Effects of surface termination on the band gap of ultrabright<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Si</mml:mi></mml:mrow><mml:mrow><mml:mn>29</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>nanoparticles: Experiments and computational models

Belomoin, G.; Rogozhina, Elena V.; Therrien, Joel; Braun, Paul V.; Abuhassan, Laila; Nayfeh, Munir H.; Wagner, Lucas K.; Mitáš, Luboš

doi:10.1103/physrevb.65.193406

Cited by 45 publications

(37 citation statements)

References 29 publications

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“…12 The 1 nm Si nanoclusters are amenable to testing and accurate first-principles simulations because they consist of a manageable number of Si and H atoms and are produced in macroscopic amounts. Thus, these particles have been attracting experimental [6][7][8][9][10][11][12] and theoretical [13][14][15][16][17][18][19] attention. Calculations based upon density functional theory with a generalized gradient exchange-correlation potential, configuration interaction, and Monte Carlo approaches suggest a filled fullerene structure for Si 29 H 24 ͑1 nm͒.…”

Section: Introductionmentioning

confidence: 99%

“…Calculations based upon density functional theory with a generalized gradient exchange-correlation potential, configuration interaction, and Monte Carlo approaches suggest a filled fullerene structure for Si 29 H 24 ͑1 nm͒. [15][16][17] The molecular structure of this hydrogenated configuration was calculated for several specific surface reconstructions, from fully constructed to nonconstructed surfaces. [15][16][17][18][19] The structure, shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

“…[15][16][17] The molecular structure of this hydrogenated configuration was calculated for several specific surface reconstructions, from fully constructed to nonconstructed surfaces. [15][16][17][18][19] The structure, shown in Fig. 1͑a͒, [15][16][17] referred to as ideal bulklike, is nearly spherical but contains a combination of hexagon and pentagon ring structures (T d point group symmetry͒ that produce a highly wrinkled or ''puckered-ball'' surface.…”

Section: Introductionmentioning

confidence: 99%

“…[15][16][17][18][19] The structure, shown in Fig. 1͑a͒, [15][16][17] referred to as ideal bulklike, is nearly spherical but contains a combination of hexagon and pentagon ring structures (T d point group symmetry͒ that produce a highly wrinkled or ''puckered-ball'' surface. It consists of a central core Si atom and four Si atoms in a tetrahedral coordination, constituting an inner core ͑inner shell͒.…”

Section: Introductionmentioning

confidence: 99%

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Excited states of tetrahedral single-coreSi29nanoparticles

et al. 2004

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We dispersed bulk crystalline Si into identical hydrogenated nanoparticles with negligible impurities and defects, which provide the opportunity for detailed comparison between measurement and theory. The UV photoluminescence of a dispersion of 1 nm silicon particles was studied. Distinct bands appear in the emission spectra with the lowest peaks in wavelength identified to be at 400, 360, and 310 nm with optimal excitation at 3.7, 4.0, and 4.6 eV, respectively. The multiple photoluminescence bands are analyzed in terms of the molecularlike energy levels of one bulklike and two nonbulklike reconstruction configurations of the filled fullerene single-core Si 29 H 24 , calculated by quantum Monte Carlo calculations and by time-dependent density functional theory. The measured bands are in close agreement with the excited states of the ideal bulklike configuration. However, there is a possibility that some of the observed bands might originate from the nonbulklike reconstructions. The Stokes shifts are discussed in terms of radiative relaxation via the molecularlike states versus charge carrier relaxation via the underlying continuum states.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Excited states of tetrahedral single-coreSi29nanoparticles

et al. 2004

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“…We used ultra-small Si nanoparticles [27][28][29][30][31] with Si-H termination. The nanoparticles are prepared from Si wafers by chemical etching in HF and H 2 O 2 using electrical or hexachloroplatinic acid catalyst.…”

