Color improvement of white-light through Mn-enhancing yellow-green emission of SrSi2O2N2:Eu phosphor for white light emitting diodes

Photoluminescence (PL) enhancement of SrSi2O2N2:Eu and the resultant color improvement of white-light were investigated via co-doping Mn with Eu. We observed that a unique absorption of host lattice of SrSi2O2N2 and its visible band emission peaked at around ∼550 nm for SrSi2O2N2:Mn2+ in the wavelength range of 450–600 nm. This highly eye-sensitive ∼550 nm-peaked band emission of SrSi2O2N2 doped with Mn2+ happens to overlap the 535 nm-peaked band emission of SrSi2O2N2 doped with Eu2+, resulting in an intensified photoluminescence in a maximum by 355%. By combining this as-prepared Mn intensified SrSi2O2N2:Eu phosphor with blue InGaN chip, the quality of white-light was improved to 93.3% for color rendering index and 3584 K for correlated color temperature.