Directing single-walled carbon nanotubes to self-assemble at water/oil interfaces and facilitate electron transfer

Both the behavior and the general key factors for assembling flexible SWNT films at the water/oil interface were investigated; the electron transfer, one of the most fundamental chemical processes, at the SWNT-sandwiched water/oil interface was also firstly illustrated using scanning electrochemical microscopy.

Green synthesis of 1-2 nm gold nanoparticles stabilized by amine-terminated ionic liquid and their electrocatalytic activity in oxygen reduction

Stable gold nanoparticles with average size 1.7 nm synthesized by an amine-terminated ionic liquid showed enhanced electrocatalytic activity and high stability.

Realization of blue, green and red emission from top-emitting white organic light-emitting diodes with exterior tunable optical films

We developed an approach to realize blue, green and red emission from top-emitting white organic light-emitting diodes (OLEDs) through depositing exterior tunable optical films on top of the OLEDs. Three primary colors for full color display including blue, green and red emission are achieved by controlling the wavelength-dependent transmittance of the multilayer optical films overlaid on the emissive layer.

One-pot green synthesis of biocompatible arginine-stabilized magnetic nanoparticles

A green one-step approach has been developed for the synthesis of amino-functionalized magnetite nanoparticles. The synthesis was accomplished by simply mixing FeCl2 with arginine under ambient conditions. It was found that the Fe2+/arginine molar ratio, reaction duration and temperature greatly influence the size, morphology and composition of magnetic nanoparticles. The arginine-stabilized magnetic nanoparticles were characterized by transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy techniques.

Green synthesis of nanowire-like Pt nanostructures and their catalytic properties

We reported a simple and effective green chemistry route for facile synthesis of nanowire-like Pt nanostructures atone step. In the reaction, dextran acted as a reductive agent as well as a protective agent for the synthesis of Pt nanostructures. Simple mixing of precursor aqueous solutions of dextran and K2PtCl4 at 80 degrees C could result in spontaneous formation of the Pt nanostructures. Optimization of the experiment condition could yield nanowire-like Pt nanostructures at 23:1 molar ratio of the dextran repeat unit to K2PtCl4.

Synthesis of Tributylphosphate Capped Luminescent Rare Earth Phosphate Nanocrystals in an Ionic Liquid Microemulsion

Uniform rare earth phosphate (REPO4, RE = La-Tb) nanocrystals were successfully synthesized in a properly designed TBP/[Omim]Cl/H2O (tributylphosphate/1-octyl-3-methyl-imidazolium chloride/water) microemulsion system. The phosphoryl groups anchored the TBP molecules oil the surfaces of the nanocrystals, and this made the nanocrystals easily dispersed in some imidazolium-based ILs. LaPO4:Eu3+ and CePO4:Tb3+ nanocrystals capped with TBP showed bright red and green emission under UV excitation, with enhanced emission intensity and lifetimes compared with the uncapped ones.

Green synthesis of highly stable platinum nanoparticles stabilized by amino-terminated ionic liquid and its electrocatalysts for dioxygen reduction and methanol oxidation

Preparation of monodispersed platinum nanoparticles with average size 2.0 nm stabilized by amino-terminated ionic liquid was demonstrated. The resulting platinum nanoparticles (Pt-IL) retained long-term stability without special protection. The Pt-IL nanoparticles exhibited high electrocatalytic activity toward reduction of oxygen and oxidation of methanol. Rotating disk electrode voltammetry and rotating ring-disk electrode voltammetry confirmed that the Pt-IL films could catalyze an almost four-electron reduction of dioxygen to water.

Effect of ancillary ligands on the properties of heteroleptic green iridium dendrimers functionalized with carbazole dendrons

A series of heteroleptic green iridium dendrimers functionalized with carbazole dendrons, such as G2(pic) and G2(acac), have been synthesized, in which picolinic acid and acetylacetone are used as the ancillary ligands, respectively. Compared with the corresponding homoleptic iridium dendrimer G2 (8%), these heteroleptic ones can be prepared under mild conditions with total yields as high as 55-67%. Both the dendrimer G2(pic) and G2(acac) display bright green emissions with photoluminescence quantum yields higher than 0.80 in toluene solution. As a result, a maximum external quantum efficiency of 7.1% (21.0 cd/A) for G2(pic) and 7.7% (25.8 cd/A) for G2(acac) has been realized based on non-doped device configuration. The state-of-art performance indicates that the heteroleptic dendrimers can be promising candidates used for non-doped electrophosphorescent devices, especially when the ease of synthesis in a large scale is considered.

