A spectrum modifying glassy luminescent layer with antireflection properties has been prepared with Eu3+ ions embedded in silica gel for solar cell applications. Preparation of such matrix by sol-gel process and change in luminescence properties in transforming from amorphous to crystalline phase are described. Luminescent Eu3+ species in amorphous silica matrix show intense red emission at 614 nm by absorbing UV/blue light. Amorphous environment with reduced symmetry for Eu3+ ions results in an unprecedented short decay time of 145 mu s for D-5(0)-F-7(2) electric dipole transition. In the crystalline monoclinic phase of Eu2O3 nanoparticles, concentration quenching of Eu3+ species reduces luminescence output. (C) 2010 Elsevier Ltd. All rights reserved.