Synthesis and luminescence properties of Li2SnO3:Mn4+ red-emitting phosphor for solid-state lighting

Novel Li 2 SnO 3 :Mn 4+ red-emitting phosphor is synthesized by high-temperature solid-state reaction method in air. Emission band of Li 2 SnO 3 :Mn 4+ phosphor within the range 620–760 nm is attributed to the 2 E → 4 A 2 electron transition of Mn 4+ ion. Excitation bands peaking at 330, 395, and 480 nm are attributed to O 2- → Mn 4+ charge transfer and 4 A 2 → ( 4 T 1 , 2 T 1 , and 4 T 2 ) transitions of Mn 4+ ion, respectively. The optimal Mn 4+ concentration is ∼0.4 mol% and the corresponding quantum efficiency and lifetime are ∼42.3% and 16.3 μs. The influences of temperature and Mn 4+ concentration to emission intensity are discussed and analysized. Lifetime data and time resolved spectra confirm that there is only a single type of Mn 4+ ion luminescent center in Li 2 SnO 3 :Mn 4+ phosphor. The influences of the crystal field and the “Mn 4+ -ligand” bonding to luminescence properties of Mn 4+ ion are summaried and analysized. The luminous mechanism is explained via Tanabe-Sugano energy level diagram and the configuration coordinate diagram of Mn 4+ in the octahedron. The results indicate that Li 2 SnO 3 :Mn 4+ phosphor has a hope to be used as red phosphor candidate for solid-state lighting.