Functional Nanomaterials (FMs) gained critical technological importance in various fields such as electronic, health care, optical communication, energy conversion and storage fields. The FMs includes inorganic, organic, hybrid, nanomaterials and soft mater possesses multiple effects such as photoelectric, ferroelectricity, piezoelectricity, magnetism, energy storage and harvesting, superconductivity, magnetocaloric effect, electromagnetic and plasmonic properties etc. These properties can be possible tune by size dependency, synthesis process (temperature, pressure, medium), and compositional fluctuation, respectively. Moreover, the nanomaterials are the bridge between the bulk, atomic/molecular structures and its design, development, enhancement of properties leads to a better life/society.
The NMSL lab keenly working on the development of various highly efficient nanostructures, microstructures, flexible films (thin/thick films) for energy conversion/storage and sensor applications.
Piezoelectric Nanogenerators (PNG) technology is highly reliable, stable and efficient approach to convert waste mechanical energy in the society such as low frequency mechanical vibrations from the machines, human body motions, ocean waves, wind/water flow motions into useful electrical energy.To date, extensive fabrication methods, growth of various one dimensional (1D)/two dimensional inorganic piezoelectric structures on plastic substrates, flexible polymer films and device designs (planar, stretchable, cylindrical or fiber) were developed to improve the PNG technology as a prominent harvesting approach for creating the sustainable independent power source to drive the low power consumed electronic devices. Moreover, the device compatibility, electrical output performance (nW/cm2 to µW/cm2) under various harsh environments and flexibility issues were optimized to think about the real-time commercialized PNG product.
Triboelectric Nanogenerators: In the era of digitalization and modernization, the wide range of applications relies on the power source, which is rechargeable batteries. For the near future, the nano and microsystems will be used for the development of environmental monitoring systems, health monitoring systems, sensors and IoT, etc. where the battery can no longer be active as the power source. To meet all these requirements, self-powered systems were proposed. The triboelectric nanogenerator was developed to harness the energy from the environment. The triboelectric nanogenerator (TENG) is a device which converts mechanical energy into electricity. The TENG works by the coupled effect of contact electrification and electrostatic induction when two different materials come in contact with each other. The TENG has the advantage of being cheap, easy to design, and has high voltage output. Furthermore, a wide range of materials is available for the TENG. From the past five years, NMSL is extensively involved in the development of self-powered systems based on TENG. The current research on TENG in NMSL involves the development of novel material for TENG, sensing applications, sustainable and biodegradable devices, blue energy harvesting, wind energy harvesting, hybrid devices, and smart toys, etc.
Supercapacitors or supercaps (SC) are energy storage devices with high power density which are considered to be support for batteries or leading to the development of next generation energy storage devices. To improve the performance of supercapacitors, focus on electrodes and electrolytes is essential. We work on wide range of materials from layered, 2D, Transition metal oxides and Chalcogenides (TMD). By tailoring their morphology and device configurations leads to increase in metrics of supercapacitors. The study of charge storage mechanism for each unique electrode and electrolyte is explored. In energy storage devices we work on aqueous, non-aqueous, organic electrolytes leading to solid and liquid state devices.
Self-powered cell: Energy conversion and storage are the primitive technologies in today’s green and renewable energy science, mostly available in separated units. As for energy conversion/harvesting depends upon the nature of sources such as solar, chemical, and mechanical. These conversions include various mechanisms for effectively converting them into electricity. Amongst them, mechanical energy harvesting (piezoelectric nanogenerators) has been developed into a powerful approach for converting low-frequency, biomechanical energy into electricity. As for as energy storage, supercapacitors is one of the predominant storages for high power, in which the electric energy is stored as chemical energy under an externally applied source which follows up electrochemical reactions occurring at the electrodes. Overall, electricity generation and energy storage are two distinct processes that are accomplished through two different and separated physical units achieving the conversions from mechanical energy to electricity and then from electric energy to chemical energy, respectively. In our proposed works, we introduce Self-charging supercapacitor power cell (SCSPC) which can directly hybridize the two processes into one, viz the mechanical energy is directly converted and simultaneously stored as chemical energy, which paves the way for developing maintenance free autonomous power systems for various electronic devices. Such an integrated SCSPC device can be charged up by mechanical deformation and vibration from the environment, provides an innovative approach for developing a new mobile power source for both self-powered systems and portable electronics.
Self-powered Sensors and Systems
Self-powered Sensors and Systems technology is the forthcoming revolution in smart technology and resulting abolish the usage of complex battery sources, external circuit components and natural sources for energy generation. These devices play a key roles at present, and will continue to do so in the near future, because they can function without any external bias voltage sources or additional processes. The importance of this technology is based on driving a system/sensor by harvesting energy from piezoelectric, triboelectric, thermal gradient or solar methods.
The piezo-phototronic effect has been a promising approach to modulate the optoelectronic properties for potential applications in flexible smart electronics. Tuning the inner piezoelectric potentials in multifunctional micro/nanomaterials improves the responsivity of optical detection upon applied strain. With the three-way coupling effect, we construct the self-powered photodetectors to cultivate bias-free and independent sensing devices/systems.