Self-powered environmental monitoring gas sensors: Piezoelectric and triboelectric approaches

For many years, gas sensors using semiconducting metal oxides and 2-D materials have provided a platform for environmental monitoring for more than two decades. However, these sensors require high operating temperature and external power supply or batteries, which is a great hindrance to their application in modern wearable/smart devices and the Internet of Things (IoT). Self-powered systems based on piezoelectric and triboelectric nanogenerators have the potential to overcome aforesaid limitations to some extent. These nanogenerators can scavenge environment mechanical energy into electrical output, which could be a promising alternative to external power source required for sensing devices, and can also be used as a source of energy for our rapidly increasing daily requirements. In this regard the new research has been proposed using the triboelectric or piezoelectric concept by coupling with gas sensing ability of semiconducting materials to avoid the inevitability of external power sources. A brief overview of the history and fundamentals about nanogenerators and potential applications of the self-supporting gas sensing system based on nanogenerators are provided in this chapter. This chapter could serve as a road map for leading researchers in the field of self-powered sensors of the next generation and highlight current developments in the area.