Microstructure design and energy transfer in Gd 2 (WO 4 ) 3 : Yb 3+ /Er 3+ phosphors

Rare-earth-doped upconverison luminescent (UCL) materials have wide application prospects in the field of nanoptoelectronics technology. However, achieving highly efficient UCL materials is still a big challenge due to the serious nonradiative energy loss in the host materials. In this research, Gd 2 (WO 4 ) 3 : Yb 3+ , Er 3+ inverse opal photonic crystals (IOPCs) were prepared using a polymethylmethacrylate (PMMA) template-assisted method, and the effects of modulations of the IOPC structure on UC emission properties of Er 3+ were investigated systemically. As a result, the emission intensity of 2 H 11/2 - 4 I 15/2 in IOPC was found to be suppressed 37.4%, and the radiative lifetimes of 4 S 3/2 - 4 I 15/2 were prolonged 1.55 times. The effects of the doping concentration on the reciprocal of fluorescence lifetimes of 4 S 3/2 - 4 I 15/2 between the IOPC and the reference (REF) samples showed that the cross-energy transfer (CET) rate and the electronic transition rate were greatly inhibited, which could be due to the effect of the modulation of the effective index on the radiative transition rate and on the decrease of nonradiative transition rate caused by periodic thin-walled structure of IOPC. The power-dependent UC emission properties validated the supposition that the IOPC structure could be effectively suppressed the local thermal effect and thermal quenching. This research presents a further step in the exploration of the new kind of UCL materials with high luminous efficiency.