Efficient Catalytic Light-Driven Micromotors Enable Low-Magnification Tracking under Photoluminescence and Applications in Complex Media

Abstract

Light-driven micromotors are easily accessible and controllable without tethering, but their development faces challenges due to the need for monochromatic light, tracking difficulties, and environmental limitations. In this work, we present Hexagon-BiVO₄ micromotors that exhibit exceptional photocatalytic efficiency and enable effective multi-wavelength propulsion in pure water under low-intensity illumination at 365, 455, 530, and 660 nm, without requiring complex optical systems. Unlike non-fluorescent particles, their photoluminescence allows detection at 4× magnification for wide-field tracking over a 17 mm working distance. This tracking capability has been validated in dark blood samples. Additionally, the micromotors sustain stable movement in complex media containing glycerol, urea, or glucose, and exhibit ionic tolerance after modification. Finally, we demonstrate their versatility in contaminated river water, with movement observed under low-intensity mercury light, and confirm their ability to decompose and remove pollutants from various water sources. Combining broad‑spectrum actuation, photoluminescence, and environmental resilience, this platform offers potential for versatile applications in targeted therapy and environmental cleanup.