Candidate: Md. Masud Rana
Title: Organic-Inorganic Nanomaterial based Highly Efficient Flexible Nanogenerator for Self-powered Wireless Electronics
Date: April 11, 2023
Time: 3:40 PM
Place: REMOTE ATTENDANCE
Supervisor(s): Ban, Dayan
Abstract:
As the world progresses toward artificial intelligence and the Internet of Things (IoT), self‐powered sensor systems are increasingly vital for sensing and detection without external power. Nanogenerators, a new technology in energy research, enable the harvesting of normally wasted energy from the environment. This technology scavenges a wide range of ambient energies, meeting the ever-expanding energy demands as conventional fossil fuel sources are depleted. This research involves designing and fabricating high-performance flexible piezoelectric nanogenerators (PENGs) and triboelectric nanogenerators (TENGs), using novel organic-inorganic hybrid nanomaterials for wireless electronics.
Structural health monitoring (SHM) is crucial in the aerospace industry to enhance aircraft safety and consistency through reliable sensor networks. Built-in sensor networks enable uninterrupted structural integrity monitoring, providing crucial information on operation conditions, deformation, and potential damage. PENGs are promising for powering wireless sensor networks in aerospace SHM applications due to their sustainability, durability, flexibility, high performance, and superior reliability. This research demonstrated a self-powered wireless sensing system based on a porous PVDF-based PENG, which is ideal for developing auto-operated sensor networks. The porous PVDF film, made from a flexible piezoelectric polymer (polyvinylidene fluoride (PVDF)) and inorganic zinc oxide (ZnO) nanoparticles, enhanced output current by ~ 11 times and output voltage by ~ 8 times, respectively, compared to a pure PVDF-based PENG. The porous PVDF-based PENG device (with a device size of A = 11.33 cm2) generated sufficient electrical energy to power a customized wireless sensing and communication unit and transfer sensor data every ~ 4 minutes. This PENG could harness energy from automobile vibration, reflecting the potential for real-life SHM systems.
Subsequently, a novel, self-assembled, highly porous perovskite/polymer (PVDF in this case) composite film was designed and developed to fabricate high-performance piezoelectric nanogenerators (PENGs). The porous structure enlarged the bulk strain of the piezoelectric composite film, resulting in a 5-fold enhancement of the strain-induced piezo potential. The use of novel hybrid halide perovskite (HHP)-Formamidinium lead bromine iodine (FAPbBr2I) material improved the conductivity of the final composite film due to its enhanced permittivity, resulting in a 15-fold amplification of the output current. These highly-efficient perovskite/polymer PENGs (P-PENGs) achieved a peak output power density of 10 µW/cm2 to run a self-powered integrated wireless electronic node (SIWEN). The P-PNGs were applied to real-life scenarios including wireless data communication, efficient energy harvesting from automobile vibrations as well as biomechanical motion. This low-temperature, full-solution synthesis approach could lead to a paradigm shift in sustainable power sources, expanding the realms of flexible PENGs.
One of the remaining concerns is the highly soluble lead component, which is one of the constituents of the PENGs that poses potential adversary impacts on human health and the environment. To address this concern, lead-free flexible piezoelectric nanogenerators (PENGs) have been developed as a substitute for lead-based energy harvesters. More specifically, an organic-inorganic hybrid perovskite (OIHP) PENG, composed of lead-free Formamidinium tin (Sn) halide perovskite (CH(NH2)2SnBr3 (FASnBr3)) nanoparticles (NPs) and a polydimethylsiloxane (PDMS) polymer matrix, was developed. The excellent piezoelectric properties of the FASnBr3 NPs was demonstrated with a high piezoelectric charge coefficient (d33) of ~ 50 pm/V through piezoelectric force microscopy (PFM) measurements. the device’s outstanding flexibility and uniform distribution properties resulted in a maximum piezoelectric peak-to-peak output voltage of 94.5 V, peak-to-peak current of 19.1 μAp, and output power density of 18.95 μW/cm2 with a small force of 4.2 N, outperforming many state-of-the-art halide perovskite-based PENGs. For the first time, a self-powered RF wireless communication between smartphones and a nanogenerator solely based on a lead-free PENG was demonstrated. The fabricated FASnBr3@PDMS nanocomposite PENG not only shows outstanding performance and reliability but also serves as a stepping-stone towards achieving self-powered Internet of Things (IoT) devices using environment-friendly perovskite piezoelectric materials.
Likewise, triboelectric nanogenerators (TENGs) are also promising energy-harvesting devices for powering the next generation of wireless electronics. TENGs’ performance relies on the triboelectric effect between the tribonegative and tribopositive layers. Fluorine-containing petroleum-based polymers, such as polytetrafluoroethylene (PTFE) are commonly used as tribonegative layers due to their high tribonegativity. However, in this study, a natural wood-derived lignocellulosic nanofibrils (LCNF) tribolayer was reported to have high tribonegativity due to the presence of natural lignin on its surface and its nanofibril morphology. LCNF nanopaper-based TENGs produced significantly higher voltage and current output than TENGs with PTFE as the tribonegative material. Assembling LCNF nanopaper into a cascade TENG generated sufficient output to power a wireless communication node to send a radio-frequency signal to a smartphone every 3 mins. This study demonstrates the potential of using LCNF as a more environmentally friendly alternative to conventional tribonegative materials based on fluorine-containing petroleum-based polymers.
Overall, this thesis explores the design and development of highly efficient and flexible nanogenerators for self-powered wireless electronics. By combining highly electroactive nanomaterials with flexible polymer matrix structures, NGs with high electric output performance and flexibility were successfully obtained. The synthesizing process for the electroactive nanomaterials was carefully designed and adopted to sustain the inherent advantages of flexible electronics. The various type of high-performance flexible NGs developed in this research work, including ZnO/PVDF porous PENGs, FAPbBr2I/PVDF based PENGs, FASnBr3/PDMS based PENGs, and LCNF nanopaper-based TENGs, provide promising solutions for energy harvesting and self-powered sensing.