Observation of two-way multichannel interaction among Dy and Eu ions in Bi2SiO5 nanophosphor

- Spectroscopic investigations of Dy3+/Eu3+ co-doped Bi2SiO5 nanophosphors were reported.
- Two way energy transfer from Dy3+ → Eu3+ and Eu3+ → Dy3+ reported.
- Bright white light emission observed due to the emission of complementary colours.
- Time resolved spectroscopy yield information of the radiative decay time.
- UV- FTIR absorption, Photo-excitation, PL and TRPL, CIE techniques were used.

A series of Dy3+ and Eu3+ ion doped Bi2SiO5 nanophosphors were synthesized by hydrothermal method. A comprehensive structural and optical characterization were performed using various techniques including powder X-ray diffraction, UV-Infrared absorption, photoluminescence, time-resolved luminescence technique etc. Crystalline size of the synthesized nanophosphors was found to be ∼25 nm, depending on the doping concentration of the active ions. Under the blue light excitations (386 nm and 393 nm) the Dy3+:Bi2SiO5 and Eu3+:Bi2SiO5 nanophosphors yield characteristic yellowish white light and yellow/red emissions, respectively. In binary co-doped, Dy:Eu:Bi2SiO5, excitation of individual ion results from another doped ion, in addition to the emission from resonantly excited ion. Observation of emission from acceptor ions, confirm the effective mutual interaction between the doped ions and existence of two-way energy transfer process. Various energy transfer parameters including the rate of energy transfer efficiency were estimated. A predominate multipole interaction was concluded for the energy transfer through multichannel interaction which yield white light on 350 nm and 386 nm excitations. CIE coordinates were estimated for various excitations which fall well within the gamut of white light.

183