Special Issue "Semiconductor Core/Shell Nanocrystals for Optoelectronic Applications"

A special issue of Nanomaterials (ISSN 2079-4991).

Deadline for manuscript submissions: closed (15 August 2017)

Special Issue Editor

Guest Editor
Dr. Nimai Mishra

Department of Nanochemistry, Italian Institute of Technology Genova, Italy
E-Mail
Phone: +15055002857
Interests: semiconductor nanocrystals; core/shell synthesis; shape control; assembly; nanowires; optoelectronic devices; thermoelectric devices

Special Issue Information

Dear Colleagues,

Core/shell semiconductor nanocrystals (quantum dots) are currently being exploited as active components in a wide range of applications in various fields, such as chemical sensing, biomedicine, and optoelectronics. While conventional single material spherical colloidal nanocrystals have shown promise in these fields due to their ease of fabrication, processibility, and salient optical properties, it may be envisaged that more applications may emerge if nanocrystals can be synthesized in shapes of higher complexity with multi-component core/shell structures and therefore increased functionality. Since the first colloidal semiconductor nanocrystals synthesis was reported in 1993, several group studied the synthesis, properties, and applications of these semiconductor nanocrystals extensively. Further advancement in the optical properties of these nanomaterials has been done in early 2000, when researcher focused on core/shell multicomponent hetero-structures. Over the years advancements have been made towards synthetic control, characterization, and device fabrications.

This Special Issue of Nanomaterials will attempt to cover the recent advancements in the core/shell semiconductor nanocrystals for optoelectronic applications, including solar cell, photodetector, and light emitting devices.

Dr. Nimai Mishra
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

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Keywords

  • semiconductor nanocrystals (quantum dots)

  • core/shell structures

  • charge separation

  • optical properties

  • device fabrications

Published Papers (4 papers)

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Research

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Open AccessArticle Effect of Alkali Metal Atoms Doping on Structural and Nonlinear Optical Properties of the Gold-Germanium Bimetallic Clusters
Nanomaterials 2017, 7(7), 184; doi:10.3390/nano7070184
Received: 16 June 2017 / Revised: 8 July 2017 / Accepted: 10 July 2017 / Published: 17 July 2017
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Abstract
A new series of alkali-based complexes, AM@GenAu (AM = Li, Na, and K), have been theoretically designed and investigated by means of the density functional theory calculations. The geometric structures and electronic properties of the species are systematically analyzed. The adsorption
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A new series of alkali-based complexes, AM@GenAu (AM = Li, Na, and K), have been theoretically designed and investigated by means of the density functional theory calculations. The geometric structures and electronic properties of the species are systematically analyzed. The adsorption of alkali metals maintains the structural framework of the gold-germanium bimetallic clusters, and the alkali metals prefer energetically to be attached on clusters’ surfaces or edges. The high chemical stability of Li@Ge12Au is revealed by the spherical aromaticity, the hybridization between the Ge atoms and Au-4d states, and delocalized multi-center bonds, as well as large binding energies. The static first hyperpolarizability (βtot) is related to the cluster size and geometric structure, and the AM@GenAu (AM = Na and K) clusters exhibit the much larger βtot values up to 13050 a.u., which are considerable to establish their strong nonlinear optical (NLO) behaviors. We hope that this study will promote further application of alkali metals-adsorbed germanium-based semiconductor materials, serving for the design of remarkable and tunable NLO materials. Full article
(This article belongs to the Special Issue Semiconductor Core/Shell Nanocrystals for Optoelectronic Applications)
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Open AccessArticle Influence of Quantum Dot Concentration on Carrier Transport in ZnO:TiO2 Nano-Hybrid Photoanodes for Quantum Dot-Sensitized Solar Cells
Nanomaterials 2016, 6(11), 191; doi:10.3390/nano6110191
Received: 15 July 2016 / Revised: 13 October 2016 / Accepted: 14 October 2016 / Published: 25 October 2016
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Abstract
Zinc oxide nanowire and titanium dioxide nanoparticle (ZnO:TiO2 NW/NP) hybrid films were utilized as the photoanode layer in quantum dot-sensitized solar cells (QDSSCs). CdSe quantum dots (QDs) with a ZnS passivation layer were deposited on the ZnO:TiO2 NW/NP layer as a
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Zinc oxide nanowire and titanium dioxide nanoparticle (ZnO:TiO2 NW/NP) hybrid films were utilized as the photoanode layer in quantum dot-sensitized solar cells (QDSSCs). CdSe quantum dots (QDs) with a ZnS passivation layer were deposited on the ZnO:TiO2 NW/NP layer as a photosensitizer by successive ion layer adsorption and reaction (SILAR). Cells were fabricated using a solid-state polymer electrolyte and intensity-modulated photovoltage and photocurrent spectroscopy (IMVS/PS) was carried out to study the electron transport properties of the cell. Increasing the SILAR coating number enhanced the total charge collection efficiency of the cell. The electron transport time constant and diffusion length were found to decrease as more QD layers were added. Full article
(This article belongs to the Special Issue Semiconductor Core/Shell Nanocrystals for Optoelectronic Applications)
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Open AccessArticle Oxidation of CO and Methanol on Pd-Ni Catalysts Supported on Different Chemically-Treated Carbon Nanofibers
Nanomaterials 2016, 6(10), 187; doi:10.3390/nano6100187
Received: 6 August 2016 / Revised: 26 September 2016 / Accepted: 30 September 2016 / Published: 18 October 2016
Cited by 3 | PDF Full-text (5639 KB) | HTML Full-text | XML Full-text
Abstract
In this work, palladium-nickel nanoparticles supported on carbon nanofibers were synthesized, with metal contents close to 25 wt % and Pd:Ni atomic ratios near to 1:2. These catalysts were previously studied in order to determine their activity toward the oxygen reduction reaction. Before
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In this work, palladium-nickel nanoparticles supported on carbon nanofibers were synthesized, with metal contents close to 25 wt % and Pd:Ni atomic ratios near to 1:2. These catalysts were previously studied in order to determine their activity toward the oxygen reduction reaction. Before the deposition of metals, the carbon nanofibers were chemically treated in order to generate oxygen and nitrogen groups on their surface. Transmission electron microscopy analysis (TEM) images revealed particle diameters between 3 and 4 nm, overcoming the sizes observed for the nanoparticles supported on carbon black (catalyst Pd-Ni CB 1:2). From the CO oxidation at different temperatures, the activation energy Eact for this reaction was determined. These values indicated a high tolerance of the catalysts toward the CO poisoning, especially in the case of the catalysts supported on the non-chemically treated carbon nanofibers. On the other hand, apparent activation energy Eap for the methanol oxidation was also determined finding—as a rate determining step—the COads diffusion to the OHads for the catalysts supported on carbon nanofibers. The results here presented showed that the surface functional groups only play a role in the obtaining of lower particle sizes, which is an important factor in the obtaining of low CO oxidation activation energies. Full article
(This article belongs to the Special Issue Semiconductor Core/Shell Nanocrystals for Optoelectronic Applications)
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Review

