Edible Dielectric Composite for the Enhancement of Performance and Electromechanical Stability of Eco-Friendly Flexible Organic Transistors

Flexible electronics utilizing unique features of natural materials is a key requirement for technological developments for the next generation, where eco-sustainability, biodegradability, low cost, high performance, and stability are some essential requirements from devices. For exploration toward unique applications such as ingestible electronics, edible natural gate dielectrics are of prime importance though rarely addressed to date in literature. Here, an edible dielectric composite of natural biopolymers and a unique approach for tuning and enhancing the electromechanical stability of flexible organic transistors are presented. Chitosan, a natural biopolymer, is proposed as a tuning agent in composite with gelatin and in modulating the dielectric properties through controlled crosslinking facilitated by the electrostatic interaction and strong hydrogen bonding between the functional groups of polymers. Exploration with various gelatin/chitosan ratios in composite infers that the controlled integration of chitosan content (10:5 composite) yields high performance in transistors and significantly improved electromechanical and thermal stability in 30-150 °C, a preferred range for flexible electronics. Low voltage operation, high electromechanical stability, circuit applicability, and high shelf life demonstrated from transistors with this proposed edible dielectric and the unique technique for tuning the dielectric properties make it very suitable for ingestible and biomedical applications.