A comprehensive phononics of phonon assisted energy transfer in the Yb³⁺ aided upconversion luminescence of Tm³⁺ and Ho³⁺ in solids

The theory of phonon assisted energy transfer is being widely used to explain the Yb³⁺ ion aided normal and upconversion emission of various rare earth ions in different Yb³⁺ co-doped solids. The reported phonon dynamics in many of these studies are either incomplete or erroneous. Here we report Yb³⁺ aided upconversion luminescence properties of Tm³⁺ and Ho³⁺ in (Yb³⁺/Tm³⁺) and (Yb³⁺/Ho³⁺) co-doped two BaO–tellurite glasses and explain their phononics in the light of Dexter's theory by proposing a comprehensive scheme. The approach is valid for other systems of different phonon structures. - Highlights: • Yb³⁺ aided upconversion luminescence properties of Tm³⁺ and Ho³⁺ in (Yb³⁺/Tm³⁺) and (Yb³⁺/Ho³⁺) co-doped two BaO–tellurite glasses, are reported. • Phonon assisted energy transfer in these systems are explained in the light of Dexter's theory by proposing a comprehensive scheme of phononics. • The approach is valid for other systems of different phonon structures