Strain-tunable electronic and optical properties of monolayer GeSe: Promising for photocatalytic water splitting applications

Nguyen, Hong T. T.; Vu, Tuan V.; Bình, Nguyễn Thị Thanh; Hoat, D.M.; Hiếu, Nguyễn Văn; Anh, Nguyen Thi Tuyet; Nguyen, Chuong V.; Phuc, Huynh V.; Jappor, Hamad Rahman; Obeid, Mohammed M.; Hieu, Nguyen N.

doi:10.1016/j.chemphys.2019.110543

Cited by 69 publications

(20 citation statements)

References 30 publications

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“…The monolayer structures of GeSe and SnSe are fully optimized. The optimized lattice parameters of monolayer GeSe and SnSe are 3.98 (4.29) Å and 4.30 (4.40) Å along zigzag (armchair) directions, which are in good agreement with the previous reported values 3.96 (4.22) Å [35] and 3.94 (4.30) Å [48] for monolayer GeSe and 4.30 (4.34) Å for monolayer SnSe [29]. Based on the optimized 2D monolayer GeSe and SnSe, the homogeneous bilayer GeSe, bilayer SnSe, and vdW heterostructure GeSe/SnSe are constructed.…”

Section: Geometry Optimization and Electronic Structuresupporting

confidence: 90%

Exceptional Thermoelectric Properties of Bilayer GeSe: First Principles Calculation

et al. 2022

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The geometry structures, vibrational, electronic, and thermoelectric properties of bilayer GeSe, bilayer SnSe, and van der Waals (vdW) heterostructure GeSe/SnSe are investigated by combining the first-principles calculations and semiclassical Boltzmann transport theory. The dynamical stability of the considered structures are discussed with phonon dispersion. The phonon spectra indicate that the bilayer SnSe is a dynamically unstable structure, while the bilayer GeSe and vdW heterostructure GeSe/SnSe are stable. Then, the electronic structures for the bilayer GeSe and vdW heterostructure GeSe/SnSe are calculated with HSE06 functional. The results of electronic structures show that the bilayer GeSe and vdW heterostructure GeSe/SnSe are indirect band gap semiconductors with band gaps of 1.23 eV and 1.07 eV, respectively. The thermoelectric properties, including electrical conductivity, thermal conductivity, Seebeck coefficient, power factor, and figure of merit (ZT) are calculated with semiclassical Boltzmann transport equations (BTE). The results show that the n-type bilayer GeSe is a promising thermoelectric material.

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Section: Geometry Optimization and Electronic Structuresupporting

confidence: 90%

Exceptional Thermoelectric Properties of Bilayer GeSe: First Principles Calculation

et al. 2022

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“…Moreover, there are approaches that allow one to generate asymmetric deformation or doping between layers and methods for its quantitative determination using a supported isotopically labeled bilayer graphene studied by in situ Raman spectroscopy [ 22 ]. The mechanically controlled bandgap was previously observed in other 2D materials [ 23 , 24 , 25 , 26 ]. However, the exceptional mechanical properties of graphene [ 27 , 28 ] provide outstanding efficiency of mechanical strain engineering in this material.…”

Section: Introductionsupporting

confidence: 61%

On the Impact of Substrate Uniform Mechanical Tension on the Graphene Electronic Structure

et al. 2020

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Employing density functional theory calculations, we obtain the possibility of fine-tuning the bandgap in graphene deposited on the hexagonal boron nitride and graphitic carbon nitride substrates. We found that the graphene sheet located on these substrates possesses the semiconducting gap, and uniform biaxial mechanical deformation could provide its smooth fitting. Moreover, mechanical tension offers the ability to control the Dirac velocity in deposited graphene. We analyze the resonant scattering of charge carriers in states with zero total angular momentum using the effective two-dimensional radial Dirac equation. In particular, the dependence of the critical impurity charge on the uniform deformation of graphene on the boron nitride substrate is shown. It turned out that, under uniform stretching/compression, the critical charge decreases/increases monotonically. The elastic scattering phases of a hole by a supercritical impurity are calculated. It is found that the model of a uniform charge distribution over the small radius sphere gives sharper resonance when compared to the case of the ball of the same radius. Overall, resonant scattering by the impurity with the nearly critical charge is similar to the scattering by the potential with a low-permeable barrier in nonrelativistic quantum theory.

