Luminescence properties of full-color single-phased phosphors for white LEDs

A series of full-color single-phased phosphors for white LEDs (W-LEDs), in the system (Y, Ln)2GeO5 (Ln = Tm, Tb, Eu), were prepared and their photoluminescence properties were characterized. The simultaneous incorporation of Eu3+, Tb3+ and Tm3+ ions in Y2GeO5 lattice can result in an integration of red, green, and blue emissions when being excited by ultraviolet light. Under excitation at 352 nm, the color tones of the (Y0.95−xTm0.01TbxEu0.04)2GeO5 phosphors change from cool white to warm white by increasing the concentration of Tb3+, while the intensities of Eu3+ emissions increase. Indeed, in the case of co-doped systems, a very efficient energy that transfers from Tb3+ to Eu3+ occurs. The present phosphors can potentially be used for the high CRI and high luminous efficient white LEDs.