Plastic substrates for organic light-emitting devices (OLED) are extremely sensitive to moisture and oxygen. A new amorphous engineering thermoplastic, nominated cyclic olefin copolymer (COC) has been used for this application, because of higher transparence, lower birefringence, lower dispersion and lower water absorption. However, COC plastic substrates can’t sustain plasma-based processing temperatures at 350°C. In this study, experiments of the moisture permeation rate testing and the thermal resistance experiments are conducted to explore the moisture diffusion barrier and thermal barrier characteristics of COC substrate deposited a SiO2 thin film on it. Silicon dioxide layer of thickness, 0.25μm, 0.5μm, and 1 μm, respectively, are fabricated by PECVD. For the permeation rate measurement, the Ca-test method is adopted. For the thermal resistance measurements, two methods of the thermocouple in vacuum environment and the IR thermography are adopted and measured results are compared. Different surface temperatures, 323.15K, 373.15K, 408.15K, and 473.15K, respectively, are applied upon the silicon dioxide film and temperature differences for varied thickness of silicon dioxide film are measured. Experimental results are presented to investigate the behaviors of moisture diffusion barrier and thermal barrier characteristics of the COC/SiO2 structure.

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