Femtosecond Direct Laser Writing of Conductive and Electrically Switchable PEDOT:PSS Optical Nanostructures

Abstract Microscale three‐dimensional (3D)‐printing, with its remarkable precision and ability to create complex structures, has transformed a wide range of applications, from micro‐optics and photonics to endoscopy and quantum technologies. In these fields, miniaturization plays a crucial role in unlocking new capabilities. However, despite these advancements, most 3D‐printed optical structures have remained static, lacking dynamic behavior and tunability. In this study, a novel approach is presented that combines direct laser writing with the electrically switchable optical properties of the conductive polymer poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS). This integration facilitates the creation of dynamic structures directly on 3D‐printed objects, marking a significant step toward adaptive optical devices. The fabrication of electrically tunable structures is demonstrated via direct laser writing using PEDOT:PSS on indium tin oxide (ITO)‐coated glass substrates, as well as beneath and atop static 3D‐printed structures. It is found that electrical conductivity as well as the greyscale behavior of PEDOT:PSS remains intact after direct laser writing. The switching speed, durability, and gradual tunability of the material are explored upon complementary metal‐oxide‐semiconductor (CMOS)‐compatible voltages ranging from −3 to +2 V. In the future, this advancement opens exciting possibilities in adaptive micro‐optics, such as switchable apertures printed directly onto micro‐optical lenses.