Department of Materials Science, University of Patras, 26504 Rio Patras, Greece, Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vass. Constantinou Avenue, 116 35 Athens, Greece, Institut de Biologie Moleculaire et Cellulaire, UPR9021 CNRS, Immunologie et Chimie Therapeutiques, 67084 Strasbourg, France, and Dipartimento di Scienze Farmaceutiche, Universita di Trieste, Piazzale Europa 1, 34127 Trieste, Italy

Chemistry of Carbon Nanotubes

Core/Shell Nanoparticles: Classes, Properties, Synthesis Mechanisms, Characterization, and 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.

The term photonic crystals appears because of the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures. During the recent years the investigation of one-, two-and three-dimensional periodic structures has attracted a widespread attention of the world optics community because of great potentiality of such structures in advanced applied optical fields. The interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.

http://ieeexplore.ieee.org/iel5/6354/16969/00781867.pdf

Photonic crystals

Carbon Nanotube Doped Polyaniline

Multipod gold nanocrystals have been synthesized via a simple solution-phase chemical reduction method at room temperature. Two types of structurally different particles are observed, including the regular tripod, which lies on the substrate with its {111} plane, and the cross-like tetrapod that sits on its {100} plane. Both structures have pods of 10 nm sizes and grow along 〈110〉 directions. Variously shaped particles, including tadpole-like or teardrop-like monopods, 90° L-shaped, 180° I-shaped, and 120° V-shaped bipods, T-shaped, Y-shaped, and regular triangular tripods, and cross-like tetrapods, have been produced. Due to the high conductivity of metal, these branched structures are quite promising considering their applications as interconnections in the “bottom-up” self-assembly approach toward future nanocircuits and nanodevices, as well as in other related fields.

Monopod, bipod, tripod, and tetrapod gold nanocrystals

Described herein are initial experimental details and properties of a silicon core, silica glass-clad optical fiber fabricated using conventional optical fiber draw methods. Such semiconductor core fibers have potential to greatly influence the fields of nonlinear fiber optics, infrared and THz power delivery. More specifically, x-ray diffraction and Raman spectroscopy showed the core to be highly crystalline silicon. The measured propagation losses were 4.3 dB/m at 2.936 µm, which likely are caused by either microcracks in the core arising from the large thermal expansion mismatch with the cladding or to SiO2 precipitates formed from oxygen dissolved in the silicon melt. Suggestions for enhancing the performance of these semiconductor core fibers are provided. Here we show that lengths of an optical fiber containing a highly crystalline semiconducting core can be produced using scalable fiber fabrication techniques.

Silicon optical fiber.

The Faraday effect provides a mechanism for achieving unidirectional light propagation in optical isolators; however, miniaturization requires large Verdet constants. High rare-earth content glasses produce suitably large Verdet values, but intrinsic fabrication problems remain. The novel powder-intube method, or a single-draw rod-in-tube method, obviates these difficulties. The powder-in-tube method was used to make silica-clad optical fibers with a high terbium oxide content aluminosilicate core. Core diameters of 2.4 µm were achieved in 125-µm-diameter fibers, with a numerical aperture of 0.35 and a Verdet constant of -20.0 rad/(T m) at 1.06 µm. This value is greater than 50% for crystals found in current isolator systems. This development could lead to all-fiber isolators of dramatically lower cost and ease of fabrication compared with their crystalline competitors.

/pdf/fabrication-of-fibers-with-high-rare-earth-concentrations-17ivqqaqt3.pdf

Fabrication of fibers with high rare-earth concentrations for Faraday isolator applications

Nanocrystalline LaF3:Nd and CaF2:Er with rare-earth concentrations ranging from 0.5 to 16.7 mol % and dispersible particle sizes less than 100 nm were synthesized by solvothermal synthesis. Optical absorption, emission, and quantum efficiency were measured for the nanocrystals. Dopant levels of 0.5 mol % rare earth exhibited the best emission characteristics, with maximum quantum efficiencies of 95 and 51% for LaF3:Nd and CaF2:Er, respectively. The nanopowders were suspended in PFCB (6F variant) polymer-in-toluene solutions to make transparent suspensions that could be cast to make transparent nanocomposites. Scattering analysis indicates that the excellent transmission can be attributed to nanocrystals dispersed in the composite at length scales less than 100 nm.

John Ballato

Papers

Carbon Nanotube Doped Polyaniline

Monopod, bipod, tripod, and tetrapod gold nanocrystals

Silicon optical fiber.

Fabrication of fibers with high rare-earth concentrations for Faraday isolator applications

Optical characterization of infrared emitting rare-earth-doped fluoride nanocrystals and their transparent nanocomposites