Structural Dynamics and Thermal Transport in Bismuth Chalcogenide Alloys

Cen, Jiayi; Pallikara, Ioanna; Skelton, Jonathan M.

doi:10.1021/acs.chemmater.1c02777

Cited by 14 publications

(19 citation statements)

References 79 publications

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“…However, Si can also form a number of clathrate phases [ 32 , 33 , 34 ] and other open-framework structures [ 35 , 36 ], at least one of which has been measuered to have a much lower thermal conductivity than diamond Si [ 37 ]. Ab inito calculations are playing an increasingly important role in building our microscopic understanding of lattice thermal conductivity, providing insight into both the origin of the intrinsically-low

of high-performance thermoelectrics such as SnSe [ 7 , 19 , 38 ] and also how material modifications such as alloying and filling can be used to optimise it [ 18 , 39 , 40 ]. Given the potential of clathrate structures in general, it is of considerable interest to use these techniques to unravel the link between the structure and thermal conductivity in the allotropes of Si.…”

Section: Introductionmentioning

confidence: 99%

Structural Dynamics, Phonon Spectra and Thermal Transport in the Silicon Clathrates

2022

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The potential of thermoelectric power to reduce energy waste and mitigate climate change has led to renewed interest in “phonon-glass electron-crystal” materials, of which the inorganic clathrates are an archetypal example. In this work we present a detailed first-principles modelling study of the structural dynamics and thermal transport in bulk diamond Si and five framework structures, including the reported Si Clathrate I and II structures and the recently-synthesised oC24 phase, with a view to understanding the relationship between the structure, lattice dynamics, energetic stability and thermal transport. We predict the IR and Raman spectra, including ab initio linewidths, and identify spectral signatures that could be used to confirm the presence of the different phases in material samples. Comparison of the energetics, including the contribution of the phonons to the finite-temperature Helmholtz free energy, shows that the framework structures are metastable, with the energy differences to bulk Si dominated by differences in the lattice energy. Thermal-conductivity calculations within the single-mode relaxation-time approximation show that the framework structures have significantly lower κlatt than bulk Si, which we attribute quantitatively to differences in the phonon group velocities and lifetimes. The lifetimes vary considerably between systems, which can be largely accounted for by differences in the three-phonon interaction strengths. Notably, we predict a very low κlatt for the Clathrate-II structure, in line with previous experiments but contrary to other recent modelling studies, which motivates further exploration of this system.

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Section: Introductionmentioning

confidence: 99%

Structural Dynamics, Phonon Spectra and Thermal Transport in the Silicon Clathrates

2022

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“…Initial structures of orthorhombic and rhombohedral Bi 2 Se 3 and rock salt and trigonal BiSe (Figure S16) were downloaded from the ICSD. We used Γ-centered Monkhorst–Pack k- point meshes to sample the Brillouin zone . The number of k- points along direction i was varied such that k i × a i , where a i is the lattice parameter along direction i , was ∼30 for geometry optimization and ∼60 for the static calculations.…”

Section: Methodsmentioning

confidence: 99%

“…We used Γ-centered Monkhorst−Pack k-point meshes to sample the Brillouin zone. 74 The number of k-points along direction i was varied such that k i × a i , where a i is the lattice parameter along direction i, was ∼30 for geometry optimization and ∼60 for the static calculations. For the strain calculations, supercells of Bi 2 Se 3 were constructed with different orientations while keeping the stoichiometry of Bi:Se to 2:3.…”

