Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, CA 92093-0448, USA.
Nanoscale. 2017 Jan 19;9(3):1292-1298. doi: 10.1039/c6nr09005b.
Thin-film optical strain sensors have the ability to map small deformations with spatial and temporal resolution and do not require electrical interrogation. This paper describes the use of graphene decorated with metallic nanoislands for sensing of tensile deformations of less than 0.04% with a resolution of less than 0.002%. The nanoisland-graphene composite films contain gaps between the nanoislands, which when functionalized with benzenethiolate behave as hot spots for surface-enhanced Raman scattering (SERS). Mechanical strain increases the sizes of the gaps; this increase attenuates the electric field, and thus attenuates the SERS signal. This compounded, SERS-enhanced "piezoplasmonic" effect can be quantified using a plasmonic gauge factor, and is among the most sensitive mechanical sensors of any type. Since the graphene-nanoisland films are both conductive and optically active, they permit simultaneous electrical stimulation of myoblast cells and optical detection of the strains produced by the cellular contractions.
薄膜光学应变传感器具有以时空分辨率映射小变形的能力，并且不需要电询问。本文描述了使用金属纳米岛修饰的石墨烯来感应小于 0.04%的拉伸变形，分辨率小于 0.002%。纳米岛-石墨烯复合薄膜在纳米岛之间存在间隙，当用苯硫醇官能化时，它们表现为表面增强拉曼散射（SERS）的热点。机械应变会增大间隙的尺寸；这种增大会削弱电场，从而削弱 SERS 信号。这种复合的 SERS 增强“压电阻抗”效应可以使用等离子体应变系数来量化，并且是任何类型的最灵敏的机械传感器之一。由于石墨烯-纳米岛薄膜既具有导电性又具有光学活性，因此它们允许同时对成肌细胞进行电刺激和对细胞收缩产生的应变进行光学检测。
