Preparation and size effect on concentration quenching of nanocrystalline Y2SiO5:Eu

Orange-Reddish Light Emitting Phosphor GdVO4:Sm3+ Prepared by Solution Combustion Synthesis

“…Tian et al [30] explained that, in Dy 3+ -doped bulk GdVO 4 :Dy phosphors, the energy transfers mainly happen between Dy 3+ ions [31,32]. In the case of nanoparticles, the energy transfer starting from the luminescent level can be more complicated, since the defects, which can act as quenching centers, in nanoparticles are more plenteous than those in bulk phosphors [29,31,33]. Due to the defects produced during the preparation process and trace impurities contained in the raw materials, the samples necessarily have quenching centers (traps) with very low concentrations.…”

“…Due to the defects produced during the preparation process and trace impurities contained in the raw materials, the samples necessarily have quenching centers (traps) with very low concentrations. When the excited luminescent center is in the vicinity of the trap, the excited energy could be transferred easily to the trap from which it is lost nonradiatively [33]. As a result, decay time should become short.…”

Highly Efficient Fluorescence of NdF3/SiO2 Core/Shell Nanoparticles and the Applications for in vivo NIR Detection

“…The results imply that the concentration quenching effect does not occur in the nanosized Nd 3þ doped fluorides. Such no concentration quenching phenomenon has been predicted by Zhang et al and Wei et al, [30,31] and similar uniform fluorescent RE NPs, such as EuF 3 , [32] CeF 3 , [33] NdVO 4 , [34] and Nd 2 O 3 , [35] have begun to attract much attention very recently. In RE materials, quenching originates in a very efficient energy transfer among the RE ions.…”

“…Consequently, those NPs quench at only high ion concentration or do not quench at all. [30,31] Although the mechanism of such phenomenon still needs more detailed investigations (the discussion about the emission quantum efficiency is shown in the Supporting Information), the results here provide new possibilities for improving fluorescent RE materials. Moreover, to suppress the vibrational quenching caused by the O-H groups on the surfaces of the NdF 3 NPs, silica shells were coated and the core/shell structures were annealed at 300 8C for 3 h to obtain NdF 3 /SiO 2 NPs.…”

Strong quenching of Y2SiO5:Pr3+ nanocrystal luminescence by praseodymium nonuniform distribution

“…Really, for a number of RE activated nanocrystals the significant suppression of nonradiative relaxation of RE excited electronic states is known [4-8, 10, 11]. The phonon confinement is also expected to affect the phononassisted energy transfer [12,13]. In RE activated nanocrystals, the higher threshold of luminescence concentration quenching is possible for the direct donor-acceptor energy transfer and for the crossrelaxation mechanisms, as far as there is always the energy difference between interacting RE electronic states and the participation of phonons is required.…”