Luminescent Functional Metal–Organic Frameworks

Fluorescent carbon nanoparticles or carbon quantum dots (CQDs) are a new class of carbon nanomaterials that have emerged recently and have garnered much interest as potential competitors to conventional semiconductor quantum dots. In addition to their comparable optical properties, CQDs have the desired advantages of low toxicity, environmental friendliness low cost and simple synthetic routes. Moreover, surface passivation and functionalization of CQDs allow for the control of their physicochemical properties. Since their discovery, CQDs have found many applications in the fields of chemical sensing, biosensing, bioimaging, nanomedicine, photocatalysis and electrocatalysis. This article reviews the progress in the research and development of CQDs with an emphasis on their synthesis, functionalization and technical applications along with some discussion on challenges and perspectives in this exciting and promising field.

Carbon quantum dots and their applications

Recent startling interest for lanthanide luminescence is stimulated by the continuously expanding need for luminescent materials meeting the stringent requirements of telecommunication, lighting, electroluminescent devices, (bio-)analytical sensors and bio-imaging set-ups. This critical review describes the latest developments in (i) the sensitization of near-infrared luminescence, (ii) “soft” luminescent materials (liquid crystals, ionic liquids, ionogels), (iii) electroluminescent materials for organic light emitting diodes, with emphasis on white light generation, and (iv) applications in luminescent bio-sensing and bio-imaging based on time-resolved detection and multiphoton excitation (500 references).

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Lanthanide luminescence for functional materials and bio-sciences

Lanthanide-based luminescent hybrid materials.

There is a special reason for reviewing this book at this time: it is the 50th edition of a compendium that is known and used frequently in most chemical and physical laboratories in many parts of the world. Surely, a publication that has been published for 56 years, withstanding the vagaries of science in this century, must have had something to offer. There is another reason: while the book is a standard fixture in most chemical and physical laboratories, including those in medical centers, it is not as frequently seen in the laboratories of physician's offices (those either in solo or group practice). I believe that the Handbook can be useful in those laboratories. One of the reasons, among others, is that the various basic items of information it offers may be helpful in new tests, either physical or chemical, which are continuously being published. The basic information may relate

Handbook of Chemistry and Physics

The effects of Ar‐ion sputtering on electrical properties of Au contacts on (100) GaAs and the role of doping concentration have been studied. The n‐GaAs was doped with 1017 or 1018 cm−3 Si or with 1018 cm−3 Te and the p‐GaAs with 1018 or 1019 cm−3 Zn. After either chemical etching or Ar‐ion beam cleaning of the GaAs, Au contacts were formed by evaporation in ultrahigh vacuum (10−9 Torr). Ion bombardment with Ar+ produced clean but nonstoichiometric, damaged GaAs surfaces. Contacts on chemically cleaned GaAs were either (nearly) ohmic or Schottky, depending upon the dopant and concentration. On sputtered GaAs, all the contacts showed soft rectification but did not act as purely Schottky contacts. The type of dopants, i.e., n or p, caused differences in the I‐V behavior, but the behavior for different dopants of the same type was very similar. Sputtering increased the depletion depth on all the samples, and the depletion depth became larger as the ion energy increased and/or the dopant concentration decrea...

The effect of sputter cleaning on Au/GaAs contacts and the role of doping

One-dimensional (1D) Gd2O3:Eu3+ nano-rods and micro-rods were prepared using a facile sol-gel precipitation method, without a template and with a post-growth heat treatment in air. Based on scanning electron microscopy (SEM) and X-ray diffraction (XRD) data, hexagonal Gd(OH)3:Eu3+ micro-rods, 60∼90 nm in diameter and 700 nm to 1 μm in length, were synthesized and then transformed by calcining (800°C, 2 hr) to cubic Gd2O3:Eu3+ with the same morphology and dimensions. Nano-rods of Eu3+ doped Gd(OH)3 and calcined Gd2O3, 60∼90 nm diameter and 150∼300 nm length, were prepared by adding polyethylene glycol (PEG) as a capping agent during the sol-gel synthesis. Photoluminescence (PL) spectra exhibited the 5D0–7F2 transitions of Eu3+ at 612 and 627 nm from excitation at 280 nm. Photoluminescence excitation (PLE) data showed that a small fraction of PL from Eu3+ resulted from direct excitation, but most PL resulted from the oxygen to europium charge-transfer band (CTB) between 250 and 280 nm.

