The absorption spectra of Ag8MIVSe6 and Ag8GeX6VI compounds

Bendorius, R. A.; Iržikevičius, A.; Kindurys, A.; Цветкова, Е. В.

doi:10.1002/pssa.2210280245

Cited by 22 publications

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“…35,36 The obtained band gaps are 0.85 and 0.8 eV for Ag 8 GeSe 6 and Ag 8 SnSe 6 , respectively, which are consistent with earlier report on family of these compounds. 37 Clearly, the estimated E g is higher for Ge based compound. Most of the argyrodites have structural phase transition at high temperatures.…”

Section: ■ Results and Discussionmentioning

confidence: 95%

“…We have performed the diffuse reflectance spectrum, which is shown in Figure a. The optical band gap, E g is estimated from the extrapolation of the (α h ν) 2 as a function of photon energy h ν, based on the equation of α h ν = B ( h ν – E g ) p , where α is the extinction coefficient, h ν is the incident photon energy, B is the absorption coefficient, and p depends upon nature of transition. , The obtained band gaps are 0.85 and 0.8 eV for Ag 8 GeSe 6 and Ag 8 SnSe 6 , respectively, which are consistent with earlier report on family of these compounds . Clearly, the estimated E g is higher for Ge based compound.…”

Section: Resultsmentioning

confidence: 99%

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Enhancement of Power Factor for Inherently Poor Thermal Conductor Ag₈GeSe₆ by Replacing Ge with Sn

Acharya

Pandey

Soni

2018

ACS Appl. Energy Mater.

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Superionic argyrodites have been identified as thermoelectric materials with inherent ultralow lattice thermal conductivity because of liquid-like behavior of cations in a relatively larger unit cell. The major drawback for these as potential thermoelectric materials is low carrier concentration and low electrical conductivity, which however can be improved by controlling the compositions while keeping the advantageous poor thermal conductivity intact. Here, we report ∼8 times enhancement of thermoelectric power factor of Ag 8 GeSe 6 by replacing Ge with metallic Sn, at high temperatures. Thus, Ag 8 SnSe 6 has been demonstrated as an efficient thermoelectric material with ZT ∼ 0.62 at 623 K, even at a very low carrier concentration (∼10 16 cm −3 ). The extremely low thermal conductivity has been explained with weakly bonded Ag ions to rigid anion sublattice and presence of low-frequency Einstein optic modes, which provide the possibility of decoupling of charge and heat transport.

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Section: ■ Results and Discussionmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 99%

Enhancement of Power Factor for Inherently Poor Thermal Conductor Ag₈GeSe₆ by Replacing Ge with Sn

Acharya

Pandey

Soni

2018

ACS Appl. Energy Mater.

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“…Infrared reflectivity measurements on crystalline β-Ag 2 S at 4.2 K show peaks at 40 and 70 cm −1 , shoulders at 90 and 140 cm −1 , a broad band near 230 cm −1 and a strong peak at 270 cm −1 [57]. Absorption spectra of Ag 8 GeS 6 show peaks around 123 cm −1 [48].…”

Section: Dynamical Propertiesmentioning

confidence: 94%

Structure of amorphous Ag/Ge/S alloys: experimentally constrained density functional study

Akola

Beuneu

Jones

et al. 2015

J. Phys.: Condens. Matter

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Density functional/molecular dynamics simulations have been performed to determine structural and other properties of amorphous Ag/Ge/S and Ge/S alloys. In the former, the calculations have been combined with experimental data (x-ray and neutron diffraction, extended x-ray absorption fine structure). Ag/Ge/As alloys have high ionic conductivity and are among the most promising candidates for future memristor technology. We find excellent agreement between the experimental results and large-scale (500 atoms) simulations in Ag/Ge/S, and we compare and contrast the structures of Ge/S and Ag/Ge/S. The calculated electronic structures, vibrational densities of states, ionic mobilities, and cavity distributions of the amorphous materials are discussed and compared with data on crystalline phases where available. The high mobility of Ag in solid state electrolyte applications is related to the presence of cavities and can occur via jumps to a neighbouring vacant site.

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“…The argyrodite Ag 8 SnSe 6 is a narrow band gap semiconductor with energy band gap of 0.82 eV [5,6].…”

Section: Introductionmentioning

confidence: 99%

The effects of strong correlations on the band structure of Ag8SnSe6 argyrodite

Syrotyuk¹,

Semkiv²,

Ільчук³

et al. 2016

Condens. Matter Phys.

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The electronic energy band spectra, as well as partial and total density of electronic states of the crystal argyrodite Ag 8 SnSe 6 have been evaluated within the projector augmented waves (PAW) approach by means of the ABINIT code. The one-electron energies have been evaluated using two functionals for exchange-correlation energy. The first one is the generalized gradient approximation (GGA) approach. The second one is the hybrid functional PBE0 composed of the semilocal GGA part and Hartree-Fock exact exchange non-local energy for strongly correlated 4d electrons of Ag atom. The second approach eliminates the Coulomb self-interaction of the Ag 4d electrons. This leads to a significant restructuring of the energy bands in the filled valence part and to an improved location of the Ag 4d -states on the energy scale, and the resulting value of the band gap is well compared with experiment. The effects of strong correlation on the electronic structure of the crystal argyrodite are considered here for the first time.

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The absorption spectra of Ag8MIVSe6 and Ag8GeX6VI compounds

Cited by 22 publications

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Enhancement of Power Factor for Inherently Poor Thermal Conductor Ag₈GeSe₆ by Replacing Ge with Sn

Enhancement of Power Factor for Inherently Poor Thermal Conductor Ag₈GeSe₆ by Replacing Ge with Sn

Structure of amorphous Ag/Ge/S alloys: experimentally constrained density functional study

The effects of strong correlations on the band structure of Ag8SnSe6 argyrodite

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The absorption spectra of Ag8MIVSe6 and Ag8GeX6VI compounds

Cited by 22 publications

References 0 publications

Enhancement of Power Factor for Inherently Poor Thermal Conductor Ag8GeSe6 by Replacing Ge with Sn

Enhancement of Power Factor for Inherently Poor Thermal Conductor Ag8GeSe6 by Replacing Ge with Sn

Structure of amorphous Ag/Ge/S alloys: experimentally constrained density functional study

The effects of strong correlations on the band structure of Ag8SnSe6 argyrodite

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Enhancement of Power Factor for Inherently Poor Thermal Conductor Ag₈GeSe₆ by Replacing Ge with Sn

Enhancement of Power Factor for Inherently Poor Thermal Conductor Ag₈GeSe₆ by Replacing Ge with Sn