Sung-Ho Liu

Patterning of metallic electrodes on flexible substrates for organic thin-film transistors using a laser thermal printing method

We report on a laser thermal printing method for transferring patterned metallic thin films on flexible plastic substrates using a pulsed CO2 laser. Aluminium and silver line patterns, with micrometre scale resolution on poly(ethylene terephthalate) substrates, are shown. The printed electrodes demonstrate good conductivity and fulfil the properties for bottom-contact organic thin-film transistors. In addition to providing the energy for transferring the film, the absorption of laser light results in a rise in the temperature of the film and the substrate. This also further anneals the film and softens the plastic substrate. Consequently, it is possible to obtain a film with better surface morphology and with its film thickness implanted in part into the plastic surface. This implantation reveals excellent characteristics in adhesion and flexure resistance. Being feasible to various substrates and executable at ambient temperatures renders this approach a potential alternative for patterning metallic electrodes.

Combination of diffractive shaper and splitter for multiple beam laser processing system

Transforming Gaussian laser beam into top-hat profile is accomplished by a four-level kinoform diffractive element. A binary diffractive grating was further integrated for generating multiple top-hat laser spots to improve the efficiency of a laser processing system.