Direct Growth of Graphene Films on 3D Grating Structural Quartz Substrates for High-Performance Pressure-Sensitive Sensors

Conformal graphene films have directly been synthesized on the surface of grating microstructured quartz substrates by a simple chemical vapor deposition process. The wonderful conformality and relatively high quality of the as-prepared graphene on the three-dimensional substrate have been verified by scanning electron microscopy and Raman spectra. This conformal graphene film possesses excellent electrical and optical properties with a sheet resistance of <2000 Ω·sq^–1 and a transmittance of >80% (at 550 nm), which can be attached with a flat graphene film on a poly­(dimethylsiloxane) substrate, and then could work as a pressure-sensitive sensor. This device possesses a high-pressure sensitivity of −6.524 kPa^–1 in a low-pressure range of 0–200 Pa. Meanwhile, this pressure-sensitive sensor exhibits super-reliability (≥5000 cycles) and an ultrafast response time (≤4 ms). Owing to these features, this pressure-sensitive sensor based on 3D conformal graphene is adequately introduced to test wind pressure, expressing higher accuracy and a lower background noise level than a market anemometer

Solvent-Free Process to Produce Three Dimensional Graphene Network with High Electrochemical Stability

Three-dimensional (3D) graphene has attracted increasing attention in electrochemical devices. However, the existing preparation technologies usually involve a solvent process, which introduces defects and functional groups into the 3D network. Here, we find the defects and functional groups influence the electrochemical stability of graphene. After an electrochemical process, the current decreases by more than 1 order of magnitude, indicating remarkable etching of graphene. To improve the electrochemical stability, we develop a solvent-free preparation process to produce 3D graphene for the first time. After growth on a 3D microporous copper by chemical vapor deposition (CVD), the copper template is removed by a high temperature evaporation process, resulting in 3D graphene network without any solvent process involved. The samples exhibit remarkably improved stability with durable time 2 times, compared with normal CVD samples, and 55 times, compared with reduced graphite oxide, and no obvious etching is observed at 1.6 V versus saturated calomel electrode, showing great potential for application in future 3D graphene-based high stable electrochemical devices