White Light Emission by Dy3+ Doped Phosphor Matrices: A Short Review.

In this review we have studied number of research papers related to white light emission from Dy3+ doped different host matrices. It is observed that most of the Dy3+doped aluminates, silicates, borates etc., emitted blue, green and red colour with specific intensities so that CIE coordinates, appeared near to white light. Correlated Colour Temperature(CCT) values of these phosphors expressed that the white light emission produced, was adaptable to human eyes. Dy3+ ions act as activator in each case. Four peaks at approximately 480,575, 670, and 757 nm could be seen in most of the Dy3+ doped phosphors. Expected transition responsible for these peaks are 4F9/2 → 6H15/2 (Blue Colour), 4F9/2 → 6H13/2 (Green-Yellow Colour), 4F9/2 → 6H11/2 (Red Colour) and 4F9/2 → 6H9/2(Brownish Red Colour). Few of the discussed phosphors exhibited long phosphorescence, starting from several minutes to few hours. Mechanism responsible for long lasting white light emission was also discussed. Five different factors, to recognize the phosphors for its suitability as commercial white light phosphor have been discussed.