Gd3+-activated narrowband ultraviolet-B persistent luminescence through persistent energy transfer

Abstract

This work reports the realization of Gd³⁺ persistent luminescence in the narrowband ultraviolet-B (NB-UVB; 310–313 nm) through persistent energy transfer from a sensitizer of Pr³⁺, Pb²⁺ or Bi³⁺. We propose a general design concept to develop Gd³⁺-activated NB-UVB persistent phosphors from Pr³⁺-, Pb²⁺- or Bi³⁺-activated ultraviolet-C (200–280 nm) or ultraviolet-B (280–315 nm) persistent phosphors, leading to the discovery of ten Gd³⁺ NB-UVB persistent phosphors such as Sr₃Gd₂Si₆O₁₈:Pr³⁺, Sr₃Gd₂Si₆O₁₈:Pb²⁺ and Y₂GdAl₂Ga₃O₁₂:Bi³⁺ as well as five ultraviolet-B persistent phosphors such as Y₃Al₂Ga₃O₁₂:Pr³⁺, Sr₃Y₂Si₆O₁₈:Pb²⁺ and Y₃Al₂Ga₃O₁₂:Bi³⁺. The persistent energy transfer from the sensitizers to Gd³⁺ is very efficient and the Gd³⁺ NB-UVB afterglow can last for more than 10 hours. This study expands the persistent luminescence research to the NB-UVB as well as the broader ultraviolet-B spectral regions. The NB-UVB persistent phosphors may act as self-sustained glowing NB-UVB radiation sources for dermatological therapy.