Small-Scale Energy Harvesting Devices for Smart Electronics

In the present era of the internet of things (IoT), wireless sensor networks will play a crucial role in detecting, monitoring, and collection of data required for the advancement of public safety, industrial automation, human healthcare, and energy management. Currently, to operate wireless network devices, batteries are the primary choice for power sources because of the ease of installation. However, they require periodic replacement due to their limitation of power and energy capacity. The solution to this limitation is energy harvesting, that can provide mechanism for recharging the batteries and extending their lifetime. In some scenarios, energy harvesters can directly function as the power source in combination with supercapacitors. In this article, energy harvesting from ambient mechanical vibrations and stray magnetic fields is described with emphasis on fundamentals governing the material selection and implementation. Small-scale energy harvesting devices are explored with relevance towards wireless sensors and biomedical applications. Further, this article provides an overview of piezoelectric, triboelectric, and magneto-mechano-electric energy harvesting. State-of-the-art energy harvesting materials and device structures are discussed addressing fabrication, modeling, and their performance.