Self-assembly and modified luminescence properties of NaY(MoO₄)₂:Tb³⁺, Eu³⁺ inverse opals.

Three-dimensional (3D) inverse opal photonic crystals can not only modulate the emissions of the inserted emitters, they also have the advantage of a large surface to volume ratio, which permits their use in noninvasive fluorescence detection. In this work, novel NaY(MoO4)2:Eu(3+) and NaY(MoO4)2:Tb(3+), Eu(3+) inverse opals were synthesized using a polymethylmethacrylate (PMMA) template by the sol-gel method. It was observed that the photoluminescence (PL) intensity and spontaneous decay rates (SDRs) of the inverse opals were suppressed, in contrast to the corresponding ground reference (REF) samples, due to the modulation of the effective refractive index (n(eff)). The concentration quenching of Eu(3+) and energy transfer from Tb(3+) to Eu(3+) were suppressed, due to the periodic empty cavity structure of the inverse opals.