Synthesis and luminescence characteristics of novel red-emitting Ba 2 TiGe 2 O 8 :Mn 4+ phosphor

Abstract Novel Ba 2 TiGe 2 O 8 :Mn 4+ red-emitting phosphor is synthesized by high-temperature solid-state reaction method in air. The excitation spectrum including two peaks at 300 nm and 435 nm covers a broad spectral region from 220 nm to 500 nm owing to the Mn 4+ - O 2− charge transfer band and the 4 A 2 → 4 T 1 and 4 T 2 transitions of Mn 4+ ion. Emission band peaking at ∼666 nm in the range of 600–750 nm can be observed due to the transition 2 E → 4 A 2 of Mn 4+ ion with the lattice vibrations. The luminescence properties indicate that Ba 2 TiGe 2 O 8 :Mn 4+ phosphor has a potential application for plant cultivation. The quantum efficiency is ∼35.6%. The optimal Mn 4+ doping concentration is ∼0.6 mol%. The decay curve and time-resolved spectra confirm that there is only a single Mn 4+ ion luminescence center in Ba 2 TiGe 2 O 8 :Mn 4+ phosphor. Temperature dependence of emission indicates that Ba 2 TiGe 2 O 8 :Mn 4+ phosphor has a good thermal stability. Luminous mechanism is explained by Tanabe-Sugano energy level diagram of Mn 4+ ion.