ZrO2/epoxy nanocomposite for LED encapsulation
ZrO2/epoxy nanocomposite for LED encapsulation
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DOI：
10.1016/j.matchemphys.2012.08.013
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发表时间：
2012-10-15
影响因子：
4.6
通讯作者：
Liu, Cheng-Yi
中科院分区：
文献类型：
--
作者：
Chung, Pao Tang;Yang, Chun Ting;Liu, Cheng-Yi
制备了ZrO 2/环氧树脂纳米复合材料，并在几种类型的LED封装中作为密封剂进行测试。该复合材料的制备是通过共混的脂环族环氧/酸酐树脂与硅烷改性的氧化锆填料在乙酸乙酯溶剂中，这是在固化前除去。对于可加工的密封剂实现的最大填料负载量为约20体积%。这导致折射率增加0.04。与纯环氧树脂相比，用该复合材料封装的大功率LED封装显示出超过10%的光输出增加。增强是超过预测的减少在芯片/密封剂界面的内部全反射。额外的增强可以追溯到异常高的散射和更好的散热。散射被发现是波长无关的，因此更符合米氏理论比瑞利一个。直接在LED封装中测量复合材料的热阻，发现比商业有机硅密封剂低16%。遗憾的是，在添加无机填料的情况下没有观察到耐久性的改善。用我们的复合材料封装的封装的温度-湿度-偏压寿命几乎与纯脂环族环氧树脂相同。因此，复合材料的耐久性在很大程度上取决于基体本身。(c)2012爱思唯尔有限公司版权所有。
ZrO2/epoxy nanocomposite has been prepared and tested as encapsulant in several types of LED package. The composite was prepared by the blending of cycloaliphatic epoxy/anhydride resin with silane-modified ZrO2 fillers in ethyl acetate solvent, which was removed before curing. The maximum filler loading achieved for a workable encapsulant was about 20% by volume. This led to an increase of 0.04 on the refractive index. A high-power LED package encapsulated with this composite showed more than 10% increase of the light output compared to that with the pure epoxy. The enhancement was more than that predicted by the reduction of internal total reflection at the chip/encapsulant interface. The extra enhancement was traced back to the unusually high scattering and a better heat dissipation. The scattering was found to be wavelength independent, thus more consistent with the Mie theory than the Rayleigh one. The thermal resistance of the composite was measured directly in a LED package and found to be 16% lower than that of a commercial silicone encapsulant. Unfortunately, no improvement on the durability was observed with the addition of inorganic fillers. The temperature-humidity-bias life-time of the packages encapsulated with our composite was practically the same as that with the pure cycloaliphatic epoxy. Therefore, the durability of the composite is largely determined by the matrix itself. (c) 2012 Elsevier B.V. All rights reserved.