2024 | Guangyao Cheng, Chit Yau Kuan, Kuan Wen Lou, and Yi-Ping Ho
Light-responsive materials play a crucial role in light-driven droplet manipulation, enabling precise control over droplet movement, merging, and trapping. This review compiles an in-depth discussion of the governing mechanisms underlying light-driven droplet manipulation, along with recent advancements in light-responsive materials and their applications. Light-driven methods offer advantages such as contactless interaction, high spatiotemporal resolution, and biocompatibility, making them promising for biochemical applications. The review covers various mechanisms, including direct optical forces, light-induced DEP forces, interfacial tension gradients, thermal convection, and bubble generation. Light-responsive materials, such as photoconductive, photovoltaic, photoisomerizable, photothermal, and pyroelectric materials, are essential for converting light into different forms of energy to manipulate droplets. Photoconductive materials like hydrogenated amorphous silicon (a-Si:H) and titanium oxide phthalocyanine (TiOPc) are widely used in OET and OEW devices for droplet manipulation. These materials enable precise control over droplet movement through changes in conductivity and electric field gradients. The review also highlights the potential of light-responsive materials in advancing droplet-based technologies for biochemical applications, emphasizing their versatility and effectiveness in manipulating droplets for various scientific and diagnostic purposes.Light-responsive materials play a crucial role in light-driven droplet manipulation, enabling precise control over droplet movement, merging, and trapping. This review compiles an in-depth discussion of the governing mechanisms underlying light-driven droplet manipulation, along with recent advancements in light-responsive materials and their applications. Light-driven methods offer advantages such as contactless interaction, high spatiotemporal resolution, and biocompatibility, making them promising for biochemical applications. The review covers various mechanisms, including direct optical forces, light-induced DEP forces, interfacial tension gradients, thermal convection, and bubble generation. Light-responsive materials, such as photoconductive, photovoltaic, photoisomerizable, photothermal, and pyroelectric materials, are essential for converting light into different forms of energy to manipulate droplets. Photoconductive materials like hydrogenated amorphous silicon (a-Si:H) and titanium oxide phthalocyanine (TiOPc) are widely used in OET and OEW devices for droplet manipulation. These materials enable precise control over droplet movement through changes in conductivity and electric field gradients. The review also highlights the potential of light-responsive materials in advancing droplet-based technologies for biochemical applications, emphasizing their versatility and effectiveness in manipulating droplets for various scientific and diagnostic purposes.