Nanoparticles doped with rare earth and transition metal ions for optoelectronic applications

Perspectives of application as phosphors of nanometer size particles doped with transition metal (TM) or rare earth (RE) ions are discussed. It is demonstrated that nanometer size can be crucial to overcome some limitations in achieving high light output. First of all, small size of host materials helps to enhance rate of host-to-impurity energy transfer, opening new efficient channels for TM or RE excitation. This effect contributes to a brighter light emission. Moreover, intra-shell transitions of TM and RE ions in doped nanoparticles show shorter luminescence decay times due to increased rates of a radiative decay. Mechanisms of emission stimulation in doped nanoparticles are discussed.