Freestanding BaTiO<sub>3</sub>‐Au Vertically Aligned Nanocomposite toward Flexible Multi‐Sensing Platform
Benson Kunhung Tsai, Jialong Huang, You‐Jun Yu, Meng Hao Lee, Benjamin Stegman, Emiliano Flores, Patrick Zhang Tong, Ke Xu, Shiyu Zhou, Jianan Shen, Jiawei Song, Yizhi Zhang, Lia Stanciu, Wenzhuo Wu, X. Zhang, Haiyan Wang
Abstract
Abstract Flexible and wearable sensors show enormous potential for personalized healthcare devices by real‐time monitoring of an individual's health. Typically, a single functional material is selected for one sensor to sense a particular physical signal while multiple materials will be selected for multi‐mode sensing. Vertically aligned nanocomposites (VANs) have recently demonstrated various material combinations and novel coupled multifunctionalities that are hard to achieve in any single‐phase material alone, including multiphase multiferroics, magneto‐optic coupling, and strong magnetic and optical anisotropy. Integrating these novel VANs into wearable sensors shows enormous potential in multi‐mode sensing owing to their multifunctional nature. In this work, the transfer of VANs onto polydimethylsiloxane as a novel flexible chemical and pressure sensor is demonstrated. For this demonstration, the classical BaTiO 3 ‐Au VAN with combined plasmonic and piezoelectric properties is used to demonstrate a multi‐sensing mechanism. A thin water‐soluble buffer of Sr 3 Al 2 O 6 serves as a buffer layer for the epitaxial growth and transfer process. The electrical output based on the piezoelectric responses and identifying 4‐mercaptobenzoic acid by surface‐enhanced Raman spectroscopy reveal great potential for free‐standing VANs in a wearable multifunctional sensing platform.