Liu Qingxian, Liu Zhiguang, Li Chenggao, Xie Kewei, Zhu Pang, Shao Biqi, Zhang Jianming, Yang Junlong, Zhang Jin, Wang Quan, Guo Chuan Fei
Department of Materials Science and Engineering Southern University of Science and Technology Shenzhen 518055 China.
Department of Mechanics and Aerospace Engineering Southern University of Science and Technology Shenzhen 518055 China.
Adv Sci (Weinh). 2020 Mar 12;7(10):2000348. doi: 10.1002/advs.202000348. eCollection 2020 May.
Human-computer interfaces, smart glasses, touch screens, and some electronic skins require highly transparent and flexible pressure-sensing elements. Flexible pressure sensors often apply a microstructured or porous active material to improve their sensitivity and response speed. However, the microstructures or small pores will result in high haze and low transparency of the device, and thus it is challenging to balance the sensitivity and transparency simultaneously in flexible pressure sensors or electronic skins. Here, for a capacitive-type sensor that consists of a porous polyvinylidene fluoride (PVDF) film sandwiched between two transparent electrodes, the challenge is addressed by filling the pores with ionic liquid that has the same refractive index with PVDF, and the transmittance of the film dramatically boosts from 0 to 94.8% in the visible range. Apart from optical matching, the ionic liquid also significantly improves the signal intensity as well as the sensitivity due to the formation of an electric double layer at the dielectric-electrode interfaces, and improves the toughness and stretchability of the active material benefiting from a plasticization effect. Such transparent and flexible sensors will be useful in smart windows, invisible bands, and so forth.
人机界面、智能眼镜、触摸屏以及一些电子皮肤都需要高度透明且灵活的压力传感元件。柔性压力传感器通常会采用微结构化或多孔的活性材料来提高其灵敏度和响应速度。然而，这些微结构或小孔会导致器件具有高雾度和低透明度，因此在柔性压力传感器或电子皮肤中同时平衡灵敏度和透明度具有挑战性。在此，对于一种由夹在两个透明电极之间的多孔聚偏二氟乙烯（PVDF）薄膜组成的电容式传感器，通过用与PVDF具有相同折射率的离子液体填充孔隙来解决这一挑战，并且该薄膜在可见光范围内的透过率从0大幅提高到94.8%。除了光学匹配外，离子液体还由于在介电 - 电极界面形成双电层而显著提高了信号强度以及灵敏度，并受益于增塑效应提高了活性材料的韧性和拉伸性。这种透明且灵活的传感器将在智能窗户、隐形带等方面有用。
