The recent advances in the micro/nanomotor field have shown great progress in the propulsion of such devices by fuel-free mechanisms. Light, as an abundant and natural source, has been demonstrated to be a promising external field to wirelessly induce the motion of these tiny micro/nanomachines, without the need of any toxic fuel or complex system set-up. This tutorial review covers the most representative examples of light-driven micro/nanomotors developed so far, which self-propelled exclusively under fuel-free conditions. Their different swimming behaviors triggered by light stimuli, divided into four main categories (schooling, phototaxis, gravitaxis and directional motion), are discussed along with their similarities with the motion modes of microorganisms. Moreover, the main parameters that influence the motion of light-driven photocatalytic-based micro/nanomotors as well as alternative strategies to develop more efficient systems are also discussed.

Center for Advanced Functional Nanorobots Department of Inorganic Chemistry University of Chemistry and Technology Prague Technicka 5 Prague 6 166 28 Czech Republic

Center for Advanced Functional Nanorobots Department of Inorganic Chemistry University of Chemistry and Technology Prague Technicka 5 Prague 6 166 28 Czech Republic and Department of Chemical and Biomolecular Engineering Yonsei University 50 Yonsei ro Seodaemun gu Seoul 03722 Korea and Future Energy and Innovation Laboratory Central European Institute of Technology Brno University of Technology Purkyňova 656 123 Brno CZ 616 00 Czech Republic

References provided by Crossref.org

Technology Roadmap of Micro/Nanorobots

Smart micro- and nanorobots for water purification

Magnetically Driven Micro and Nanorobots