A novel blue-emitting KCa4(BO3)3:Ce3+ phosphor for white LED application

A blue-emitting phosphor KCa4(BO3)3 doped with Ce3+ was prepared by solid state reaction. Its phase purity and synthesis temperature were investigated by powder X-ray diffraction (XRD). The optical properties were studied by photoluminescence (PL) and photoluminescence excitation (PLE) spectra. In addition, the temperature-dependent PL measurement was also carried out. The phosphor showed a broad and strong blue emission centered at 428 nm under near ultraviolet light excitation at 370 nm. Ce3+ ions in the three Ca sites of the host showed the similar centroid shift (ɛc) and crystal field splitting (ɛcfs). The quantum efficiency of the phosphor with optimal doping concentration was 68% of that of commercial blue phosphor BaMgAl10O17:Eu2+. It indicated the promising applicability as a blue-emitting phosphor for UV-converting white light-emitting diodes.

Excitation and emission spectra of KCB:0.02Ce3+ (Peak deconvolution of excitation and emission bands are indicated as dashed lines. The inset shows the image of the KCB:0.02Ce3+ phosphor excited at 365 nm in a UV box)Figure optionsDownload as PowerPoint slide