Highly biodegradable piezoelectric flexible wearable tactile sensors with amino acid crystals: a paradigm shift towards smart transient electronics

Abstract

The unprecedented interest towards flexible and portable electronics of the modern tech-savvy world increases the burden of e-waste. This work presents a biodegradable, wearable electronic skin (e-skin) with precise tactile sensing capability to address this challenge. The functional layers have been designed by fabricating β-glycine structures within gelatine matrix. These enhance the piezoelectric nature of the functional layer, yielding a piezoelectric coefficient of 22.5 pm/V. The fabricated self-powered e-skin demonstrates an excellent output voltage of 2.1 ± 0.1 V, yielding dynamic pressure sensitivity of 41.3 ± 1.3 mV/kPa with an ultralow response time of 1.0 ± 0.1 ms. Additionally, this e-skin effectively senses static pressure as low as 0.35 Pa in the form of a rice grain with a distinguishable output signal exhibiting the highest sensitivity of 1.74 ± 0.07 Pa⁻¹. Further, a matrix structure based on the e-skin obtains the 2d projection of any unknown objects placed over it. Furthermore, the e-skin demonstrates efficient application in real-time wireless human–machine interactions. More significantly, the fabricated e-skin degrades within 7 days in tap water. Therefore, the abilities of the fabricated devices upgrade their potential in not only continuous health care monitoring but also human–machine interaction, enabling it as a smart green candidate for next-generation biodegradable flexible electronics.