A5062606091- Advanced Thermoelectric Materials and Devices
- Chalcogenide Semiconductor Thin Films
- Thermal properties of materials
- Thermal Radiation and Cooling Technologies
- Advanced Thermodynamics and Statistical Mechanics
- Heusler alloys: electronic and magnetic properties
- Thermal Expansion and Ionic Conductivity
- 2D Materials and Applications
- Phase-change materials and chalcogenides
- Perovskite Materials and Applications
- Quantum Dots Synthesis And Properties
- Perfectionism, Procrastination, Anxiety Studies
- Thermodynamic and Structural Properties of Metals and Alloys
- Rare-earth and actinide compounds
- Topological Materials and Phenomena
- Intermetallics and Advanced Alloy Properties
- Semiconductor materials and interfaces
- Machine Learning in Materials Science
- Advanced Sensor and Energy Harvesting Materials
- Optical properties and cooling technologies in crystalline materials
- Advanced battery technologies research
- Electrocatalysts for Energy Conversion
- Physics of Superconductivity and Magnetism
- Advanced Battery Materials and Technologies
- Advanced Semiconductor Detectors and Materials
Tongji University
2016-2025
Materials Science & Engineering
2025
Materials Research Center
2025
Peking University
2016
Collaborative Innovation Center of Quantum Matter
2016
California Institute of Technology
2010-2014
Chinese Academy of Sciences
2006-2009
Shanghai Institute of Ceramics
2006-2009
Michigan State University
2009
University of Chinese Academy of Sciences
2008
Thermoelectric transport properties of p-type PbTe:Na, with high hole concentrations approximately 1020 cm−3, are reinvestigated from room temperature to 750 K. The greatly enhanced Seebeck coefficient at these doping levels can be understood by the presence a sharp increase in density states around Fermi level. As result, thermoelectric figure merit, zT, reaches ∼1.4 influence heavy carriers may contribute similarly zT observed related PbTe-based systems such as Tl-doped PbTe and...
High Seebeck coefficient by creating large density-of-states effective mass through either electronic structure modification or manipulating nanostructures is commonly considered as a route to advanced thermoelectrics. However, density-of-state due flat bands leads transport mass, which results in simultaneous decrease of mobility. In fact, the net effect such high lower thermoelectric figure merit, zT, when carriers are predominantly scattered phonons according deformation potential theory...
Thermoelectrics are being rapidly developed for waste heat recovery applications, particularly in automobiles, to reduce carbon emissions. PbTe-based materials with small (<20 nm) nanoscale features have been previously shown high thermoelectric figure-of-merit, zT, largely arising from low lattice thermal conductivity at temperatures. Separating the various phonon scattering mechanisms and electronic contribution is a serious challenge understanding, further optimizing, these...
PbSe was expected to have a smaller bandgap and higher thermalconductivity than PbTe. Instead, these values are about the same at high temperature leading comparable thermoelectric figure of merit, with zT> 1 achieved in heavily doped p-type PbSe.
The opportunity to use solid-state thermoelectrics for waste heat recovery has reinvigorated the field of in tackling challenges energy sustainability. While thermoelectric generators have decades proven reliability space, from 1960s present, terrestrial uses so far been limited niche applications on Earth because a relatively low material efficiency. Lead telluride alloys were some first materials investigated and commercialized but their full potential only recently revealed be greater...
Phonon scattering by nanostructures and point defects has become the primary strategy for minimizing lattice thermal conductivity (κL ) in thermoelectric materials. However, these scatterers are only effective at extremes of phonon spectrum. Recently, it been demonstrated that dislocations remaining mid-frequency phonons as well. In this work, varying concentration Na Pb0.97 Eu0.03 Te, determined dominant microstructural features defects, dislocations, nanostructure interfaces. This study...
Abstract High-efficiency thermoelectric materials require a high conductivity. It is known that large number of degenerate band valleys offers many conducting channels for improving the conductivity without detrimental effects on other properties explicitly, and therefore, increases performance. In addition to strategy converging different bands, semiconductors provide an inherent nestification, equally enabling effective valley degeneracy. Here we show as example simple elemental...
