High-Transconductance,Highly Elastic,Durable and Recyclable All-Polymer Electrochemical Transistors with 3D Micro-Engineered Interfaces

Organic electrochemical transistors(OECTs)have emerged as versatile platforms for broad applications spanning from flexible and wearable integrated circuits to biomedical monitoring to neuromorphic computing.A variety of materials and tailored micro/nanostructures have recently been developed to realized stretchable OECTs,however,a solid-state OECT with high elasticity has not been demonstrated to date.Herein,we present a general platform developed for the facile generation of highly elastic all-polymer OECTs with high transconductance(up to 12.7 mS),long-term mechanical and environmental durability,and sustainability.Rapid prototyping of these devices was achieved simply by transfer printing lithium bis(trifluoromethane)sulfonimide doped poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS/LiTFSI)microstructures onto a resilient gelatin-based gel electrolyte,in which both depletion-mode and enhancement-mode OECTs were produced using various active channels.Remarkably,the elaborate 3D architectures of the PEDOT:PSS were engineered,and an imprinted 3D-microstructured channel/electrolyte interface combined with wrinkled electrodes provided performance that was retained(>70%)through biaxial stretching of 100%strain and after 1000 repeated cycles of 80%strain.Furthermore,the anti-drying and degradable gelatin and the self-crosslinked PEDOT:PSS/LiTFSI jointly enabled stability during>4 months of storage and on-demand disposal and recycling.This work thus represents a straightforward approach towards high-performance stretchable organic electronics for wearable/implantable/neuromorphic/sustainable applications.

Multiscale nanowire-microfluidic hybrid strain sensors with high sensitivity and stretchability

Nanomaterials with low-dimensional morphology have been explored for enhancing the performance of strain sensors,but it remains difficult to achieve high stretchability and sensitivity simultaneously.In this work,a composite structure strain sensor based on nanomaterials and conductive liquid is designed,demonstrated,and engineered.The nanowire-microfluidic hybrid(NMH)strain sensor responds to multiscale strains from 4%to over 400%,with a high sensitivity and durability under small strain.Metal nanowires and carbon nanotubes are used to fabricate the NMH strain sensors,which simultaneously exhibit record-high average gauge factors and stretchability,far better than the conventional nanowire devices.Quantitative modeling of the electrical characteristics reveals that the effective conductivity percolation through the hybrid structures is the key to achieving high gauge factors for multiscale sensing.The sensors can operate at low voltages and are capable of responding to various mechanical deformations.When fixed on human skin,the sensors can monitor large-scale deformations(skeleton motion)and small-scale deformations(facial expressions and pulses).The sensors are also employed in multichannel,interactive electronic system for wireless control of robotics.Such demonstrations indicate the potential of the sensors as wearable detectors for human motion or as bionic ligaments in soft robotics.