Thermal conductivity is a crucial material property for a diverse range of energy technologies, ranging from thermal management of high power electronics to thermal insulation for building envelopes. This review discusses recent advances in achieving high and low thermal conductivity ( k ) as relevant for energy applications, from high- k heat spreaders to low- k insulation. We begin with a brief introduction to the physics of heat conduction from both theoretical and computational perspectives. The heart of the review is a survey of recent advances in high- and low- k materials. The discussion of good heat conductors for thermal management includes inorganics and polymers in both bulk and low dimensional forms. For insulators, the discussion covers the effects of chemical composition, crystal structure, and defects and porosity. Promising areas for future research in both fundamental materials science and engineering technologies are noted.

In this study, the growth of scandium nitride (100) single crystals with high electron mobility and high thermal conductivity was demonstrated by physical vapor transport (PVT). Single crystals were grown in the temperature range of 1900 °C–2140 °C under a nitrogen pressure between 15 and 20 Torr. Single crystal tungsten (100) was used as a nearly lattice constant matched seed crystal. Growth for 20 days resulted in a 2 mm thick crystal. Hall-effect measurements revealed that the layers were n-type with a 300 K electron concentration and a mobility of 2.17 × 10²¹ cm⁻³ and 73 cm²/V s, respectively. Consequently, this ScN crystal had a low electrical resistivity, 3.94 × 10⁻⁵ Ω cm. The thermal conductivity was in the range of 51–56 W/m K, three times higher than those in previous reports for ScN thin films. This study demonstrates the viability of the PVT crystal growth method for producing high quality bulk scandium nitride single crystals.

The recent push for the “materials by design” paradigm requires synergistic integration of scalable computation, synthesis, and characterization. Among these, techniques for efficient measurement of thermal transport can be a bottleneck limiting the experimental database size, especially for diverse materials with a range of roughness, porosity, and anisotropy. Traditional contact thermal measurements have challenges with throughput and the lack of spatially resolvable property mapping, while non-contact pump-probe laser methods generally need mirror smooth sample surfaces and also require serial raster scanning to achieve property mapping. Here, we present structured illumination with thermal imaging (SI-TI), a new thermal characterization tool based on parallelized all-optical heating and thermometry. Experiments on representative dense and porous bulk materials as well as a 3D printed thermoelectric thick film (∼50 μm) demonstrate that SI-TI (1) enables paralleled measurement of multiple regions and samples without raster scanning; (2) can dynamically adjust the heating pattern purely in software, to optimize the measurement sensitivity in different directions for anisotropic materials; and (3) can tolerate rough (∼3 μm) and scratched sample surfaces. This work highlights a new avenue in adaptivity and throughput for thermal characterization of diverse materials.