Computational study of the relative stabilities of ZnS clusters, for sizes between 1 and 4nm

Hamad, Said; Catlow, C. Richard A.

doi:10.1016/j.jcrysgro.2006.05.024

Cited by 52 publications

(72 citation statements)

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“…week ending 30 APRIL 2010 hypothetical TBS polymorphs predicted to date are (i) BCT, although known experimentally for BeO, has also been proposed as a possible extended phase in ZnO and ZnS nanostructures (BCT-ZnO [17,18], BCT-ZnS [19]) and, (ii) the SOD polymorph (sharing the same underlying 4CN as the low-density silicate sodalite [15]) recently proposed for ZnO (SOD-ZnO [20]) and SiC (SOD-SiC [21]). Furthermore, for BN, which is not strictly a TBS as it crystallizes under ambient conditions as the three-connected h-BN polymorph, ABW-BN (again with a 4CN originally found as a silicate) and BCT-BN have been predicted [22].…”

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confidence: 99%

Apparent Scarcity of Low-Density Polymorphs of Inorganic Solids

2010

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For most inorganic solids, very few dense polymorphs and no low-density polymorphs are observed. Taking a wide range of tetrahedrally-coordinated binary solids (e.g., ZnO, GaN) as a prototypical system, we show that the apparent scarcity of low-density polymorphs is not due to significant structural or energetic limitations. Using databases of periodic networks as sources of novel crystal structures, followed by ab initio energy minimization, we predict a dense spectrum of low-density low-energy polymorphs. The diverse range of materials considered indicates that this is likely to be a general phenomenon. DOI: 10.1103/PhysRevLett.104.175503 PACS numbers: 61.50.Ah, 61.66.Fn, 71.15.Nc, 82.75.Fq The structure and properties of inorganic solids are intimately linked to such an extent that even different structures of the same composition (so-called polymorphs) often have widely differing properties and applications. For boron nitride (BN), for example, the soft hexagonal layered polymorph (h-BN) is used as a lubricant, while the cubic polymorph (wurtzite structure) is extremely hard and is employed as an industrial abrasive. Germanium also exhibits more than one polymorph (or more strictly ''allotrope'' for elemental systems) having very different optical properties; with the diamond structured -germanium having an indirect band gap, and the recently synthesized lowdensity clathrate-II structure [1] a direct gap. Evidently, having access to more than one polymorph can significantly extend the range of properties and applications of a particular compound. For the vast majority of inorganic solids, however, typically only three or fewer distinct polymorphs have been prepared experimentally and a similarly small number of hypothetical polymorphs have been proposed. Moreover, where more than one polymorph is known, these extra phases very rarely have a significantly lower density than the most stable polymorph.In stark contrast to this situation, silica (SiO 2 ) has been prepared as more than 40 polymorphs [2], the majority of which are considerably less dense than -quartz; the most stable polymorph under ambient conditions. The rich polymorphism of silica, especially in its low-density forms, allows for fine-tuning of applications (e.g., gas separation membranes) by choosing the best suited polymorph. In addition, 100 000þ hypothetical silica polymorphs have been predicted theoretically as fourfold-connected networks (4CNs) [3][4][5][6][7], a large fraction of which, after accurate theoretical evaluation as silica materials, were found to have comparable energetics to experimentally prepared polymorphs [8,9]. Similarly rich polymorphism has only been further observed for a select group of other inorganic solids, for example, aluminophosphates (AlPO 4 ). A tantalizing hint that there may as yet exist a greater pool of experimentally accessible polymorphs for many other inorganic solids is given by the recent low temperature deposition synthesis of the tetrahedral wurtzite polymorph of LiBr [10] (after previous theor...

