Top emerging technologies for self-powered nanosystems: nanogenerators and nanopiezotronics

Developing wireless nanodevices and nanosystems are of critical importance for sensing, medical science, defense technology and even personal electronics. Power sources are indispensable for independent, sustainable, maintain-free and continuous operations of implantable biosensors, ultrasensitive chemical and biomolecular sensors, nanorobotics, micro-electromechanical systems, remote and mobile environmental sensors, homeland security and even portable/wearable personal electronics. It is highly desired for wireless devices and even required for implanted biomedical devices to be self-powered without using battery. This is a key step towards self-powered nanosystems. The near future research is the integration of multi-functional nanodevices into a nanosystem so that it can function as a living species with capabilities of sensing, controlling, communicating and actuating/responding. A nanosystem is composed of not only nanodevices but also nano-power-source (or nano-battery). We now consider the following occasions. In cases where individual sensors are difficult to get to (e.g., in hostile territory), or if the sensor network consists of a large number of nodes distributed over a large geographic area, then it may not be possible to replace batteries when required. A self sufficient power source deriving its power from the environment and thus not requiring any maintenance would be very desirable. In order for any system to be self sufficient, it must harness its energy from its surrounding environment and store this harnessed energy for later use. The goal for nanotechnology is to build self-powered nanosystems that exhibit ultrasmall size, supersensitivity, extraordinary multi-functionality and extremely low power consumption.