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

ZnS:Cu,Al,Au phosphor degradation under electron excitation

Synthesis and characterization of highly luminescent ZnS-passivated CdS:Mn (CdS:Mn/ZnS) core/shell structured nanocrystals are reported Mn-doped CdS core nanocrystals are produced ranging from 15 to 23 nm in diameter with epitaxial ZnS shell of wider band gap via a reverse micelle process UV irradiation-stimulated photo-oxidation of the ZnS shell results in formation of sulfate (ZnSO4) as determined by x-ray photoelectron spectroscopy, which increases the photoluminescence emission intensity and subsequent photostability Luminescent relaxation lifetime data present two different decay components, consisting of slow decay emission from the Mn center and a fast decay emission from a defect-related center The impact of the density of surface defect states upon the emission spectra is discussed

CdS:Mn nanocrystals passivated by ZnS: Synthesis and luminescent properties

Controlled shape growth of Eu- or Tb-doped luminescent Gd2O3 colloidal nanocrystals.

Recent progress in the development of transparent thin-film transistors for integration with flexible displays is discussed Specifically, the fabrication and properties of ZnO-based thin-film transistors on glass are described Top-gate-type thin-film transistors with transparent n-type ZnO as the active channel layer have been fabricated via wet photolithography processing The ZnO layers were deposited using pulsed laser deposition A low leakage current of 10−7 A cm−2 was realized with amorphous HfO2 or (Ce, Tb)MgA11O19 as the gate dielectric N-channel depletion-mode operation was shown for the undoped ZnO thin-film transistors Phosphorus-doped ZnO and (Zn, Mg)O were also utilized as channel materials in order to realize a reduction in carrier density The current–voltage measurements demonstrate an enhancement-mode device operation for the thin-film transistors with P-doped (Zn, Mg)O as the active channel layer and HfO2 serving as the gate dielectric

http://iopscience.iop.org/article/10.1088/0268-1242/20/8/012/pdf

Progress in semiconducting oxide-based thin-film transistors for displays

Reactions between electron beam evaporated thin films of Ni/Au, Pd/Au, and Cr/Au on p-GaN with a carrier concentration of 9.8 × 1016 cm−3 were investigated in terms of their structural and electronic properties both as-deposited and following heat treatments up to 600°C (furnace anneals) and 900°C (RTA) in a flowing N2 ambient. Auger electron spectroscopy (AES) depth profiles were used to study the interfacial reactions between the contact metals and the p-GaN. The electrical properties were studied using room temperature current-voltage (1-V) measurements and the predominant conduction mechanisms in each contact scheme were determined from temperature dependent I-V measurements. The metallization schemes consisted of a 500 A interfacial layer of Ni, Pd, or Cr followed by a 1000 A capping layer of Au. All schemes were shown to be rectifying as-deposited with increased ohmic character upon heat treatment. The Cr/Au contacts became ohmic upon heating to 900°C for 15 seconds while the other schemes remained rectifying with lower breakdown voltages following heat treatment. The specific contact resistance of the Cr/Au contact was measured to be 4.3×10−1 Ωcm2. Both Ni and Cr have been shown to react with the underlying GaN above 400 °C while no evidence of a Pd:GaN reaction was seen. Pd forms a solid solution with the Au capping layer while both Ni and Cr tend to diffuse through the capping layer to the surface. All contacts were shown to have a combination of thermionic emission and thermionic field emission as their dominant conduction mechanism, depending on the magnitude of the applied reverse bias.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S1946427400243261

Paul H. Holloway

Papers

ZnS:Cu,Al,Au phosphor degradation under electron excitation

CdS:Mn nanocrystals passivated by ZnS: Synthesis and luminescent properties

Controlled shape growth of Eu- or Tb-doped luminescent Gd2O3 colloidal nanocrystals.

Progress in semiconducting oxide-based thin-film transistors for displays

Comparison of Ni/Au, Pd/Au, and Cr/Au Metallizations for Ohmic Contacts to p-GaN