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In this study, we explore the effects of Zn doping on the electronic, optical, and thermoelectric properties of α-SnSe in bulk and monolayer forms, employing density functional theory calculations. By varying the doping concentrations, we aim to understand the characteristics of Zn-doped SnSe in both systems. Our analysis of the electronic band structure using (PBE), (SCAN), and (HSE06) functionals reveals that all doped systems exhibit semiconductor-like behavior, making them suitable for applications in optoelectronics and photovoltaics. Notably, the conduction bands in SnSe monolayers undergo changes depending on the Zn concentration. Furthermore, the optical analysis indicates a decrease in the dielectric constant when transitioning from bulk to monolayer forms, which is advantageous for capacitor production. Moreover, heavily doped SnSe monolayers hold promise for deep ultraviolet applications. Examining the thermoelectric transport properties, we observe that Zn doping enhances the electrical conductivity in bulk SnSe at temperatures below 500 K. However, the electronic thermal conductivity of monolayer samples is lower compared to bulk samples, and it decreases consistently with increasing Zn concentrations. Additionally, the Zn-doped 2D samples exhibit high Seebeck coefficients across most of the temperature ranges investigated. [ABSTRACT FROM AUTHOR]

Single-crystal SnSe holds the world record for high thermoelectric performance. However, the efficiency of polycrystalline SnSe is limited due to high thermal conductivity (κ) and low electronic conductivity (σ) compared to single-crystal SnSe. Here, we report the low κ and high σ on SnSe with Si doping using semi-classical Boltzmann transport theory and first-principles calculations. Our calculated phonon dispersion curves and elastic constants of the SixSn1−xSe alloys (x varied from 0 to 0.25) show the thermodynamic and mechanical stability. Our density functional theory (DFT)-calculated elastic moduli of the α-SnSe match well with theoretical and experiment reports. The electronic properties are calculated using diversity of exchange-correlation functionals. The band gap for pristine α-SnSe is estimated to be 0.88 eV using the hybrid functional (HSE06), which is in excellent agreement with the experimental value 0.86 eV. The G0W0+Bethe–Salpeter Equation, which incorporates combined electron–electron (e–e) and electron–hole (e–h) interactions, is used to calculate the optical characteristics of pure and Si-alloyed α-SnSe. Our DFT-calculated Seebeck coefficient for SixSn1−xSe alloys for all Si doping concentrations revealed p-type behavior. At 770 K, for x = 0.25, SixSn1−xSe is found to have the lowest thermal conductivity of ~ 0.16 Wm - 1 K - 1 attributed to the high lattice anharmonicity. Our results propose a novel strategy to enhance the optical and thermoelectric properties in the SnSe-based thermoelectric materials. [ABSTRACT FROM AUTHOR]

Half-Heusler alloys are anticipated to impact real applications for instance industrial waste heat recovery due to their high thermoelectric (TE) properties, good thermal stability, and excellent elastic properties. The state-of-the-art density functional theory (DFT) is used to calculate the electronic structure, magnetic, elastic, thermodynamic, and transport properties of the cubic CrMnS half-Heusler (HH) alloy. Ferromagnetic (FM) configuration is found to be energetically most favorable than non-magnetic (NM) and antiferromagnetic (AFM) states for the HH CrMnS alloy. The spin‐resolved band structure of HH CrMnS prevails its half‐metallicity at the Fermi level with a total magnetic moment of 1 μ B . The cohesive and formation energy analysis along with the phonon dispersion curve indicate that HH CrMnS is a chemically, thermodynamically, and vibrationally stable compound. Elastic properties for the studied compound show its mechanical stability, anisotropic & brittle nature with high hardness, and Debye temperature of 410 K. Thermodynamic parameters are also calculated which depict the stability of the studied alloy at varied pressure and temperature. Furthermore, thermoelectric (TE) properties indicate that HH CrMnS alloy has a maximum value of power factor (PF) equal to 3.3 × 1011 WK−2 m−1 s−1 at 1000 K and ZT value of 0.72 at 600 K. The vibrational and mechanical stability, higher bandgap (~ 0.96 eV) and 100% spin-polarization demonstrate that HH CrMnS can be a potential alloy for TE and spintronic applications. [ABSTRACT FROM AUTHOR]

Summary: We present a comparative study on the structural, electronic, elastic, and thermoelectric properties of the cubic inverse‐perovskites A3OX (where A = Li, Na, K and X = Cl, Br, I) by density functional theory (DFT). The cohesive, formation, and elastic properties analysis indicates that all studied materials are chemically, thermodynamically, and mechanically stable. Electronic properties reveal that all the inverse A3OX perovskite are direct bandgap semiconductors except Li3OCl and Li3OBr with ionic nature which is confirmed by electron localization function (ELF) analysis. We have also calculated Debye temperature (ΘD) and Grüneisen parameter (γ) to determine the lattice thermal conductivity for all the A3OX materials. Furthermore, thermoelectric (TE) properties are explored by calculating the Seebeck coefficient (S), electronic thermal conductivity, power factor (PF), electrical conductivity (σ/τ), lattice thermal conductivity, and ZT value. Our investigated A3OX inverse‐perovskites provide a fertile base that can improve the overall TE performance for TE applications and green energy production. [ABSTRACT FROM AUTHOR]

