Lattice thermal conductivity is one of the most important thermoelectric parameters in determining energy conversion efficiency materials. However, lattice evaluation requires time-consuming first-principles (quasi)phonon calculations, which limits seeking high-performance materials through high-throughput computations. Here, we establish a methodology to determine Debye temperature $\mathrm{\ensuremath{\Theta}}$, Gr\"uneisen parameter $\ensuremath{\gamma}$, and $\ensuremath{\kappa}$ using...

Cu chalcopyrites exhibit excellent thermoelectric performance because of their high thermopower and low thermal conductivity. Conversely, despite that Ag have even lower conductivity than the Cu-based ones, they generally display performance. The underlying physics for disparity between Cu- Ag-based materials remains unclear. In this work we investigate transport ternary $AM{\mathrm{Se}}_{2}$ $(A=\mathrm{Cu}/\mathrm{Ag}; M=\mathrm{Ga}/\mathrm{In})$ using first-principles methods. We reveal...

The high-throughput (HT) computational method is a useful tool to screen high-performance functional materials. In this work, using the deformation potential under single band model, we evaluate carrier relaxation time and establish an electrical descriptor (χ) characterized by effective masses based on simple rigid approximation. can be used reasonably represent maximum power factor without solving electron Boltzmann transport equation. Additionally, Grüneisen parameter (γ), of lattice...

Understanding the structural and physical origins of low thermal conductivity behavior is essential for improving searching high-efficiency thermoelectric materials. Natural minerals are cheap usually have conductivities. The lattice conductivities two isostructural natural materials, chalcostibite ${\mathrm{CuSbS}}_{2}$ emplectite ${\mathrm{CuBiS}}_{2}$, substantially in experimental measurements. In particular, ${\mathrm{CuBiS}}_{2}$ much lower than that ${\mathrm{CuSbS}}_{2}$. Using...

Forming ordered structure instead of solid solution is an effective strategy to maintain the excellent electrical properties and achieve high thermoelectric in double HH compounds.

The hexagonal phase of $\mathrm{AgBiS}{\mathrm{e}}_{2}$ has been discovered as a promising thermoelectric material for room-temperature applications. However, its basic conduction type is still ambiguous, and current ZT value pretty low. To improve the performance $\mathrm{AgBiS}{\mathrm{e}}_{2}$, we apply band engineering to modify structure by introducing defects increase degeneracy. From calculated intrinsic point defect formation energies at different growth conditions, clarify that...

Half-Heusler (HH) compounds are one of the state-of-the-art thermoelectric materials with high electrical properties. The properties (electrical and thermal properties) many HH have not been investigated yet. Therefore, discovery novel promising (intrinsically power factor possible low conductivity) is highly needed. Here, we carry out high-throughput computations on 95 (including 75 thermodynamically stable 20 mechanically stable) compounds. Using experimentally well-studied NbFeSb ZrNiSn...

SnTe is an attractive candidate for applications as a p-type thermoelectric semiconductor. The pristine compound exhibits poor performance at high temperatures because of its hole concentration, small band gap, and large energy difference between the light heavy bands (ΔE(L – Σ)). To overcome these problems, we investigate structure changes upon addition trivalent dopants based on tight-binding (TB) model density functional theory (DFT) calculations. We find that tuning relative on-site...

We calculate the lattice thermal conductivities of pyrite-type ZnSe2 at pressures 0 and 10 GPa using linearized phonon Boltzmann transport equation. obtain a very low value [0.69 W/(mK) room temperature GPa], comparable to best thermoelectric materials. The vibrational spectrum is characterized by isolated high-frequency optical modes due stretching Se-Se dimers low-frequency rotation Zn atoms around these dimers. are strong anharmonicity will substantially increase three-phonon scattering...

