Visualization Recording and Storage of Pressure Distribution through a Smart Matrix Based on the Piezotronic Effect

• Published in: Advanced materials (Weinheim) Vol. 29; no. 26
• Main Authors: Han, Xun, Du, Weiming, Chen, Mengxiao, Wang, Xiandi, Zhang, Xiaojia, Li, Xiaoyi, Li, Jing, Peng, Zhengchun, Pan, Caofeng, Wang, Zhong Lin
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.07.2017
• Subjects: Bleaching; Computer memory; electrochromic devices; Electrochromism; External pressure; Materials science; Medical electronics; Military applications; Nanowires; Piezoelectricity; piezotronic effect; Polarization; Pressure distribution; Pressure sensors; pressure visualization, pressure recording; Recording; Spatial resolution; Stress concentration; Tungsten oxides; Visualization; Zinc oxide; ZnO nanowire arrays; electrochromic devices; pressure visualization, pressure recording; piezotronic effect; ZnO nanowire arrays
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.201701253

Pressure sensors that can both directly visualize and record applied pressure/stress are essential for e‐skin and medical/health monitoring. Here, using a WO3‐film electrochromic device (ECD) array (10 × 10 pixels) and a ZnO‐nanowire‐matrix pressure sensor (ZPS), a pressure visualization and recording (PVR) system with a spatial resolution of 500 µm is developed. The distribution of external pressures can be recorded through the piezotronic effect from the ZPS and directly expressed by color changes in the ECD. Applying a local pressure can generate piezoelectric polarization charges at the two ends of the ZnO nanowires, which leads to the tuning of the current to be transported through the system and thus the color of the WO3 film. The coloration and bleaching process in the ECD component show good cyclic stability, and over 85% of the color contrast is maintained after 300 cycles. In this PVR system, the applied pressure can be recorded without the assistance of a computer because of the color memory effect of the WO3 material. Such systems are promising for applications in human‐electronic interfaces, military applications, and smart robots. A pressure visualization and recording system is achieved by integrating a piezotronic pressure sensor and a WO3 electrochromic device (ECD). In this system, the pressure is expressed by color changes in the ECD, and the color change can be retained. Such systems may have applications in human–electronic interfaces, military applications, and smart robots.