Section: Methodsmentioning

confidence: 99%

Wideband luminescence from bandgap-matched Mg-based Si core-shell geometry nanocomposite

et al. 2018

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We use wet treatment to integrate red-luminescent Si nanoparticles with Mg-based wide-bandgap insulators Mg(OH) and MgO (5.7 and 7.3 eV respectively). In the process, Mg2+ is reduced on Si nanoparticle clusters, while suffering combustion in water, producing a spatially inhomogeneous Mg(OH)2/MgO-Si nanoparticle composite with an inner material predominantly made of Si, and a coating consisting predominantly of magnesium and oxygen (“core-shell” geometry). The nanocomposite exhibit luminescence covering nearly entire visible range. Results are consistent with formation of Mg(OH)2/MgO phase with direct 3.43-eV bandgap matching that of Si, with in-gap blue-green emitting states of charged Mg and O vacancies. Bandgap match with nanocomposite architecture affords strong enough coupling for the materials to nearly act as a single hybrid material with novel luminescence for photonic and photovoltaic applications.

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Mechanochemical Synthesis of Blue Luminescent Alkyl/Alkenyl‐Passivated Silicon Nanoparticles

Heintz¹,

Fink²,

Mitchell³

2007

Advanced Materials

141

118

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Silicon is a key material in the microelectronics industry. Recently, there has been great interest in nanocrystalline phases of silicon due to their size dependent electronic and optical properties.[1] Nanoparticles with physical dimensions less than the bulk Bohr exciton radius of silicon (4 nm) typically display intense photoluminescence due to quantum size effects and have potential use both in optoelectronic devices [2][3][4] and as fluorescent biomarkers. [5,6] In the case of crystalline silicon nanoparticles, the photoluminescence (PL) will shift to higher energies as the average size of the nanoparticles is reduced. [7,8] Particle sizes of the order of ∼ 1 nm have been termed "ultrabright" and show an intense emission in the blue region of the visible spectrum. [9][10][11] In addition to a dependence on the particle size, the photoluminesence of silicon nanoparticles is also influenced by the nature of the passivating layer on the particle surface. [12][13][14][15] Passivation of the surface provides chemical stability to air-oxidation and Ostwald ripening and also ties down defect states at the surface caused by dangling bonds. Successful passiviation of the silicon surface has been recently achieved by chemically inert alkyl groups. A surface passivated with strong Si-C bonds is chemically stable and the effective band gap of the silicon nanoparticle is relatively unperturbed by the alkyl passivation.[16] Alkyl passivated nanoparticles have been previously produced by chemical and electrochemical etching of bulk silicon, [17][18][19][20] the reduction of halosilanes, [21,22] the oxidation of metal silicides, [23,24] and the thermal decomposition of silanes in the gas phase [25][26][27] and supercritical fluids.[28] Each of these approaches requires the use of highly reactive or corrosive chemicals and often requires the modification of unstable hydrogen or halogen terminated surfaces. [29,30] Direct approaches, commonly involving the mechanical scribing of silicon in the presence of reactive organic reagents, have found success in the patterning of silicon surfaces though reaction of a freshly exposed surface with the organic reagent. [31][32][33][34] However, these techniques are limited to large and regular surfaces, and are not practical for use with nanoparticles. Here we describe a novel top-down procedure for the synthesis of stable alkyl/alkenyl passivated silicon nanoparticles using high energy ball milling (HEBM). [35] The main advantage of this mechanochemical approach is the simultaneous production of silicon nanoparticles and the chemical passivation of the particle surface by alkyl/alkenyl groups covalently linked through strong Si-C bonds. The overall procedure for production of alkyl/alkenyl passivated silicon nanoparticles is illustrated in Figure 1. A milling vial is loaded under inert atmosphere with non-spherical millimeter-sized pieces of semiconductor-grade silicon and either an alkene or alkyne. Stainless steel milling balls are added to the vial, which is then sealed and placed in...

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Effects of surface termination on the band gap of ultrabrightSi29nanoparticles: Experiments and computational models

Cited by 45 publications

References 29 publications

Excited states of tetrahedral single-coreSi29nanoparticles

Excited states of tetrahedral single-coreSi29nanoparticles

Wideband luminescence from bandgap-matched Mg-based Si core-shell geometry nanocomposite

Mechanochemical Synthesis of Blue Luminescent Alkyl/Alkenyl‐Passivated Silicon Nanoparticles

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