A novel thermally stable Ba3Bi2(BO3)4:Eu3+ red phosphor for solid state lighting application

Highlights: • Prospective Ba₃Bi₂(BO₃)₄:Eu³⁺ red phosphor was prepared and structurally characterized. • The optimum doping concentration of Ba₃Bi₂(BO₃)₄:Eu³⁺ was determined to be 50 at.%. • Concentration quenching occurs if Eu³⁺ ions redistribute over three cation sites. -- Abstract: This paper reports the structural and optical properties of novel Ba₃Bi₂(BO₃)₄:Eu³⁺ red-emitting phosphor. Concentration series of Ba₃Bi₂(BO₃)₄:Eu³⁺ powders were prepared using crystallization from a melt. Powder X-ray diffraction data confirmed formation of single phase samples. Distribution of Eu³⁺ ions over three cation sites were refined for Ba₃(Bi_1-xEu₎₂(BO₃)₄ solid solutions (x = 0.05, 0.35 and 0.8) from single-crystal XRD data. Emission and excitation spectra of Eu³⁺-doped Ba₃Bi₂(BO₃)₄ phosphors show characteristic lines attributed to the intraconfigurational 4f-4f transitions. The optimal Eu³⁺ doping concentration in Ba₃Bi₂(BO₃)₄ host was found to be 50 at.%, whereas concentration quenching phenomenon occurred through dipole-dipole interaction. ⁵D₀ lifetime slightly changed with increase of doping concentration, showing average value of 1.64 ms. The CIE chromaticity coordinates of Ba₃Bi₂(BO₃)₄:Eu³⁺ 50 at.% phosphor was determined to be (0.65, 0.35) which is close to the NTSC standard values (0.67, 0.33) for potential red phosphors. The obtained results show that the Ba₃Bi₂(BO₃)₄:Eu³⁺ phosphors are promising candidates for solid state lighting application.