Single- and dual-band emission CaNb2O6:Mn2+: Synthesis and luminescence properties

Now free rare earth ions doped materials have attracted a lot of attention. In this work, CaNb 2 O 6 :Mn 2+ with a pure phase is synthesized by solid-state method in the reducing atmosphere. The crystal structure and luminescence properties of host (CaNb 2 O 6 ) and CaNb 2 O 6 :Mn 2+ are investigated. Host (CaNb 2 O 6 ) under excitation ultraviolet (UV) light emits blue light. CaNb 2 O 6 :Mn 2+ can show tunable emission from blue to white. Under excitation 260 nm, blue emission of CaNb 2 O 6 :Mn 2+ is observed owing to the 4 T 1 ( 4 G) →  6 A 1 ( 6 S) transition of Mn 2+ . When the excitation wavelength is 314 nm, CaNb 2 O 6 :Mn 2+ emits white light due to the 4 T 1 ( 4 G) →  6 A 1 ( 6 S) transition of Mn 2+ and the 6 A 1 (6S) 4 T 1 (4G) →  6 A 1 (6S) 6 A 1 (6S) transition in Mn 2+ - Mn 2+ dimers. We measure the concentration dependent spectra of CaNb 2 O 6 :Mn 2+ and make sure the optimal Mn 2+ doping concentration (∼0.8 mol%). We infer that the concentration quenching mechanism is the electric multipolar interaction between nearest-neighbor ions. Based on the temperature dependent spectra of CaNb 2 O 6 :Mn 2+ , we came to the conclusion that CaNb 2 O 6 :Mn 2+ has a good thermal stability. We analyze the concentration and thermal quenching mechanisms and explain the luminous mechanism by the Tanabe-Sugano energy level diagram of Mn 2+ ion. This research results provide a framework for creating Mn 2+ -doped luminescent materials .