By Nina Sing
Imagine being able to use your own body and environment as an electrical outlet to power small electronic devices. Dr. Wang’s research enables users to convert mechanical energy such as body movements, noises, or vibrations into usable electricity. Dr. Wang’s research on self-powered nanosystems has pioneered academia and industry for studying micro-nano-systems. Through his innovative research Dr. Wang is dedicated to shaping the future of electronics with sustainable energy.
N: Can you begin by telling me a little about your background as a researcher and what prompted your focus on sustainable research?
W: I have been working in nanoscience for the last 30 years. My original research was on nanomaterial synthesis and characterization using transmission electron microscopy. Later, I realized that nano is beautiful, but it has to be useful! I began to think about its properties and special applications. I came out with the idea of the nanogenerator in 2005 for converting tiny mechanical motion energy into electricity using ZnO [zinc oxide] nanowires.
N: What was your inspiration behind the self-powering nanotechnology?
W: When I worked on small, tiny nano-devices, we would usually use a large power source to power them, which made the system large and inconvenient. I began to think about how to make the entire system operate by itself without an external power source. This [idea] is possible because the power consumption of a nanodevice is extremely low. I [coined] the idea of self-powering nanotechnology in 2005-2006, and have been focused on it ever since. Now this field is well received because of the fast development of the internet, sensor networks, wearable electronics and more.
N: Your research states that the self-powered nanotechnology aims at harvesting energy from the environment to power micro/nano-system based sensor network. What kind of energy from the environment is being harvested and where is it being harvested from?
W: Energy that can be harvested includes, solar energy from light, vibration/motion energy from individuals, [thermal] energy if there is a temperature variation. But for humans, the main energy [harvested] is body motion energy.
N: Can you briefly describe the process of how harvested energy can be converted into usable energy?
W: We utilize two effects of harvesting body motion energy. One is piezoelectric materials such as ZnO. This uses the electric potential created by a mechanical straining of ZnO. The other is the use triboelectric effect. The latter is much more efficient than the former. This [triboelectric effect] uses potential [energy] generated by two surfaces after physical contact [as a result of] transferred electrostatic charges. Triboelectric nanogenerators (TENGs) are universally available, cheap, and have wide applications.
N: What issues have you/did you face when developing the science behind nanogenerators?
W: A lot of issues, such as the stability of materials and devices, improvement of efficiency, packaging the devices, and improving its life time.
N: How soon do you see the capability of self-powered systems being integrated into small electronics?
W: It is being integrated in a number of cases. Ever since I proposed the self-powering idea, we now can make a temperature sensor, humidity sensor, motion/vibration sensor, chemical senor, biosensor, heart beat monitor, small electronic watch, a small scientific calculator and many more, to be self-powered with wireless data transmission. This will be a hugely important area for health care, security, environmental monitoring, and wearable electronics.
N: Why do you believe sustainable energy is a relevant issue to focus your research on?
W: Humans care about a few major things: health, security and sustainability. Because of my background in physics and materials science, energy is a natural choice. I started the field of nanoenergy in 2005, which has been the focus of my research for the last 12 years.