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

In this paper we explore relationships between bird species richness and environmental factors in New York State, focusing particularly on how spatial scale, autocorrelation and nonstationarity affect these relationships. We used spatial statistics, Getis-Ord Gi*(d), to investigate how spatial scale affects the measurement of richness “hot-spots” and “cold-spots” (clusters of high and low species richness, respectively) and geographically weighted regression (GWR) to explore scale dependencies and nonstationarity in the relationships between richness and environmental variables such as climate and plant productivity. Finally, we introduce a geovisualization approach to show how these relationships are affected by spatial scale in order to understand the complex spatial patterns of species richness.

https://www.mdpi.com/2220-9964/4/2/783/pdf

Exploring spatial scale, autocorrelation and nonstationarity of bird species richness patterns

Powder phosphors of ZnS:Ag,Cl coated with SiO2 (22 or 130 nm nanoparticles), SnO2 or Al2O3 showed different cathodoluminescent (CL) brightness versus time (temporal CL quenching) behavior as compared to noncoated phosphors. At high current density (e.g., 300–800 μA/cm2), the CL emission intensity of coated ZnS:Ag,Cl decayed over the first ∼15 s of electron beam irradiation, which was postulated to result from a large concentration of nonradiative surface centers generated during surface modification of the phosphor, and from localization of generated electrons at the surface due to primary beam-induced internal electric fields. During the first ∼15 s of excitation, generated electrons are postulated to be redistributed by this induced internal electric fields, resulting in increased nonradiative surface recombination between electrons and holes. The formation of a nonradiative surface layer either from electron-stimulated surface chemical reactions on coated or from heat treatment of noncoated ZnS:Ag,Cl powder phosphors were shown to affect temporal CL quenching.

Effects of coatings on temporal cathodoluminescence quenching in ZnS:Ag,Cl phosphors

Chlorine (Cl2 or BCl3, with additions of Ar or N2), fluorine (SF6/Ar) and methane/hydrogen (CH4/H2/Ar or CH4/H2/N2) based plasmas have been examined as a function of composition, source and sample chuck power, and pressure, for dry etching of the typical luminescent sulphide phosphors (ZnS, SrS), conductive electrode materials [indium tin oxide, (ITO) and TiW] and insulators (Al2O3, alumina/titania-ATO) used in thin film electroluminescent displays. It is necessary to have both a high ion flux and an ion energy above a particular threshold (typically ⩾125 eV) in order to achieve practical etch rates for the high bond strength materials such as Al2O3, alumina/titania and SrS. The fastest etch rates for ZnS, Al2O3 and aluminum tin oxide are obtained with Cl2/Ar for SrS with SF6/Ar and for ITO with CH4/H2/Ar.

Paul H. Holloway

Papers

Exploring spatial scale, autocorrelation and nonstationarity of bird species richness patterns

Effects of coatings on temporal cathodoluminescence quenching in ZnS:Ag,Cl phosphors

Comparison of plasma chemistries for dry etching thin film electroluminescent display materials

Chemical reactions at metal/compound semiconductor interfaces: Au and GaAs

Carbon Auger peak shape measurements in the characterization of reactions on (001) diamond