Energy transfer process between Eu3+ and wide-band-gap SnO2 nanocrystals in silica films studied by photoluminescence excitation and time-resolved photoluminescence techniques

Eu³⁺ ions embedded in silica thin films co-doped with SnO₂ nanocrystals were fabricated by sol–gel and spin-coating methods. SnO₂ nanocrystals with controllable sizes were synthesized through precisely controlling the Sn concentrations. The influences of doping and annealing conditions on the photoluminescence intensity from SnO₂ nanocrystals are systematically investigated. The effective energy transfer from the defect states of SnO₂ nanocrystals to nearby Eu³⁺ ions has revealed by the selective photoluminescence excitation spectra. The efficiency of the Förster resonance energy transfer is evaluated by the time-resolved photoluminescence measurements, which is about 29.1 % based on the lifetime tests of the SnO₂ emission.