Blue emitting hybrid organic-inorganic materials

Undoped and Eu2+ or Ce3+-doped hybrid organic-inorganic materials were prepared at room temperature from hydrolysis and condensation of organohydrosilanes (HSi(CH3)(OCH2CH3)(2), HSi(OCH2CH3)(3)), alkoxysilanes (Si(CH3)(OCH2CH3)(3)) and zirconium propoxide in the presence of EUCl3 or Ce(NO3)(4), 2NH(4)NO(3). The transition metal alkoxide catalyzed cleavage of the Si-H bonds was used to reduce in situ at room temperature the rare earth cations. Depending on the chemical strategy, the resulting hybrid materials can be processed as transparent bulks or coatings, which exhibit a good transparency in the UV-visible domain (cut-off at 250-280 nm). Both the undoped matrices and the rare earth-doped matrices exhibit a strong blue emission. The nature of different emitting species is clearly assigned by using their very different kinetics of fluorescence (tau similar to 50 ns for Ce3+, tau < 1 mus for Eu2+ tau similar to 3 and 4 mus for the undoped matrices) and through excitation experiments. (C) 2001 Elsevier Science B.V. All rights reserved.