microstructural analysis showed that substituting Sc with Zr did not drastically alter the phase composition but changed the elemental distribution: Sc was uniform, while Zr segregated to center of dendritic cell. Zr addition also refined the grain size from 488 to 338 μm. An optimal aging treatment at 300 °C for 3 h was established, which enhanced hardness for all alloys via precipitation of Al3Sc/Al3(Sc,Zr) particles. However, this Zr substitution reduced thermal conductivity (from 184.7 to 168.0 W/mK) and ultimate tensile strength (from 269 to 206 MPa), though it improved elongation at fracture (from 4.6 to 7.1%). All aged alloys exhibited high corrosion resistance in 5.7% NaCl + 0.3% H2O2 water solution, with Zr-containing variants showing a lower corrosion rate and better pitting resistance. The study confirms the potential of tuning Sc/Zr ratios in Al–Zn–Ca alloys to achieve a favorable balance of strength, ductility, thermal conductivity, and corrosion resistance.

Gallium-based liquid metals (LMs) are materials that possess some unique properties. Just like any other metal, they have high thermal conductivity and low interfacial resistance, but they are in a liquid phase at room temperature. In contrast to mercury alloys, gallium alloys are non-toxic. They don’t evaporate and they can’t be inhaled. The viscosity of those alloys is very similar to water, but they are six times as dense as water. All those properties make Gallium-based liquid metals very good candidates for thermal interface material (TIM) in electronics applications. On the other hand, the reaction and incompatibility of those alloys with some metals is one of the challenges for this type of TIM. The other challenge is that those materials are not just thermally, but also electrically conductive and that is not a desirable property for TIM. A suitable barrier that will prevent any leakage of LMs and the best way to apply the appropriate volume of LM in high-volume production (HVP) would be one of the most important things for any application. A key challenge is applying the liquid metal consistently through a traditional dispensing method due to its property and behavior which involves high surface tension. Through advanced dispensing techniques like jetting technology liquid metal can be applied reliably on a flat, uneven surface or in arrays of minuscule confined spaces or cavities. This paper highlights the dispensing quality, weight repeatability from one substrate to another, and valve hardware stability. This paper will also address the challenges faced during dispensing of liquid metal in high volume manufacturing, and how to achieve desired bondline thickness with jet dispensing for higher throughput and process reliability.

ABSTRACT Photovoltaic (PV) panels undergo significant efficiency losses and reduced reliability due to temperature rise during operation. This study introduces a hybrid cooling system combining flint-based porous media with water-cooling channels to enhance heat dissipation. Flint, known for its high thermal conductivity and durability, is employed as a natural porous material to improve conductive and convective cooling. Outdoor experiments were conducted on 30 W polycrystalline PV modules to evaluate the influence of porosity (0.35–0.48) and coolant flow rate (1–2 L/min) on thermal performance. A three-stage protocol was followed: (1) comparing porous versus non-porous cooling, (2) determining the optimal porosity, and (3) calibrating flow rate for peak efficiency. Results showed a 27% temperature reduction, with surface temperatures dropping from 50.9°C to 37.7°C under peak conditions. The system improved power output by 12.3% and electrical efficiency by 13.5%, with optimal performance at 0.35 porosity and 2 L/min. The hybrid design balanced cost and efficiency, achieving a lower levelized cost of energy ($0.103/kWh) than water cooling alone ($0.105/kWh). Environmental analysis revealed a 360.15 kg CO₂ reduction over 15 years and a 3.5% annual efficiency gain compared to uncooled PV. Although annual carbon credit gains were modest ($0.36), the system’s scalability offers long-term sustainability benefits.

The review is intended to systematize the latest achievements and the most promising methods in polycrystalline diamond saw blade dressing used for dicing Si and SiC wafers. Dicing, or die singulation, is important in IC assembly, and the quality of the die edges influences the final product quality. Reducing chipping size and width has been a scientific problem over the last few decades. Many techniques were proposed to solve it. The most practical solutions involved optimizing processing factors and cutting direction in accordance with the crystallographic structure of the wafers, since silicon and silicon carbide are hard and brittle materials with low fracture toughness, high hardness, and high thermal conductivity. Wear of the PCD saw blade is also a contributing factor to the formation of chipping and cracks. Dressing allows the bond material removal and diamond grain liberation, where grit size plays a critical role. Dressing techniques were divided into two groups depending on the nature of the exposure, and a combined technique of dressing–coating–redressing was also observed. The less significant chipping size effect was observed for the combined technique in dicing Si wafers when the effect of the techniques based on the mechanical and electrophysical exposures was more significant.

