With the benefits of device simplicity and functionality, optoelectrowetting (OEW) has been studied as a liquid-handling approach for lab-on-a-chip applications. Recent studies have further demonstrated three-dimensional (3D) OEW technology by using a polymer-based photoconductive material, titanium oxide phthalocyanine (TiOPc), which allows device fabrication on flexible substrates via a low-temperature spin-coating method. However, one critical drawback of this TiOPc material is its low-quality photoconductive property and thus corresponds to very poor OEW modulation. Our study herein presents light absorption of the TiOPc largely enhanced by using plasmonic nanoparticles to significantly improve OEW performance for effective light-driven droplet manipulation. Metallic nanoparticles dispersed on the TiOPc layer enable to induce plasmonic light scattering with an increased optical path length. Consequently, more light rays can be absorbed onto the TiOPc and dramatically increase its photoconductivity to enhance OEW performance. Our measurement studies have verified a 2-order improvement in the TiOPc’s light absorption performance by using aluminum (Al) nanoparticles. We have experimentally demonstrated that a 4 µm thick layer of Al nanoparticles fabricated with a 2.0 wt% solution enables 60.4° more contact angle modulation than the one used with no nanoparticles. The droplet dynamics study has also presented the light-actuation speed of a droplet as 12.5 mm/s enhanced by plasmonic light scattering, which is a 39-fold faster speed than that without nanoparticles. Our plasmonic nanoparticle-enhanced OEW technology can offer device simplicity, flexibility and functionality, while providing much enhanced OEW performance useful for various digital microfluidic (DMF) applications by allowing effective light-driven droplet manipulations.

利用设备简单性和功能性的优势，光电湿法（OEW）已作为一种芯片实验室应用的液体处理方法进行了研究。最近的研究进一步证明了通过使用基于聚合物的光电导材料氧化钛酞菁（TiOPc）的三维（3D）OEW技术，该技术可以通过低温旋涂方法在柔性基板上制造器件。然而，该TiOPc材料的一个关键缺点是其低质量的光电导性能，因此对应于非常差的OEW调制。本文的研究显示，通过使用等离激元纳米颗粒显着提高OEW性能以有效进行光驱动液滴操作，可大大增强TiOPc的光吸收。分散在TiOPc层上的金属纳米颗粒能够以增加的光程长度引发等离子体光散射。因此，更多的光线可以吸收到TiOPc上，并显着提高其光电导率，从而增强OEW性能。我们的测量研究证明，通过使用铝（Al）纳米颗粒，TiOPc的光吸收性能提高了2倍。我们已经通过实验证明，用2.0重量％的溶液制备的4微米厚的Al纳米颗粒层比没有使用纳米颗粒的Al纳米颗粒能提供更多的60.4°接触角调制。液滴动力学研究还表明，通过等离激元光散射，液滴的光致动速度为12.5 mm / s，比不使用纳米粒子的速度快39倍。