With the rapid development of the information network society, data communication between computers and smartphones (the Internet) has become highly active, and today, even digital home appliances utilize the Internet. In the near future, not only such information terminals and appliances but also a wide variety of sensors will be installed everywhere and connected to the Internet. This will enable the collection of information on various objects—machines, the human body, structures, and natural entities—from around the world, and even allow the remote control of machines based on such information. This is the coming era of the Internet of Things (IoT). However, to drive sensors in isolated environments, compact self-powered devices capable of generating electricity over long periods under installation conditions are required. Therefore, energy harvesting devices that can generate power by recovering energy from unused sources such as waste heat and mechanical vibrations are becoming increasingly important.
Meanwhile, in the integrated circuits used in current information and communication devices, enormous energy consumption has become a serious issue. Although efforts have been made toward the development of energy-saving devices, it is estimated that nearly 60% of the input energy is wasted as heat. Thus, it is ideal not only to pursue “energy saving” but also to reuse energy by generating electricity from waste heat. To achieve this, thermal management—the control of heat transfer, dissipation, and conversion into electricity—plays a crucial role. At present, materials with nanoscale structures (nanomaterials) are expected to enable flexible and precise thermal management. To realize IoT technologies using such approaches, it is essential to develop energy-harvesting nanomaterials composed of ubiquitous elements (such as O, Si, Fe, and Zn) that are inexpensive, non-toxic, and abundant in nature.
In Nakamura Laboratory, we aim to address these societal challenges by harnessing thermal management for energy harvesting. We design and fabricate nanomaterials composed of ubiquitous elements based on the principles of quantum mechanics, solid-state physics, and heat and carrier transport. Specifically, our research focuses on the following four areas.
