Indian scientists have in a path-breaking achievement fabricated a simple, cost-effective transparent nanogenerator that can generate electricity from vibrations all around for use in optoelectronics, self-powered devices, and other biomedical applications.
The device is also highly efficient, robust, and gives reproducible output over long hours of operation. The results have been published in Journal of Nanoscience and Nanotechnology.
Some of the unconventional methods to generate electricity include piezoelectric, thermoelectric, and electrostatic techniques used in devices like touch screens and electronic displays.
The triboelectric nanogenerators (TENG) make use of mechanical energy in the form of vibrations present everywhere in different forms to generate electricity. The energy harvesting TENG works on the principle of creation of electrostatic charges via instantaneous physical contact of two dissimilar materials followed by generation of potential difference when a mismatch is introduced between the two contacted surfaces through a mechanical force. This mechanism drives the electrons to move back and forth between the conducting films coated on the back of the tribo layers.
The methods employed till now to design TENG use expensive fabrication methods like photolithography or reactive ion etching, and additional process such as electrode preparation.
Dr. Shankar Rao and his team from the Centre for Nano and Soft Matter Sciences, Bengaluru, an institute under the Government’s Department of Science & Technology, have designed a transparent TENG, using thermoplastic polyurethanes (TPU) either in the form of electrospun nanofibers or as a flat film using the simpler Doctor’s blade technique, along with Polyethylene terephthalate (PET) as tribo layers.
TPU nanofibers are obtained from the electrospinning (ES) technique. The Doctor’s blade technique, a routine procedure adapted in a variety of situations, squeezes the material through a blade and the substrate yielding a uniform thin layer. The easy availability of the active material and the simplicity of the fabrication process make it cost-effective over currently available fabrication techniques.
The fabricated device could light up eleven LEDs by gentle hand tapping and could be a potential candidate for use in optoelectronics, self-powered devices, and other biomedical applications.