Tunable white light emitting Sr2V2O7:Bi3+phosphors: Role of bismuth ion

Publication date: 15 September 2017
Source:Materials & Design, Volume 130
Author(s): Santosh K. Gupta, K. Sudarshan, R.M. Kadam
Phase purity, optical properties and defects in new near white light emitting rare earth free Sr2V2O7:Bi³⁺phosphors were investigated. Emission spectrum of Sr2V2O7 displayed two peaks at all excitation wavelength approximately around 450 (P1) and 600nm (P2). With increase in the excitation wavelength; emission intensity increases and there is a red and blue shift in Peak P1 and P2, respectively. On bismuth doping, the two Peaks P1 and P2 slowly starts merging and become a single broad peak at 5% doping. Bismuth doping also reduces the emission peak energy. This is attributed to substitution of Bi³⁺ at Sr²⁺ site which would distort VO4 tetrahedra, thereby reducing the energy difference between the ³T and ¹A levels of VO4³⁻ distorted tetrahedral. This dual role of bismuth doping and excitation energy leads to interesting tunability in white emission from cool to warm white. This opens a new arena in phosphor research because of great role of white LEDs (both warm and cool) in outdoor and indoor lighting.

Graphical abstract

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