White Light Emission From Tb3+/Sm3+ Codoped LiYF4 Single Crystal Excited by UV Light

LiYF₄ single crystals codoped with Tb³⁺/Sm³⁺ ions were synthesized by the vertical Bridgman method. When excited by 374-nm ultraviolet light, the crystals emit violet-blue, blue, green, yellow, orange, and red light. The white light as a result of a combination of these emissions can be achieved from Tb³⁺ (1.25 mol%) and Sm³⁺ (2.22 mol%) codoped LiYF₄ crystal with chromaticity coordinates of x = 0.3143, y = 0.3484, and color temperature T_c = 6322 K by 374-nm excitation. Both chromaticity coordinates and photoluminescence intensity vary with the concentration of rare earth dopants and the excitation wavelengths. This crystal may be a potential candidate for the UV-light excited white LED device.