A single Eu2+-activated high-color-rendering oxychloride white-light phosphor for white-light-emitting diodes

Abstract

Single-phased, high-color-rendering index (CRI) white-light phosphors are emerging as potential phosphor-converted white-light-emitting diodes (WLEDs) and as an alternative to blends of tricolor phosphors. However, it is a challenge to create a high CRI white light from a single-doped activator. Here, we present a high CRI (Ra = 91) white-light phosphor, Sr5(PO4)3-x(BO3)xCl:Eu2+, composed of Sr5(PO4)3Cl as the beginning member and Sr5(BO3)3Cl as the end member. This work utilized the solid-solution method, and tunable Eu2+ emission was achieved. Color-tunable Eu2+ emissions in response to structural variation were observed in Sr5(PO4)3-x(BO3)xCl solid solutions. This was further confirmed using X-ray Rietveld refinement, electron paramagnetic resonance spectroscopy, and in the photoluminescence spectra. The color-tunable emissions included the white light that originated from the combination of the blue emission of Sr5(PO4)3Cl:Eu2+ and an induced Eu2+ yellow emission at approximately 550 nm in the solid solution. Importantly, the white-light phosphors showed a greater R9 = 90.2 under excitation at 365 nm. This result has rarely been reported in the literature and is greater than that of (R9 = 14.3) commercial Y3Al5O12:Ce3+-based WLEDs. These findings demonstrate the great potential of Sr5(PO4)3-x(BO3)xCl:0.04Eu2+ as a white-light phosphor for near-UV phosphor-converted WLEDs. These results also provide a shortcut for developing a high CRI white-light phosphor from a single Eu2+-doped compound.

Deep red MGe4O9:Mn4+(M = Sr, Ba) phosphors: structure, luminescence properties and application in warm white light emitting diodes

“…To evaluate the performance of artificial lighting in WLEDs, there are two essential parameters that widely used in the lighting community which called Color Rendering Index (CRI) and Correlated Color Temperature (CCT). 25 Based on the results of measurement, as Table 1 shows, under the 20mA current excitation, the CCT is 7115K and CRI is 76.3 for LED chip + YAG:Ce 3+ system. On the other hand, the CCT is 3082 K and CRI is 92.1 for the system of InGaN chip-YAG:Ce 3+ -BGO:Mn 4+ , and the CCT is 3440 K, CRI is 89.1 for the system of InGaN chip-YAG:Ce 3+ -SGO:Mn 4+ .…”

Dual-Mode Manipulating Multicenter Photoluminescence in a Single-Phased Ba9Lu2Si6O24:Bi3+, Eu3+ Phosphor to Realize White Light/Tunable Emissions

“…According to the fitting analyses, the decay curves of the Bi 3+ emission at 410 and 485 nm are non-exponential, indicating that there is more than one relaxation process. The average lifetimes τ avg of these samples can be estimated using the simple equation 28 :where I(t) is the luminous intensity at time t . According to equation (3), the average lifetimes of Bi 3+ were evaluated and listed in Table S2.…”

White light emitting thermally stable bismuth phosphate phosphor Ca3Bi(PO4)3:Dy3+ for solid‐state lighting applications

“…Presently, the commercial approach comprises of blue emitting InGaN chip with yellow emitting (YAG: Ce 3+ ) phosphor . However, this approach has disadvantages such as halo effect, low color rendering index (CRI) index R a ≤65) and high correlated color temperature (CCT) due to the lack of red color . Another approach has been widely investigated, which is based on the ultraviolet/near‐ultraviolet (UV/n‐UV) chip with the combination of red, green, and blue (RGB) phosphors .…”

“…6,7 However, this approach has disadvantages such as halo effect, low color rendering index (CRI) index R a ≤65) and high correlated color temperature (CCT) due to the lack of red color. [7][8][9] Another approach has been widely investigated, which is based on the ultraviolet/near-ultraviolet (UV/n-UV) chip with the combination of red, green, and blue (RGB) phosphors. 10,11 This approach provides better CRI and CCT but increases the synthesis processing time and cost of the device.…”