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Carbon based nanomaterials such as carbon nanotube and graphene have attracted more and more attention due to their unique physical and chemical properties. As flexible conducting films, these materials present unprecedented great performance in electronic components and flexible nanodevices.
Recently, Professor Ting Zhang's group, at Suzhou Institute of Nanotech and Nanobionics of Chinese Academy of Sciences (SINANO.CAS), has made great research progress in carbon based nanomaterials for flexible/stretchable electronics and their applications in wearable smart systems. They successfully prepared high-quality carbon nanomaterials based free-standing ultrathin films, and demonstrated their applications in flexible gas sensors, artificial electronic skins, and flexible non-contact sensing devices, which were widely considered to be the most important components for the next generation of wearable/attachable electronic systems.
Reduced graphene oxide (r-GO), a new material derived from chemically modified graphene, is believed to be a promising candidate for flexible electronics due to its tunable bandgap and large surface area with special 2D structures because of the atomic thickness. It is still crucial to find a convenient way to assemble r-GO ultrathin films with controllable thickness and high quality.
Professor Zhang Ting's group proposed an effective and reproducible way to assemble r-GO ultrathin films with controllable thicknesses. The obtained r-GO ultrathin films possess high transparency (>82% at 550 nm), tunable sheet resistance, uniform electric conductivity, and structural homogeneity in wafer scale. Also, the thicknesses of r-GO ultrathin films in the range of 89-148 nm were controlled by using solvents with different surface tension. These ultrathin films could be transferred to any target substrate for further applications. Moreover, they demonstrated the flexible matrix panel (including 10×10 pixels) based on r-GO ultrathin films for noncontact humidity sensing, which is capable of close proximity sensing without touching, with the performance of high spatial resolution, high sensitivity, low operation voltage, and short response time. This device provides a distinct approach for human-machine interaction, complementary to the traditional touch panel in applications that require contact mode.