For the first time the segregation of doped ions in YVO4:Pr3+ and YVO4:Er3+,Yb3+ nanocrystals was revealed by means of spectroscopic techniques. Luminescence spectra are modified due to doped ions redistribution within nanocrystal volume. Variation of heat treatment temperature allows us to determine the diffusion-depended nature of observed doped ions redistribution within the volume of nanocrystal and to trace this process.
Optical Materials 34(12), 1998–2001 (2012)

Comparing the luminescence properties of nanosized and macroscopic LaPO4:Ce,Tb powders are performed in wide spectral range using synchrotron radiation. In the present study, LaPO4:Ce,Tb nanopowder was produced by means of a microwave-induced synthesis in ionic liquids, whereas the bulk sample represents a commercial lamp phosphor. Emission and excitation of both, Ce3+ and Tb3+ luminescence, is observed to be different when comparing bulk and nanosized LaPO4:Ce,Tb. In particular, it was shown that the fine structure of the Ce3+ as well as the Tb3+ related emission is poorly resolved for the nanomaterial. It is suggested that the nanoparticles surface plays a key role regarding the perturbation of rare-earth ions and changes their luminescence properties. Furthermore, it is demonstrated that allowed f–d transitions on Tb3+ at high energy are significantly suppressed for nanosized LaPO4:Ce,Tb. Energy transfer is required to initiate Tb3+ emission even in the vacuum ultraviolet spectral range.
Optical Materials, Vol.33, 2011, pp. 1102-1105

Paramagnetic derivatives of tolan, anthracene, and terphenyl of the A−Sp−R• type, where A is an aromatic group, R• is a stable radical center, and Sp is a spacer, were synthesized.
ChemInform, 2002, V.32, Issue 4

CdSe/ZnS quantum dots in solution ad in condensed phase have been investigated by methods of laser induced luminescence. Anti-stokes photoluminescence (APL) of CdSe/ZnS nanoparticles in the solutions and in the films has been studied under action of laser radiation of various wavelengths. The dependencies of APL of CdSe/ZnS nanoparticles ensembles on exciting radiation intensity, temperature and quantum dots concentration have been studied. It is shown that the mechanism of APL formation in CdSe/ZnS nanoparticles is thermal.

Laser-induced luminescence of multilayer structures based on the solids of CdSe and CdSe/ZnS nanocrystals, different organic semiconductors and on the layers of organic semiconductors with embedded nanocrystals has been investigated. Drastic decrease of luminescence quantum yield is observed in the films of CdSe nanocrystals on organic semiconductors compared to those on optical glasses. The luminescence of the nanocrystals in the matrices of organic semiconductors and in multilayer structures is shown to be suppressed. The effects observed are explained by the transfer of photogenerated carriers from the nanocrystals to the molecules of organic semiconductors. The presence of the charge transfer is confirmed by a drastic increase in the conductivity (by 2 - 4 orders of magnitude) and in photo-voltaic effect at the presence of CdSe and CdSe/ZnS nanocrystals in the structures under investigation. The prospects of using the multilayer structures for development new materials for solar cells are discussed.

Semiempirical quantum chemical simulations have been undertaken to obtain the self-consistent atomic and electronic structure of the two basic electron defects in MgO crystals: F+ and F centres (one and two electrons trapped by an O vacancy, Va. The calculated absorption and luminescence energies agree well with the experimental data; the excited states of both defects are found to be essentially delocalised over nearest-neighbour cations. The activation energy for diffusion is found to increase monotonically in a series Va → F+ → F centre (2.50eV, 2.72 eV and 3.13 eV, respectively).
Materials Science and Engineering B Volume 37, Issues 1-3, February 1996, Pages 212-214