Excited electronic states and optical spectra of ZnS and CdS crystallites in the ≊15 to 50 Å size range: Evolution from molecular to bulk semiconducting properties

Rossetti, R.; Hull, Robert; Gibson, J. M.; Brus, L. E.

doi:10.1063/1.448727

Cited by 561 publications

(239 citation statements)

References 14 publications

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“…The relationship between size and optical spectra was first established and confirmed for ZnS and CdS colloidal semiconductor nanoparticles (NPs) by Rosetti et al [1][2][3]. Since then, numerous investigations have been carried out to synthesize colloidal semi-conductors (NCs), and the interest continues to increase [4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Laser-assisted synthesis, and structural and thermal properties of ZnS nanoparticles stabilised in polyvinylpyrrolidone

Onwudiwe

Krüger

Jordaan

et al. 2014

Applied Surface Science

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Research Highlights-Zinc sulphide (ZnS) nanoparticles were synthesised by laser irradiation -The structural and morphological properties of the prepared samples were analysed -Larger particles were obtained by using Na 2 S instead of TAA as the sulphur source.-Phonon softening and line broadening of the peaks were observed -Size reduction occurred in the samples obtained from both sources Graphical Abstract AbstractZinc sulphide (ZnS) nanoparticles have been synthesised by a green approach involving laser irradiation of an aqueous solution of zinc acetate (Znac 2 ) and sodium sulphide (Na 2 S·9H 2 O) or thioacetamide (TAA) in polyvinylpyrrolidone (PVP). The structural and morphological properties of the prepared samples were analysed using a transmission electron microscope, TEM, a high resolution transmission electron microscope, HRTEM, X-ray diffraction, and Raman spectroscopy.The thermal properties were studied using a simultaneous thermal analyser (SDTA). Better dispersed and larger particles were obtained by using sodium sulphide (Na 2 S) instead of TAA as the sulphur source. X-ray diffraction (XRD) analyses and Raman measurement show that the particles have a cubic structure, which is usually a low temperature phase of ZnS. There were phonon softening and line broadening of the peaks which are attributed to the phonon confinement effect. The average crystallite size of the ZnS nanoparticles estimated from the XRD showed a reduction in size from 13.62 to 10.42 nm for samples obtained from Na 2 S, and 9.13 to The absorption spectra showed that the nanoparticles exhibit quantum confinement effects.

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Section: Introductionmentioning

confidence: 99%

Laser-assisted synthesis, and structural and thermal properties of ZnS nanoparticles stabilised in polyvinylpyrrolidone

Onwudiwe

Krüger

Jordaan

et al. 2014

Applied Surface Science

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“…In recent years, semiconductor nanoparticles exhibit specific properties due to the quantum confinement effects. As a consequence of their size in the nanometric range and the special luminescent properties, a widening of the band gap is caused when the spatial dimension is reduced (Brus 1986;Rossetti et al 1985;Hu and Zhang 2006). In semiconductors, the quantum confinement modulates the band structure of the nanoparticles, and hence, many properties can be tuned by changing the nanoparticles size.…”

Section: Introductionmentioning

confidence: 99%

Studies on the dielectric properties of CdS nanoparticles

Sagadevan

2013

Appl Nanosci

146

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CdS is one of the most important II-VI semiconductors with applications in solar cells, optoelectronics and electronic devices. CdS nanoparticles were synthesized by the wet chemical method. The crystal structure and grain size of the particles were determined by X-ray diffraction. The optical properties were studied by the ultraviolet-visible absorption spectrum. The dielectric properties of CdS nanoparticles were studied in the frequency range of 50 Hz-5 MHz at different temperatures. The frequency dependence of the dielectric constant and dielectric loss is found to decrease with an increase in the frequency at different temperatures. The dielectric properties of CdS nanoparticles are found to be significantly enhanced specially in the low frequency range due to confinement. Further, electronic properties, such as valence electron plasma energy, average energy gap or Penn gap, Fermi energy and electronic polarizability of the CdS nanoparticles were calculated. The AC electrical conductivity measurements reveal that the conduction depends on both the frequency and the temperatures.

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“…In recent years, semiconductor nanoparticles exhibit specific properties due to the quantum confinement effects, as a consequence of their size in nanometric range and the special luminescent properties caused by widening the band gap when the spatial dimension is reduced (Brus 1986;Rossetti et al 1985;Hu and Zhang. 2006).…”

Section: Introductionmentioning

confidence: 99%

Optical, electrochemical and thermal properties of Co2+-doped CdS nanoparticles using polyvinylpyrrolidone

2014

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Co 2? (1-5 and 10 %)-doped cadmium sulfide nanoparticles were synthesized by the chemical precipitation method using polyvinyl pyrrolidone (PVP) as a surfactant. The X-ray diffraction results showed that Co ions were successfully incorporated into the CdS lattice and the transmission electron microscopy results revealed that the synthesized particles were aligned as rod-like structures. The absorption spectra of all the prepared samples (undoped and doped) were significantly blue shifted (472-504 nm) from the bulk CdS (512 nm). However, the absorption spectra of the doped samples were red shifted (408-504 nm) with respect to the doping concentrations (1-5 and 10 %). Furthermore, a dramatic blue shift absorption is observed at 472 nm for PVP-capped CdS:Co 2? (4 %) nanoparticles. In the photoluminescence study, two emission peaks were dominated in the green region at 529 and 545 nm corresponding the CdS:Co 2? nanoparticles. By correlating optical and EPR spectral data, the site symmetry of Co 2? ion in the host lattice was determined as both octahedral and tetrahedral. The presence of functional groups in the synthesized nanoparticles was identified by Fourier transform infrared spectroscopy. The thermal stability of the Co ions in CdS nanoparticles was studied by TG-DTA. In addition, an electrochemical property of the undoped and doped samples was studied by cyclic voltammetry for electrode applications.

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Excited electronic states and optical spectra of ZnS and CdS crystallites in the ≊15 to 50 Å size range: Evolution from molecular to bulk semiconducting properties

Cited by 561 publications

References 14 publications

Laser-assisted synthesis, and structural and thermal properties of ZnS nanoparticles stabilised in polyvinylpyrrolidone

Laser-assisted synthesis, and structural and thermal properties of ZnS nanoparticles stabilised in polyvinylpyrrolidone

Studies on the dielectric properties of CdS nanoparticles

Optical, electrochemical and thermal properties of Co2+-doped CdS nanoparticles using polyvinylpyrrolidone

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