Tin selenide-based materials have attracted much attention recently because of their unique properties. This study employs first-principles calculations and density functional theory (DFT) to investigate the impact of Bismuth and Zinc co-doping on the electronic, mechanical, and thermoelectric properties of SnSe. The co-doped system exhibits a triclinic crystal structure and shows enhanced electrical conductivity and the generation of n-type carriers. The co-doped SnSe also demonstrates improved mechanical stability, higher susceptibility to shear deformation, and increased deformability under shear stresses. Thermoelectric calculations reveal significantly enhanced power factor (PF) values compared to pristine SnSe and single-doped Zn and Bi SnSe structures, with a maximum PF of 63.0 μV/Kcm at 800 K. These findings highlight the potential of Bi and Zn co-doped SnSe as a promising high-performance thermoelectric material and provide valuable insights for further research in SnSe-based materials. • Used first-principles & DFT: Bismuth & Zinc co-doping effects on SnSe. • Enhanced electrical conductivity & n-type carrier generation in co-doped SnSe. • Co-doped SnSe: Lower shear/Young's modulus, higher Poisson's ratio. Enhanced adaptability for varied applications. • Marked PF value enhancement in co-doped SnSe vs. pristine & single-doped structures. • Detailed insights into mechanisms guiding thermoelectric behaviour in SnSe-based materials. [ABSTRACT FROM AUTHOR]

Tin selenide-based materials have attracted much attention recently because of their unique properties. This study investigates the effect of Sodium and Iodine co-doping on the optoelectronic, mechanical, and thermoelectric properties of orthorhombic SnSe via First-principles calculations. Na/I co-doped crystal was found to have a triclinic structure, and its electronic bandgap is 0.325 ​eV, whereas the calculated band gap of the pristine SnSe is 0.824 ​eV using SCAN functional. Na/I co-doping alters the Fermi level of SnSe up to its conduction bands, resulting in an n -type system. Furthermore, the static dielectric constant shows that the doped system could be suitable for capacitors and solar cell applications. According to the calculated elastic constants, the doped system is stable. Moreover, it has a negative Poisson's ratio value suggesting it's auxetic sensor material. The thermoelectric performance is examined from 300 ​K to 800 ​K across a broad range of carrier concentrations for the doped and undoped SnSe systems. We have found that Na/I co-doping enhances the electrical conductivity and the Seebeck coefficient of SnSe. The highest power factor calculated for the doped system was 27.9 μ V / K c m at carrier concentration of n ≅ − 3 × 10 20 c m − 3 . [Display omitted] • Structure, optoelectronic, and thermoelectric properties of Na/I co-doped SnSe. • DFT calculations show an n -type behavior for the doped system. • Na/I doped system show an enhancement of Seebeck coefficient, electrical conductivity and hence the power factor. [ABSTRACT FROM AUTHOR]

Half-Heusler (HH) alloys are a well-known and extensively researched family of thermoelectric (TE), magnetic, and spintronic materials. Doping may significantly increase the thermoelectric conversion efficiency of these materials; nevertheless, practical applications remain far. As a result, the hunt for superior parent TE alloys is critical. Using extensive first-principles density functional calculations, we predicted a novel class of vanadium-based four HH VXTe alloys, where X is one of the four elements: Cr, Mn, Fe, and Co. Their TE properties, as well as their mechanical, magnetic, electrical, and structural stability, have been studied in depth. Their mechanical and thermodynamic stability is confirmed using the predicted elastic constants, formation and cohesive energies, and phonon spectra. A comprehensive analysis of elastic constants and moduli demonstrates that HH VXTe alloys possess elastic anisotropy with reasonably good machinability, higher melting and Debye temperatures, mixed bonding characteristics with ionic and covalent contributions, and brittle nature, except for VCoTe, which is ductile. We find that the ground state of HH VCrTe and VFeTe is ferrimagnetic, while HH VCoTe is ferromagnetic and HH VMnTe is non-magnetic. Three VXTe (X = Cr, Fe, & Co) alloys demonstrated half-metallicity with 100% spin-polarization, whereas HH VMnTe is an 18-electron indirect semiconductor. In the studied HH VXTe alloys, most of the heat flow is caused by the phonon-group velocity of the acoustic phonons. Further studies on the relationship between carrier concentration and temperature dependence of TE properties reveal that the high ZT ∼1.2 at 1000 K of the pristine HH VMnTe alloy is obtained due to its high-power factor of 249.4 × 10 12 W m − 1 K − 2 and this value is greater than the values of some known pristine and doped HH TE materials. Our findings pave the way for further investigation into the HH VXTe alloys in the quest for improved TE and spintronic materials for use in domains that necessitate high thermoelectricity and spintronic performance. [ABSTRACT FROM AUTHOR]