This paper reports on an optoelectrofluidic platform which consists of the organic photoconductive material, titanium oxide phthalocyanine (TiOPc), and the photocrosslinkable polymer, poly (ethylene glycol) diacrylate (PEGDA). TiOPc simplifies the fabrication process of the optoelectronic chip due to requiring only a single spin-coating step. PEGDA is applied to embed the moldless PEGDA-based microchannel between the top ITO glass and the bottom TiOPc substrate. A real-time control interface via a touch panel screen is utilized to select the target 15？μm polystyrene particles. When the microparticles flow to an illuminating light bar, which is oblique to the microfluidic flow path, the lateral driving force diverts the microparticles. Two light patterns, the switching oblique light bar and the optoelectronic ladder phenomenon, are designed to demonstrate the features. This work integrating the new material design, TiOPc and PEGDA, and the ability of mobile microparticle manipulation demonstrates the potential of optoelectronic approach. 1. Introduction The microparticle manipulation by using either optical forces or electrokinetics has been getting important and popular, especially in fields like lab-on-a-chip. The former utilize a laser beam to trap microparticles toward the focal point. The invention of optical tweezers [1–3] and the various development of the holographic optical tweezers [4, 5] have established a convenient platform to manipulate either single or multimicroparticles. However, the requirement of high N.A. value lens in optical tweezers to perform a high focal laser beam highly reduces the working distance and constrains the application [6, 7]. The latter such as dielectrophoresis (DEP) induces microparticle polarized in a nonuniform electric field to either attract or repel toward the field maximum or minimum [8, 9]. General methods to generate nonuniform electric field are to fabricate metal electrodes on the glass substrate. The fixed metal pattern limits the flexiblity to manipulate microparticle. Recently, Chiou et al. integrated the optical flexibility and the electronic approach to present optoelectronic tweezers (OETs) [10]. Its various applications have been applied in biological field [11]. Photoconductive material is a key character of the OET. The amorphous silicon (a-Si) is usually fabricated on an ITO glass to prevent the charges [12]. While the light pattern with proper absorbing wavelength is projected onto the a-Si layer, the resistance within the illumination region is reduced and the charges transport through the
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