Gao Zuoxuan, Mi Yuhang, Wang Mengtong, Liu Xiaohu, Zhang Xiong, Gao Kaifang, Shi Lihong, Mugisha E R, Chen Hongjian, Yan Wenbo
Opt Express. 2021 Feb 1;29(3):3808-3824. doi: 10.1364/OE.417225.
Development of photovoltaic water-microdroplet manipulation using LN:Fe crystals has to meet the requirement of the hybrid and heating-avoided design of biological lab-on-chips. To fulfill this, we demonstrate a successful manipulation of a water microdroplet on a hydrophobic substrate by utilizing the long-range photovoltaic interaction from a distant LN:Fe crystal (see Visualization 1). The maximal manipulation distance (MMD) is found to be dependent on the laser-illumination intensity at the LN:Fe crystal and it can be tuned up to a sub-centimeter level (∼4 mm). Basing on the two-center model of light-induced charge transport in the LN:Fe crystal, we establish an analytic model to describe the force balance during the microdroplet manipulation under a long-range photovoltaic interaction. Either shortening the manipulation distance or increasing the illumination intensity can enhance the photovoltaic interaction and increase the velocity of the microdroplet being manipulated. An abrupt shape change followed by a fast repelling movement of the water microdroplet is observed under a strong photovoltaic interaction (see Visualization 2).
利用掺铁铌酸锂（LN:Fe）晶体开发光伏水微滴操控技术，必须满足生物芯片混合式且避免加热设计的要求。为实现这一点，我们通过利用来自远处掺铁铌酸锂晶体的远程光伏相互作用，成功演示了在疏水基板上对水微滴的操控（见可视化1）。发现最大操控距离（MMD）取决于掺铁铌酸锂晶体处的激光照射强度，并且可以调节到亚厘米级别（约4毫米）。基于掺铁铌酸锂晶体中光致电荷传输的双中心模型，我们建立了一个解析模型，以描述远程光伏相互作用下微滴操控过程中的力平衡。缩短操控距离或增加光照强度均可增强光伏相互作用，并提高被操控微滴的速度。在强光伏相互作用下，观察到水微滴会出现突然的形状变化，随后快速排斥移动（见可视化2）。
