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Hexagonal boron nitride and silicone rubber (h-BN/SR) composites were prepared by the mechanical stirring method, and their crystal morphology, chemical structure, thermal properties, and compression stress–strain performance were investigated. The experimental results suggest that silicone rubber combined with h-BN exhibits better thermal conductivity and mechanical properties. When the proportion of h-BN is 30 wt%, the thermal conductivity of the h-BN/SR composite material is 0.58 W/m∙K, which is 3.4 times that of pure silicone rubber. At the same time, the compressive strength of h-BN/SR is 4.27 MPa, which is 6.7 times that of pure silicone rubber. Furthermore, the finite element model was employed to numerically analyze the thermal behavior of a battery with a h-BN/SR composite as the thermal interface material. The analytical results show that the highest temperature of the battery decreased when using h-BN/SR as the thermal interface material in the battery thermal management system. The h-BN/SR composite can thus effectively improve the safety properties of batteries.

In this work, expanded graphite/paraffin/silicone rubber composite phase-change materials (PCMs) were prepared by blending the expanded graphite (EG), paraffin wax (PW) and silicone rubber (SR) matrix. It has been shown that PW fully penetrates into the three dimensional (3D) pores of EG to form the EG/PW particles, which are sealed by SR and evenly embedded in the SR matrix. As a result of the excellent thermal stability of SR and the capillary force from the 3D pores of EG, the EG/PW/SR PCMs are found to have good shape stability and high reliability. After being baked in an oven at 150 °C for 24 h, the shape of the EG/PW/SR PCMs is virtually unchanged, and their weight loss and latent heat drop are only 7.91 wt % and 11.3 J/g, respectively. The latent heat of the EG/PW/SR composites can reach up to 43.6 and 41.8 J/g for the melting and crystallizing processes, respectively. The super cooling of PW decreased from 4.2 to 2.4 due to the heterogeneous nucleation on the large surface of EG and the sealing effect of the SR. Meanwhile, the thermal conductivity of the EG/PW/SR PCMs reaches 0.56 W·m−1·K−1, which is about 2.8 times and 3.73 times of pure PW and pristine SR, respectively. The novel EG/PW/SR PCMs with superior shape and thermal stabilities will have a potential application in heat energy storage and thermal interface materials (TIM) for electronic devices.

For many optoelectronic applications, it is desirable for the lanthanide-doped phosphors to have broad excitation spectrum. The excitation mechanism of the lanthanide-doped YVO4, a high quantum efficient lasing material, primarily originates from the energy transfer process from the host VO43− complexes to the lanthanide ions, which has an excitation spectral bandwidth range of 230−330 nm. For applications in silicon solar cells, such phosphors can convert ultraviolet light to visible light for more efficient power generation, but this spectral range is still not broad enough to cover the entire ultraviolet spectrum of solar light. In this work, a novel core-shell and inorganic−organic hybridization strategy has been employed to fabricate Eu3+-doped YVO4 nanoparticles to broaden their photoluminescence excitation spectral bandwidth to the range of 230−415 nm, covering the entire ultraviolet spectrum of solar light and enabling their potential applications in silicon solar cells.

Lanthanide-doped hexagonal β-NaYF4 crystals have received much attention in recent years due to their excellent photoluminescence properties. However, lanthanide-doped β-NaYF4 crystals with micron and submicron scales as well as uniform morphology have received less attention. In this study, Eu3+-doped β-NaYF4 (β-NaYF4:Eu3+) crystals of micron and submicron size scales were synthesized using the solvothermal method with ethylene glycol as the solvent. The β-NaYF4:Eu3+ crystals were highly crystallized. A comparison of the characteristics of the β-NaYF4:Eu3+ crystals synthesized with and without the use of oleic acid as a surfactant was conducted. It was found that the utilization of oleic acid as a surfactant during their synthesis greatly decreased their particle size from micron to submicron scale, while adding a small amount of ethanol further reduced their particle size. In addition, they exhibited much smoother surfaces and more uniform morphologies, which were hexagonal prism bipyramids. The microstructural characteristics and photoluminescence properties of the β-NaYF4:Eu3+ crystals were studied in detail. Results showed that β-NaYF4:Eu3+ crystals prepared with the aid of oleic acid as a surfactant during their synthesis exhibited stronger photoluminescence.

Directionally solidified multicrystalline silicon (mc-Si)-based solar cells have dominated the global photovoltaic market in recent years. The photovoltaic performance of mc-Si solar cells is strongly influenced by their crystalline defects. The occurrence of minicrystallization results in much smaller grain size and, therefore, a larger number of grain boundaries in mc-Si ingots. Dislocations in the minicrystallized regions have been rarely investigated in the literature. In this work, optical microscopy was used to investigate dislocations in the mincrystallized regions in mc-Si ingots grown by the directional solidification method. The distribution of dislocations was found to be highly inhomogeneous from one grain to another in the mincrystallized regions. High inhomogeneity of dislocation distribution was also observed in individual grains. Serious shunting behavior was observed in the mc-Si solar cells containing minicrystallized regions, which strongly deteriorates their photovoltaic properties. The shunting was found to be highly localized to the minicrystallized regions.