Ca_2B_5O_9CL:Eu~(2+), A Suitable Blue-Emitting Phosphor for n-UV Excited Solid-State Lighting

摘要

Blue-emitting Ca_2B_5O_9Cl: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 5d→4f 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 BaMg-Al_(10)O_(17):Eu~(2+) (BAM). Ca_2B_5O_9Cl:Eu~(2+) is a good blue component phosphor for n-UV excited solid-state lighting.