A New Facile Route to Flexible and Semi-Transparent Electrodes Based on Water Exfoliated Graphene and their Single-Electrode Triboelectric Nanogenerator.

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordWearable technologies are driving current research efforts to self-powered electronics, for which novel high-performance materials such as graphene and low-cost fabrication processes are highly sought.The integration of high-quality graphene films obtained from scalable water processing approaches in emerging applications for flexible and wearable electronics is demonstrated. A novel method for the assembly of shear exfoliated graphene in water, comprising a direct transfer process assisted by evaporation of isopropyl alcohol is developed. It is shown that graphene films can be easily transferred to any target substrate such as paper, flexible polymeric sheets and fibers, glass, and Si substrates. By combining graphene as the electrode and poly(dimethylsiloxane) as the active layer, a flexible and semi-transparent triboelectric nanogenerator (TENG) is demonstrated for harvesting energy. The results constitute a new step toward the realization of energy harvesting devices that could be integrated with a wide range of wearable and flexible technologies, and opens new possibilities for the use of TENGs in many applications such as electronic skin and wearable electronics.We acknowledge financial support from: the European Commission (H2020-MSCA-IF-2015- 704963), the UK Engineering and Physical Sciences Research Council (EPSRC) Grant no. EP/K017160/1, EP/K010050/1, EP/M001024/1, EP/M002438/1, and EP/L015331/1 (the EPSRC Centre for Doctoral Training in Metamaterials), the Royal Society international Exchanges Scheme 2016/R1, the Leverhulme Trust (Grant "Quantum Revolution")