Significance of nano-materials, designs consideration and fabrication techniques on performances of strain sensors - A review

Flexible electronics have become fast-growing fields after the discovery of various nanomaterials especially in the area of flexible strain sensors. High flexibility, stretchability, sensitivity, and compatibility are some essential requirements of flexible strain sensors. Currently developed nanomaterials have shown excellent performances as functional materials in sensing devices. These materials are preferred over conventional materials due to their stable mechanical and electronic behavior in diverse applications. This article presents current research progress in flexible and stretchable strain sensors. The performance of six nanomaterials i.e. Graphene, Carbon Nanotubes (CNTs), MXene, Metal Nanowires, Conducting Polymers, and Liquid Metals, used as a flexible conductive element in various strain sensors is evaluated. The compatibility of presently used fabrication techniques with these nanomaterials is highlighted. The importance of design and structures in the performance of strain sensors is also briefly discussed. In the last, challenges which limit the use of these nanomaterials in flexible electronics are also discussed.