CsCl Modified Ge–Ga–S Glasses Codoped with Eu 2+ and Mn 2+ : A Potential Yellow Phosphor for Solid‐State Lighting

Notably enhanced Mn 2+ yellow emission is observed in CsCl modified and Eu 2+ / Mn 2+ codoped Ge – Ga – S glasses under near‐ultraviolet ( NUV ) excitation. The plausible efficiency of energy transfer ( ET ) from Eu 2+ to Mn 2+ is as high as 91%, which is obtained by measurement of luminescence decay of Eu 2+ in samples doped with and without Mn 2+ . The Eu 2+ / Mn 2+ codoping significantly increases the excitation cross section at the NUV region, which is at heart of the enhanced Mn 2+ yellow emission. The ET processes responsible for the enhanced luminescence are discussed.