Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: lanthanide(III) ions

Sortuj według:

Ogranicz wyniki do:

Porfiryny zamknięte w żelu krzemionkowym

Wiglusz R. J.

Wiadomości Chemiczne

2011

[Z] 65, 7-8

675-703

The need for new, chemically and physically stable luminescent materials operating with UV excitations has stimulated research on luminescence properties of doped sol–gel material. In this work, it has been presented a technology of production of silica gels doped with organic molecules, lanthanide compounds and organic/inorganic composites. Optical properties of these materials as functions of temperature, concentration and excitation wavelength are presented. Dynamics of excited states has been discussed based on the decay times and emission efficiencies data. Mechanisms of ligand-to-metal energy transfer as well as other processes affecting emission efficiency are considered. Silica sol–gels doped with di-aminoacid derivatives of porphyrins: PP(Ser)2(Arg)2, PP(Ala)2(Arg)2, PP(Met)2(Arg)2, where Met, Arg and Ser denote methionine, serine and arginine aminoacids, respectively, and H2TTMePP {tetrakis[4-(trimethylammonio)phenyl]-21H,23H-porphine} have been obtained and spectroscopically studied. These materials can find applications as phosphors or sensors of UV irradiation.

Luminescence based on energy transfer in xerogels doped with Tb2-xEux(WO4)3

Grobelna B.

Optica Applicata

2008

Vol. 38, nr 1

39-47

A series of luminescent materials consisting of Tb2-xEux (WO4)3 entrapped in silica xerogel were successfully prepared. The parameter x in the formula changed from 0.4 to 2. Spectroscopic properties such as absorption and luminescence of optically active ions were studied at room temperature. Owing to the energy transfer from the WO42- groups (ligand-metal charge transfer, (LMCT)) the lanthanide ions show their characteristic emissions in Tb2-xEux(WO4)3 entrapped in silica xerogel, i.e., 5D0 › 7FJ (J = 0, 1, 2, 3, 4) transition for Eu3+ ion and 5D4 › 7FJ (J = 6, 5, 4, 3) transition for Tb3+ ion. The energy transfer is effective for the mixed tungstate salt Tb1.35Eu0.65(WO4)3 entrapped in silica xerogel. The Eu(III) emission intensity in the materials under study increases with an increase in the annealing temperature from 600 to 900 °C. This is due to the removal of the effective O -H quenchers from the coordination sphere of the Eu(III) ion.