Cubic ZnTiO3 nanocrystal doped with Ni2+ ion has been synthesized by sol-gel method at a lower temperature (600℃). 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.

PbS nanoparticles embedded in a novel silica glass have been achieved in the present sutdy by sol-gel processing. Their fluorescence properties have been evaluated nand 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 comosite consists of two emission peaks (440 and 605 nm). The Pb2+ions in the sol-gel silica glass show sharp emission band. This novel luminescene form the samples isassigned to the composite structure of Pbs nanoparticles and porous silica glasses.

Nanometer-scale ZnS, ZnS: Cu, ZnS:Pb, and Zns co-dopedwith Cu2+ and Pb2+ have been synthesized wusing a chemical preciptiation method. X-ray differation analysis shows that the diameter of the praticles is 2-4 nm. These nanocrystals can be doped with copper and lead during the syntheiss without altering the X-ray diffration pattern. However, doping has shifted the luminescence to 530nm (Cu2+ -doped) and 500-550nm (co-doped with Cu2+ and Pb2+). In the case of ZnS: Pb nanocrystals, a relatively broad emission band (color range form blue to yellow)has heen observed and ists excitation wavelength shows a red shift. The photouminescence intensity increases as the Zns nanoparticles co-dopedwith Pd2+ and Cu2+. The resultsstrongly suggest that doped Zns nanocrystals, especially two kinds of metals activated Zns nanocrystals, form a new class of luminescent materials.

Nanocrystalline ZrO2 particles doped with Dy3+ ions have been synthesized by a simple co-precipitation method. The structural and optical properties of Dy3+-doped ZrO2 particles are investigated using the X-ray powder diffraction, transmission electron microscopy, and photoluminescence spectroscopy. The photoluminescence characteristics originating from Dy3+-doping in the ZrO2 nanoparticles were systematically investigated. Experimental results reveal that the luminescence can be affected by both the calcining temperature and the Dy3+ concentration in the ZrO2 nanoparticles.

In this paper, Dy3+-doped ZnO nanocrystals have been synthesized via a simple combustion method. The as-prepared cuboid-like ZnO nanocrystals appear to be single hexagonal crystalline phase with an average diameter of 20nm. The characteristic luminescence of doped Dy3+ ions has been evaluated, and the highly enhanced photoluminescence of Dy3+ ions can be obtained by Li+ doping.

Nanocrystalline SnO2 particles have been synthesized by a simple sol-gel method. The structural and optical properties of these SnO2 particles are investigated using X-ray powder diffraction, transmission electron microscopy, UV-visible absorption, and photoluminescence spectroscopy. The oxygen-vacancies-related photoluminescence of pure, cerium-, and manganese-doped SnO2 nanoparticles was systematically investigated. The origin of the luminescence is assigned to the recombination of electrons in a conduction band with holes in the Vo ** center. Experimental results reveal that increasing calcining temperature can decrease the oxygenvacanciesrelated luminescence intensity of the sample. After introducing Ce3+/Mn2+ ions into the host, the oxygenacancies-related luminescence has been enhanced remarkably resulting from the formation of many more oxygen vacancies. The dependence of the oxygen-vacancies-related luminescence intensity on the Ce3+/Mn2+ concentration is also discussed