Controllable Red, Green, Blue (RGB) and Bright White Upconversion Luminescence of Lu2O3:Yb3+/Er3+/Tm3+ Nanocrystals through Single Laser Excitation at 980 nm

Lu2O3:Yb3+/Er3+/Tm3+ nanocrystals have been successfully synthesized by a solvothermal process followed by a subsequent heat treatment at 800 degrees C. Powder X-ray diffraction, transmission electron microscopy, upconversion photoluminescence spectra, and kinetic decay were used to characterize the samples. Under single-wavelength diode laser excitation of 980 nm, the bright blue emissions of Lu2O3:Yb3+, Tm3+ nanocrystals near 477 and 490 nm were observed due to the (1)G(4)-> H-3(6) transition of Tm3+. The bright green UC emissions of Lu2O3:Er3+ nanocrystals appeared near 540 and 565 nm were observed and assigned to the H-2(11/2)-> I-4(15/2) and S-4(3/2)-> I-4(15/2) transitions, respectively, of Er3+. The ratio of the intensity of green luminescence to that of red luminescence decreases with an increase of concentration of Yb3+ in Lu2O3:Er3+ nanocrystals.

In Situ Preparation and Luminescent Properties of CeF3 and CeF3:Tb3+ Nanoparticles and Transparent CeF3:Tb3+/PMMA Nanocomposites in the Visible Spectral Range

CeF3 and CeF3:Tb3+ nanoparticles were prepared by reverse microemulsion with a functional monomer, methyl methacrylate (MMA), as the oil phase, and CeF3:Tb3+/poly (methyl methacrylate) (PMMA) nanocomposites were obtained via polymerization of the MMA monomer. The nanoparticles and nanocomposites have been well characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), low- and high-resolution transmission electron microscope (TEM), selected-area electron diffraction (SAED), thermogravimetric analysis (TGA), UV/vis transmission spectra, photoluminescence excitation, and emission spectra and luminescence decays. The well-crystallized CeF3 and CeF3:Tb3+ nanoparticles are spherical with a mean diameter of 15 nm. They show the characteristic emission of Ce3+ 5d-4f (313 nm, D-2-F-2(5/2); 323 nm, D-2-F-2(7/2)) and Tb3+ D-5(4)-F-7(J) (J = 6-3, with D-5(4)-F-7(5) green emission at 541 nm as the strongest one) transitions, respectively.

Simultaneous blue, green, and red emission from diblock copolymer micellar films: a new approach to white-light emission

White-light emission is achieved from a single layer of diblock copolymer micelles containing green- and red-light-emitting dyes in the separate micellar cores and blue-light-emitting polymer around their periphery, in which fluorescence resonance energy transfer between fluorophores is inhibited due to micelle isolation, resulting in simultaneous emission of these three species.

In situ preparation and luminescent properties of LaPO4:Ce3+, Tb3+ nanoparticles and transparent LaPO4:Ce3+, Tb3+/PMMA nanocomposite

LaPO4:Ce3+, Tb3+ nanoparticles were prepared by the reverse microemulsion with functional monomer, methyl methacrylate (MMA) as oil phase, and LaPO4:Ce3+, Tb3+/poly(methyl methacrylate) (PMMA) nanocomposite was obtained via polymerization of MMA monomer. The nanoparticles and nanocomposite have been well characterized by XRD, SEM, TEM, UV/vis spectrum, photoluminescence excitation and emission spectra and luminescence decays. The obtained solid nanocomposite LaPO4:Ce3+, Tb3+/PMMA is highly transparent and exhibits strong green photoluminescence upon UV excitation, due to the integration of luminescent LaPO4:Ce3+, Tb3+ nanoparticles. The luminescent lifetime of Tb3+ is determined to be 1.25 ms in the nanocomposite. (C) 2009 Elsevier Inc. All rights reserved.

High efficiency fluorescent white organic light-emitting diodes with red, green and blue separately monochromatic emission layers

Highly efficient fluorescent white organic light-emitting diodes (WOLEDs) have been fabricated by using three red, green and blue, separately monochromatic emission layers. The red and blue emissive layers are based on 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidin-4-yl-vinyl)-4H-pyran (DCJTB) doped N,N'-di(naphthalene-1-yl)-N,N'-diphenyl-benzidine (NPB) and p-bis(p-N,N-diphenyl-amino-styryl) benzene (DSA-ph) doped 2-methyl-9,10-di(2-naphthyl) anthracene (MADN), respectively; and the green emissive layer is based on tris(8-hydroxyquionline)aluminum(Alq(3)) doped with 10-(2-benzothiazolyl)-2,3,6,7-tetrahydro-1,1,7,7-tetramethyl- 1H,5H,1[H-(1)-benzopyropyrano(6,7-8-i,j)quinolizin-1]-one (C545T), which is sandwiched between the red and the blue emissive layers. It can be seen that the devices show stable white emission with Commission International de L'Eclairage coordinates of (0.41, 0.41) and color rendering index (CRI) of 84 in a wide range of bias voltages.

Bridged triphenylamines as novel host materials for highly efficient blue and green phosphorescent OLEDs

Two bridged triphenylamine-triphenylsilane (BTPASi) hybrids have been designed as host materials for phosphorescent OLEDs; devices with the novel host materials achieve maximum external quantum efficiencies as high as 15.4% for blue and 19.7% for green electrophosphorescence.