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A pyridinium dye with N-butyl-carbazole as an electron donor group and pyridinium cation as electron acceptor group has been synthesized. The crystal structure and photophysical properties of the dye in different solvents are researched. The interaction between the dye and DNA is also researched. The results reveal that the dye can be used as a DNA probe.

Organic modified sol-gel glass with tetraethylorthosilicate (TEOS), methyl triethoxysilane (MTEOS) and vinyltriethoxysilane (VTEOS) as raw material, ethanol as solvent and nitric acid as catalytic agent have been prepared. The influence caused by the amount of catalytic agent, water and the ratio of TEOS/MTEOS or TEOS/VTEOS on properties of porosity has been investigated. The optimal ration of MHNO3/MTEOS and Mwater/MTEOS were obtained. The modification of sol-gel glass using organic groups results in some decrease of porosity.

A D-π-D type of organic dye 2,7-di[4-(N,N-diphenylamino)styryl]-9-n-pentyl-9H- carbazole (DPSPC) with diphenylamine as donor group and styrene-carbazole-styrene as conjugation bridge has been synthesized. The photophysical properties of the dye in different solvents and poly methyl methacrylate/organic modified sol-gel glasses are researched. The results indicate that the fluorescence properties of the organic dye in composite glass increase relative to that in solvents and there are no fluorescence quenching in high doped concentration in composite glass matrixes. The dye has higher stability in the composite glass than that in solution.

Zn2SiO4 single-doped and co-doped with Mn2+ ions and Pb2+ ions has been prepared by a sol–gel process. The luminescent properties of the samples have been investigated. From the excitation and emission spectral analysis, it was found that the emission peaks vary with the change of the excitation wavelength. An enhanced luminescent characteristic of Mn2+ ions (in blue and green spectral zones) has been observed, due to the energy transfer from the Pb2+ ion to the Mn2+ ion. The emission peaks originate from the d–d transitions of the Mn2+ ion. However, the relative intensities of the peaks show a dependence on the concentration of the Pb2+ ion.

Several donor-π-donor (D-π-D), acceptor-π-acceptor (A-π-A), and donor-π-acceptor (D-π-A) types of organic compounds with fluorene as π bridge and dimesitylboryl group as electron acceptor, which show strong two-photon excited blue fluorescence, have been synthesized and structurally investigated. The symmetric A-π-A type of compound exhibits the shortest wavelength of two-photon excited fluorescence (TPEF) at λem=405 nm under the excitation of λex=730 nm; the unsymmetric D-π-A type of compound with diphenylamino as donor exhibits the most intense TPEF at blue region (λem=484 nm) with a two-photon absorption cross-section of 425 GM under λex=800 nm.

We have synthesized a series of new D−π−A compounds that feature various electron donors and a fixed benzothiazolyl unit as an electron acceptor. The crystal structure of compound 3 [trans,trans-2-{4-[(4-N-carbazolyl)styryl]styryl}-1,3benzothiazole, CSSB] was determined. All these compounds show high fluorescence quantum yields and 3 in toluene gives the most intense blue emission around 450 nm with a quantum yield of Φ = 0.69. When excited at 800 nm by a Ti:sapphire femtosecond laser, these compounds exhibit strong two-photon-excited fluorescence (TPEF) in the blue-to-orange region. The measured TPEF cross-section of compound 2 [trans,trans-2-{4-[4-(N,N-diphenylamino)styryl]styryl}-1,3-benzothiazole, DPSSB], for example, is about 6.1 times that of Coumarin 307. Photophysical data indicate that these compounds are polar in the ground state and have an enhanced polarity in the excited state, and that the electron donating ability of a dialkylamino group is much stronger than that of a diarylamino group. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Cu-doped, Ce-doped and CuCe-doped SrAl 2 O 4 luminescent materials have been synthesized by solid state reaction at 1200 °C and weak oxidation atmosphere. The photoluminescence (PL) and excitation spectra of the doped samples have been investigated at room temperature. The excitation spectrum of Ce 4+ -doped SrAl 2 O 4 sample consists of two sharp bands, one in the ultraviolet (381 nm) and the other in the visible (517 nm) part of the spectrum. The PL spectra of Ce 4+ -doped SrAl 2 O 4 sample vary with the changing of the excitation wavelength. Because of the energy transfer between Cu 2+ and Ce 4+ , the PL and excitation spectra of the sample co-doped with Cu 2+ and Ce 4+ are dramatically different from that of Ce 4+ -doped sample. Also, the PL spectra of the co-doped sample change with using different excitation wavelength.

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 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.