Special Issue "Current Trends in Up-Converting Nanoparticles"

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

Deadline for manuscript submissions: closed (31 January 2015)

Special Issue Editor

Guest Editor
Prof. Dr. John Capobianco (Website)

Concordia University Research Chair in Nanoscience, Department of Chemistry and Biochemistry, Co-Director Centre for NanoScience Research, Concordia University, 7141 Sherbrooke St. W., SP 275.13, Montreal, Quebec, H4B 1R6, Canada
Interests: upconversion; lanthanides; synthesis of lanthanide doped nanoparticles; bioimaging; MRI; PDT; photoswitching

Special Issue Information

Dear Colleagues,

Upconverting nanomaterials have received enormous attention over the past years, resulting in a plethora of applications, which impact our daily lives. These applications cover a range of fields (from chemistry, physics and biology, to medicine, engineering and electronics), and may be considered to cover four broad categories: optoelectronics, bio-nanomedicine, security and alternative energy. The enormous number of publications, which has accelerated since the late 90’s and the continued development of upconverting nanomaterials reflect this.

This issue of Nanomaterials will consider the synthesis, characterization, functionalization and applications (MRI, PDT, imaging, theranostic, photovoltaic, optoelectonics) of upconverting nanomaterials.

Prof. Dr. John Capobianco
Guest Editor

Submission

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. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as 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 refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Nanomaterials 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). English correction and/or formatting fees of 250 CHF (Swiss Francs) will be charged in certain cases for those articles accepted for publication that require extensive additional formatting and/or English corrections.

Keywords

  • upconversion
  • nanomaterials
  • synthesis
  • bionanomedicine
  • optoelectronic
  • solar cells
  • fluorescence energy transfer

Published Papers (6 papers)