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“…Among the plethora of 2D group-IV metal monochalcogenides, GeSe polymorphs have been deeply investigated for application in several fields, including photovoltaics, 95−98 photodetectors, 82,99−105 (tunnel) field-effect transistors, 106−109 spintronic, 110,111 piezoelectric actuators, 88,112 and ferroelectric devices, 113 and energy storage systems, 114−117 beyond to be proposed as water splitting photo(electro)catalysts. 61,62,68,93 Density functional theory (DFT) calculations revealed that its cleavage energy from the corresponding orthorhombic bulk structure is around 0.45 J m −2 , 62 which is similar or slightly superior to those calculated for other 2D materials, including graphene (0.3−0.4 J m −2 , 118,119 experimental value: 0.37 J m −2 ), 120 several transition metal dichalcogenides 121 (e.g., MoS 2 , 0.29 J m −2 ), 121 group-V elemental materials (e.g., phosphorene, 03−0.4 J m −2 ), 122,123 and several group-IIIA metal monochalcogenides (e.g., GaSe, 0.29 J m −2 ). 57,58 These results suggest that 2D GeSe can be easily produced through the exfoliation of its bulk counterpart, including either micromechanical cleavage-based exfoliation 124−126 or scalable liquid-phase exfoliation (LPE) methods.…”

Section: ■ Introductionmentioning

confidence: 99%

Liquid-Phase Exfoliated GeSe Nanoflakes for Photoelectrochemical-Type Photodetectors and Photoelectrochemical Water Splitting

Bianca

Zappia

Bellani

et al. 2020

ACS Appl. Mater. Interfaces

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Photoelectrochemical (PEC) systems represent powerful tools to convert electromagnetic radiation into chemical fuels and electricity. In this context, two-dimensional (2D) materials are attracting enormous interest as potential advanced photo(electro)catalysts and, recently, 2D group-IVA metal monochalcogenides have been theoretically predicted to be water splitting photocatalysts. In this work, we use density functional theory calculations to theoretically investigate the photocatalytic activity of single-/few-layer GeSe nanoflakes for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) in pH conditions ranging from 0 to 14. Our simulations show that GeSe nanoflakes with different thickness can be mixed in the form of nanoporous films to act as nanoscale tandem systems, in which the flakes, depending on their thickness, can operate as HER-and/or OER photocatalysts. On the basis of theoretical predictions, we report the first experimental characterization of the photo(electro)catalytic activity of single-/few-layer GeSe flakes in different aqueous media, ranging from acidic to alkaline solutions: 0.5 M H 2 SO 4 (pH 0.3), 1 M KCl (pH 6.5), and 1 M KOH (pH 14). The films of the GeSe nanoflakes are fabricated by spray coating GeSe nanoflakes dispersion in 2-propanol obtained through liquid-phase exfoliation of synthesized orthorhombic (Pnma) GeSe bulk crystals. The PEC properties of the GeSe nanoflakes are used to design PEC-type photodetectors, reaching a responsivity of up to 0.32 AW −1 (external quantum efficiency of 86.3%) under 455 nm excitation wavelength in acidic electrolyte. The obtained performances are superior to those of several self-powered and low-voltage solution-processed photodetectors, approaching that of self-powered commercial UV−Vis photodetectors. The obtained results inspire the use of 2D GeSe in proof-of-concept water photoelectrolysis cells.

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Strain-tunable electronic and optical properties of monolayer GeSe: Promising for photocatalytic water splitting applications

Cited by 69 publications

References 30 publications

Exceptional Thermoelectric Properties of Bilayer GeSe: First Principles Calculation

Exceptional Thermoelectric Properties of Bilayer GeSe: First Principles Calculation

On the Impact of Substrate Uniform Mechanical Tension on the Graphene Electronic Structure

Liquid-Phase Exfoliated GeSe Nanoflakes for Photoelectrochemical-Type Photodetectors and Photoelectrochemical Water Splitting

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