Tunable emission, energy transfer, and charge compensation in the CaSb2O6:Eu3+, Bi3+ phosphor

Novel CaSb2O6:Eu3+, Bi3+ phosphor is synthesized by solid-state reaction method in air. Their crystal structures are investigated. Luminescence properties of CaSb2O6:Eu3+, CaSb2O6:Bi3+, and CaSb2O6:Eu3+, Bi3+ phosphors are compared, analyzed and explained, respectively. Tunable emission of CaSb2O6:Eu3+, Bi3+ phosphor with excitation 298 nm can be observed by changing Eu3+ or Bi3+ concentration. Energy transfer (ET) and charge compensation in CaSb2O6:Eu3+, Bi3+ phosphor are observed and analyzed via its luminescence properties. Lifetimes of CaSb2O6:5 %Eu3+, yBi3+ phosphor (0.5 ≤ y ≤ 5 mol%) are investigated, which further confirm that ET process can be formed between Eu3+ ion and Bi3+ ion. The luminous mechanism is explained via the energy level diagrams of Bi3+ and Eu3+ ions. The emission properties indicate that CaSb2O6:Eu3+, Bi3+ phosphor has a potential application for white LEDs based on near UV (~394 nm) LED chip.