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 degrees C and 210 degrees 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. (C) 2016 Elsevier B.V. All rights reserved.