Crystal structure insight aided design of SrGa2Si2O8:Mn2+ with multi-band and thermally stable emission for high-power LED applications

Mn2+ ion is commonly used as a luminescent center of phosphors for long-wave emission, however, it is difficult to achieve Mn2+-activated phosphors with both broadband emission and high thermal stability, which limits their application in the field of high-power phosphor-converted white light-emitting diodes (PC-wLEDs). In this work, from the viewpoint of crystal structure, we develop a novel Mn2+-doped phosphor, SrGa2Si2O8:Mn2+, to realize multi-band and thermal-stable emission. We found that the multiple band emission originates from three Mn2+-induced luminescence centers, i.e. Mn2+ in Ga3+ site, Mn2+ in Sr2+ site, and Mn2+-Mn2+ dimers, due to their different crystal field environments. Meanwhile, excellent thermal-stable emission (up to 200 degrees C) is obtained as a result of the energy transfer between the traps and the luminescence centers. What is more, the different energy transfer paths of the SrGa2Si2O8:Mn2+ lead to a red-shift of emission, which can help to improve color rendering index of light sources. Our results demonstrate that this new phosphor shows a potential for the application of high-power PC-wLEDs.