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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. [Copyright &y& Elsevier]

The photoluminescence (PL) properties of the Mn, Pb co-doped ZrO2 nanocrystals have been investigated in detail. A relatively broad and strong emission band centered at about 640 nm was observed originating from the 4T1 (4G) to the 6A1 (6S) transition of Mn2+. In the presence of Pb2+, the luminescent intensities of the ZrO2: Mn nanocrystals have been greatly enhanced due to the energy transfer from Pb2+ to Mn2+. As a concentration quenching exists, the optimum value of Pb2+ is 5%. [Copyright &y& Elsevier]

Ni2+-doped SiO2, Al2O3–99SiO2 glasses have been prepared by sol–gel method. The effect of Al3+ on the photoluminescence (PL) properties of Ni2+-doped SiO2 has been studied. Ni2+-doped sol–gel SiO2 glass shows an emission band at 510 nm, which is attributed to the d–d transition 1T2(1D)→3A2(3F) of Ni2+ in octahedral sites. The emission of Ni2+ ions is greatly enhanced by the addition of Al3+ into SiO2. The study on Fourier transform infrared spectroscopy (FT-IR) and UV–Vis absorption spectra shows that the glass network and coordination environment of Ni2+ are changed after adding Al3+ into SiO2. [Copyright &y& Elsevier]

Pb2+ ions doped ZnTiO3 nanocrystal has been prepared by a sol–gel process. The X-ray diffraction patterns indicate that the doped sample exhibits a cubic ZnTiO3 structure. From the luminescence spectra analysis, the introduction of Pb2+ ions into ZnTiO3 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 Pb2+ ions. The luminescence due to Pb2+-involved centers can be ascribed to the Pb2+-related charge-transfer transition in ZnTiO3 nanocrystals. [Copyright &y& Elsevier]

The changing presented during the heating of sol–gel derived Zn2SiO4 doped with Ni2+ have been investigated by X-ray diffraction (XRD) and differential thermal analysis (DTA). When calcining temperature <700 °C, the XRD patterns of the sample show the characteristic peaks of ZnO crystal and non-crystalline SiO2. When calcining temperature >900 °C, XRD pattern of the sample shows the characteristic peaks of α-Zn2SiO4 crystal phase. Also, the excitation and emission spectra of the undoped and Ni2+-doped samples have been investigated. Stable green–yellow–red emission has been observed from Zn2SiO4 crystalline phase. A novel photoluminescence (PL) phenomenon has been observed from Ni2+-doped Zn2SiO4. [Copyright &y& Elsevier]

The effect of Ph–NH–CH2– group (Ph: phenyl) on the luminescence properties of silica xerogel by sol–gel method has been investigated. The absorption spectra, excitation spectra and emission spectra of Ph–NH–CH2– group embedded in the network of silica xerogel have a red shift with increasing the ratios of Ph–NH–CH2– group in the samples. The relative photoluminescence (PL) intensity of the hybrid silica xerogel sample decreases with increasing the ratios of Ph–NH–CH2– group. From the complex luminescent centers, the novel luminescence properties have been observed from the hybrid silica xerogel sample containing Ph–NH–CH2– group. [Copyright &y& Elsevier]

The luminescence of sol–gel derived Zn2SiO4 powder samples doped with Pb2+ ions has been reported. The emission spectra of Pb2+-doped Zn2SiO4 can be adjusted by changing the excitation wavelength. The blue, green, yellow and red emission peaks have all been observed from Pb2+-doped Zn2SiO4 powder samples. [Copyright &y& Elsevier]