_Flexible triboelectric nanogenerators for a self-charging system in mobile electronics

Triboelectric nanogenerators (TENGs) have emerged as versatile and scalable solutions for mechanical energy harvesting and self-powered sensors in wearable systems and smart textiles. By converting low-frequency biomechanical movements into usable electrical energy, TENGs show great potential for applications in sustainable electronics, health monitoring, and human– machine interfaces. However, developing materials and fabrication processes that combine high performance, flexibility, environmental stability, and scalability remains a challenge.

This thesis investigates the use of graphene-based materials and aqueous-phase processing techniques for the fabrication of flexible, textile-compatible TENGs integrated into self-powered sensor platforms. Special emphasis is placed on sustainable manufacturing methods, such as printing and solution-based processing, as well as the development of graphene electrode solutions suitable for integration into flexible and textile technologies. In the first part, aqueous graphene solutions were used to fabricate TENGs through simple and scalable methods, resulting in devices with promising electrical performance and good stability.

In the second stage, graphene electrodes were directly printed onto textiles, enabling their conformable integration into garments. These devices demonstrated reliable performance under bending and repeated mechanical deformation, proving effective for real-time biomechanical monitoring. In the third phase, multimodal triboelectric sensors were developed and embedded in smart textiles, capable of detecting different types of human motion—such as extension, bending, and sliding—within a single device architecture.

This multimodal capability was achieved through strategic textile structural design combined with a wireless data transmission system. Overall, this work contributes to the advancement of smart textiles and sustainable wearable electronics by proposing eco-friendly graphene-based TENGs produced through scalable methods, with potential applications in energy harvesting and physiological monitoring.