TY  - JOUR
A1  - Tiseanu, Carmen
A1  - Lorenz-Fonfria, Victor A.
A1  - Geßner, André
A1  - Kumke, Michael Uwe
A1  - Gagea, Bogdan
T1  - Comparative luminescence study of terbium-exchanged zeolites silylated with alkoxysilanes
N2  - Terbium-exchanged ZSM-5, MOR and (H)BEA zeolites were silylated with phenyl-, vinyl- and hexadecyl trimethoxysilanes via a post-synthesis grafting. All samples were investigated by means of PXRD, FT-IR, TGA, physical adsorption, DR-UV-Vis and time-resolved photoluminescence spectroscopy. From the comparison of the photoluminescence decays of terbium-exchanged in parent (non-silylated) and silylated zeolites, it resulted that the silylation efficiency of the various alkoxysilanes is determined by the type of zeolite and follows the sequences: phenyl > vinyl > hexadecyl > parent for ZSM-5, hexadecyl a parts per thousand phenyl a parts per thousand vinyl > parent for MOR and hexadecyl > phenyl a parts per thousand vinyl > a parts per thousand parent for BEA zeolites, respectively.
Y1  - 2009
UR  - http://www.springerlink.com/content/100190
U6  - https://doi.org/10.1007/s10854-008-9597-1
SN  - 0957-4522
ER  - 
TY  - JOUR
A1  - Tiseanu, Carmen
A1  - Pârvulescu, Victor I.
A1  - Kumke, Michael Uwe
A1  - Dobroiu, Svako
A1  - Geßner, André
A1  - Simon, Simion
T1  - Effects of support and ligand on the photoluminescence properties of siliceous grafted europium complexes
N2  - Europium ions were introduced in SiO2 and MCM-41 via two different pathways: (1) grafting the europium complexes with two alkoxide structures, 3-(2-imidazolin-1-yl)-propyl-triethoxysilane (IPTES) and aminopropyltrimethoxysilane (APTMS), and (2) functionalization of the SiO2 support with silicon 4- carboxylbutyltriethoxide followed by subsequent addition of the europium ions. The new materials were characterized using nitrogen adsorption isotherms at -196 degrees C, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, Fourier transform infrared, NMR, DR-UV-vis, steady-state emission and excitation, and time-resolved photoluminescence spectroscopy. Spectral changes found in the time-resolved photoluminscence spectra strongly point to the distribution of europium ions on a range of environments in both SiO2 and MCM-41 supports. The average europium photoluminescence lifetimes decrease within the order: Eu3+-IPTES/SiO2 (550 mu s) > Eu3+-APTMS/SiO2 (425 mu s) > Eu3+-APTMS/MCM-41 (370 mu s) > Eu3+-IPTES/MCM-41 (320 mu s) > Eu3+-CABES/SiO2 (240 mu s). The photoluminescence quantum efficiency has the largest value, of 22%, for Eu3+-IPTES/SiO2, while the most reduced value, of 9%, was measured for Eu3+-CABES/SiO2.
Y1  - 2009
UR  - http://pubs.acs.org/journal/jpccck
U6  - https://doi.org/10.1021/Jp808411e
SN  - 1932-7447
ER  -