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Research

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Open AccessArticle Synthesis of Upconversion β-NaYF4:Nd3+/Yb3+/Er3+ Particles with Enhanced Luminescent Intensity through Control of Morphology and Phase
Nanomaterials 2015, 5(1), 218-232; doi:10.3390/nano5010218
Received: 27 January 2015 / Revised: 11 February 2015 / Accepted: 12 February 2015 / Published: 24 February 2015
Cited by 6 | PDF Full-text (1056 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Hexagonal NaYF4:Nd3+/Yb3+/Er3+ microcrystals and nanocrystals with well-defined morphologies and sizes have been synthesized via a hydrothermal route. The rational control of initial reaction conditions can not only result in upconversion (UC) micro and nanocrystals with [...] Read more.
Hexagonal NaYF4:Nd3+/Yb3+/Er3+ microcrystals and nanocrystals with well-defined morphologies and sizes have been synthesized via a hydrothermal route. The rational control of initial reaction conditions can not only result in upconversion (UC) micro and nanocrystals with varying morphologies, but also can produce enhanced and tailored upconversion emissions from the Yb3+/Er3+ ion pairs sensitized by the Nd3+ ions. The increase of reaction time converts the phase of NaYF4:Nd3+/Yb3+/Er3+ particles from the cubic to the hexagonal structure. The added amount of oleic acid plays a critical role in the shape evolution of the final products due to their preferential attachment to some crystal planes. The adjustment of the molar ratio of F/Ln3+ can range the morphologies of the β-NaYF4:Nd3+/Yb3+/Er3+ microcrystals from spheres to nanorods. When excited by 808 nm infrared laser, β-NaYF4:Nd3+/Yb3+/Er3+ microplates exhibit a much stronger UC emission intensity than particles with other morphologies. This phase- and morphology-dependent UC emission holds promise for applications in photonic devices and biological studies. Full article
(This article belongs to the Special Issue Current Trends in Up-Converting Nanoparticles)
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Open AccessArticle One-Pot Solvothermal Synthesis of Highly Emissive, Sodium-Codoped, LaF3 and BaLaF5 Core-Shell Upconverting Nanocrystals
Nanomaterials 2014, 4(1), 69-86; doi:10.3390/nano4010069
Received: 17 December 2013 / Revised: 2 January 2014 / Accepted: 2 January 2014 / Published: 8 January 2014
Cited by 4 | PDF Full-text (1665 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
We report a one-pot solvothermal synthesis of sub-10 nm, dominant ultraviolet (UV) emissive upconverting nanocrystals (UCNCs), based on sodium-codoped LaF3 and BaLaF5 (0.5%Tm; 20%Yb) and their corresponding core@shell derivatives. Elemental analysis shows a Na-codopant in these crystal systems of ~20% [...] Read more.
We report a one-pot solvothermal synthesis of sub-10 nm, dominant ultraviolet (UV) emissive upconverting nanocrystals (UCNCs), based on sodium-codoped LaF3 and BaLaF5 (0.5%Tm; 20%Yb) and their corresponding core@shell derivatives. Elemental analysis shows a Na-codopant in these crystal systems of ~20% the total cation content; X-ray diffraction (XRD) data indicate a shift in unit cell dimensions consistent with these small codopant ions. Similarly, X-ray photoelectron spectroscopic (XPS) analysis reveals primarily substitution of Na+ for La3+ ions (97% of total Na+ codopant) in the crystal system, and interstitial Na+ (3% of detected Na+) and La3+ (3% of detected La3+) present in (Na)LaF3 and only direct substitution of Na+ for Ba2+ in Ba(Na)LaF5. In each case, XPS analysis of La 3d lines show a decrease in binding energy (0.08–0.25 eV) indicating a reduction in local crystal field symmetry surrounding rare earth (R.E.3+) ions, permitting otherwise disallowed R.E. UC transitions to be enhanced. Studies that examine the impact of laser excitation power upon luminescence intensity were conducted over 2.5–100 W/cm2 range to elucidate UC mechanisms that populate dominant UV emitting states. Low power saturation of Tm3+ 3F3 and 3H4 states was observed and noted as a key initial condition for effective population of the 1D2 and 1I6 UV emitting states, via Tm-Tm cross-relaxation. Full article
(This article belongs to the Special Issue Current Trends in Up-Converting Nanoparticles)
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Open AccessArticle Enhanced Upconversion Luminescence in Yb3+/Tm3+-Codoped Fluoride Active Core/Active Shell/Inert Shell Nanoparticles through Directed Energy Migration
Nanomaterials 2014, 4(1), 55-68; doi:10.3390/nano4010055
Received: 11 December 2013 / Revised: 30 December 2013 / Accepted: 30 December 2013 / Published: 3 January 2014
Cited by 14 | PDF Full-text (2535 KB) | HTML Full-text | XML Full-text
Abstract
The luminescence efficiency of lanthanide-doped upconversion nanoparticles is of particular importance for their embodiment in biophotonic and photonic applications. Here, we show that the upconversion luminescence of typically used NaYF4:Yb3+30%/Tm3+0.5% nanoparticles can be enhanced by ~240 [...] Read more.
The luminescence efficiency of lanthanide-doped upconversion nanoparticles is of particular importance for their embodiment in biophotonic and photonic applications. Here, we show that the upconversion luminescence of typically used NaYF4:Yb3+30%/Tm3+0.5% nanoparticles can be enhanced by ~240 times through a hierarchical active core/active shell/inert shell (NaYF4:Yb3+30%/Tm3+0.5%)/NaYbF4/NaYF4 design, which involves the use of directed energy migration in the second active shell layer. The resulting active core/active shell/inert shell nanoparticles are determined to be about 11 times brighter than that of well-investigated (NaYF4:Yb3+30%/Tm3+0.5%)/NaYF4 active core/inert shell nanoparticles when excited at ~980 nm. The strategy for enhanced upconversion in Yb3+/Tm3+-codoped NaYF4 nanoparticles through directed energy migration might have implications for other types of lanthanide-doped upconversion nanoparticles. Full article
(This article belongs to the Special Issue Current Trends in Up-Converting Nanoparticles)
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Open AccessArticle Tuning NaYF4 Nanoparticles through Alkaline Earth Doping
Nanomaterials 2013, 3(4), 583-591; doi:10.3390/nano3040583
Received: 10 October 2013 / Revised: 20 October 2013 / Accepted: 21 October 2013 / Published: 24 October 2013
Cited by 7 | PDF Full-text (581 KB) | HTML Full-text | XML Full-text
Abstract
Phase and size of lanthanide-doped nanoparticles are the most important characteristics that dictate optical properties of these nanoparticles and affect their technological applications. Herein, we present a systematic study to examine the effect of alkaline earth doping on the formation of NaYF [...] Read more.
Phase and size of lanthanide-doped nanoparticles are the most important characteristics that dictate optical properties of these nanoparticles and affect their technological applications. Herein, we present a systematic study to examine the effect of alkaline earth doping on the formation of NaYF4 upconversion nanoparticles. We show that alkaline earth doping has a dual function of tuning particle size of hexagonal phase NaYF4 nanoparticles and stabilizing cubic phase NaYF4 nanoparticles depending on composition and concentration of the dopant ions. The study described here represents a facile and general strategy to tuning the properties of NaYF4 upconversion nanoparticles. Full article
(This article belongs to the Special Issue Current Trends in Up-Converting Nanoparticles)

