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arXiv · 2411.11931

Understanding the Origin of a Second Mobility Reversal in Optoelectrically Powered Metallo-Dielectric Janus Particles

Sankha Shuvra Das·Pablo Garcia-Sanchez·Antonio Ramos·Gilad Yossifon
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Abstract

While previous studies indicated the mobility reversal of an electrically-powered metallo-dielectric Janus particle (JP) with increasing frequency, here we report an intriguing second mobility reversal observed in optoelectronically-driven JPs. In contrast to the commonly used setup with parallel ITO-coated glass substrates to induce a uniform electric field orthogonal to the velocity direction, this setup incorporates a thin photoconductive layer deposited on the bottom ITO-coated glass substrate. We have found that the reversal is associated with the asymmetry of the bottom substrate's photoconductivity, localized underneath the JP, resulting from the self-shading effect of the metallic hemisphere under top optical illumination. Numerous control tests, including optical illumination from the bottom, along with numerical simulations, support this hypothesized mechanism

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Sankha Shuvra Das, Pablo Garcia-Sanchez, Antonio Ramos, Gilad Yossifon. 2024-11-18. Understanding the Origin of a Second Mobility Reversal in Optoelectrically Powered Metallo-Dielectric Janus Particles. https://arxiv.org/abs/2411.11931

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