that of conventional narrow-bandgap semiconductors, which enable SWCNTs to be used in semitransparent or transparent photodetectors with thinner active materials. [7] In addition, it has been theoretically and experimentally demonstrated that multiple electron-hole pairs can be generated from one high-energy photon in S-SWCNTs, [8,9] which provides the possibility for fabricating high performance photoelectronic devices.Apart from the different device architectures, the SWCNT-based photodetectors have been extensively investigated using different nanotube types as a light absorber, such as individual SWCNT, aligned SWCNT arrays, SWCNT networks, and SWCNT films. [3,10,11] Compared with the former two types, the SWCNT film/networks favor the largescale fabrication of high-performance photodetectors with low-cost due to their simple process, high optical absorption, and good device reliability. To improve the performance of SWCNT-based photodetectors, low-dimensional carbon allotropes are widely used to form all-carbon heterojunctions with SWCNTs due to the intimate electronic coupling between the two sp 2 -hybridized carbon allotropes. [12] In addition, the devices with planar structures are adopted, in which the exciton diffusion along the SWCNTs plays a major role while the exciton diffusion perpendicular to the films is suppressed. Park et al. [13] demonstrated an SWCNT/C 60 -based phototransistor with the C 60 serving as electron traps and the SWCNTs as the hole carrier. The maximum responsivity and detectivity are 97.5 A W −1 at gate voltage of −2 V and 1.17 × 10 9 Jones at 1 kHz, respectively. Except for 0D C 60 , 2D graphene has also been demonstrated to enhance significantly the carrier separation by forming the Schottky junctions with S-SWCNTs due to exceedingly high carrier mobility and thermal conductivity. [14,15] Liu et al. [3,16] demonstrate an effective charge transfer between SWCNTs and graphene in the planar nanohybrids. Zhang et al. [17] developed the SWCNT film/graphene Schottky junctions for visible-NIR photodetector. The device exhibits a fast response time of 68 µs and good reproducibility in a wide range of 50-5400 Hz. However, it is still a big challenge to further improve the performance. First, the ultrathin S-SWCNT layer means poor optical absorption, which will be difficult to meet the different application requirements. While dark current will be increased with increasing the thickness or density of SWCNTs. On the other hand, continuous graphene sheets in the planar nanohybrids give a very large dark Single-walled carbon nanotube (SWCNT)/graphene Schottky junctions have great potential for high-performance all-carbon photodetector due to their excellent optical and electronic properties and efficient charge transfer. However, the further improvement of device performance is limited by the low absorption of ultrathin SWCNTs and large dark current of continuous graphene nanosheets. Here a proof-of-concept photodetector is reported using SWCNT/separated graphene (SGR) hybrid networks. The ...

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Metal oxide/reduced graphene oxide (RGO) heterojunctions have been widely used to fabricate room-temperature gas sensors due to large specific surface areas of RGO nanosheets and enhanced carrier separation efficiency at the interface. However, the sheet stacking of RGO nanosheets limits the full utilization of metal oxide/RGO heterojunctions. Herein, we demonstrate a high-performance room-temperature NO 2 gas sensor based on 3D Fe 3 O 4 @RGO p-n heterojunctions with a core-shell structure, which were synthesized by self-assembly method and further reduction. The effects of different Fe 3 O 4 /RGO ratios and the relative humidity on the sensing performances have been investigated. The experimental results suggest that the 3D Fe 3 O 4 @RGO sensor exhibits a good selectivity and high sensitivity of 183.1% for 50 ppm NO 2 , which is about 8.17 times higher than that of the pure 2D RGO sensor. When exposed to 50 ppb of NO 2 , the response value still reaches 17.8%. This enhanced sensing performance is mainly ascribed to the formed heterojunctions and the larger surface area of RGO nanosheets. This 2D to 3D heterostructure strategy provides a general route to fabricating ultrahigh-performance room-temperature RGO-based gas sensors.

In this article, magnetorheological colloid was adopted to coat a stainless steel substrate, which was cured under magnetic field to form magnetic roughness surface. Superhydrophobicity had been verified in the experiments, and the influential factors on the hydrophobic performance had been explored. A regular sawtooth structure model was proposed to relate the hydrophobicity with the formed surface microstructure. With the self-cleaning and bonding strength testing, the magnetic roughness surface is promising to keep sustainable superhydrophobicity in the self-cleaning or drag reduction applications.