Conventional binary light-driven micromotors, based on semiconducting photocatalysts and metal junctions, have mostly shown limited speed and charge separation/transport due to their not well-designed interfaces. Here ZnO/Pt Janus micromotors with atomically smooth interfaces are introduced, which show fast light-driven and fuel-free propulsion (15 body-length s−1). Furthermore, the speed of ZnO/Pt micromotors is increased by ≈60% with a few atomic amorphous TiO2 photocatalyst interlayers. The new photocatalysts' interfaces, i.e., ZnO/TiO2, provide type II heterojunctions, leading to an increase in the number of electron/hole pairs and then improving the electron transfer to Pt metal. This effective charge separation/transfer results in a faster electrophoretic motion of the novel ternary ZnO/TiO2/Pt micromotors. The concept of the type II heterojunction, which is well known in photocatalysis communities, is used in light-driven micromotors as a new approach and paves the way for the next-generation of faster fuel-free “green” micromotors.
Bibliographical noteFunding Information:
This work was supported by the project Advanced Functional Nanorobots (reg. No. CZ.02.1.01/0.0/0.0/15_003/0000444 financed by the EFRR). Z.S. was supported by the Czech Science Foundation (GACR No. 17-11456S) and by the Neuron Foundation for Science.
All Science Journal Classification (ASJC) codes
- Materials Science(all)