A highly efficient narrow-band blue phosphor of Bi3+-activated cubic borate Ba3Lu2B6O15 towards backlight display applications

Abstract

A novel narrow-band blue emitting phosphor of Bi 3+ -activated cubic borate Ba 3 Lu 2 B 6 O 15 is synthetized by solid state reaction, which benefited from a highly symmetrical crystal structure. Ba 3 Lu 2 B 6 O 15 :Bi 3+ shows great application potential in LCD backlight display attributed to its extreme color purity of 97.76%, high internal quantum efficiency of 90.6% and weak chromaticity drift. • FWHM = 35.5 nm. • IQE = 90.6%. • Excellent thermal stability. • Energy level scheme. • 90.06% NTSC. Developing innovative efficient phosphors featured with a narrow-band emission is essential for present white light-emitting diodes (wLEDs) towards high-performance liquid–crystal display (LCD) backlights applications, especially for Bi 3+ -activated phosphors. Herein, we synthesized a near-ultraviolet (n-UV) excitable narrow-band blue-emitting Ba 3 Lu 2 B 6 O 15 :Bi 3+ (BLB:Bi 3+ ) phosphor. It exhibits a narrow band emission (full-width at half-maximum, FWHM = 35.5 nm), high color purity of 97.76%, surprisingly high internal quantum efficiency (IQE) which reached up to 90.6%, excellent thermal stability (85%@150 °C of the integrated emission intensity at room temperature) and reversibility and high consistency. The outstanding photoluminescence properties of Bi 3+ are attributed to a highly symmetrical crystal field environment and tightly connected polyhedral network of Ba 3 Lu 2 B 6 O 15 . In addition, the energy level scheme is constructed from the calculated electronic structure to explore the difference in luminescence stability of Ce and Bi doped BLB phosphors. The pc-wLED device fabricated using commercial green β -Sialon:Eu 2+ , red K 2 SiF 6 :Mn 4+ , and as-prepared blue BLB:Bi 3+ phosphor on a 365 nm n-UV chip covered 90.06% of the color space of National Television System Committee (NTSC) standard, suggesting great potential for industrial applications as LCD backlighting.