Multi-Light-Responsive Quantum Dot Sensitized Hybrid Micromotors with Dual-Mode Propulsion.

CdS quantum dots/C tubular micromotors with chemical/multi-light-controlled propulsion and "on-the-fly" acceleration capabilities are described. In situ growth of CdS quantum dots on the outer fullerene layer imparts this layer with light-responsive properties in connection to inner Pt, Pd or MnO layers. This is the first time that visible light is used to drive bubble-propelled tubular micromotors. The micromotors exhibit a broad absorption range from 320 to 670 nm and can be wirelessly controlled by modulating light intensity and peroxide concentration. The built-in accelerating optical system allows for the control of the velocity over the entire UV/Vis light spectra by modulating the catalyst surface chemistry. The light-responsive properties have been also exploited to accelerate the chemical dealloying and propulsion of micromotors containing a Cu/Pd layer. Such dual operated hybrid micromotors hold considerable promise for designing smart micromachines for on-demand operations, motion-based sensing, and enhanced cargo transportation.