Ca2B5O9Cl:Eu2+, A Suitable Blue-Emitting Phosphor for n-UV Excited Solid-State Lighting

Blue‐emitting Ca 2 B 5 O 9 Cl:Eu 2+ phosphors have been synthesized by solid state reaction. The photoluminescence excitation (PLE) spectra show broad‐band absorptions and can match the emission of near ultraviolet (n‐UV) chip well. At lower Eu 2+ concentration, the emission band can be resolved into two bands, which is assigned to the 5 d →4 f transition of Eu 2+ ions substituting two different Ca 2+ sites. At higher Eu 2+ concentration, the energy transfer from Eu(1) to Eu(2) happens and is very efficient. At higher temperature the phosphor exhibits a lower temperature quenching effect. The fluorescence lifetimes are short enough for application in solid‐state lighting. The electroluminescence spectrum indicates that the emission of chip can almost be absorbed by phosphor and down‐converted into an intensive blue light. The chromaticity coordinates of fabricated light‐emitting‐diodes (LEDs) is very close to that of BaMgAl 10 O 17 :Eu 2+ (BAM). Ca 2 B 5 O 9 Cl:Eu 2+ is a good blue component phosphor for n‐UV excited solid‐state lighting.