Free-Standing Carbon Nanotube Embroidered Graphene Film Electrode Array for Stable Neural Interfacing.

Implantable neural probes that are mechanically flexible yet robust are attractive candidates for achieving stable neural interfacing in the brain. Current flexible neural probes consist mainly of metal thin-film electrodes integrated on micrometer-thick polymer substrates, making it challenging to achieve electrode-tissue interfacing on the cellular scale. Here, we describe implantable neural probes that consist of robust carbon nanotube network embroidered graphene (CeG) films as free-standing recording microelectrodes. Our CeG film microelectrode arrays (CeG_MEAs) are ultraflexible yet mechanically robust, thus enabling cellular-scale electrode-tissue interfacing. Chronically implanted CeG_MEAs can stably track the activities of the same population of neurons over two months. Our results highlight the potential of ultraflexible and free-standing carbon nanofilms for stable neural interfacing in the brain.

Flexible and highly responsive photodetectors based on heterostructures of MoS2and all-carbon transistors.

Heterostructures of graphene and transition-metal dichalcogenides (TMDCs) are promising candidates for high-performance flexible photodetectors because of their high photoresponsivity and detectivity. However, the mechanical stability of current flexible photodetectors is limited, due to a mechanical mismatch between their two-dimensional channel materials and metallic contacts. Herein, we develop a type of mechanically stable, highly responsive, and flexible photodetector by integrating MoS2and all-carbon transistors. By combining the high mobility of graphene with the strong light-matter interactions of MoS2, our heterostructure photodetector exhibits a greatly improved photoresponse performance, compared with individual graphene or MoS2photodetectors. In addition, the mechanical properties of the all-carbon electrodes are a good match for those of the active two-dimensional channels, resulting in greatly improved electrical stability of the heterostructure photodetector under mechanical deformation. These capabilities make our heterostructure photodetector a promising candidate for flexible photodetection and photoimaging applications.

Carbon nanotube spiderweb promoted growth of hierarchical transition metal dichalcogenide nanostructures for seamless devices.

Hierarchical transition metal dichalcogenide (h-TMDC) nanostructures with abundant active edge sites and good electrical conductivity hold great promise for numerous applications. Here, we report a general method for the chemical synthesis of a series of large-area, free-standing h-TMDC films and their devices by using carbon nanotube (CNT) spiderwebs as both growth promoters and electrical/mechanical reinforcement networks. Our approach allows the seamless integration of h-TMDC nanostructures with abundant active edge sites and CNT networks with good electrical conductivity and mechanical flexibility. As a proof of concept, h-MoSe2/CNT hybrid films with CNT contacts have been chemically synthesized and applied as flexible electrocatalytic devices for hydrogen evolution reaction (HER). Owing to the seamless connection between the CNT contacts and the electroactive h-TMDC/CNT nanostructures, the flexible electrocatalytic devices exhibited excellent mechanical stability and maintained stable electrocatalytic performance under cyclic bendings. Our method can be readily extended to the large-scale production of various h-TMDC/CNT hybrid films and their seamless devices.

Flexible Micropillar Electrode Arrays for In Vivo Neural Activity Recordings.

Flexible electronics that can form tight interfaces with neural tissues hold great promise for improving the diagnosis and treatment of neurological disorders and advancing brain/machine interfaces. Here, the facile fabrication of a novel flexible micropillar electrode array (µPEA) is described based on a biotemplate method. The flexible and compliant µPEA can readily integrate with the soft surface of a rat cerebral cortex. Moreover, the recording sites of the µPEA consist of protruding micropillars with nanoscale surface roughness that ensure tight interfacing and efficient electrical coupling with the nervous system. As a result, the flexible µPEA allows for in vivo multichannel recordings of epileptiform activity with a high signal-to-noise ratio of 252 ± 35. The ease of preparation, high flexibility, and biocompatibility make the µPEA an attractive tool for in vivo spatiotemporal mapping of neural activity.