Special Issue "Colloidal Nanocrystals: Synthesis, Characterization and Application"

A special issue of Crystals (ISSN 2073-4352). This special issue belongs to the section "Crystal Engineering".

Deadline for manuscript submissions: closed (30 November 2016)

Special Issue Editors

Guest Editor
Dr. Roberto Comparelli

CNR-IPCF Division of Bari, Italy
Website | E-Mail
Interests: inorganic nanocrystals; photocatalysis; plasmonics nanoparticles; nanocrystals functionalization; nanoscale microscopy
Guest Editor
Dr. Lucia Curri

CNR-IPCF Division of Bari, Italy
Website | E-Mail
Interests: colloidal nanoparticles; nanoparticles assembly; bioconjugated nanomaterials; heterostructured and composite nanomaterials
Guest Editor
Dr. Marinella Striccoli

CNR-IPCF Division of Bari, Italy
Website | E-Mail
Interests: colloidal nanocrystals; semiconductors; optical properties; nanocomposites; Hybrid materials

Special Issue Information

Dear Colleagues,

Inorganic nanocrystals and nanoparticles have aroused increasing attention in the last few years due to their original size/shape dependent optoelectronic, thermodynamic, mechanical and catalytic properties. The ability to strongly exploit the original potential of such nano-objects and access their properties relies on the ability of finely tune their size, shape, crystalline phase, and surface chemistry. In this regard, soft chemistry routes provide suitable tools to a priori design and synthetize nano-object with tailored physical-chemical properties as function of the final purpose. Furthermore, conveying the peculiar properties of inorganic nanocrystals to the mesoscopic scale and integrating them in macroscopic entities is the key point to properly exploit their unprecedented functionality for biomedical, optoelectronic, catalytic, energy conversion applications.

We invite contributors to submit original papers that account for recent advances in the field of inorganic nanocrystal and nanoparticles synthesis and characterization, their surface engineering and functionalization, and their applications.

The potential topics include, but are not limited to:

  • Synthesis of inorganic nanocrystals
  • Modeling of inorganic nanocrystals synthesis and properties
  • Fundamental properties of inorganic nanocrystals
  • Advances in characterization techniques of inorganic nanocrystals
  • Surface functionalization of inorganic nanocrystals
  • Inorganic nanocrystal based nanocomposites
  • Energy conversion applications
  • Catalytic processes assisted by inorganic nanocrystals
  • Bioconjugation of nanoparticles and nanocrystals and their biomedical applications
  • (Bio)sensing applications

Dr. Roberto Comparell
Dr. Lucia Curri
Dr. Marinella Striccoli
Guest Editors

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.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Crystals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Colloidal (Inorganic) nanocrystals
  • Nanocrystal synthesis
  • Nanostructured catalysts
  • Energy conversion
  • Nanomedicine
  • (Bio)sensors

Published Papers (9 papers)

