Extended broadband luminescence of dodecahedral multisite Ce3+ ions in garnets {Y3}[MgA](BAlSi)O12 (AÂ = Sc, Ga, Al; BÂ = Ga, Al)

- Ce3+ doped multicomponent garnets containing Y, Mg, Si, Al, Ga or Sc were synthesized.
- Heterovalent substitution leads to local structural disorders in garnets.
- Extended broadband luminescence of Ce3+ is obtained in multicomponent garnets.
- Multi-site Ce3+ ions determine emission band broadening and Stokes shift increase.

Cerium doped Y3MgAlAl2SiO12, Y3MgScAl2SiO12, Y3MgGaAl2SiO12 and Y3MgScGaAlSiO12 garnet phosphors have been synthesized by using a high temperature solid-state reaction method and studied by optical spectroscopy techniques. It has been revealed that the emission spectra from all the synthesized samples contain the multiplicity of spectral bands due to the 5d - 4f transitions of Ce3+ ions occupying dodecahedral yttrium sites with varying local environment. The largest red shift of Ce3+ luminescence compared to YAG:Ce3+ is observed for a Y3MgAlAl2SiO12:Ce3+ phosphor. Additional substitution of Al3+ by larger cations Ga3+ or/and Sc3+ has resulted in the blue shift of the luminescence spectrum and the strongest blue shift is observed for Y3MgScGaAlSiO12:Ce3+. The multi-site nature of Ce3+ luminescence leads to the Stokes shift increase of emission and the considerable broadening of Ce3+ emission spectra for the studied garnets in comparison of YAG:Ce3+.