Deep-red-emitting SrLa2Sc2O7:Mn4+ phosphor: Synthesis and photoluminescence properties

Novel deep-red-emitting SrLa 2 Sc 2 O 7 :Mn 4+ phosphors with different Mn 4+ contents are successfully synthesized in air by the conventional high-temperature solid-state reaction method. The crystal structure, morphology, phase purity, luminescence properties, concentration quenching, decay lifetimes, and temperature dependent emission spectra are systematically investigated and analyzed. SrLa 2 Sc 2 O 7 :Mn 4+ phosphor presents broad excitation band with different excitation peaks from 220 nm to 620 nm owing to the O 2− - Mn 4+ charge transfer and 4 A 2 → ( 4 T 1 , 2 T 2 , and 2 T 2 ) transitions of Mn 4+ ion and shows intense deep-red emission peaking at 704 nm in the range of 650–800 nm because of the 2 E → 4 A 2 transition of Mn 4+ ion. The optimal Mn 4+ concentration in SrLa 2 Sc 2 O 7 :Mn 4+ phosphor is ∼0.6 mol%. The chromaticity coordinates of the SrLa 2 Sc 2 O 7 :0.6%Mn 4+ phosphor are (x = 0.732, y = 0.268), locating in deep-red region. The mechanism of concentration quenching is inferred to be dipole-dipole interaction. The luminous mechanism, concentration quenching, and temperature quenching are explained by using the Tanabe–Sugano diagram and configurational coordinate diagram of the Mn 4+ ion in SrLa 2 Sc 2 O 7 :Mn 4+ phosphor. The experimental results on SrLa 2 Sc 2 O 7 :Mn 4+ phosphor can offer the helps for the development of other Mn 4+ doped deep-red-emitting phosphor.