Review

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Open AccessFeature PaperReview Rare Earth Ion-Doped Upconversion Nanocrystals: Synthesis and Surface Modification
Nanomaterials 2015, 5(1), 1-25; doi:10.3390/nano5010001
Received: 3 November 2014 / Accepted: 10 December 2014 / Published: 25 December 2014
Cited by 9 | PDF Full-text (1361 KB) | HTML Full-text | XML Full-text
Abstract
The unique luminescent properties exhibited by rare earth ion-doped upconversion nanocrystals (UCNPs), such as long lifetime, narrow emission line, high color purity, and high resistance to photobleaching, have made them widely used in many areas, including but not limited to high-resolution displays, [...] Read more.
The unique luminescent properties exhibited by rare earth ion-doped upconversion nanocrystals (UCNPs), such as long lifetime, narrow emission line, high color purity, and high resistance to photobleaching, have made them widely used in many areas, including but not limited to high-resolution displays, new-generation information technology, optical communication, bioimaging, and therapy. However, the inherent upconversion luminescent properties of UCNPs are influenced by various parameters, including the size, shape, crystal structure, and chemical composition of the UCNPs, and even the chosen synthesis process and the surfactant molecules used. This review will provide a complete summary on the synthesis methods and the surface modification strategies of UCNPs reported so far. Firstly, we summarize the synthesis methodologies developed in the past decades, such as thermal decomposition, thermal coprecipitation, hydro/solvothermal, sol-gel, combustion, and microwave synthesis. In the second part, five main streams of surface modification strategies for converting hydrophobic UCNPs into hydrophilic ones are elaborated. Finally, we consider the likely directions of the future development and challenges of the synthesis and surface modification, such as the large-scale production and actual applications, stability, and so on, of the UCNPs. Full article
(This article belongs to the Special Issue Current Trends in Up-Converting Nanoparticles)
Open AccessReview Recent Advance of Biological Molecular Imaging Based on Lanthanide-Doped Upconversion-Luminescent Nanomaterials
Nanomaterials 2014, 4(1), 129-154; doi:10.3390/nano4010129
Received: 23 December 2013 / Revised: 23 January 2014 / Accepted: 27 January 2014 / Published: 6 February 2014
Cited by 29 | PDF Full-text (2979 KB) | HTML Full-text | XML Full-text
Abstract
Lanthanide-doped upconversion-luminescent nanoparticles (UCNPs), which can be excited by near-infrared (NIR) laser irradiation to emit multiplex light, have been proven to be very useful for in vitro and in vivo molecular imaging studies. In comparison with the conventionally used down-conversion fluorescence imaging [...] Read more.
Lanthanide-doped upconversion-luminescent nanoparticles (UCNPs), which can be excited by near-infrared (NIR) laser irradiation to emit multiplex light, have been proven to be very useful for in vitro and in vivo molecular imaging studies. In comparison with the conventionally used down-conversion fluorescence imaging strategies, the NIR light excited luminescence of UCNPs displays high photostability, low cytotoxicity, little background auto-fluorescence, which allows for deep tissue penetration, making them attractive as contrast agents for biomedical imaging applications. In this review, we will mainly focus on the latest development of a new type of lanthanide-doped UCNP material and its main applications for in vitro and in vivo molecular imaging and we will also discuss the challenges and future perspectives. Full article
(This article belongs to the Special Issue Current Trends in Up-Converting Nanoparticles)
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