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Research

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Open AccessArticle The CeOX and MnOX Nanocrystals Supported on TiO2–Graphene Oxide Catalysts and Their Selective Catalytic Reduction Properties at Low Temperature
Crystals 2017, 7(6), 159; doi:10.3390/cryst7060159
Received: 23 February 2017 / Revised: 26 May 2017 / Accepted: 29 May 2017 / Published: 2 June 2017
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Abstract
A series of 9%CeOx–MnOx/TiO2–GO nanocomposites with different molar ratios of Ce/Mn were synthesized by the sol-gel and ultrasonic impregnation methods and characterized by field emission scanning electron microscope (FESEM), high resolution transmission electron microscopy (HRTEM), N2
[...] Read more.
A series of 9%CeOx–MnOx/TiO2–GO nanocomposites with different molar ratios of Ce/Mn were synthesized by the sol-gel and ultrasonic impregnation methods and characterized by field emission scanning electron microscope (FESEM), high resolution transmission electron microscopy (HRTEM), N2 adsorption (BET) analysis, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT–IR). The results showed that various valences of Ce and Mn oxides were uniformly distributed on the surface of TiO2–GO multilayered supports. The coexistence of various valences of Ce and Mn oxides can improve the redox performance of the catalyst. With the introduction of Ce, the amount of MnO2 and non-stoichiometric MnOx/Mn, the total oxygen and chemisorbed oxygen content, and the electron transfer ability of the catalyst increased significantly. When the molar ratio of Ce/Mn was 0.3, the catalysts exhibited high selective catalytic reduction activity (more than 99% at 180 °C) and N2 selectivity. The presence of hydrophilic groups on the surface of the GO was considered as the critical factor influencing the H2O resistance of the catalyst. Due to the pre-sulfuring process of GO, serious sulfation of the active component can be prevented, and the catalyst exhibited excellent SO2 resistance. Full article
(This article belongs to the Special Issue Colloidal Nanocrystals: Synthesis, Characterization and Application)
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Open AccessArticle Colloidal Nanocrystalline Semiconductor Materials as Photocatalysts for Environmental Protection of Architectural Stone
Crystals 2017, 7(1), 30; doi:10.3390/cryst7010030
Received: 2 November 2016 / Revised: 23 December 2016 / Accepted: 14 January 2017 / Published: 20 January 2017
Cited by 2 | PDF Full-text (4533 KB) | HTML Full-text | XML Full-text
Abstract
Rod-shaped TiO2 nanocrystals (TiO2 NRs), capped by oleic acid molecules (OLEA), were synthesized with controlled size, shape and surface chemistry by using colloidal routes. They were investigated for application as coating materials for preserving architectural stone of monumental and archaeological interest,
[...] Read more.
Rod-shaped TiO2 nanocrystals (TiO2 NRs), capped by oleic acid molecules (OLEA), were synthesized with controlled size, shape and surface chemistry by using colloidal routes. They were investigated for application as coating materials for preserving architectural stone of monumental and archaeological interest, in consideration of their self-cleaning and protection properties. For this purpose, two different deposition techniques, namely casting and dipping, were tested for the application of a nanocrystal dispersion on a defined stone type, as a relevant example of porous calcarenites, namely the Pietra Leccese, a building stone widely used in monuments and buildings of cultural and historic interest of the Apulia region (Italy). The physical properties of the stone surface were investigated before and after the treatment with the prepared nanostructured materials. In particular, colour, wettability, water transfer properties and stability of the coating were monitored as a function of time and of the application method. The self-cleaning properties of the TiO2 NRs coated surfaces were tested under simulated and real solar irradiation. The obtained results were discussed in the light of the specific surface chemistry and morphology of TiO2 NRs, demonstrating the effectiveness of TiO2 NRs as an active component in formulations for stone protection. Full article
(This article belongs to the Special Issue Colloidal Nanocrystals: Synthesis, Characterization and Application)
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Open AccessArticle Synthesizing Iron Oxide Nanostructures: The Polyethylenenemine (PEI) Role
Crystals 2017, 7(1), 22; doi:10.3390/cryst7010022
Received: 23 November 2016 / Revised: 6 January 2017 / Accepted: 9 January 2017 / Published: 12 January 2017
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Abstract
Controlled synthesis of anisotropic iron oxide nanoparticles is a challenge in the field of nanomaterial research that requires an extreme attention to detail. In particular, following up a previous work showcasing the synthesis of magnetite nanorods (NRs) using a two-step approach that made
[...] Read more.
Controlled synthesis of anisotropic iron oxide nanoparticles is a challenge in the field of nanomaterial research that requires an extreme attention to detail. In particular, following up a previous work showcasing the synthesis of magnetite nanorods (NRs) using a two-step approach that made use of polyethylenenemine (PEI) as a capping ligand to synthesize intermediate β-FeOOH NRs, we studied the effect and influence of the capping ligand on the formation of β-FeOOH NRs. By comparing the results reported in the literature with those we obtained from syntheses performed (1) in the absence of PEI or (2) by using PEIs with different molecular weight, we showed how the choice of different PEIs determines the aspect ratio and the structural stability of the β-FeOOH NRs and how this affects the final products. For this purpose, a combination of XRD, HRTEM, and direct current superconducting quantum interference device (DC SQUID) magnetometry was used to identify the phases formed in the final products and study their morphostructural features and related magnetic behavior. Full article
(This article belongs to the Special Issue Colloidal Nanocrystals: Synthesis, Characterization and Application)
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Open AccessArticle Structural and Quantitative Investigation of Perovskite Pore Filling in Mesoporous Metal Oxides
Crystals 2016, 6(11), 149; doi:10.3390/cryst6110149
Received: 29 September 2016 / Revised: 5 November 2016 / Accepted: 9 November 2016 / Published: 16 November 2016
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Abstract
In recent years, hybrid organic–inorganic perovskite light absorbers have attracted much attention in the field of solar cells due to their optoelectronic characteristics that enable high power conversion efficiencies. Perovskite-based solar cells’ efficiency has increased dramatically from 3.8% to more than 20% in
[...] Read more.
