Duo Rong Yuan

Synthesis and luminescence properties of SnO2 nanoparticles

Abstract Nanometer-scale SnO 2 particles have been synthesized by a simple sol–gel method. The samples were characterized by X-ray diffraction, Fourier transform infrared (FTIR), UV–Vis absorption and photoluminescence spectroscopy. The as-prepared SnO 2 nanoparticles appear to be single tetragonal crystalline phase and the diameter is about 2.6 nm. The origin of luminescence is assigned to the recombination of electrons in singly occupied oxygen vacancies with photoexcited holes in the valence band.

Luminescent characteristics of Eu3+ in SnO2 nanoparticles

Abstract Nanometer-scale SnO2 particles have been synthesized by a simple coprecipitation method. X-ray diffraction analysis shows that the diameter of the particles is 2.6 nm after heat treatment at 400 °C for 2 h. The UV–visible absorptive spectra and photoluminescence spectra have been used to study the luminescence character of Eu3+ ions. The characteristic emission and concentration quenching of Eu3+ ions can be observed. The results also reveal that the Eu3+ ions can be situated not only at the surface of the SnO2 nanoparticles but also in the host lattice, though the relative quantity is very small.

The luminescence of PbS nanoparticles embedded in sol–gel silica glass

Abstract PbS nanoparticles embedded in a novel silica glass have been achieved in the present study by sol–gel processing. Their fluorescence properties have been evaluated and compared with those of un-doped glass. A novel luminescent phenomenon has been observed from the composite of PbS nanoparticles and the sol–gel silica glass. The photoluminescence (PL) spectrum of the composite consists of two emission peaks (440 and 605 nm). The Pb 2+ ions in the sol–gel silica glass show sharp emission band. This novel luminescence from the samples is assigned to the composite structure of PbS nanoparticles and porous silica glasses.

Structure and photoluminescence properties of sol–gel TiO2–SiO2 films

TiO2–SiO2 films (Ti/Si=1:1) have been prepared by the sol–gel method. The structure and photoluminescence (PL) properties of the films heat-treated at different temperatures have been investigated. The films appear composed of TiO2 nanocrystallites in anatase form embedded in SiO2-rich matrix. Emission bands are observed in all the heat-treated films. This PL is attributed to various defects resulting from thermal treatment and crystallization of TiO2 and to energy levels in the mixed oxide matrix.

Luminescent properties of Mn2+-doped SnO2 nanoparticles

Abstract The room temperature photoluminescent properties of manganese-doped tin oxide nanoparticles are reported. The samples are crystalline with a tetragonal rutile structure of tin oxide. The FTIR and the UV–Vis absorptive spectra of the samples have also been investigated. The photoluminescence spectra are measured at room temperature as a function of different calcining temperatures and the Mn2+ concentration, respectively. The luminescence processes are associated with oxygen vacancies in the host and related with the recombination of electrons in singly occupied oxygen vacancies with photoexcited holes in the valence band.

Photoluminescence characteristics of Pb2+ ion in sol–gel derived ZnTiO3 nanocrystals

Abstract Pb 2+ ions doped ZnTiO 3 nanocrystal has been prepared by a sol–gel process. The X-ray diffraction patterns indicate that the doped sample exhibits a cubic ZnTiO 3 structure. From the luminescence spectra analysis, the introduction of Pb 2+ ions into ZnTiO 3 results in novel luminescent properties. A red emission band fixed at 620 nm has been observed. The relative intensities of the bands vary with the concentration of Pb 2+ ions. The luminescence due to Pb 2+ -involved centers can be ascribed to the Pb 2+ -related charge-transfer transition in ZnTiO 3 nanocrystals.

Photoluminescence of sol–gel derived ZnTiO3:Ni2+ nanocrystals

Cubic ZnTiO3 nanocrystal doped with Ni2+ ion has been synthesized by sol–gel method at a lower temperature (600 °C). The crystallinity of the doped sample was characterized by the X-ray diffraction (XRD) patterns and the infrared spectra (IR). The photoluminescence (PL) spectra of the sample measured at different excitation wavelength reveal a novel luminescent phenomenon in blue, green and red region, which can be attributed to the 3T1(3P)–3A2(3F), 1T2(1D)–3A2(3F) and 1T2(1D)–3T2(3F) transitions of Ni2+ ion, respectively. The position of the emission peak does not change greatly with the excitation wavelength. However, the luminescent intensities vary with changing the concentration of Ni2+ ion in ZnTiO3.

Preparation and luminescence characteristics of nanocrystalline SnO2 particles doped with Dy3

Abstract Nano-scaled SnO 2 particles doped with Dy 3+ have been synthesized by a simple sol–gel method. The samples were characterized by X-ray diffraction, transmission electron micrograph, UV-visible absorption and photoluminescence spectroscopy. The as-prepared SnO 2 nanoparticles appear to be single tetragonal crystalline phase and the diameter is about 2.6xa0nm. The hypersensitive transition ( 4 F 9/2 → 6 H 13/2 of Dy 3+ ) is dominated in the emission spectra resulting from the distorted crystal lattice at which Dy 3+ ions locate. And the dependence of the luminescence intensity on Dy 3+ concentration is also discussed.

Preparation and characterization of sol-gel derived ZnTiO3 nanocrystals

Nanometer scale cubic ZnTiO{sub 3} has been synthesized by sol-gel method at a lower temperature (600 deg. C). X-ray diffraction (XRD) analysis shows that the average crystalline size of the sample is {approx}8-10 nm. The cubic to hexagonal phase transition of ZnTiO{sub 3} is clearly observed from the XRD patterns of the sample. The thermal behavior of the sample was characterized by the thermogravimetric/differenthermal analysis (TG/DTA), XRD patterns, and the infrared spectra (IR). Transmission electron microscope (TEM) observations of the sample reveal a high microstructural uniformity.

Luminescence of Cu2+ and In3+ co-activated ZnS nanoparticles

Abstract Zinc sulfide (ZnS) nanoparticles co-doped with Cu2+ and In3+ ions have been prepared by precipitation from homogeneous solutions of zinc, copper and indium salt compounds, with S2− as precipitating anion formed by decomposition of thioacetamide. The estimated average crystallite size of doped and undoped ZnS nanometer scale samples is about 2–3 nm from X-ray diffraction patterns. Novel luminescence characteristics (green emission, λem∼530–550 nm) have been observed from the co-doped ZnS nanocrystals at room temperature. The emission wavelength and relative photoluminescense intensity of the co-doped samples vary with changing the impurity ratios of Cu2+ and In3+.