A high color purity deep red emitting phosphor SrGe4O9:Mn4+ for warm white LEDs

• A high color purity deep red emitting phosphor SrGe4O9:Mn4 + was prepared successfully.
• The concentration quenching of Mn4 + mainly occurs due to electric multipolar interaction mechanism.
• The fluorescence of Mn4 + in SrGe4O9 shows good thermal stability.
• SrGe4O9:Mn4 + may be a potential red phosphor matching with blue LED for warm w-LEDs.

The discovery of non-rare-earth doped oxide red phosphor, particularly excitable by light in the wavelength from 380 to 480 nm, is of great interest in the field of energy-efficient w-LED lighting. Here, we report a potential candidate of red phosphor for warm w-LEDs. Mn4 +-doped SrGe4O9 phosphors that show deep red emission upon blue excitation were prepared by a solid-state reaction route. The luminescent performance is characterized by steady-state photoluminescence (PL) spectra, fluorescence decay curves and temperature-dependent photoluminescence measurements. The concentration quenching phenomenon is clarified. The resistance of Mn4 + photoluminescence to thermal impact after a cycle experiment by heating and cooling the sample between 35 °C and 210 °C has also been studied. It proves that SrGe4O9:Mn4+ possesses good thermal stability. Based on configuration coordinate schematic diagram, the thermal quenching mechanism is discussed. It may be a potential red phosphor which is applied to the package of a blue LED for warm w-LEDs.

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