First-principles characterization of two-dimensional (CH3(CH2)3NH3)2(CH3NH3)n−1GenI3n+1 perovskite

Wu, Liyuan; Lu, Pengfei; Li, Yuheng; Sun, Yan; Wong, Joseph; Yang, Kesong

doi:10.1039/c8ta10055a

Cited by 61 publications

(46 citation statements)

References 55 publications

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“…Recently, indium selenide (InSe), a III-VI group layered metal-chalcogenide compound, is of great interest both experimentally and theoretically. The atomic layer of InSe has been reported to successfully synthesized via physical [5–10] and chemical methods [11–14], and the applications of InSe nanosheet on sensors [15], optoelectronics, and photodetectors have been explored. Srinivasa et al reported the fabrication of few-layer InSe photodetectors with high responsivity and a broad spectral detection from the visible to near-infrared region [6].…”

Section: Introductionmentioning

confidence: 99%

Strain Effect on Thermoelectric Performance of InSe Monolayer

Wang

Han

et al. 2019

Nanoscale Res Lett

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Strain engineering is a practical method to tune and improve the physical characteristics and properties of two-dimensional materials, due to their large stretchability. Tensile strain dependence of electronic, phonon, and thermoelectric properties of InSe monolayer are systematically studied. We demonstrate that the lattice thermal conductivity can be effectively modulated by applying tensile strain. Tensile strain can enhance anharmonic phonon scattering, giving rise to the enhanced phonon scattering rate, reduced phonon group velocity and heat capacity, and therefore lattice thermal conductivity decreases from 25.9 to 13.1 W/mK when the strain of 6% is applied. The enhanced figure of merit indicates that tensile strain is an effective way to improve the thermoelectric performance of InSe monolayer. Electronic supplementary material The online version of this article (10.1186/s11671-019-3113-9) contains supplementary material, which is available to authorized users.

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Section: Introductionmentioning

confidence: 99%

Strain Effect on Thermoelectric Performance of InSe Monolayer

Wang

Han

et al. 2019

Nanoscale Res Lett

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“…Our previous calculations on

{(BA)}_{2} {(MA)}_{n - 1} {Ge}_{n} {normalI}_{3 n + 1}

shows that its exciton binding energies range from 202 to 190, 150, and 34 meV for n = 1, 2, 3, and ∞ , respectively. [ 130 ] Tsai et al calculated the exciton binding energy of

{(BA)}_{2} {(MA)}_{n - 1} {Pb}_{n} {normalI}_{3 n + 1}

at n = 3 and 4 and it was close to that of

{(MA)PbI}_{3}

, in agreement with the absence of excitonic signatures in their optical absorption spectra. [ 39 ] This suggests that the excitons in

{(BA)}_{2} {(MA)}_{n - 1} {Pb}_{n} {normalI}_{3 n + 1}

at n = 3 and 4 are nearly ionized at room temperature, leading to free carrier‐dominated charge transport.…”

Section: Propertiesmentioning

confidence: 73%

“…In prior work, our research team analyzed the origin of lead‐free 2DHP,

{(BA)}_{2} {(MA)}_{n - 1} {Ge}_{n} {normalI}_{3 n + 1}

from DFT calculations. [ 130 ] The calculated decomposition energies range from 1.13 to 0.69 eV to 0.62 to 0.23 eV for n = 1, 2, 3, and ∞ respectively. The higher stability of 2DHPs was attributed to the higher decomposition energies than that of 3DHPs and the origin was explained from the Bader charge analysis.…”

Section: Propertiesmentioning

confidence: 99%

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2D Hybrid Halide Perovskites: Synthesis, Properties, and Applications

