The design of a ceramic phosphor plate with functional materials for application in high power LEDs

Ji, Eun Kyung; Song, Young Hoon; Bak, Sang Hwan; Jung, Mong Kwon; Jeong, Byung Woo; Lee, Dong Bok; Yoon, Dae–Ho

doi:10.1039/c5tc02795k

Cited by 38 publications

(12 citation statements)

References 15 publications

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“…Compared to single crystals, polycrystalline ceramics allow for a controllable microstructure (such as pores, secondary phases, grain boundaries, and grain sizes) and offer great freedom in controlling the light scattering and absorption processes . Moreover, phosphor ceramics possess outstanding characteristics such as high thermal conductivity, superior mechanical strength, and excellent chemical and physical stability . Ji et al.…”

Section: Survey Of Laser Phosphorsmentioning

confidence: 99%

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Color Conversion Materials for High‐Brightness Laser‐Driven Solid‐State Lighting

Wang

Hirosaki

et al. 2018

Laser & Photonics Reviews

276

191

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Solid‐state lighting is advancing toward higher power, higher brightness, and smaller size to cope with the market competitiveness, and laser‐driven solid‐state lighting technology is springing up owing to its super‐high brightness and compactness. These developments put forward new requirements for color conversion materials (i.e., phosphors). Here, the state‐of‐art achievements in laser phosphors are summarized, and the topics of luminescence saturation, light extraction efficiency, and light uniformity encountered in laser lighting technology are discussed. Several typical types of color converters, such as single crystal, phosphor ceramics, phosphor‐in‐glass, phosphor films, and quantum‐well light‐emitting diodes, are comparatively overviewed and discussed. The cutting‐edge applications of high‐brightness white laser light in lighting, displays, healthcare, and communications are summarized. The challenges and outlook in laser‐driven solid‐state lighting and some empirical rules for designing novel laser phosphors are highlighted.

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Section: Survey Of Laser Phosphorsmentioning

confidence: 99%

“…Ji et al. addressed that the green‐emitting LuAG:Ce phosphor ceramic had a smaller thermal quenching and a higher thermal conductivity (4–5 W m −1 K −1 ) than the parent powder . Tang et al.…”

Section: Survey Of Laser Phosphorsmentioning

confidence: 99%

Color Conversion Materials for High‐Brightness Laser‐Driven Solid‐State Lighting

Wang

Hirosaki

et al. 2018

Laser & Photonics Reviews

276

191

View full text Add to dashboard Cite

show abstract

“…Indeed, it has been demonstrated that thermal conductivity is almost eight times larger in ceramic phosphor than their parent powder phosphor. This characteristic helps dissipate heat and reduce thermal quenching . In addition, it presents higher fracture toughness than glass ceramic and glasses used for the phosphor in glass (PIG) approaches.…”

Section: Introductionmentioning

confidence: 99%

Dual color tuning in Ce³⁺‐doped oxyfluoride ceramic phosphor plate for white LED application

et al. 2018

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Ceramic phosphor plates of cerium (Ce3+)‐doped oxyfluoride were fabricated by the solid‐state reaction method. These phosphors exhibit efficient emission, with the novel feature of color tuning by varying both the doping concentration and excitation wavelength. As the Ce3+ concentration increases, the excitation spectrum broadens by a factor of 1.6, and the excitation peak wavelength shifts from 390 to 435 nm, and there is a variation in excitation energy of ~ 10%. Luminescence spectrum of low Ce3+ concentration samples is tuned from blue to green with the change of excitation wavelength. The emission peak exhibits a shift of 58 nm into the red spectral region, varying the Ce3+ concentration from 0.05 to 0.1 mol%; whereas this shift is only 6 nm when Ce3+ content changes from 0.25 to 1 mol%. Photoluminescence (PL) quantum yield has achieved 76%. The crystal structure was examined using X‐ray diffraction to explain its possible influence on the redshift luminescence. A proof of concept of white LED was constructed using a 450 nm blue LED chip with an oxyfluoride phosphor plate, showing a luminous efficacy (LE) of 64 lm/W with a color rendering index of 74.

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“…29 To improve the required characteristics of the PCP, other materials can be added to the raw materials during the synthesis process. Ji et al 30 and Lee et al 31 in which two phosphor crystals with green and red emission bands were present. They reported that the use of the CaO-SiO 2 system as the host glass obtained a PGP having broad emission bands for good color rendering.…”

Section: Types and Characteristics Of Phosphor Platesmentioning

confidence: 99%

Review—Phosphor Plates for High-Power LED Applications: Challenges and Opportunities toward Perfect Lighting

Kim

Viswanath

Unithrattil

et al. 2017

ECS J. Solid State Sci. Technol.

