Research
Energy Harvesting utilizing Nanomaterials
Mechanical motion-based energy harvesting concept has huge technological interest in accordance with growing popularity of portable smart electronics. It is becoming more feasible due to advanced research for nano-electronics to operate at extremely low power-consumption so that the energy scavenged from the environment may be sufficient to meet their working modes. Solar and thermal energies are most common and feasible sources of energy to be scavenged in our surroundings. However, these types of energies are time and location dependent. Especially for personal electronics, mechanical energy is most likely reliable and independent energy source since human activities are mostly based on mechanical movements regardless of environments. Harvesting energy from body motion or human activity has a strong potential, which can untie modern personal life from messy connections of wire for electric power supply. According to such concept, nanowire-based nanogenerators (NGs) built on textile fibers or solid substrates were demonstrated for harvesting mechanical energy produced by friction-motion of two fibers or ultrasonic waves. For scavenging the energy from mechanical movements especially human activities, until now, it is important to explore wearable and sustainable technologies that work at low frequencies and at various amounts/directions of deformation and that are based on flexible and durable materials.
'Stand-alone' Nanosystem
The future research of nanotechnology is mostly attracted to the areas of integrating various nanodevices into a nanosystem. It can act like living creatures with multi-functions such as sensing, communicating, controlling and responding (left figure). Surely, a nanosystem requires an energy source to make it stand alone and independent. Harvesting energy from the environment can be very attractive way for powering nanosystems. It will be used to power nanodevices without using battery. Aside from developments of superior components in nano-scale, its synergetic hybridization method for individual part also has to be explored simultaneously. Once energy harvesting nanotechnology is able to drive any kind of nano-devices, the unique assembling technology will be in charge of a realization of self-powered system. Until now, there has been little unique nanotechnology to assemble energy harvesting part with any other functional device. Therefore, a development of unique hybridized strategy should be a key step towards stand-alone self-powered nanosystems.
Manufacturing of Functional Nanodevices
Nanoscale devices based on nanometerials have been considered impractical due to difficulties of positioning and controlling. We present a strategy to overcome these fundamental problems and build highly-ordered patterns of nanomaterials. In this strategy, we utilize molecular interaction to position nanomaterials into desired structure.
Significantly, patterned nanostructures were mostly stable enough to go through additional process such as conventional microfabrication steps. Large-scale field effect transistor array can be fabricated via the patterning method. Top-gated electrical characteristics were investigated as well. Considering the increased interests in functional nanodevices for the future technology, our strategy should have a significant impact on various industrial applications.