| Summary: | 碩士 === 國防大學理工學院 === 化學工程碩士班 === 101 === Optically transparent polymers have been widely used in various optical applications such as the optical coatings and encapsulation materials for optical devices. With increasing demand for high performance in these applications, a high refractive index and high thermal stability are especially important in order to increase the optical efficiency and lifetime of the devices. Encapsulation materials for light emitting diodes (LEDs) need to operate at high temperatures for a long time, and therefore especially require a high thermal stability and resistance to yellowing. Yellowing due to thermal decomposition decreases the transparency and reduces the light extraction efficiency of these devices. Thus, the device reliability and lifetime of high-brightness LEDs can be limited by the characteristics of the encapsulation materials. In addition, a high refractive index of the encapsulation material is required for high efficiency light extraction from an LED, significantly improving its illumination performance. In this study, a series of composite materials, including 3-Isocyanatopropyltriethoxysilane (IPTES), phenyltriethyloxysilane (PTEOS) and bisphenol A epoxy resin, were used as precursors to synthesize phenyl hybrimer/epoxy composites through a sol–gel copolymerization technique to act as light emitting diode (LED) encapsulation materials. The properties of the materials, including optical transmittance, refractive index, thermal stability, and thermal and UV resistance, were characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM).
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