3D Stretchable Devices: Laser‐Patterned Electronic and Photonic Structures

Abstract

Realizing three‐dimensional stretchable structures of functional materials with a minimum footprint on Silicone polymer is highly desirable in soft robotics, stretchable electronics, and photonics. However, material processing on a stretchable substrate requires a sophisticated deposition system with integrated substrate cooling facilities, delamination of materials from the stretchable substrate due to stretching‐releasing cycles, and coating the functional materials. Here, a methodology to address these challenges using in situ graphitization within silicone polymer, referring to transforming the material into graphite‐like structures using three‐dimensional laser printing is reported. In this case, the graphitization process occurs due to the interaction of the material with a spatially controllable, tightly focused femtosecond laser beam in the confined region within the polymer. Three‐dimensional printed embedded, stretchable electrodes and varifocal lenses of thickness 1/20th compared to the epidermis layer thickness of human skin, which can contribute to achieving compact, highly sensitive wearable sensing and imaging systems are demonstrated and characterized. This process will open a new door for forming non‐metallic stretchable three‐dimensional conductors and photonics with minimum exposure to atmospheric conditions and a pathway to interface with thin films to develop low‐dimensional devices. These graphitized three‐dimensional structures can make them integral to intelligent skins, e‐textiles, and implantable devices.