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).

/pdf/lanthanide-luminescence-for-functional-materials-and-bio-1w9cppwf8r.pdf

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

Effect of oxygen pressure on the orientation of YBa2Cu3O7−xSrTiO3 films deposited on (1102) Al2O3 substrates

Predicting potential and actual distributions of species has become an active research area in biogeography. Recent debate about the appropriate term for these models – “niche models” or “species distribution models” – stems from confusion over the original niche theory on which they are both based. While niche theory itself has evolved in ecology, there are three main niche concepts that have remained the most relevant for niche models. These concepts and how they inform the development and practice of niche modeling are summarized.


Keywords:

applied biogeography;
bioclimatic envelope;
niche conservatism;
predictive biogeography;
species distribution models

Niche Theory and Models

The growth sequence of Al, Ge, and Ni metals was shown to dramatically affect the amount of heat treatment time required to convert the electrical properties from Schottky to ohmic behavior. Differences in the heat treatment times required to convert from rectifying to ohmic contact were dependent on the doping concentration of the contact layer and on the heat treatment temperature. Interdiffusion of component elements and phase formation have been studied to determine the origin of these effects. Auger depth profiles and X-ray diffraction have been used to determine the interdiffusion and phase formation resulting from various types of thermal processing. Elemental profiles and identification of phases of Ni-Ga, Ni-As, and Ni-Ga-Ge will be used to explain the origin of ohmic behavior.

The Effects of Growth Sequence on the Electronic Properties of Al-Ge-Ni Ohmic Contacts on (001) GaAs

The microstructural properties and interdiffusion reactions of Au/Ge/Ni, Ti/Pt/Au, WSi x and AuBe contacts on GaN and In 0.5 Ga 0.5 N have been examined using Scanning Electron Microscopy and Auger Electron Spectroscopy. The WSi x contacts possess excellent thermal stability and retained good structural properties at annealing temperatures as high as 800°C on GaN. The electrical characteristics of WSi x contacts on In 0.5 Ga 0.5 N had a specific contact resistivity of 1.48×10 −5 Ωcm 2 and an excellent surface morphology following annealing at 700°C. The increase in contact resistance observed at higher temperatures was attributed to intermixing of metal and semiconductor. In contrast the Ti/Pt/Au and Au/Ge/Ni contacts were stable only to ≤ 500°C. AuBe contacts had the poorest thermal stability, with substantial reaction with GaN occurring even at 400°C. The WSi x contact appears to be an excellent choice for high temperature GaN electronics applications.

Paul H. Holloway

Papers

Effect of oxygen pressure on the orientation of YBa2Cu3O7−xSrTiO3 films deposited on (1102) Al2O3 substrates

Niche Theory and Models

The Effects of Growth Sequence on the Electronic Properties of Al-Ge-Ni Ohmic Contacts on (001) GaAs

Thermal Stability of Ohmic Contacts to n-InxGa1−xN

Low-temperature synthesis of red-emitting nanostructured La2O2S2:Eu3+ phosphor