Efficient spectral regulation in Ce:Lu3(Al,Cr)5O12 and Ce:Lu3(Al,Cr)5O12/Ce:Y3Al5O12 transparent ceramics with high color rendering index for high-power white LEDs/LDs

Abstract

Realizing a high color rendering index (CRI) in Ce:LuAG transparent ceramics (TCs) with desired thermal stability is essential to their applications in white LEDs/LDs as color converters. In this study, based on the scheme of configuring the red component by Cr3+ doping, an efficient spectral regulation was realized in Ce,Cr:LuAG TCs. A unilateral shift phenomenon could be observed in both photoluminescence (PL) and photoluminescence excitation (PLE) spectra of TCs. By constructing TC-based white LED/LD devices in a remote excitation mode, luminescence properties of Ce,Cr:LuAG TCs were systematically investigated. The CRI values of Ce:LuAG TC based white LEDs could be increased by a magnitude of 46.2%. Particularly, by combining the as fabricated Ce,Cr:LuAG TCs with a 0.5 at% Ce:YAG TC, surprising CRI values of 88 and 85.5 were obtained in TC based white LEDs and LDs, respectively. Therefore, Ce,Cr:LuAG TC is a highly promising color convertor for high-power white LEDs/LDs applied in general lighting and displaying.

Study on a Highly Thermostable Dy3+-Activated Borophosphate Phosphor

“…The PL spectra of BZBP:0.13Dy 3+ at different temperatures are measured, as shown in Figure a. The PL intensity exhibits a slight decrease as temperature rises, which is related to the thermal quenching effect. − In Figure b, the PL intensities at 423 and 473 K can retain 92 and 88% of the initial value, separately, displaying superior luminescence thermostability compared to that of the Dy 3+ -activated oxide phosphors reported (Table ). Meanwhile, according to the relationship between ln­[( I 0 / I ( T ))–1]­and 1/ kT derived from eq S6, the activation energy barrier ( E a ) is determined to be 0.175 eV (Figure c).…”

Simplified Single‐Step Fabrication of Composite Transparent Ceramics

“…It shows the accuracy of the designated photoluminescent region and the possibility of producing precise composite phosphor configurations, allowing flexible design of more efficient high-powder multisector/multicomponent ceramic phosphor plates. [36][37][38] For instance, an approach using stacked layers or quadrant separators for combining two kinds of phosphors-inglass materials was demonstrated by Kim et al [38] Their phosphor plate design exhibited improved performance by preventing blue light leakage and increasing spectral uniformity.…”

A review on magneto-optical ceramics for Faraday isolators

“…The Verdet constant, thermal conductivity, thermo-optical properties and laser damage threshold of MO ceramics are almost equal to that of the crystals with the same composition. What's more, by using the fabrication method of transparent ceramics, it's possible to obtain incongruent melting and high melting point materials [94][95][96][97][98], which greatly expands the range of MO material selection. Unlike the difficulty in obtaining large size MO crystals, the size of the ceramics is limited only the size of the available equipment in theory.…”