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confidence: 99%

Apparent Scarcity of Low-Density Polymorphs of Inorganic Solids

2010

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“…Nanoparticles have been modeled with bidimensional slabs of increasing thickness d (from 0.5 to about 6 nm), characterized by two infinite dimensions (x, y) and a finite thickness, and cut from the bulk so as to expose the most stable ZnS surface, the (110) [29]. Stoichiometric ZnS slabs (Zn/S ratio equal to 1/1) have been considered, in agreement with the experimental and theoretical reports [28,[48][49][50][51]. Surface Energy (E s ) is calculated as:…”

Section: Dft Modelingmentioning

confidence: 85%

Effect of Post-Synthesis Treatments on the Properties of ZnS Nanoparticles: An Experimental and Computational Study

Balantseva

Camino

Ferrari

et al. 2015

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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-This work deals with the characterization of ZnS NanoParticles (NP), prepared by precipitation employing thioacetamide as sulfur source at different reaction time length. The attention is focused on the modification induced on structural, surface and electronic properties of ZnS NP by post-synthesis treatments. These were aimed at removing from the samples surface adsorbed reactants, by washing or thermal treatments, both in air or vacuum. The effect of these parameters is followed by X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Fourier Transform InfraRed (FTIR), gas-volumetric and ThermoGravimetric Analysis (TGA). Moreover, the effect of nanostructuration on the semiconducting material band gap is evaluated by Diffuse Reflectance UV-Vis (DR UV-Vis) spectroscopy. Density Functional Theory (DFT) calculations have been employed to clarify the role of the adsorbed reactants on the surface stability and to assess the relationship between particle size and band gap value.Résumé -Effet des traitements après-synthèse sur les propriétés de nanoparticules de ZnS : une étude expérimentale et computationnelle -Ce travail concerne la caractérisation de nanoparticules de ZnS préparées par précipitation en présence de ThioAcétAmide (TAA) comme source de soufre. On a étudié, en particulier, les modifications des propriétés structurelles, superficielles et électroniques en fonction des paramètres de synthèse (temps, solvant et source de soufre) et des traitements après-synthèse considérés. Ces derniers avaient pour but d'éliminer les réactifs adsorbés sur la surface par lavages ou traitements thermiques à l'air ou sous vide. L'effet des différents traitements a été suivi par diffraction des rayons X (XRD), microscopie de transmission électronique (TEM), spectroscopie infra rouge à transformée de Fourier (FTIR), analyse volumétrique des gaz et thermogravimétrie (TGA). En outre, l'effet de la nanostructure sur les propriétés de la largeur de bande du matériau semi-conducteur a été évalué par spectroscopie de reflectance UV-Vis (DR UV-Vis). Des théories de la fonctionnelle de la densité (DFT) ont été utilisées pour clarifier le rôle des réactifs adsorbés sur la stabilité de la surface et pour établir une relation entre la dimension des particules et la largeur de bande.

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“…One is by starting from the low-energy isomers of (ZnS) n [18][19][20][21][22][23][24], (BeO) n [30], (MgO) n [41][42][43][44][45][46][47][48][49][50][51] and (AuSR) n [17] clusters as reported in literatures. The other is by unbiased global search by the combination of genetic algorithm (GA) and DFT method, which has been successfully applied in the structural prediction of a number 5 of systems [30,[56][57][58][59][60][61].…”

Section: Computational Detailsmentioning

confidence: 99%

“…The catenane structure becomes the most stable at n=10-12, followed by the double helical and crown structures. For (ZnS) n [18][19][20][21][22][23][24], (ZnO) n [25][26][27][28][29], (BeO) n [30] and (BN) n [31][32][33][34][35][36][37][38][39][40] clusters, the structures are rings and cages. Earlier studies have shown that the most stable structure for (ZnS) n clusters with n = 10-47 are hollow polyhedral clusters [19].…”

Section: Introductionmentioning

confidence: 99%

Secondary bonding networks in small (HgS)n clusters: A theoretical investigation

Cheng

2015

Computational and Theoretical Chemistry

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Computational study of the relative stabilities of ZnS clusters, for sizes between 1 and 4nm

Cited by 52 publications

References 36 publications

Apparent Scarcity of Low-Density Polymorphs of Inorganic Solids

Apparent Scarcity of Low-Density Polymorphs of Inorganic Solids

Effect of Post-Synthesis Treatments on the Properties of ZnS Nanoparticles: An Experimental and Computational Study

Secondary bonding networks in small (HgS)n clusters: A theoretical investigation

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