Synthesis and luminescent characteristics of one-dimensional europium doped Gd2O3 phosphors

Blue Carbon ecosystems such as mangroves, saltmarshes and seagrasses have been shown to sequester large amounts of carbon, and subsequently are receiving renewed interest from policy experts in light of climate change. Globally, seagrasses remain the most understudied of these ecosystems, with their total geographic extent largely unknown due to challenges in mapping dynamic coastal environments. As such, species distribution models (SDMs) have been used to identify areas of high suitability, in order to inform our understanding of where unmapped meadows may be located or to identify suitable sites for restoration and/or enhancement efforts. However, many SDMs parameterized to project seagrass distributions focus on physical and not anthropogenic variables (i.e., dredging, aquaculture), which can have negative impacts on seagrass meadows. Here we used verified datasets to identify the potential distribution of Zostera marina and Zostera noltei at a national level for the Republic of Ireland, using 19 environmental variables including both physical and anthropogenic. Using the Maximum Entropy method for developing the SDM, we estimated approximately 95 km2 of suitable habitat for Z. marina and 70 km2 for Z. noltei nationally with high accuracy metrics, including Area Under the Curve (AUC) values of 0.939 and 0.931, respectively for the two species. We found that bathymetry, maximum sea-surface temperature (SST) and minimum salinity were the most important environmental variables that explained the distribution of Z. marina and that high standard deviation of SST, mean SST and maximum salinity were the most important variables in explaining the distribution of Z. noltei. At a national level, we noted that it was primarily physical variables that determined the geographic distribution of seagrass, not anthropogenic variables. We unexpectedly modelled areas of high suitability in locations of anthropogenic disturbance (i.e., dredging, high pollution risk), although this may be due to the binary nature of SDMs capturing presence-absence and not the size and condition of the meadows, suggesting a need for future research to explore the finer scale impacts of anthropogenic activity. Subsequently, this research should foster discussion for researchers and practitioners working on sustainability projects related to Blue Carbon.

Assessing the Impact of Physical and Anthropogenic Environmental Factors in Determining the Habitat Suitability of Seagrass Ecosystems

73-2: Invited Paper: High-Performance Quantum Dot Light Emitting Diodes and their Challenges

Using e-beam lithography techniques we have patterned Ni wire widths down to less than 100 nm. The patterning techniques were utilized either to fabricate nanodeposition masks for further direct deposition of Ni and subsequent liftoff or to deposit Nb wire structures used for Ar ion-mill etch masks on top of Ni thin films. The resulting Ni nanowire structures showed strong differences in transport as well as differing morphologies measured by atomic force microscopy (AFM) and scanning electron microscopy. In the case of fabricating nanodeposition masks, direct deposition of Ni was performed by magnetron sputtering, thermal evaporation, and e-beam evaporation. In the resulting nanowires, e-beam evaporated wires show the best residual resistance and magnetoresistance (MR) characteristics. AFM results showed the nanowires produced by evaporation to have granular structure. The nanowires fabricated by dry etching surpassed all nanowires fabricated by direct deposition and liftoff in both residual resistances ...

Paul H. Holloway

Papers

The effect of sputter cleaning on Au/GaAs contacts and the role of doping

Synthesis and luminescent characteristics of one-dimensional europium doped Gd2O3 phosphors

Assessing the Impact of Physical and Anthropogenic Environmental Factors in Determining the Habitat Suitability of Seagrass Ecosystems

73-2: Invited Paper: High-Performance Quantum Dot Light Emitting Diodes and their Challenges

Comparative study of Ni nanowires patterned by electron-beam lithography and fabricated by lift-off and dry etching techniques