Discovery of near-infrared persistent phosphorescence and Stokes luminescence in Cr3+ and Nd3+ doped GdY2Al3Ga2O12 dual mode phosphors

Abstract

The near-infrared (NIR) luminescence materials have attracted great attention on account of their potential applications in optical imaging field. In this paper, a series of Cr3+ and Nd3+ doped GdY2Al3Ga2O12 phosphors with luminescence in the biological windows were synthesized using a solid-state reaction method. The crystal field parameters, concentration dependent photoluminescence and persistent luminescence properties of Cr3+ were discussed in detail. Nd3+ ions exhibit perfect NIR to NIR Stokes luminescence in the host. The influence of Nd3+ doping concentration was studied by emission spectra and decay curves. Taking the advantages of both Cr3+ and Nd3+, dual mode phosphors with NIR persistent luminescence and NIR to NIR Stokes luminescence were designed and achieved. Based on the energy transfer process, persistent luminescence and thermo-luminescence curves, the luminescence mechanism was proposed.