A New Blue-Emitting Oxohalide Phosphor Sr₄OCl₆:Eu²⁺ for Thermally Stable, Efficient White-Light-Emitting Devices under Near-UV

Abstract

New blue-emitting Sr 4 OCl 6 :Eu 2+ (SOC:Eu 2+ ) phosphor was prepared by solid-state reaction. Structural properties including phase purity were analyzed through Rietveld analysis, using X-ray powder diffraction. The photoluminescence (PL) property of the SOC:Eu 2+ phosphor was explored, for its successful application in the white light-emitting devices (WLED) industry. The SOC:Eu 2+ phosphor exhibits broad excitation spectra ranging from 250 to 425 nm, and an intense broad blue emission band centered at 446 nm under λ ex = 370 nm. The optimum concentration of Eu 2+ in Sr 4−x Eu x OCl 6 was found with x = 0.02 (0.5 mol %). The temperature-dependent PL studies have been investigated, and the phosphor exhibits strong thermal quenching resistance, retaining the luminance of ∼91% at 200 °C. The WLED device was fabricated by integrating the blue-emitting Sr 3.98 Eu 0.02 OCl 6 with commercial red-and green-emitting phosphor, excited with near UV LED chip (λ ex = 395 nm), and shows excellent CIE chromaticity coordinates (x = 0.32, y = 0.33). The structural stability of the host, good thermal stability, and excellent CIE coordinates suggest that SOC:Eu 2+ is a promising blue component for application in the white LED industry.

Luminescent properties and energy transfer studies of color-tunable LuBO 3 : Ce 3+ /Tb 3+ /Eu 3+ phosphors

“…A series of Ce 3+ -doped, Ce 3+ /Tb 3+ co-doped and Ce 3+ /Tb 3+ /Eu 3+ tri-doped LuBO 3 LED prototypes, with the surface mount device (SMD), were prepared by combining optimized-composition LuBO 3 : 0.01Ce 3+ , 0.09Tb 3+ (green) and LuBO 3 : 0.01Ce 3+ , 0.50Tb 3+ , 0.005Eu 3+ (red) phosphor with NUV LED chips (385 nm emitting). The NUV chips was fixed in an SMD package and connected to electrodes.…”

“…In order to further investigate the luminescence dynamics of the samples, the lifetimes of Ce 3+ emission in LuBO 3 [32]. But the reason for such a high Tb 3+ content is unclear.…”

“…In recent decades, phosphors emitting visible colors under the excitation of near UV 5 (NUV) light have particularly attracted much attention as wavelength converters for light emitting diodes (LEDs) [1,2]. Since human eyes are insensitive to UV light (350-400 nm) and spectral parameters are solely controlled by phosphors, NUV-based phosphor-converted (pc) white LEDs are expected to have higher color-rendering index (CRI) and lower correlated color temperature (CCT) than commercial blue-base pc white LEDs [3,4]. Presently, Eu 2+ -doped (oxy)nitride phosphors, e.g., β-SiAlON:Eu 2+ and CaAlN 3 : Eu 2+ , have been developed as efficient green and red-emitting phosphors from the aspects of high quantum efficiency, wide excitation wavelength ranging from UV to blue region, and high chemical and thermal stabilities [5,6].…”

“…Preliminary investigations on the photoluminescence of Ce 3+ , Tb 3+ , Eu 3+ , Pr 3+ single-doped [19][20][21], Ce 3+ /Yb 3+ co-doped LuBO 3 [22] were reported. However, detailed analysis on the PL properties of Ce 3+ /Tb 3+ co-doped and Ce 3+ /Tb 3+ /Eu 3+ tri-doped LuBO 3 have not been done yet to our knowledge. In this work, the luminescent properties, quantum efficiencies and thermal stability of Ce 3+ /Tb 3+ co-doped and Ce 3+ /Tb 3+ /Eu 3+ tri-doped LuBO 3 system were reported.…”

Crystal structure and Temperature-Dependent Luminescence Characteristics of KMg4(PO4)3:Eu2+ phosphor for White Light-emitting diodes

“…Recently, a great attention has been focused on white LEDs as solid-state lighting and as components of display devices because of their low energy consumption, high efficiency, long operational lifetime (>100 000h), environmental friendliness and high material stability1234. There are several ways to assemble the white LEDs.…”