Energy transfer behavior of Fe3+ to Cr3+ in LiAl5O8 phosphors

Abstract

We present the energy transfer (ET) and simultaneous excitation (SE) between Cr3+ and Fe3+ ions in LiAl5O8 phosphors prepared by the modified sol-gel method, using anhydrous glucose as a chelating agent. A model for the ET and SE dynamics was developed considering that the 8c and 12d aluminum sites are occupied by Fe3+ and Cr3+ ions, respectively. In the proposed model, a SE of Cr3+ and Fe3+ at 227 nm and an efficient energy transfer occurs from Fe3+ to Cr3+ dopant, leading to dual emission consisting of 2E1 g→4A2 g (669 nm) transition from Cr3+ ions and 4T1 g(4G)→6A1 g(6S) transition from Fe-dopant state (715 nm).