(Invited) Transfer Printing of 2D Materials for Ultrathin Wearable/Implantable Electronics

Recent application of 2D materials on flexible electronics has provided new possibility on biocompatible, ultrathin biomedical electronics. Graphene and MoS2 each are getting attention as next-generation 2D metal and semiconductor materials. However, electrical characteristics of the final integrated electronics are usually lower than expected due to the residue of polymer sacrificial layer during the transfer process. To achieve high-performance biomedical electronics, several strategies have been employed, such as the designed assembly of high-quality nanomaterials, combination of unconventional manufacturing processes with existing micro-processing technologies, new design of individual devices with deformable structures, and disease-specific system-level integration of diverse soft electronics. Here, we describe transfer printing methods for residue-free 2D materials and show ultrathin flexible biomedical devices for wearable/implantable applications. Graphene based transparent sensors and actuators can be utilized for invisible tele-medical healthcare devices, and graphene-MoS 2 heterostructures can be applied to the ultrathin curved image sensors for the retina prosthetics.