• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.1
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• pp.8-17
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• 2023

In conventional liquid crystal display(LCD) manufacturing process, Indium Tin Oxide(ITO) as transparent electrode and rubbing process of polyimide as alignment layer are essential process to apply electric field and align liquid crystal molecules. However, there are some limits that deposition of ITO requires high vacuum state, and rubbing process might damage the device with tribolectric discharge. In this paper, we made nanocomposite with PEDOT:PSS and MWNT to replace ITO and constructed alignment layer by nano imprint lithography with nano wrinkle pattern, to replace rubbing process. These replacement made that only one PEDOT:PSS/MWNT film can function as two layers of ITO and polyimide alignment layer, which means simplification of process. Transferred nano wrinkle patterns functioned well as alignment layer, and we found out lowered threshold voltage and shortened response time as MWNT content increase, which is related to increment of electric conductivity of the film. Through this study, it may able to contribute to process simplification, reducing process cost, and suggesting a solution to disadvantage of rubbing process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.1-7
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• 2017

Cobalt silicide was used as a counter electrode in order to confirm its reliability in dye-sensitized solar cell (DSSC) devices. 100 nm-Co/300 nm-Si/quartz was formed by an evaporator and cobalt silicide was formed by vacuum heat treatment at $700^{\circ}C$ for 60 min to form approximately 350 nm-CoSi. This process was followed by etching in $80^{\circ}C$-30% $H_2SO_4$ to remove the cobalt residue on the cobalt silicide surface. Also, for the comparison against Pt, we prepared a 100 nm-Pt/glass counter electrode. Cobalt silicide was used for the counter electrode in order to confirm its reliability in DSSC devices and maintained for 0, 168, 336, 504, 672, and 840 hours at $80^{\circ}C$. The photovoltaic properties of the DSSCs employing cobalt silicide were confirmed by using a simulator and potentiostat. Cyclic-voltammetry, field emission scanning electron microscopy, focused ion beam scanning electron microscopy, and energy dispersive spectrometry analyses were used to confirm the catalytic activity, microstructure, and composition, respectively. The energy conversion efficiency (ECE) as a function of time and ECE of the DSSC with Pt and CoSi counter electrodes were maintained for 504 hours. However, after 672 hours, the ECEs decreased to a half of their initial values. The results of the catalytic activity analysis showed that the catalytic activities of the Pt and CoSi counter electrodes decreased to 64% and 57% of their initial values, respectively(after 840 hours). The microstructure analysis showed that the CoSi layer improved the durability in the electrolyte, but because the stress concentrates on the contact surface between the lower quartz substrate and the CoSi layer, cracks are formed locally and flaking occurs. Thus, deterioration occurs due to the residual stress built up during the silicidation of the CoSi counter electrode, so it is necessary to take measures against these residual stresses, in order to ensure the reliability of the electrode.