Russo, SaverioCraciun, MonicaAlghamdi, Mashael2024-10-292024https://hdl.handle.net/20.500.14154/73361Green energy plays a pivotal role in addressing the pressing challenges of climate change, air pollution, and environmental degradation. Triboelectric nanogenerators (TENGs) are a promising source of green energy harvesting that have attracted significant research attention in recent years. Despite the plethora of triboelectric materials currently available, the exploration of novel materials remains a significant obstacle in enhancing the output performance of triboelectric nanogenerators. In this thesis, I explore the role of different triboelectric materials in the development of novel TENGs and their applications. The triboelectric materials under examination encompass starch-based MAPbI3 perovskites, cellulose nanocrystals, and Ti3C2Tx MXenes. By systematically investigating the electrical characteristics of these materials when incorporated into TENG devices, this thesis aims to provide valuable insights into the field of sustainable energy sources. It places a specific focus on advancing the understanding of triboelectric nanogenerator technology and overcoming challenges related to material discovery for enhanced performance. Recently, perovskites have gained significant attention as promising materials for TENGs. This thesis presents novel results demonstrating that the incorporation of starch into perovskites not only modulates the output triboelectric performance but also influences the position of MAPbI3/starch composites in the triboelectric series. Systematic triboelectric measurements were conducted on perovskite/starch films with varying starch concentrations, paired with diverse Polymers such as Nitrile, Kapton, Nylon, PET, and paper. The study further investigates the impact of electrode selection (gold or ITO) on triboelectric performance. Remarkably, the ITO-MAPbI3/starch (15%) composite-based TENG exhibited an optimal maximum power density of 18.5 W/m2 at a load resistance of 160 GΩ. This achievement surpasses the performance levels previously reported for perovskite material-based TENGs. Cellulose nanocrystals are a promising material for TENGs due to their high surface-to-volume ratio, excellent mechanical properties, and biocompatibility. This thesis presents novel findings concerning the long- term performance of TENGs based on cellulose nanocrystals as the triboelectric layer and graphene as the electrode. The study, conducted three years post-device-fabrication, explores the influence of both the number of cellulose nanocrystal (CNC) layers and their concentration on the triboelectric performance of the device. Notably, the investigation identifies and optimizes a TENG with superior long-term performance. Furthermore, this optimized TENG, distinguished for its sustained functionality, is employed in the unique application of harvesting energy generated from piano playing. The harnessed energy is then utilized to charge a capacitor, showcasing the practical implications and novel contributions of the research presented in this thesis. MXenes stand out as highly promising materials for TENGs, offering the potential to significantly enhance the efficiency and functionality of these energy harvesting devices. Despite the recognized benefits, unlocking the full spectrum of MXenes' capabilities for green energy applications requires continued research efforts. This thesis contributes novel findings that highlight the crucial role of MXenes in increasing the performance of TENGs. Through a comprehensive investigation, the study explores the influence of aging, thickness, and the synthesis method employed in MXene-based TENGs. These results not only enrich the current understanding of MXene applications but also provide valuable insights for future advancements in the field of energy harvesting and sustainable technologies. The novel contributions of this research extend to elucidating the importance of MXene-based TENGs in diverse applications, specifically in humidity sensing and the fabrication of keyboards. Furthermore, the thesis explores an innovative approach towards energy harvesting, specifically focusing on the design of a novel system tailored for extracting energy from keyboard typing. Finally, I contribute to the area of triboelectric nanogenerator-based keyboard which stands out as a pivotal example of human-machine interaction. Leveraging the dependency of triboelectric output signals on keyboard button contact areas, I systematically optimize the design through various experiments, including the selection of triboelectric materials, connection types, and button or finger coverings. Open-circuit voltage signals prove superior indicators of contact area changes compared to short-circuit current or electric charge signals. The optimized design, featuring silicone-based TENGs for letter buttons, demonstrates high voltage values and significant deviation in response to contact area changes. MXene-based TENGs exhibit stability when paired with various materials, emphasizing their versatility. These findings exemplify the potential of triboelectric nanogenerators for human-machine interaction, particularly in the context of intelligent keyboards.296enTENGPVSKMXenecelluloseThesis