Efficient Conductivity Enhancement of Flexible Polyaniline Films Induced by Ultrafast Photoexcitation

Polyaniline (PANI) exhibits remarkable electrical conductivity and mechanical flexibility, rendering it widely applicable in flexible electronic devices. For instance, it serves as a channel layer material in Organic Electrochemical Transistors (OECTs). In OECTs, the conductivity of the channel layer plays a pivotal role in dictating the switching speed and current‐carrying capacity of the device. Proton acid doping represents an efficacious approach to enhancing the conductivity of polymers. However, the efficiency of direct doping of protic acid is low, thereby imposing limitations on the conductivity of polyaniline. In this study, ultrafast photoexcitation was implemented to efficiently improve the conductivity of camphor sulfonic acid (CSA) doped PANI films. Upon reaching a laser fluence of 166.2 mJ cm ⁻² , the conductivity of PANI films experienced a remarkable increment of nearly four orders of magnitude, soaring to 117.6 S m ⁻¹ , while its sheet resistance decreased to 170.9 Ω sq ⁻¹ . Meanwhile, fs‐laser‐treated PANI‐CSA films exhibited excellent stability. The PANI‐based OECT device was prepared, and the transconductance escalated from 0.113 to 0.503 mS, representing an increase exceeding fourfold. Our work provides a simple, eco‐friendly, and sustainable processing technology for the preparation of high‐performance PANI flexible conductive films, showing great application potential for flexible electronic devices.