Enhanced photoluminescence features of Eu3+-modified di-ureasil-zirconium oxocluster organic-inorganic hybrids

In this work, a series of transparent di-ureasil hybrids containing different amounts of methacrylic acid modified zirconium tetrapropoxide (ZrMcOH) nanoclusters (5-85 mol%) and incorporating EuCl3 and [Eu(tta)(3)(H2O)(2)](tta = thenoyltrifluoroacetonate) complex were prepared. These hybrids are multi-wave-length emitters due to the convolution of the host intrinsic emission (electron-hole recombinations occurring in siliceous and urea cross-linkages) Eu3+ intra-4f(6) transitions. The ZrMcOH incorporation deviates the maximum excitation wavelength of the hybrid host intrinsic emission from the UV (365 nm) to the blue (420 nm) and enhances the absolute emission quantum yield from 6.0 +/- 0.6% to 9.0 +/- 0.9%, and contributes to an increase in the D-5(0) lifetime values, quantum efficiency due to a decrease in the non-radiative transition probability and OH groups coordinated to the Eu3+ ions. (C) 2010 Elsevier B.V. All rights reserved.