Abstract
Digital microfluidic system is a promising technique for transporting droplet by using the phenomenon of electrowetting effect; we can control the small droplet containing drugs, particles and cells. Every droplet can be controlled individually to prevent it from the possible contamination. Recently, our Lab proposed a new organic optoelectrowetting (OEW) chip by using the organic photoconductive material Titanyl phthalocyanine (TiOPc). The organic OEW chip has some advantages such as is low coast, simple fabrication; high photosensitivity and mass production, but it also has the similar disadvantage like the organic semiconductor. One reason of the low electric performance with the organic OEW chip is that the high permittivity dielectric layer cannot be applied in our chip because of the requirement of high temperature fabrication. Recently, a new dielectric layer fabrication in low temperature and high electric performance has been developed to be successfully using in organic semiconductor to increate performance. In this research study, we are the first group to introduce the new dielectric layer fabrication in the organic OEW chip to enhance our chip performance. The new dielectric layer fabrication is named as organic-inorganic composite film fabrication. In this research study, we use hydrothermal method and sol-gel method to make the nano Barium titanate powder and using SEM and X-ray diffraction technology to analyze the lattice and particle size of Barium titanate powder. We use the Nano Dispersion Technology and thin film processing technique to make the high permittivity composite film on our chip. We use the impedance measurement to check the permittivity of the composite film. The composite film has the parameters as follows-percentage concentration: 1.8wt%, permittivity: 24, thickness: 789nm, surface roughness: 0.88nm. We have successfully reduced the required driving voltage from 62V to 18V because of the high permittivity character of the composite film.