Section: ■ Conclusionmentioning

confidence: 99%

Spontaneous Seed Formation during Electrodeposition Drives Epitaxial Growth of Metastable Bismuth Selenide Microcrystals

et al. 2022

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Materials with metastable phases can exhibit vastly different properties from their thermodynamically favored counterparts. Methods to synthesize metastable phases without the need for high-temperature or high-pressure conditions would facilitate their widespread use. We report on the electrochemical growth of microcrystals of bismuth selenide, Bi2Se3, in the metastable orthorhombic phase at room temperature in aqueous solution. Rather than direct epitaxy with the growth substrate, the spontaneous formation of a seed layer containing nanocrystals of cubic BiSe enforces the metastable phase. We first used single-crystal silicon substrates with a range of resistivities and different orientations to identify the conditions needed to produce the metastable phase. When the applied potential during electrochemical growth is positive of the reduction potential of Bi3+, an initial, Bi-rich seed layer forms. Electron microscopy imaging and diffraction reveal that the seed layer consists of nanocrystals of cubic BiSe embedded within an amorphous matrix of Bi and Se. Using density functional theory calculations, we show that epitaxial matching between cubic BiSe and orthorhombic Bi2Se3 can help stabilize the metastable orthorhombic phase over the thermodynamically stable rhombohedral phase. The spontaneous formation of the seed layer enables us to grow orthorhombic Bi2Se3 on a variety of substrates including single-crystal silicon with different orientations, polycrystalline fluorine-doped tin oxide, and polycrystalline gold. The ability to stabilize the metastable phase through room-temperature electrodeposition in aqueous solution without requiring a single-crystal substrate broadens the range of applications for this semiconductor in optoelectronic and electrochemical devices.

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“…An example is given by penta-CN 2 , where the lone-pair electrons increase the bond homogenization, leading to a higher lattice thermal conductivity in comparison with graphene . In (Bi 2 ) m (Bi 2 Te 3 ) n , the effect of lone-pair electrons are only activated in a zigzag Bi dual layer where intense localized vibration occurs, while the structural distortion is quenched in Bi 2 Te 3 quintuple sublayers as the compound adopts a higher-symmetry phase . DFT calculations suggested that Bi 2 sublayers contribute mostly to the vibrations of low-energy phonon acoustic branches in both (Bi 2 ) 1 (Bi 2 Se 3 ) 2 and (Bi 2 ) 1 (Bi 2 Te 3 ) 2 , although the mixture of vibrations of Bi 2 and the quintuple layers is relatively stronger in (Bi 2 ) 1 (Bi 2 Te 3 ) 2 , which leads to a smaller anisotropy of thermal conductivity of (Bi 2 ) 1 (Bi 2 Te 3 ) 2 in comparison to (Bi 2 ) 1 (Bi 2 Se 3 ) 2 . , …”

Section: Mimic Of Two-dimensional Transport Behaviorsmentioning

confidence: 99%

Bulk Superlattice Analogues for Energy Conversion

Bai

Xiao

2022

J. Am. Chem. Soc.

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Energy storage and conversion in a clean, efficient, and safe way is the core appeal of a modern sustainable society, which is built on the development of multifunctional materials. Superlattice structures can integrate the advantage of their sublayers while new phenomena may arise from the interface, which play key roles in modern semiconductor technology; however, additional concerns such as stability and yield challenge their large-scale applications in industrial products. In this Perspective we focus our interest on a distinctive category of easily available multilayered inorganic materials that have well-defined subunit structures and can be regarded as bulk superlattice analogues. We illustrate several specific combining forms of subunits in bulk superlattice analogues, including soft/rigid sublayers, electron/phonon transport sublayers, quasi-two-dimensional layers, and intercalated metal layers. We hope to provide insights into material design and broaden the application scope in the field of energy conversion by integrating the versatility of subunits into these bulk superlattice analogues.

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Structural Dynamics and Thermal Transport in Bismuth Chalcogenide Alloys

Cited by 14 publications

References 79 publications

Structural Dynamics, Phonon Spectra and Thermal Transport in the Silicon Clathrates

Structural Dynamics, Phonon Spectra and Thermal Transport in the Silicon Clathrates

Spontaneous Seed Formation during Electrodeposition Drives Epitaxial Growth of Metastable Bismuth Selenide Microcrystals

Bulk Superlattice Analogues for Energy Conversion

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