Abstract Hafnia has become a promising thermal protective material due to its low thermal conductivity and high mechanical strength. However, it is difficult to balance the densification and grain growth of the material with the traditional sintering technology. In this study, HfO 2 ceramics with high‐density (97.4%), ultra‐fine grain size (149 nm), enhanced mechanical properties of hardness (12.23 GPa), and fracture toughness (3.00 MPa m 1/2 ), low thermal conductivity (3.75 W m −1 K −1 ) and excellent ablation‐resistant properties were prepared under a high pressure (200 MPa) and a low temperature (1350°C) by spark plasma sintering (SPS) from nanocrystalline raw power (77.4 nm). According to calculation, the relative density could reach up to78.9% after the contribution of plastic deformation under high pressure of 200 MPa at 1350°C without thermal diffusion. The high pressure induced high‐density lattice distortions such as lamination faults and twins in HfO 2 ceramics. These lattice distortions contributed to high mechanical strength and low thermal conductivity.

4H-SiC has been studied and applied in power semiconductor devices due to its wider band gap and higher thermal conductivity than those of Si and hence has great potential for power devices operating at high powers and high temperatures. The introduction of the superjunction (SJ) structure for the power MOSFETs enables further reduction in the ON resistance while maintaining the breakdown voltage. In this work, we examined the dc and ac performance of the 1.2 kV 4H-SiC SJ double-implanted MOSFET (DMOSFET) with different configurations of pillars by the Atlas device simulator. The simulation results suggest the step-shape SJ DMOSFET can further reduce the specific ON resistance and the gate-drain capacitance while maintaining the breakdown voltage compared with the optimized conventional SJ DMOSFET. In addition, that the multi-pillar SJ DMOSFET demonstrates better performance than that of the optimized conventional SJ DMOSFET was also verified in this work.

Lead-free GeTe is a promising thermoelectric material; however, its performance is hindered by intrinsically high carrier concentrations arising from Ge vacancies and relatively high lattice thermal conductivity. Here, a synergistic alloying strategy combining band engineering and defect modulation is proposed to simultaneously optimize electronic and phonon transport in CuAgSe-alloyed GeTe. The delocalized Cu ions substantially enhance carrier mobility, while CuAgSe alloying induces band flattening and convergence that increase the effective mass and synergistically boost electrical transport. Furthermore, the introduction of hierarchical structural defects-including point defects, planar vacancies, and Cu-rich nanoprecipitates-intensifies phonon scattering over multiple length scales, leading to a strong suppression of lattice thermal conductivity. Consequently, a peak zT of 2.02 at 603 K and an average zT of 1.22 (303-803 K) are achieved. A seven-pair device exhibits a conversion efficiency of 6.02% at a temperature difference of 382 K. This work demonstrates an effective co-optimization pathway toward high-performance, lead-free GeTe-based thermoelectrics.

Photoisomeric azobenzene-based phase-change storage materials (AZO-PCMs)/polymer fabrics have garnered significant interests for solvent-free and photocontrolled phase transition storage applications. Nevertheless, high molecular weight and low thermal conductivity of polymer fabrics lead to restricted energy and power density. Here, optically switched and high-energy wearable solar thermal fabrics (STFs) are developed by templating different AZO-PCMs to functionalized carbon nanofiber cloth (FCFC). Thereinto, the AZO-PCMs are utilized as photocontrollable phase-change energy storage materials, while the FCFC is applied as a flexible, high thermal conductivity, and low-mass substrate to further significantly improve the energy storage capacity by enhanced intermolecular interactions (particularly the H-bonds) and achieve rapid heat release under visible light excitation. By optimizing the molecular structure, loading capacity, and photoexcitation condition, a high energy density of 58.44 Wh kg-1 and a high thermal conductivity of 3.13 W m-1 K-1 can be obtained. Surprisingly, a high power density of 1402.56 W kg-1 is implemented under green light, which is 3420 times as much as that by spontaneous heat release in the dark, showing an effectively light-actuated heat release. Moreover, the excellent bending, long-cycling stability, and large temperature rise of this wearable STFs have been proved for effective body temperature regulation.