Synthesis and near-infrared luminescence of La3GaGe5O16:Cr3+ phosphors

A novel Cr3+-doped La3GaGe5O16 phosphor was synthesized by a solid-state reaction, and the phase formation and microstructure, near-infrared (NIR) photoluminescence (PL) properties and PL thermal stability were investigated in detail. The excitation spectrum of La3GaGe5O16:Cr3+ at 270, 415 and 573 nm corresponded to three spin-allowed Cr3+ d-d intra-transitions of (4)A(2)-T-4(1) (P-4), (4)A(2)-T-4(1) (F-4), and (4)A(2)-T-4(2) (F-4), respectively, among which the main red emission peak observed at 700 nm is identified, which is due to the E-2-(4)A(2) transition from Cr3+ ions. It is further proved that the dipole-dipole interactions result in the concentration quenching of Cr3+ in La3GaGe5O16:Cr3+ phosphors, and the energy-transfer distance at the quenching concentration was around 26.90 A. Moreover, thermal quenching luminescence results reveal that La3GaGe5O16:Cr3+ exhibits good thermal stability. The above results indicate that La3GaGe5O16:Cr3+ has potential practical applications in luminescence solar concentrators with broad-band absorption.