127

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In the past decades, solid-state lighting based on phosphors as energy converters has been a fast-growing industry. Phosphorconverted white light-emitting diodes (pc-wLEDs) enable high-power applications and miniaturization; for this, the phosphor must have good stability and high efficiency. In order to satisfy this demand, phosphor plates have been proposed instead of conventional organic-based phosphor binders. In this review, such phosphor plates are categorized according to their synthesis methods, and the advantages and disadvantages of each category are detailed. In addition, we describe the major aspects of phosphor plates that require improvement for applications in high-power devices. For the fabrication of high-power LEDs, the phosphor configuration, color purity, porosity, and particle size of glass powders are key properties to enhance the luminescence efficiency and reduce the generation of heat inside wLED packages, thereby improving thermal stability. The advent of authentic, energy-efficient lighting in the home and workplace significantly affected the modern way of life. Beginning with the mass production of incandescent light bulbs, and with the subsequent evolution of fluorescence lights, lighting technology has developed rapidly in the last few decades. Since Edison's incandescent bulb in 1879, 1 artificial lighting has been developed to increase power output and decrease the size of the system. The development of red light-emitting diodes (LEDs) in 1962 2 and blue LEDs in 1993 3 allowed innovation in lighting and display. In particular, combinations of blue LEDs and yellow phosphors are used for many applications because they can realize cheap and efficient white solid-state lighting with several advantages including long lifetimes, eco-friendly behavior, and the capacity of miniaturization. 4-6In phosphor-converted white LEDs (pc-wLEDs), the phosphor converter dispersed in silicon resin (phosphor-in-silicon; PiS) is directly packed on a blue InGaN chip.7 When driven by a bias current, the emitted blue light absorbed by the phosphor is emitted as yellow light; together with the transmitted blue light, this constitutes white luminescence. However, this method lacks a red component, which entails the drawbacks of a poor color rendering index (CRI) and limited correlated color temperature (CCT). To overcome these drawbacks, one proposed method mixes yellow phosphors with phosphors having green to red emissions under blue excitation. 8 In pc-wLEDs, the color is primarily determined by the ratio of the blue emission from the LED chip to the yellow to red emission from the phosphor. However, the efficacy and brightness are determined by the converted yellow to red emission, as it contributes the bulk of lumens. In this configuration, the heat generated from the LED chip and phosphor cannot be efficiently dissipated because of the poor thermal stability and weak thermal conductivity of the resin, which causes luminous decay and color shifting in white light-emitting diodes (wLEDs).9 When the tempe...

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The design of a ceramic phosphor plate with functional materials for application in high power LEDs

Abstract: Here we report the design of a ceramic phosphor plate made up of different functional materials, such as SiO2 and MgO, and Lu3Al5O12:Ce3+ (LuAG:Ce) for the fabrication of remote phosphors in high-power LED applications.

Cited by 38 publications

References 15 publications

Color Conversion Materials for High‐Brightness Laser‐Driven Solid‐State Lighting

Color Conversion Materials for High‐Brightness Laser‐Driven Solid‐State Lighting

Dual color tuning in Ce³⁺‐doped oxyfluoride ceramic phosphor plate for white LED application

Review—Phosphor Plates for High-Power LED Applications: Challenges and Opportunities toward Perfect Lighting

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The design of a ceramic phosphor plate with functional materials for application in high power LEDs

Abstract: Here we report the design of a ceramic phosphor plate made up of different functional materials, such as SiO2 and MgO, and Lu3Al5O12:Ce3+ (LuAG:Ce) for the fabrication of remote phosphors in high-power LED applications.

Cited by 38 publications

References 15 publications

Color Conversion Materials for High‐Brightness Laser‐Driven Solid‐State Lighting

Color Conversion Materials for High‐Brightness Laser‐Driven Solid‐State Lighting

Dual color tuning in Ce3+‐doped oxyfluoride ceramic phosphor plate for white LED application

Review—Phosphor Plates for High-Power LED Applications: Challenges and Opportunities toward Perfect Lighting

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Product

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Dual color tuning in Ce³⁺‐doped oxyfluoride ceramic phosphor plate for white LED application