A high-efficiency, broadband-excited cyan-emitting Ba3Lu2B6O15:Ce3+,Tb3+ phosphor for near-UV-pumped white light-emitting diodes

Abstract

In this present work, we reported on a novel cyan-emitting phosphor Ba3Lu2B6O15:Ce3+,Tb3+ prepared by a conventional solid-state method and evaluated its potential as a candidate for application in white light-emitting diodes (WLEDs). X-ray diffraction (XRD), photoluminescence (PL) and photoluminescence excitation (PLE) spectra, CIE color coordinates, internal quantum efficiency (IQE), and temperature-dependent PL spectra were used to characterize the Ba3Lu2B6O15:Ce3+,Tb3+ phosphor. We found that this phosphor showed strong and broad absorption in 300–425 nm wavelength region, and under excitation at 373 nm it exhibited intense cyan emission due to the combination of blue emission of Ce3+ ions peaking at 446 nm and green emission of Tb3+ ions peaking at 542 nm. The energy transfer process from Ce3+ to Tb3+ ions in the Ba3Lu2B6O15:Ce3+,Tb3+ phosphor was studied. The optimized cyan-emitting Ba3Lu2B6O15:0.03Ce3+,0.2 Tb3+ sample showed CIE color coordinates of (0.204, 0.239) and its IQE was measured to be about 51%. The performance of this phosphor was further tested by investigating its thermal stability, and the obtained results demonstrated that this phosphor possessed good luminescence thermal stability and color thermal stability. Finally, we fabricated a WLED lamp by coating the Ba3Lu2B6O15:0.03Ce3+,0.2 Tb3+ cyan-emitting phosphor with a red-emitting CaAlSiN3:Eu2+ phosphor on a 365 nm-emitting LED chip, and when driven by a 180 mA forward bias current such WLED device produced intense white light with a color rendering index of 88, a correlated color temperature of 4213 K, and CIE color coordinates of (0.375, 0.388).