  The advancements in nanotechnology, material science, and electrical
engineering have shrunk the sizes of electronic devices down to the
micro/nanoscale. This brings the opportunity of developing the Internet of Nano
Things (IoNT), an extension of the Internet of Things (IoT). With nanodevices,
numerous new possibilities emerge in the biomedical, military fields, and
industrial products. However, a continuous energy supply is needed for these
devices to work. At the micro/nanoscale, batteries cannot supply this demand
due to size limitations and the limited energy contained in the batteries.
Internet of Harvester Nano Things (IoHNT), a concept of Energy Harvesting (EH),
which converts the existing different energy sources, which otherwise would be
dissipated to waste, into electrical energy via electrical generators. Sources
for EH are abundant, from sunlight, sound, water, and airflow to living
organisms. IoHNT methods are significant assets to ensure the proper operation
of the IoNT; thus, in this review, we comprehensively investigate the most
useful energy sources and IoHNT principles to power the nano/micro-scaled
electronic devices with the scope of IoNT. We discuss the IoHNT principles,
material selections, challenges, and state-of-the-art applications of each
energy source for both in-vivo and in vitro applications. Finally, we present
the latest challenges of EH along with future research directions to solve the
problems regarding constructing continuous IoNT containing various self-powered
nanodevices. Therefore, IoHNT represents a significant shift in nanodevice
power supply, leading us towards a future where wireless technology is
widespread. Hence, it will motivate researchers to envision and contribute to
the advancement of the following power revolution in IoNT, providing unmatched
simplicity and efficiency.
