Synthesis and luminescence properties of novel deep red emitting phosphors <font>Li</font>₂<font>MgGeO</font>₄:<font>Mn</font>⁴⁺

Abstract

Novel deep red phosphor Li 2 MgGeO 4 : Mn 4+ is synthesized by high temperature solid state reaction method in air. The strongest PL band peaking at ~ 671 nm in the range of 600–750 nm is due to the 2 E → 4 A 2 transition of Mn 4+ ion and the PLE spectra shows broad band peaking at ~ 323 within the range 220–550 nm owing to the 4 A 2 → 4 T 1 transitions of Mn 4+ ion. The optimum Mn 4+ doping concentration is about 0.4 mol.%. The luminous mechanism is explained by Tanabe–Sugano diagram of Mn 4+ ion. The results indicate that red phosphor Li 2 MgGeO 4 : Mn 4+ is a beneficial phosphor for use in white light-emitting-diodes (LEDs).