Tunable and White Light Emission of a Single-Phased Ba2Y(BO3)2Cl:Bi3+,Eu3+ Phosphor by Energy Transfer for Ultraviolet Converted White LEDs

White or tunable photoluminescence of phosphors is of great significance for their practical applications in the light-emitting diodes. In this work, Ba2Y(BO3)2Cl:Bi3+,Eu3+ phosphors were fabricated, and their photoluminescence properties were investigated. Three difference luminescence peaks located at 366, 410, and 490 nm were observed in the single Bi3+-doped Ba2Y(BO3)2Cl phosphor under the excitation of ultraviolet light attributed to three various Bi3+ sites occupied in the Ba2Y(BO3)2Cl host. By tuning the excitation wavelength from three various Bi3+ sites, the tunable luminescence properties were obtained. The energy transfer from Bi3+ at various sites to Eu3+ were observed in the Ba2Y(BO3)2Cl:Bi3+,Eu3+ phosphors by an electric dipole–dipole interaction. The tunable and white luminescence was obtained by changing the Eu3+ concentration or excitation wavelength. The light-emitting diodes with the white light emission were constructed by coupling Bi3+ and Eu3+ codoped Ba2Y(BO3)2Cl phosphors with the UV chip, which indicated that the Bi3+ and Eu3+ codoped Ba2Y(BO3)2Cl phosphors can act as a promising candidate for the UV converted WLEDs.