Sungkyunkwan University · 材料科学
Professor Sang-il Kim's research lab specializes in advanced thermoelectric materials, focusing on band engineering, nanostructuring, and defect engineering to enhance the thermoelectric figure of merit (zT). The lab investigates electronic and thermal transport phenomena in bismuth antimony telluride (Bi-Sb-Te) alloys and other chalcogenide systems, with particular emphasis on achieving high-performance thin films and bulk materials through cation doping, epitaxial growth, and heterostructure integration. Their work bridges fundamental electronic structure theory with practical device applications, aiming to improve energy conversion efficiency for solid-state cooling and power generation.
Figures are computed from collected data and may differ slightly.
Band engineering is one of core approaches to improve the performance of thermoelectric materials via the Seebeck coefficient enhancement. However, the conclusion that is often found in the literature is that the band engineering has been achieved in haste when a simple increase in a density-of-states effective mass is observed. In this review, a theoretical background to the band convergence, the most effective band engineering strategy to improve the thermoelectric power factor, is provided. I
Thermoelectrics, which can generate electricity from a temperature difference, or vice versa, is a key technology for solid-state cooling and energy harvesting; however, its applications are constrained owing to low efficiency. Since the conversion efficiency of thermoelectric devices is directly obtained via a figure of merit of materials, zT, which is related to the electronic and thermal transport characteristics, the aim here is to elucidate physical parameters that should be considered to u
An improved thermoelectric figure of merit (<italic>zT</italic>) of 0.14 at 795 K was obtained in 7% Si doped InSe due to the emergence of the flat band.
Cation substitutional doping is an effective approach to modifying the electronic and thermal transports in Bi₂Te₃-based thermoelectric alloys. Here we present a comprehensive analysis of the electrical and thermal conductivities of polycrystalline Pb-doped p-type bulk Bi<sub>0.48</sub>Sb<sub>1.52</sub>Te₃. Pb doping significantly increased the electrical conductivity up to ~2700 S/cm at <i>x</i> = 0.02 in Bi<sub>0.48-x</sub>Pb<sub>x</sub>Sb<sub>1.52</sub>Te₃ due to the increase in hole carrier
Separation of epitaxial thin films on a growth substrate and transfer onto other materials for functional heterostructures have boosted the transformative impact on science and technology. However, this scheme has proved challenging in thin-film thermoelectrics but promises a vast range of applications beyond the limited device configurations of bulk thermoelectrics. Here, the high-quality Bi0.5Sb1.5Te3 (BST) epitaxial thin film on a sapphire substrate grown by spontaneous van der Waals epitaxy
Bi2Te3 is a good candidate to be used in thermoelectric generators. For a higher efficiency of the generators, shifting the temperature at which Bi2Te3 performs best to higher temperatures is required. Bipolar thermal conductivity suppression is the most effective approach to improve high-temperature thermoelectric performance. However, characterization of the bipolar thermal conductivity is challenging because it is related to individual contribution to Seebeck coefficient and electrical conduc
Excess Cu has been reported as an effective way to enhance the thermoelectric performance of n-type Bi2Te3-based alloys as well as to secure the reproducibility of their electronic properties. However, the effect of Cu doping into Bi2Te3 lattice is also known to be complex since Cu can occupy either interlayer or cation/anion sites, depending on conditions. Herein, Cu doping behavior in a binary Bi2Te3 prepared by a conventional melt-solidification process was demonstrated, and corresponding cha
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