Optoelectronic properties of (ZnO)60 isomers

Caddeo, Claudia; Malloci, Giuliano; Angelis, Filippo De; Colombo, Luciano; Mattoni, Alessandro

doi:10.1039/c2cp42037f

Cited by 15 publications

(14 citation statements)

References 53 publications

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“…A core-cage structure for (ZnO) 34 has been proposed as the most stable in [ 10 , 11 ], while [ 12 ] have predicted the hollow cage structures formed by (ZnO) 2 squares and (ZnO) 3 hexagons. In the case of (ZnO) 60 , the studies [ 13 , 14 ] revealed an energetically preferred sodalite motif, while nested cage configuration was predicted to be the most stable in [ 10 , 11 ]. Such differences indicate that there is a strong dependence of the calculated binding energy on the details of the computational framework adopted.…”

Section: Introductionmentioning

confidence: 99%

Ab Initio Study of Structural and Electronic Properties of (ZnO) n “Magical” Nanoclusters n = (34, 60)

et al. 2017

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Density functional theory studies of the structural and electronic properties of nanoclusters (ZnO)n (n = 34, 60) in different geometric configurations were conducted. For each cluster, an optimization (relaxation) of structure geometry was performed, and the basic properties of the band structure were investigated. It was established that for the (ZnO)34 nanoclusters, the most stable are fullerene-like hollow structures that satisfy the rule of six isolated quadrangles. For the (ZnO)60 nanoclusters, different types of isomers, including hollow structures and sodalite-like structures composed from (ZnO)12 nanoclusters, were investigated. It was determined that the most energetically favorable structure was sodalite-type structure composed of seven (ZnO)12 clusters with common quadrangle edges.

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Section: Introductionmentioning

confidence: 99%

Ab Initio Study of Structural and Electronic Properties of (ZnO) n “Magical” Nanoclusters n = (34, 60)

et al. 2017

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“…28 From these results, the relative stability of the isomers considered strongly depends on the computational scheme adopted. 31 Likewise, two isomers have been proposed to explain the unmatched stability of the (CdSe) 33 stoichiometry, namely a core@cage cluster ((CdSe) 5 @(CdSe) 28 ) 19 and a wurtzite-like arrangement. 32 However, the simple analysis of the energy differences can not be conclusive to determine the lowest-lying isomer.…”

Section: Introductionmentioning

confidence: 99%

“…30,36 Motivated by the recent experimental work by Wang et al, 38 where the magic (CdSe) 13 has been isolated for the first time, we further progress in the characterization of the putative isomers of (CdSe) 13 and of their amine-capped counterparts. As already made for (ZnO) 60 , 31 energy calculations are combined with TDDFT spectra in order to identify the isomer found in the experiment. Our results are in excellent agreement with the experimental measurements recorded in toluene.…”

Section: Introductionmentioning

confidence: 99%

A DFT/TDDFT study on the optoelectronic properties of the amine-capped magic (CdSe)13 nanocluster

Azpiroz

Matxain

Infante

et al. 2013

Phys. Chem. Chem. Phys.

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Motivated by the recent experiments by Wang et al. (Angew. Chem., Int. Ed. 2012, 51, 6154-6157), in which the alkylamine-capped magic-size (CdSe)13 has been isolated for the first time, we report on the computational modeling of the putative low-lying isomers of (CdSe)13, both bare and ligand-protected. According to Density Functional Theory (DFT) calculations, the core@cage configuration Se@Cd13Se12, consisting of a Se atom incarcerated in the center of a puckered Cd13Se12 cage, lies lower in energy than fullerene- and wurtzite-like structures. Methylamine-capped nanoclusters present average bond energies per ligand of about 20 kcal mol(-1), while bond energy decomposition schemes show this interaction to be mostly electrostatically-driven. The computed Time-Dependent-DFT (TDDFT) spectrum of the lowest-lying methylamine-protected (CdSe)13 isomer essentially coincides with the experiment, with a notable blueshift of the absorption features induced by the ligands. The LUMO has been found to be the acceptor orbital for all the lowest-lying electronic excitations, in both the bare and methylamine-capped clusters, which could explain the narrow emission profiles inherent in semiconductor nanostructures. In addition, the attachment of pyridine and aniline molecules has been evaluated. Interestingly, the molecular orbitals of these aromatic amines located on the edges of the valence and conduction bands may act as trap states, in agreement with experimental evidences. In the particular case of pyridine molecules, unoccupied orbitals intrude into the HOMO-LUMO gap of the cluster.

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“…ZnO nanoclusters have been studied extensively 2,47,[57][58][59][60][61][62][63][64][65][66][67][68][69][70][71] and most of the studies report that the larger LM structures typically resemble bubbles and nanotubes. As we have access to the data published by Al-Sunaidi et al, 47 and as it is the first and only systematic study that also includes the low energy metastable (ZnO) n configurations up to n = 32, we have used these results as our benchmark.…”

Section: (Zno) N N = 1-32mentioning

confidence: 99%

An efficient genetic algorithm for structure prediction at the nanoscale

2017

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We have developed and implemented a new global optimization technique based on a Lamarckian genetic algorithm with the focus on structure diversity. The key process in the efficient search on a given complex energy landscape proves to be the removal of duplicates that is achieved using a topological analysis of candidate structures. The careful geometrical prescreening of newly formed structures and the introduction of new mutation move classes improve the rate of success further. The power of the developed technique, implemented in the Knowledge Led Master Code, or KLMC, is demonstrated by its ability to locate and explore a challenging double funnel landscape of a Lennard-Jones 38 atom system (LJ). We apply the redeveloped KLMC to investigate three chemically different systems: ionic semiconductor (ZnO), metallic Ni and covalently bonded C. All four systems have been systematically explored on the energy landscape defined using interatomic potentials. The new developments allowed us to successfully locate the double funnels of LJ, find new local and global minima for ZnO clusters, extensively explore the Ni and C (the buckminsterfullerene, or buckyball) potential energy surfaces.

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Optoelectronic properties of (ZnO)60 isomers

Cited by 15 publications

References 53 publications

Ab Initio Study of Structural and Electronic Properties of (ZnO) n “Magical” Nanoclusters n = (34, 60)

Ab Initio Study of Structural and Electronic Properties of (ZnO) n “Magical” Nanoclusters n = (34, 60)

A DFT/TDDFT study on the optoelectronic properties of the amine-capped magic (CdSe)13 nanocluster

An efficient genetic algorithm for structure prediction at the nanoscale

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