Coordination polymers, especially porous coordination polymers have attracted much attention due to novel structures and potential applications. Biphenyl-3,5,3′,5′-tetracarboxylate (3, 5-H4bptc) biphenyl-3,4,3′,4′-tetracarboxylate 4-H4bptc) been used in construction of polymers. In this paper, a series metal–organic framework constructed from biphenyl-2,4,2′,4′-tetracarboxylate (2,4-H4bptc), [Zn(2,4-H2bptc)(4,4′-bipy)·H2O]n (1), {[Zn3(2,4-Hbptc)2(2,2′-bpy)2]·2H2O}n (2),...

Based on the first-principles calculations, we have investigated in detail bandgap opening of silicene nanomeshes. Different to mechanism induced by sublattice equivalence breaking, method degenerate perturbation through breaking bond symmetry could split π-like bands inversion preserved nanomeshes, resulting into πa1 - πa2 and πz1 πz2 band sets with sizable energy intervals. Besides nanomeshes Dirac point being folded Γ point, intervals are however apart away from Fermi level leave...

The purpose of this study is to understand the differentiated impact politics- and science-oriented education on pro-environmental behavior among university students. A questionnaire was designed sent more than 14,000 students from 152 universities in China using snowball sampling method. In questionnaire, environmental knowledge divided innovatively into two parts: Science-oriented spread by traditional politics-oriented through political education. structural equation model used conduction...

Lattice thermal conductivity is a crucial parameter for thermoelectric (TE) applications. In pyrite-type metal dichalcogenides, it observed that the type of atom has significant influence in phonon properties and lattice conductivities, but physical origin not clear. this paper, we show that, posttransition (such as Zn or Cd) because fully occupied ${d}^{10}$ orbitals inside valence bands are relatively localized, enhanced symmetry-controlled $s\text{\ensuremath{-}}d$ coupling effects atoms...

The thermoelectric (TE) properties of the three pyrite-type IIB-${\mathrm{VIA}}_{2}$ dichalcogenides (${\mathrm{ZnS}}_{2}, {\mathrm{CdS}}_{2}$, and ${\mathrm{CdSe}}_{2}$) are systematically investigated compared with those prototype ${\mathrm{ZnSe}}_{2}$ to optimize their TE properties. Using phonon Boltzmann transport equation, we find that they all have ultralow lattice thermal conductivities. By analyzing vibrational properties, this is attributed soft modes derived from loosely bound...

To improve the understanding of optical image resolution transmission-mode GaAs photocathode, by establishing surface scattering analysis model AlGaAs window layer, we have researched effect height distribution variance σ on transfer function (STF) and point spread (PSF) photocathode. The simulation results show that decrease is beneficial to resolution. This improvement mainly attributed in input light energy attenuation spatial diffusion caused smaller σ, thus signal noise ratio degraded increased.

Doping (or substitution)-induced modification of the electronic structure to increase density states (eDOS) near Fermi level is considered as an effective strategy enhance Seebeck coefficient, and may consequently boost thermoelectric performance. Through density-functional theory calculations Mn-substituted TiFe2-xMnxSn compounds, we demonstrate that d-states substituted Mn atoms induce a strong resonant energy. Our experimental results are in good agreement with calculations. They show...

An infrared perfect absorber structure is designed based on GaAs/Au/SiO2 metamaterial with numerical simulation, in which gold split ring resonators (SRR) embedded the GaAs layer. The absorption exceeds 99% at 1360 nm under plane wave excitation its polarization perpendicular to opening direction of SRR. When parallel direction, 97% and 56% 970 2070 nm, respectively, realize dual-band absorption. peaks are effectively modulated by controlling surface current density distribution resonant...

In this paper, the matrix difference method is used to calculate photoelectron continuity equation and outgoing electron flux density equation. The effects of GaAsP/AlGaAsP recombination rate, diffusion coefficient, activation layer thickness on time-resolved characteristics quantum efficiency a GaAsP photocathode are systematically studied, accuracy theoretical calculation verified by experiments. response speed can be greatly improved adjusting reasonably.