ZrO2/epoxy nanocomposite for LED encapsulation

Chung, Pao Tang; Yang, Chun; Wang, Sho Hsun; Chen, Chien Wei; Chiang, Anthony S.T.; Liu, Cheng Yi

doi:10.1016/j.matchemphys.2012.08.013

Cited by 61 publications

(21 citation statements)

References 41 publications

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“…The sol-gel process of the alkoxide zirconium inside the epoxy matrix was performed in the presence of acetic acid [14,15], hexahydrophthalic anhydride [16] or acetyl acetone [17] to control the hydrolysis/ condensation reactions. Epoxy/ZrO 2 nanocomposite was also reported by Chung et al [18] using silane-modified ZrO 2 fillers. The zirconia particles were previously prepared by the precipitation of zirconyl chloride using methacrylic acid and triethanolamine as chelating agents.…”

Section: Introductionsupporting

confidence: 53%

Zirconium-methacrylate oxoclusters as new hybrid materials for the modification of epoxy systems

et al. 2015

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Oxozirconium clusters bearing methacrylate moiety (ZrMe) were synthesized by sol-gel process and used in epoxy networks to develop epoxy-based nanocomposites with potential application as encapsulant for light-emitting diode. Diglycidyl ether of bisphenol A-based epoxy resin was previously functionalized with acrylic acid to introduce some vinyl groups in the matrix and improve its interaction with the oxocluster. The ZrMe particles were previously dispersed in the epoxy matrix or in the 4-methyl-tetrahydrophthalic anhydride used as hardener, and the systems were cured with anhydride or with a combination of anhydride and benzoyl peroxide. The last compound promotes the covalent bond between the epoxy matrix and the ZrMe through free radical reactions between the vinyl groups. The dispersion of ZrMe into the epoxy matrix resulted in a significant increase in viscosity, mainly for systems dispersed with a combination of high shear mechanical mixing and ultrasonification. The dispersion of ZrMe into the anhydride resulted in nanocomposites with higher transparency, better dispersion of the oxocluster into the matrix bulk, as observed by transmission electron microscopy, and higher thermal conductivity, mainly for systems cured with anhydride and peroxide. The use of anhydride in combination with BPO also resulted in significant increase in glass transition temperature.

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Section: Introductionsupporting

confidence: 53%

Zirconium-methacrylate oxoclusters as new hybrid materials for the modification of epoxy systems

et al. 2015

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“…Many further schemes to increase the effective refractive index of the packaging material that all can improve the light extraction efficiency have been proposed and tested 16 – 21 using either nanoparticle-epoxy nanocomposite or nanoparticle-loaded-epoxy or epoxy materials incorporated with filler powders or engineered epoxy resins to name a few. The purpose of populating the encapsulating material with nanoparticles (NPs)—composed of transparent metal oxides (or combination of metal oxides, a group II–VI materials, or alloys of Zn, Se, S, Te, Ti, and Zr, or even GaN, SiN, or AlN) with sub-wavelength sizes ranging from 1/5 to 1/20 of the LED wavelength—all of larger refractive index than of the host, is as follows.…”

Section: Introductionmentioning

confidence: 99%

Nanoparticle meta-grid for enhanced light extraction from light-emitting devices

2020

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Based on a developed theory, we show that introducing a meta-grid of sub-wavelength-sized plasmonic nanoparticles (NPs) into existing semiconductor light-emitting-devices (LEDs) can lead to enhanced transmission of light across the LED-chip/encapsulant interface. This results from destructive interference between light reflected from the chip/encapsulant interface and light reflected by the NP meta-grid, which conspicuously increase the efficiency of light extraction from LEDs. The “meta-grid”, should be inserted on top of a conventional LED chip within its usual encapsulating packaging. As described by the theory, the nanoparticle composition, size, interparticle spacing, and distance from the LED-chip surface can be tailored to facilitate maximal transmission of light emitted from the chip into its encapsulating layer by reducing the Fresnel loss. The analysis shows that transmission across a typical LED-chip/encapsulant interface at the peak emission wavelength can be boosted up to ~99%, which is otherwise mere ~84% at normal incidence. The scheme could provide improved transmission within the photon escape cone over the entire emission spectrum of an LED. This would benefit energy saving, in addition to increasing the lifetime of LEDs by reducing heating. Potentially, the scheme will be easy to implement and adopt into existing semiconductor-device technologies, and it can be used separately or in conjunction with other methods for mitigating the critical angle loss in LEDs.

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“…Nanocomposites promise to be a class of materials with tunable and novel properties, and have therefore been at the center of considerable research efforts both in optics [1][2][3][4][5][6][7][8][9][10][11] and other fields [12][13][14][15]. In optics, most of the attention has been directed towards high-refractive index coatings, which can for example be used to enhance the efficiencies of LEDs [11].…”

Section: Introductionmentioning

confidence: 99%

Using effective medium theories to design tailored nanocomposite materials for optical systems

Werdehausen

Staude

Burger

et al. 2018

Current Developments in Lens Design and Optical Engineering XIX

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Modern optical systems are subject to very restrictive performance, size and cost requirements. Especially in portable systems size often is the most important factor, which necessitates elaborate designs to achieve the desired specifications. However, current designs already operate very close to the physical limits and further progress is difficult to achieve by changing only the complexity of the design. Another way of improving the performance is to tailor the optical properties of materials specifically to the application at hand. A class of novel, customizable materials that enables the tailoring of the optical properties, and promises to overcome many of the intrinsic disadvantages of polymers, are nanocomposites. However, despite considerable past research efforts, these types of materials are largely underutilized in optical systems. To shed light into this issue we, in this paper, discuss how nanocomposites can be modeled using effective medium theories. In the second part, we then investigate the fundamental requirements that have to be fulfilled to make nanocomposites suitable for optical applications, and show that it is indeed possible to fabricate such a material using existing methods. Furthermore, we show how nanocomposites can be used to tailor the refractive index and dispersion properties towards specific applications.

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ZrO2/epoxy nanocomposite for LED encapsulation

Cited by 61 publications

References 41 publications

Zirconium-methacrylate oxoclusters as new hybrid materials for the modification of epoxy systems

Zirconium-methacrylate oxoclusters as new hybrid materials for the modification of epoxy systems

Nanoparticle meta-grid for enhanced light extraction from light-emitting devices

Using effective medium theories to design tailored nanocomposite materials for optical systems

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