Transfer-Printing of Insoluble Conducting Polymer for Soft 3D Conformal All-Organic Transistors

The development of high-precision insoluble conducting polymer patterns for soft electronics is extremely challenging, mainly because of the incompatibility of the synthesis process with the underlying layers. In this study, a novel transfer-printing method is designed that enables the fabrication of photolithographic insoluble conducting polypyrrole (PPy) electrode patterns on soft substrates with high precision, demonstrating compatibility with various soft organic functional layers. Excellent mechanical stability, good biocompatibility, ultra-smooth surface, and outstanding conformability are observed. The photolithographic PPy electrode patterns, combined with an elastic organic semiconductor and dielectric, produce conformal all-organic transistors with mobility of 1.8 cm² V^-1 s^-1. This study paves the way to use insoluble conducting polymers to develop complex, high-density flexible patterns and offers a promising organic electrode for the new-generation soft all-organic electronics.