Wong

Yang

2020

Solar RRL

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The hybrid organic-inorganic halide perovskites have emerged as one class of most promising light-harvesting materials for the next-generation solar cells because of their exceptional optoelectronic properties and low-temperature solution processability that allows for large-scale fabrication. [1-14] The hybrid halide perovskites are one class of semiconductors in a formula of ABX 3 that comprises a network of corner-sharing BX 6 octahedra. In this structure, A is an organic cation such as methylammonium (MA: CH 3 NH þ 3); B is a divalent metal cation such as Pb 2þ and Sn 2þ , located in the center; and X is a monovalent anion such as Cl À , Br À , and I À. These structural and compositional features determine their exceptional optoelectronic properties such as tunable bandgaps, [6-11] high absorption coefficient, [7-9,12-14] long carrier diffusion length [14-17] and lifetime, [6,17-23] low trap density, [16,17] and high carrier mobility. [7,8,14,17,24-27] Just in the past few years, the power conversion efficiency (PCE) of these halide perovskites solar cells at labscale testing has increased from 3.8% to 25.2% (in the perovskite/silicon tandem device). [28] Despite promising applications of halide perovskites in the photovoltaic industry, there are still several major challenges that inhibit their large-scale industrial applications. [29-32] These challenges include poor stability in ambient conditions, particularly in the moisture environment, and the demand for lead-free perovskites. For instance, ðMAÞPbI 3 will degrade into MAI and PbI 2 in ambient conditions in which the water molecules will facilitate the degradation process, sharply dropping perovskite thin film absorption in a matter of days. [33] Although encapsulation can mitigate the degradation from water molecules, [34] the hybrid perovskites were considered as intrinsically unstable in the long term due to unfavorable formation enthalpies. [35,36] 2D hybrid perovskites (2DHPs) offer a promising solution to overcome this instability issue. [37-47] The 2D nature refers to the layer structure of corner-sharing inorganic octahedra. These inorganic metal halide layers are interdigitated between bulky organic molecules such as butylammonium (BA: CH 3 ðCH 2 Þ 3 NH þ 3). The bulky organic molecules are bonded to the inorganic octahedra via hydrogen bonds, causing the large hydrophobic chain to orient away from the inorganic perovskite layers. This configuration forms organic bilayers that separate neighboring sheets, creating a repeating pattern of organic and inorganic layers that define the 2DHP crystal structure, see Figure 1. 2DHPs demonstrate some advantageous materials properties compared to the 3D hybrid perovskites (3DHPs), including high materials stability and robustness in the presence of water, [39,50] reasonable performance, and cheap solution processability. [37,51-54] Moreover, the interchangeability of the large organic cations and the control of layer dimensionality allow for greater tunability and flexibility of the physical and optoelect...

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“…In the past decades, various low dimensional nanomaterials have been considered as important functional materials due to their outstanding physical and chemical properties [1–25]. As a direct wide bandgap semiconductor with the bandgap of 3.37 eV at room temperature, zinc oxide has attracted much attention for its excellent optical and electrical performance [26, 27].…”

Section: Introductionmentioning

confidence: 99%

Effects of organic solvents on morphologies, photoluminescence, and photocatalytic properties of ZnO nanostructures

Cai

Chang

et al. 2019

Micro & Nano Letters

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Employing organo-metal zinc acetylacetonate (Zn(acac) 2) as the zincic source, various zinc oxide (ZnO) products with different morphologies have been synthesised via a typical solvothermal method in different polar organic solvents. Quasi-spherical and rod-like structures with diverse sizes are successfully fabricated in the methanol, ethanol, 1-propanol, isopropanol, and acetone solutions of NaOH, respectively. Moreover, their microstructures and morphologies have been investigated by X-ray powder diffraction and electron microscopy. A possible growth mechanism has been proposed. The various morphologies of ZnO are attributed to the discrepant polarity and viscosity of organic solvents and the supersaturation levels of reactants. Furthermore, the size-depended photoluminescence and photocatalytic properties of various structures of ZnO are also studied. It is believed that the different but regular photoelectric behaviours are resulting from the surface states and specific surface areas which are related to the exposed polarity facets as well as the size of ZnO particles.

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First-principles characterization of two-dimensional (CH₃(CH₂)₃NH₃)₂(CH₃NH₃)_n−1Ge_nI_3n+1 perovskite

Abstract: A novel two-dimensional Ge-based hybrid perovskite is proposed for potential optoelectronic applications.

Cited by 61 publications

References 55 publications

Strain Effect on Thermoelectric Performance of InSe Monolayer

Strain Effect on Thermoelectric Performance of InSe Monolayer

2D Hybrid Halide Perovskites: Synthesis, Properties, and Applications

Effects of organic solvents on morphologies, photoluminescence, and photocatalytic properties of ZnO nanostructures

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