High‐Conductivity and Super‐Resolution PEDOT:PSS Patterns by Femtosecond Laser‐Induced Dissociation and Reconstruction for Efficient Electromagnetic Interference Shielding and Ultrafast Response Electrochromic

Abstract Conductive polymer poly(3, 4‐ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) has important applications in multiple fields of optoelectronics. Combining micronano fabrication methods, high‐resolution PEDOT:PSS patterns can be obtained, but doping with photosensitive resins as a main method often compromises intrinsic properties, especially conductivity. Therefore, creating high‐conductivity and super‐resolution PEDOT:PSS patterns without relying on doped photoresists remains crucial. In this study, a femtosecond laser‐induced dissociation and reconstruction (FLIDR) is utilized to fabricate PEDOT:PSS patterns with conductivity up to 851 S cm −1 and the highest resolution reported to date less than 400 nm. Additionally, 3D spatial micropatterns of PEDOT:PSS are achieved without the use of photopolymer resins for the first time. The electromagnetic interference (EMI) shielding performance of PEDOT:PSS obtained through FLIDR is evaluated, indicating an efficient EMI shielding effectiveness of 65.5 dB at a thickness of just 0.045 mm and an exceptional specific shielding effectiveness of 1455.6 dB mm −1 . Meanwhile, the high‐resolution PEDOT:PSS patterns are used to develop an all‐solid‐state electrochromic (EC) device with an ultrafast response of less than 0.4 s and excellent stability. Further, the EC device is also utilized in multi‐level covert anti‐counterfeiting.