Energy transfer from Bi3+ to Ho3+ triggers brilliant single green light emission in LaNbTiO6:Ho3+, Bi3+ phosphors

Abstract

Excitation of Ho³⁺ and Bi³⁺ co-doped LaNbTiO₆ particles with 453 nm blue light gave an intense single green glow. All the phosphors were synthesized via a facile sol–gel and combustion approach, and the crystal structure, particle morphology, photoluminescence (PL) properties of the phosphors and energy transfer between Bi³⁺ and Ho³⁺ were also investigated. The large spectral overlap between the broad emission band of Bi³⁺ around 425–570 nm and the excitation band of Ho³⁺ supports the efficient energy transfer from Bi³⁺ to Ho³⁺, which enhances the PL intensity remarkably. When the PL intensity is considered, the best composition for producing green light is LaNbTiO₆:4 mol% Ho³⁺, 2 mol% Bi³⁺. The luminescence mechanisms of Ho³⁺ doped and Ho³⁺/Bi³⁺ co-doped in the LaNbTiO₆ host were also discussed.