Site Occupancies, Electron-Vibration Interaction and Energy Transfer of CaMgSi O : Eu , Mn Phosphors for Potential Temperature-Sensing and Anti-counterfeiting Applications.

Eu -, Mn - and Eu -Mn -doped CaMgSi O phosphors have been prepared by a high-temperature solid-state reaction. Systematic investigation of the concentration- and temperature-dependent luminescence of Mn showed that Mn ions occupy two distinct sites in CaMgSi O . Electron-vibration interaction (EVI) analyses of Mn ions revealed Huang-Rhys factors of 4.73 and 2.82 as well as effective phonon energies of 313 and 383 cm for the two sites. Eu -Mn energy transfer is also discussed, and its efficiency is estimated by lifetime and luminescence spectra. The different thermal quenching behaviours of Eu and Mn , the distinct emission colours of Eu (blue, band peak at ∼451 nm) and Mn (yellow-red range, band peaks at ∼583 and 693 nm) endow the co-doped samples with potential applications in luminescence thermometry and temperature-/excitation wavelength-responsive dual anti-counterfeiting.