Solution-Processed Flexible Organic Field-Effect Transistors with Biodegradable Gelatin as the Dielectric Layer: An Approach Toward Biodegradable Systems

High-performance flexible organic field-effect transistors with natural protein gelatin as a dielectric layer and solution-processed TIPS-pentacene as an active layer were fabricated on a flexible poly­(ethyleneterephthalate) substrate. The fabricated devices exhibited high performance and electromechanical stability, demonstrating high field-effect mobility with near-zero threshold voltage and the I on to I off ratio approaching 105 with a low operating voltage of −5 V. Devices exhibited highly stable electrical characteristics under multiple transfer scan measurements. The flexible nature of these devices was tested through the tensile strain test by subjecting them to a 5 mm bending radius. High electromechanical stability was observed with minuscule variation in the electrical parameters under strain application. These flexible devices were demonstrated for circuit and sensing applications. Under the humidity exposure test, the devices responded quickly with rapid response and recovery time and acted as a humidity sensor. This property was utilized for real time health monitoring applications by testing these devices as a breath rate analyzer. In addition, to test the credibility of these flexible devices in circuit applications, the external load invertor circuits were demonstrated before and after applying strain to these devices.