Luminescence properties and tunable emission of Ca3MgSi2O8:Eu3+, Bi3+ phosphor with Bi3+ → Eu3+ energy transfer

In this work, Ca 3 MgSi 2 O 8 :Bi 3+ , Ca 3 MgSi 2 O 8 : x Eu 3+ ( x  = 0, 2, 4, 6, 8, and 10 mol%), and Ca 3 MgSi 2 O 8 :6%Eu 3+ , yBi 3+ ( y  = 2, 4, 6, 8, and 10 mol%) phosphors are prepared via the high-temperature solid-state reaction method in air. Their crystal structure and luminescence properties are studied. The excitation spectrum with two peaks at ~ 250 and 320 nm of Ca 3 MgSi 2 O 8 :Bi 3+ phosphor can be observed in the range of 225–380 nm because of the 1 S 0 → 1 P 1 and 3 P 1 transitions, and its emission spectrum peaking at ~ 410 nm is in the region from 340 to 650 nm owing to the 3 P 1,0 → 1 S 0 transition of Bi 3+ ion. The excitation spectrum of Ca 3 MgSi 2 O 8 :Eu 3+ phosphor in the range of 220–550 nm is found owing to the f – f transition of Eu 3+ ion, and its emission spectrum under excitation at 394 nm includes five emission spectral bands in the region from 575 to 720 nm due to the 5 D 0 → 7 F 0 , 7 F 1 , 7 F 2 , 7 F 3 , and 7 F 4 transitions of Eu 3+ ion. The luminous performance improvement of Ca 3 MgSi 2 O 8 :Eu 3+ phosphor via co-doping Bi 3+ ions is investigated. The emission spectra of Ca 3 MgSi 2 O 8 :Eu 3+ , Bi 3+ phosphor under excitation at 320 and 394 nm mainly come from the 5 D 0 → 7 F 0 , 7 F 1 , 7 F 2 , 7 F 3 , and 7 F 4 transitions of Eu 3+ ion due to energy transfer from Bi 3+ to Eu 3+ ions. We observe the tunable emission properties of Ca 3 MgSi 2 O 8 :Eu 3+ , Bi 3+ phosphor and use the energy level diagrams of Bi 3+ and Eu 3+ ions to explain the luminous mechanism. The results infer that Ca 3 MgSi 2 O 8 :Eu 3+ , Bi 3+ phosphor has application prospect in white light-emitting diode excited by near ultraviolet light.