Abstract To minimize the lattice thermal conductivity in thermoelectrics, strategies typically focus on scattering of low-frequency phonons by interfaces and high-frequency point defects. In addition, mid-frequency dense dislocations, localized at grain boundaries, has been shown to reduce improve thermoelectric performance. Here we propose a vacancy engineering strategy create dislocations grains. Pb 1− x Sb 2 /3 Se solid solutions, cation vacancies are intentionally introduced, where after...
The band structure of PbTe can be manipulated by alloying with MgTe to control the degeneracy. This is used stabilize optimal carrier concentration, making it less temperature dependent, demonstrating a new strategy improve overall thermoelectric efficiency over broad range.
PbSe is a surprisingly good thermoelectric material due, in part, to its low thermal conductivity that had been overestimated earlier measurements. The figure of merit, zT, can exceed 1 at high temperatures both p-type and n-type PbSe, similar found PbTe. While the lead chalcogenides (PbSe PbTe) benefit from valley degeneracy (12 or more temperature) valence band, versions are limited 4 conduction band. Yet achieve zT nearly as chalcogenides. This effect be attributed weaker electron-phonon...
Taking La‐ and I‐doped PbTe as an example, the current work shows effects of optimizing thermoelectric figure merit, zT , by controlling doping level. The high effectiveness allows carrier concentration to be precisely designed prepared control Fermi In addition energy tuning, La‐doping modifies conduction band, leading increase in density states effective mass that is confirmed transport, infrared reflectance hard X‐ray photoelectron spectroscopy measurements. such a band structure...
Compared to commercially available p‐type PbTe thermoelectrics, SnTe has a much bigger band offset between its two valence bands and higher lattice thermal conductivity, both of which limit peak thermoelectric figure merit, zT only 0.4. Converging or introducing resonant states is found enhance the electronic properties, while nanostructuring more recently interstitial defects reduce conductivity. Even with an integration some strategies above, existing efforts do not enable exceeding 1.4...
Abstract Electron and phonon transport characteristics determines the potential of thermoelectric materials for power generation or refrigeration. This work shows that, different from most high performance with dominant acoustic scattering, promising ZrNiSn based half‐Heusler solid solutions exhibit an alloy scattering dominated charge transport. A low deformation a are found solutions, which is beneficial to maintain relatively electron mobility despite large effective mass, can be...
Thermoelectric transport properties of n-type PbTe1−xIx with carrier concentrations ranging from 5.8 × 1018–1.4 1020 cm−3 are reinvestigated room temperature to 800 K. The electronic properties, resistivity and Seebeck coefficient in this study effectively consistent prior reports, however the thermal conductivity has been found be historically overestimated. reassessment combination careful control density by iodine doping, reveals a significantly larger figure merit, zT ∼ 1.4, than often...
Abstract Forming solid solutions has long been considered an effective approach for good thermoelectrics because the lattice thermal conductivities are lower than those of constituent compounds due to phonon scattering from disordered atoms. However, this effect could also be compensated by a reduction in carrier mobility electron same disorder. Using detailed study n‐type (PbTe) 1– x (PbSe) solution (0 ≤ 1) as function composition, temperature, and doping level, quantitative modeling...
Significance Higher carrier mobility can contribute to a larger power factor, so it is important identify effective means for achieving higher mobility. Since governed by the band structure and scattering mechanism, its possible enhancement could be obtained manipulating either or both of these. Here, we report substantial in tuning mechanism n-type Mg 3 Sb 2 -based materials. The ionized impurity these materials has been shifted into mixed acoustic phonons impurities. Our results clearly...
Half‐Heusler (HH) compounds are important high temperature thermoelectric (TE) materials and have attracted considerable attention in the recent years. High figure of merit zT values 0.8 to 1.0 been obtained n‐type ZrNiSn‐based HH compounds. However, developing performance p‐type still a big challenge. Here, it is shown that new alloy with band degeneracy 8, Ti‐doped FeV 0.6 Nb 0.4 Sb, can achieve 0.8, which one highest reported Although effective mass this system found be high, may lead low...
Due to point defect phonon scattering, formation of solid solutions has long been considered as an effective approach for enhancing thermoelectric performance through reducing the lattice thermal conductivity. The scattering phonons by defects mainly comes from mass and strain fluctuations between guest host atoms. Both can be maximized interstitial atoms and/or vacancies in a crystal. Here, demonstration Cu is shown, leading extremely low conductivity 0.5 W m −1 K SnTe‐Cu 2 Te solutions....