In recent years, hybrid organic–inorganic perovskite light absorbers have attracted much attention in the field of solar cells due to their optoelectronic characteristics that enable high power conversion efficiencies. Perovskite-based solar cells’ efficiency has increased dramatically from 3.8% to more than 20% in just a few years, making them a promising low-cost alternative for photovoltaic applications. The deposition of perovskite into a mesoporous metal oxide is an influential factor affecting solar cell performance. Full coverage and pore filling into the porous metal oxide are important issues in the fabrication of highly-efficient mesoporous perovskite solar cells. In this work, we carry out a structural and quantitative investigation of CH3NH3PbI3 pore filling deposited via sequential two-step deposition into two different mesoporous metal oxides—TiO2 and Al2O3. We avoid using a hole conductor in the perovskite solar cells studied in this work to eliminate undesirable end results. Filling oxide pores with perovskite was characterized by Energy Dispersive X-ray Spectroscopy (EDS) in Transmission Electron Microscopy (TEM) on cross-sectional focused ion beam (FIB) lamellae. Complete pore filling of CH3NH3PbI3 perovskite into the metal oxide pores was observed down to X-depth, showing the presence of Pb and I inside the pores. The observations reported in this work are particularly important for mesoporous Al2O3 perovskite solar cells, as pore filling is essential for the operation of this solar cell structure. This work presents structural and quantitative proof of complete pore filling into mesoporous perovskite-based solar cells, substantiating their high power conversion efficiency. Full article
(This article belongs to the Special Issue Colloidal Nanocrystals: Synthesis, Characterization and Application)
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Open AccessArticle Stable Photocatalytic Paints Prepared from Hybrid Core-Shell Fluorinated/Acrylic/TiO2 Waterborne Dispersions
Crystals 2016, 6(10), 136; doi:10.3390/cryst6100136
Received: 25 July 2016 / Revised: 13 October 2016 / Accepted: 19 October 2016 / Published: 24 October 2016
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Abstract
The contamination of air and water is one of the major concerns towards the development of a sustainable world in the 21st century. In this context many efforts are devoted to the design of photocatalytic paints able to degrade chemical and biological impurities
[...] Read more.
The contamination of air and water is one of the major concerns towards the development of a sustainable world in the 21st century. In this context many efforts are devoted to the design of photocatalytic paints able to degrade chemical and biological impurities present in air and water. In this work, the photocatalytic activity of hybrid films formed from the blends of pure acrylic or core/shell fluorinated/acrylic waterborne dispersions and photocatalytic titanium dioxide (TiO2) nanoparticle dispersions was first assessed. The films show photocatalytic activity (inactivation of the Escherichia coli bacteria under UV irradiation) at the substrate-film interface, but very reduced activity in the air-film interface due to the substantially lower amount of the TiO2 nanoparticles in the vicinity of this interface. In a second step, the fluorinated/(meth)acrylic core-shell hybrid dispersions were used as binders in the formulation of waterborne photocatalytic paints and the stability of the paints, in terms of gloss retain and color change, was assessed during 5000 hours of accelerated weathering tests (QUV-B). Although a decrease in gloss retention and increased color change occurs during the first 1000 hours of exposure, no further change of these properties takes place, which is an excellent indication of stable photocatalytic paints. Full article
(This article belongs to the Special Issue Colloidal Nanocrystals: Synthesis, Characterization and Application)
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Open AccessArticle Water-Soluble CdTe/CdS Core/Shell Semiconductor Nanocrystals: How Their Optical Properties Depend on the Synthesis Methods
Crystals 2016, 6(10), 133; doi:10.3390/cryst6100133
Received: 31 July 2016 / Revised: 3 October 2016 / Accepted: 7 October 2016 / Published: 15 October 2016
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Abstract
We conducted a comparative synthesis of water-soluble CdTe/CdS colloidal nanocrystalline semiconductors of the core/shell type. We prepared the CdS shell using two different methods: a one-pot approach and successive ionic layer adsorption and reaction (SILAR); in both cases, we used 3-mercaptopropionic acid (MPA)
[...] Read more.
We conducted a comparative synthesis of water-soluble CdTe/CdS colloidal nanocrystalline semiconductors of the core/shell type. We prepared the CdS shell using two different methods: a one-pot approach and successive ionic layer adsorption and reaction (SILAR); in both cases, we used 3-mercaptopropionic acid (MPA) as the surface ligand. In the one-pot approach, thiourea was added over the freshly formed CdTe dispersion, and served as the sulfur source. We achieved thicker CdS layers by altering the Cd:S stoichiometric ratio (1:1, 1:2, 1:4, and 1:8). The Cd:S ratios 1:1 and 1:2 furnished the best optical properties; these ratios also made the formation of surface defects less likely. For CdTe/CdS obtained using SILAR, we coated the surface of three differently sized CdTe cores (2.17, 3.10, and 3.45 nm) with one to five CdS layers using successive injections of the Cd2+ and S2– ions. The results showed that the core size influenced the optical properties of the materials. The deposition of three to five layers over the surface of smaller CdTe colloidal nanocrystals generated strain effects on the core/shell structure. Full article
(This article belongs to the Special Issue Colloidal Nanocrystals: Synthesis, Characterization and Application)
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Open AccessArticle Self-Assembly of Gold Nanocrystals into Discrete Coupled Plasmonic Structures
Crystals 2016, 6(9), 117; doi:10.3390/cryst6090117
Received: 25 July 2016 / Revised: 25 August 2016 / Accepted: 31 August 2016 / Published: 14 September 2016
Cited by 1 | PDF Full-text (3226 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Development of methodologies for the controlled chemical assembly of nanoparticles into plasmonic molecules of predictable spatial geometry is vital in order to harness novel properties arising from the combination of the individual components constituting the resulting superstructures. This paper presents a route for
[...] Read more.
Development of methodologies for the controlled chemical assembly of nanoparticles into plasmonic molecules of predictable spatial geometry is vital in order to harness novel properties arising from the combination of the individual components constituting the resulting superstructures. This paper presents a route for fabrication of gold plasmonic structures of controlled stoichiometry obtained by the use of a di-rhenium thio-isocyanide complex as linker molecule for gold nanocrystals. Correlated scanning electron microscopy (SEM)—dark-field spectroscopy was used to characterize obtained discrete monomer, dimer and trimer plasmonic molecules. Polarization-dependent scattering spectra of dimer structures showed highly polarized scattering response, due to their highly asymmetric D∞h geometry. In contrast, some trimer structures displayed symmetric geometry (D3h), which showed small polarization dependent response. Theoretical calculations were used to further understand and attribute the origin of plasmonic bands arising during linker-induced formation of plasmonic molecules. Theoretical data matched well with experimentally calculated data. These results confirm that obtained gold superstructures possess properties which are a combination of the properties arising from single components and can, therefore, be classified as plasmonic molecules. Full article
(This article belongs to the Special Issue Colloidal Nanocrystals: Synthesis, Characterization and Application)
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Review

