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Highly efficient rare-earth-free deep red emitting phosphor La <sub/>2</sub> Li <sub/>1?y</sub> Sb <sub/>1?x</sub> O <sub/>6</sub> : <i>x</i> Mn <sup>4+</sup> , <i>y</i> Mg <sup>2+</sup> : application in high-power warm w-LEDs
摘要： Phosphor-in-glass (PiG), which serves as both a luminescent convertor and organic encapsulation material in high-power white light-emitting diodes (w-LEDs), has become a prospective research hotspot owing to its high transparency and thermal stability. However, YAG:Ce3+ PiG-based LED devices still suffer from a lack of a red component. Therefore, the development of red phosphors with excellent quantum efficiency and superior thermal stability is urgent. Herein, a highly efficient La2Li1?ySb1?xO6:xMn4+,yMg2+ red phosphor with a broadband emission ranging from 670 to 720 nm was fabricated via a conventional solid-state reaction. By co-doping Mg2+ in La2LiSbO6:Mn4+, the emission intensity was enhanced significantly, which reaches as high as 10 times that of the single-doped La2LiSbO6:Mn4+. It is proposed that the Mg2+ dopant can compensate imbalanced charges for the substitution of Sb5+ by Mn4+ and interrupt adverse energy transfer among the Mn4+ activators. Impressively, a maximum quantum yield of up to 80.3% is achieved and about 80% emission intensity is retained at the temperature of 423 K. Furthermore, the crystal field strength (Dq) and Racah parameters (B and C) together with the nephelauxetic ratio (b1) were calculated based on the obtained spectroscopic data. By embedding the red-emitting La2LiSbO6:Mn4+,Mg2+ phosphor and yellow-emitting YAG:Ce3+ phosphor into TeO2-based glass, an inorganic PiG composite as a color converter to replace organic silicone was acquired. The excellent optical parameters and tunable chromaticity feature of the fabricated w-LEDs were achieved by adjusting the mass ratio of La2LiSbO6:Mn4+,Mg2+ to YAG:Ce3+ in the PiG plate, where the correlated color temperature changed from cool white (6555 K) to warm (4130 K) and the color rendering index increased from 73.7 to 86.6 under an operating current of 300 mA.
关键词： Phosphor-in-glass,quantum yield,red phosphor,Mg2+,thermal stability,w-LEDs,Mn4+
更新于2025-11-20 15:33:11
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Hybrid nanoparticle layers toward enhanced luminescence of phosphor plates for white LEDs
摘要： MgF2 porous nanoparticle-silica hybrid coating layers were utilized to enhance luminescence efficiency of phosphor plates for white light emitting diodes (wLEDs). Silica and chemically synthesized porous MgF2 nanoparticles were sequentially deposited by spin coating on the phosphor plate with phosphor-in-glass (PiG) configuration. Microscopic investigation the hybrid film suggested intermixing of silica and porous MgF2 nanoparticles. Numerical estimation based on transfer matrix method expected a significant reduction in reflectance and enhancement of transmission spectra by the hybrid coating. In accordance, the photoluminescence intensity of phosphor plates showed a drastic improvement and quantum yield were enhanced from 30% (for bare PiG plate) to 45% (for hybrid layer coated PiG plate). When assembled with blue LEDs, hybrid nanoparticle coating on the PiG phosphor plates improved luminescence efficacy from 40 lm/W to 49 lm/W without deterioration of chromaticity during operation. In addition, mechanical durability of the hybrid thin film was confirmed by abrasion test. Conformal coating of matching layer consisting of porous MgF2 nanoparticles and silica can provide an efficient route to highly luminescent white LEDs with mechanical stability.
关键词： refractive index,phosphor-in-glass,nanoparticles,Luminescence,Hybrid coating
更新于2025-09-23 15:21:01
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Fabrication and analysis of PiG-based LEDs with WO3-doped TeO2-based glass
摘要： Phosphor-converted white light-emitting diodes (pc-WLEDs) were fabricated using low-melting-temperature TeO2-based glass powders, which are a potential packaging material. The novel glass component, TeO2-B2O3-ZnO-Na2O doped with WO3, showed a high transmittance of above 80% and had a refractive index (1.83) that matched that of the phosphors well. Warm pc-WLEDs were fabricated using a 460-nm blue chip combined with YAG:Ce3+ yellow phosphors, Li2MgTiO4:Mn4+, Hf4+ red phosphors, and TeO2-based glass powders or silicone. The differences between phosphor-in-glass (PiG) and phosphor-in-silicone (PiS) pc-WLEDs are reported in detail. Based on a long-term heating test, color deviations, correlated color temperatures (CCTs), and the color rendering index (CRI), the PiG-based pc-WLEDs showed excellent stability and less deviation in terms of the CIE coordinates as compared to the PiS-based pc-WLEDs. The luminescence efficiency, CCT, and CRI of the optimized PiG-based pc-WLED were 41.32 lm/W, 4570 K, and 83.31, respectively, making this pc-WLED a good candidate for pc-WLED applications.
关键词： Phosphor-in-glass,pc-WLED
更新于2025-09-16 10:30:52