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Open AccessFeature PaperReview Complex-Morphology Metal-Based Nanostructures: Fabrication, Characterization, and Applications
Nanomaterials 2016, 6(6), 110; doi:10.3390/nano6060110
Received: 21 April 2016 / Revised: 18 May 2016 / Accepted: 21 May 2016 / Published: 6 June 2016
Cited by 4 | PDF Full-text (9511 KB) | HTML Full-text | XML Full-text
Abstract
Due to their peculiar qualities, metal-based nanostructures have been extensively used in applications such as catalysis, electronics, photography, and information storage, among others. New applications for metals in areas such as photonics, sensing, imaging, and medicine are also being developed. Significantly, most of
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Due to their peculiar qualities, metal-based nanostructures have been extensively used in applications such as catalysis, electronics, photography, and information storage, among others. New applications for metals in areas such as photonics, sensing, imaging, and medicine are also being developed. Significantly, most of these applications require the use of metals in the form of nanostructures with specific controlled properties. The properties of nanoscale metals are determined by a set of physical parameters that include size, shape, composition, and structure. In recent years, many research fields have focused on the synthesis of nanoscale-sized metallic materials with complex shape and composition in order to optimize the optical and electrical response of devices containing metallic nanostructures. The present paper aims to overview the most recent results—in terms of fabrication methodologies, characterization of the physico-chemical properties and applications—of complex-morphology metal-based nanostructures. The paper strongly focuses on the correlation between the complex morphology and the structures’ properties, showing how the morphological complexity (and its nanoscale control) can often give access to a wide range of innovative properties exploitable for innovative functional device production. We begin with an overview of the basic concepts on the correlation between structural and optical parameters of nanoscale metallic materials with complex shape and composition, and the possible solutions offered by nanotechnology in a large range of applications (catalysis, electronics, photonics, sensing). The aim is to assess the state of the art, and then show the innovative contributions that can be proposed in this research field. We subsequently report on innovative, versatile and low-cost synthesis techniques, suitable for providing a good control on the size, surface density, composition and geometry of the metallic nanostructures. The main purpose of this study is the fabrication of functional nanoscale-sized materials, whose properties can be tailored (in a wide range) simply by controlling the structural characteristics. The modulation of the structural parameters is required to tune the plasmonic properties of the nanostructures for applications such as biosensors, opto-electronic or photovoltaic devices and surface-enhanced Raman scattering (SERS) substrates. The structural characterization of the obtained nanoscale materials is employed in order to define how the synthesis parameters affect the structural characteristics of the resulting metallic nanostructures. Then, macroscopic measurements are used to probe their electrical and optical properties. Phenomenological growth models are drafted to explain the processes involved in the growth and evolution of such composite systems. After the synthesis and characterization of the metallic nanostructures, we study the effects of the incorporation of the complex morphologies on the optical and electrical responses of each specific device. Full article
(This article belongs to the Special Issue Semiconductor Core/Shell Nanocrystals for Optoelectronic Applications)
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