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Open AccessFeature PaperReview Functionalisation of Colloidal Transition Metal Sulphides Nanocrystals: A Fascinating and Challenging Playground for the Chemist
Crystals 2017, 7(4), 110; doi:10.3390/cryst7040110
Received: 27 December 2016 / Revised: 22 March 2017 / Accepted: 24 March 2017 / Published: 14 April 2017
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Abstract
Metal sulphides, and in particular transition metal sulphide colloids, are a broad, versatile and exciting class of inorganic compounds which deserve growing interest and attention ascribable to the functional properties that many of them display. With respect to their oxide homologues, however, they
[...] Read more.
Metal sulphides, and in particular transition metal sulphide colloids, are a broad, versatile and exciting class of inorganic compounds which deserve growing interest and attention ascribable to the functional properties that many of them display. With respect to their oxide homologues, however, they are characterised by noticeably different chemical, structural and hence functional features. Their potential applications span several fields, and in many of the foreseen applications (e.g., in bioimaging and related fields), the achievement of stable colloidal suspensions of metal sulphides is highly desirable or either an unavoidable requirement to be met. To this aim, robust functionalisation strategies should be devised, which however are, with respect to metal or metal oxides colloids, much more challenging. This has to be ascribed, inter alia, also to the still limited knowledge of the sulphides surface chemistry, particularly when comparing it to the better established, though multifaceted, oxide surface chemistry. A ground-breaking endeavour in this field is hence the detailed understanding of the nature of the complex surface chemistry of transition metal sulphides, which ideally requires an integrated experimental and modelling approach. In this review, an overview of the state-of-the-art on the existing examples of functionalisation of transition metal sulphides is provided, also by focusing on selected case studies, exemplifying the manifold nature of this class of binary inorganic compounds. Full article
(This article belongs to the Special Issue Colloidal Nanocrystals: Synthesis, Characterization and Application)
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Open AccessReview X-ray Diffraction: A Powerful Technique for the Multiple-Length-Scale Structural Analysis of Nanomaterials
Crystals 2016, 6(8), 87; doi:10.3390/cryst6080087
Received: 22 June 2016 / Revised: 19 July 2016 / Accepted: 29 July 2016 / Published: 4 August 2016
Cited by 5 | PDF Full-text (5191 KB) | HTML Full-text | XML Full-text
Abstract
During recent decades innovative nanomaterials have been extensively studied, aiming at both investigating the structure-property relationship and discovering new properties, in order to achieve relevant improvements in current state-of-the art materials. Lately, controlled growth and/or assembly of nanostructures into hierarchical and complex architectures
[...] Read more.
During recent decades innovative nanomaterials have been extensively studied, aiming at both investigating the structure-property relationship and discovering new properties, in order to achieve relevant improvements in current state-of-the art materials. Lately, controlled growth and/or assembly of nanostructures into hierarchical and complex architectures have played a key role in engineering novel functionalized materials. Since the structural characterization of such materials is a fundamental step, here we discuss X-ray scattering/diffraction techniques to analyze inorganic nanomaterials under different conditions: dispersed in solutions, dried in powders, embedded in matrix, and deposited onto surfaces or underneath them. Full article
(This article belongs to the Special Issue Colloidal Nanocrystals: Synthesis, Characterization and Application)
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