Highly modified spontaneous emission in NaY(MoO4)2:Yb3+/Er3+ inverse opal photonic crystals

The up-conversion luminescence (UCL) of rare earth (RE) ion doped nanomaterials has attracted extensive interest because of its wide and great potential application. However, the lower UCL efficiency due to the local thermal effect among the ions is still an obstacle for real application. Photonic modulation is a novel way to suppress the local thermal effect and cross relaxation. In this work, NaY(MoO4)(2):Yb3+/Er3+ inverse opal photonic crystals (IOPCs) were fabricated through the poly methylmethacrylate (PMMA) template and the modification of the IOPC structure on the emission spectra and dynamic of Er3+ ions was systemically studied. It is interesting to observe that in the IOPCs, the high-order UCL H-2(9/2) -> I-4(15/2) was relatively enhanced. At the same time, the local thermal effect induced by laser irradiation was suppressed. The studies on UCL dynamics indicated that the nonradiative transition rate of Er3+ was considerably suppressed. The facts above indicated that in the IOPCs, the UCL efficiency of Er3+ was improved due to the periodic macroporous structure.