Deep-red emitting La3Ga5SiO14:Mn4+ phosphors with outstanding thermal stability

In this work, deep-red-emitting La 3 Ga 5 SiO 14 :Mn 4+ (LGS:Mn 4+ ) phosphors were successfully fabricated using high-temperature solid-state synthesis techniques, and a series of features were characterized. The phase and lattice information of the phosphors were determined through X-ray diffraction and Rietveld refinement. The microstructure and elemental characteristics were analyzed using scanning electron microscope. Infrared spectroscopy revealed the lattice vibration characteristics of the phosphors. The UV-visible absorption spectra demonstrated the absorption characteristics and band gap. Luminescence measurements showed that LGS:0.05 %Mn 4+ phosphors emit the bright deep-red light at 713 nm when excited at 365 nm, which originates from the 2 E g → 4 A 2g transitions of Mn 4+ ions. The optimum doping concentration for Mn 4+ is x = 0.25 mol% and the concentration quenching mechanism is attributed to dipole-dipole interactions. The lifetime of Mn 4+ ion decreases monotonically with the addition of Mn 4+ ions owing to the non-radiative transition effects. In addition, the prepared LGS:0.25 mol%Mn 4+ phosphors exhibit good thermostability, with an activation energy of 0.637 eV