Surface and size effects and energy transfer phenomenon on the luminescence of nanocrystalline X1-Y2SiO5:Eu3+

Optical luminescence of nanocrystalline Y2-xEuxSiO5 arises from four distinct sites. We shaw that one previously uncharacterized sites is a Eu3+ ion near the surface of the nanocrystal. The energy transfer rate between the two main sites varies with temperature and Eu3+ concentration and the dynamics of this transfer is explained theoretically. Luminescent quenching occurs at a much higher concentration and stronger luminescent intensity than in bulk Y2SiO5Eu3+. This is due to the hindering effects of particle boundaries to energy transfer. (C) 2000 Elsevier Science S.A. All rights reserved.