Synthesis of ternary oxide ZnGeO nanowire networks and their deep ultraviolet detection properties.

Ternary oxide ZnGeO with a wide bandgap of 4.84 eV, as a candidate for fourth generation semiconductors, has attracted a great deal of attention for deep ultraviolet (DUV) photodetector applications, because it is expected to be blind to the UV-A/B band (290-400 nm) and only responsive to the UV-C band (200-290 nm). Here, we report on the synthesis of ZnGeO nanowire (NW) networks by lower pressure chemical vapor deposition and investigate their corresponding DUV detection properties.

Single-Step Selective Laser Writing of Flexible Photodetectors for Wearable Optoelectronics.

The increasing demand for wearable optoelectronics in biomedicine, prosthetics, and soft robotics calls for innovative and transformative technologies that permit facile fabrication of compact and flexible photodetectors with high performance. Herein, by developing a single-step selective laser writing strategy that can finely tailor material properties through incident photon density control and lead to the formation of hierarchical hybrid nanocomposites, e.g.

All-Graphene-Based Highly Flexible Noncontact Electronic Skin.

Noncontact electronic skin (e-skin), which possesses superior long-range and high-spatial-resolution sensory properties, is becoming indispensable in fulfilling the emulation of human sensation via prosthetics. Here, we present an advanced design and fabrication of all-graphene-based highly flexible noncontact e-skins by virtue of femtosecond laser direct writing (FsLDW). The photoreduced graphene oxide patterns function as the conductive electrodes, whereas the pristine graphene oxide thin film serves as the sensing layer.

Paper/Carbon Nanotube-Based Wearable Pressure Sensor for Physiological Signal Acquisition and Soft Robotic Skin.

A wearable and flexible pressure sensor is essential to the realization of personalized medicine through continuously monitoring an individual's state of health and also the development of a highly intelligent robot. A flexible, wearable pressure sensor is fabricated based on novel single-wall carbon nanotube /tissue paper through a low-cost and scalable approach. The flexible, wearable sensor showed superior performance with concurrence of several merits, including high sensitivity for a broad pressure range and an ultralow energy consumption level of 10 W.

All-inkjet-printed flexible ZnO micro photodetector for a wearable UV monitoring device.

Fabrication of small-sized patterns of inorganic semiconductor onto flexible substrates is a major concern when manufacturing wearable devices for measuring either biometric or environmental parameters. In this study, micro-sized flexible ZnO UV photodetectors have been thoroughly prepared by a facile inkjet printing technology and followed with heat treatments. A simple ink recipe of zinc acetate precursor solution was investigated.

Inkjet-printed optoelectronics.

Inkjet printing is a powerful and cost-effective technique for deposition of liquid inks with high accuracy, which is not only of great significance for graphic applications but also has enormous potential for the direct printing of optoelectronic devices. This review highlights a comprehensive overview of the progress that has been made in optoelectronics fabrication by the inkjet printing technique. The first part briefly covers the droplet-generation process in the nozzles of printheads and the physical properties affecting droplet formation and the profiles of the printed patterns.

Direct Preparation of Carbon Nanotube Intramolecular Junctions on Structured Substrates.

Leveraging the unique properties of single-walled carbon nanotube (SWNT) intramolecular junctions (IMJs) in innovative nanodevices and next-generation nanoelectronics requires controllable, repeatable, and large-scale preparation, together with rapid identification and comprehensive characterization of such structures. Here we demonstrate SWNT IMJs through directly growing ultralong SWNTs on trenched substrates. It is found that the trench configurations introduce axial strain in partially suspended nanotubes, and promote bending deformation in the vicinity of the trench edges.

Catalyst-Free, Selective Growth of ZnO Nanowires on SiO2 by Chemical Vapor Deposition for Transfer-Free Fabrication of UV Photodetectors.

Catalyst-free, selective growth of ZnO nanowires directly on the commonly used dielectric SiO2 layer is of both scientific significance and application importance, yet it is still a challenge. Here, we report a facile method to grow single-crystal ZnO nanowires on a large scale directly on SiO2/Si substrate through vapor-solid mechanism without using any predeposited metal catalyst or seed layer. We found that a rough SiO2/Si substrate surface created by the reactive ion etching is critical for ZnO growth without using catalyst.

Improved photovoltaic performance of multiple carbon-doped ZnO nanostructures under UV and visible light irradiation.

We report synthesis of multiple carbon-doped ZnO nanostructures by using carbon cloth as substrates to obtain multiple hollow ZnO microtube-nanowire structures. X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy analysis clearly show that carbon is doped into ZnO through substitution of carbon for oxygen in the growth and annealing processes. Upon exposure to 633-nm red laser, a distinct photoresponse can be observed, which indicates that carbon doping in ZnO can well extend its light harvesting to visible light region.

Three-dimensional plasmonic photoanodes based on Au-embedded TiO(2) structures for enhanced visible-light water splitting.

Plasmon-assisted visible light photocatalysis presents a possible solution for direct solar-to-fuel production. Here we investigate the plasmon-enhanced photocatalytic water splitting using different TiO2/Au electrode structures. Experimental data demonstrates that the Au embedded in TiO2 (Au-in-TiO2) electrode greatly outperforms the Au sitting on TiO2 (Au-on-TiO2) electrode.

Clothing polymer fibers with well-aligned and high-aspect ratio carbon nanotubes.

It is believed that the crucial step towards preparation of electrical conductive polymer-carbon nanotube (CNT) composites is dispersing CNTs with a high length-to-diameter aspect ratio in a well-aligned manner. However, this process is extremely challenging when dealing with long and entangled CNTs. Here in this study, a new approach is demonstrated to fabricate conductive polymer-CNT composite fibers without involving any dispersion process.

Ultra-sensitive and wide-dynamic-range sensors based on dense arrays of carbon nanotube tips.

Electrochemical electrodes based on dense and vertically aligned arrays of multi-walled carbon nanotubes (MWCNTs) were produced. The open tips of individual hollow nanotubes are exposed as active sites while the entangled nanotube stems encapsulated in epoxy collectively provide multiplexed and highly conductive pathways for charge transport. This unique structure together with the extraordinary electrical and electrochemical properties of MWCNTs offers a high signal-to-noise ratio (thus high sensitivity) and a large detection range, compared with other carbon-based electrodes.

Photoresponse of multi-walled carbon nanotube-copper sulfide (MWNT-CuS) hybrid nanostructures.

In situ synthesized MWNT-CuS hybrid nanostructures were fabricated into ultrasensitive photodetectors. Upon exposure to light illumination, the MWNT-CuS devices showed pronounced photocurrent with a response time less than 0.5 s even under zero bias.

Carbene-functionalized single-walled carbon nanotubes and their electrical properties.

Pure metallic single-walled carbon nanotubes (m-SWCNTs) are very desirable for many electrode and interconnecting applications. However, the lack of reliable processing techniques to sort m-SWCNTs from the as-synthesized SWCNT samples is an obstacle to these applications. The effects of carbene-based covalent functionalization on the electrical properties of an isolated m-SWCNT, a semiconducting (s)-SWCNT, and a mixture network of both m- and s-SWCNTs are reported.

Tuning array morphology for high-strength carbon-nanotube fibers.

Vertically aligned carbon-nanotube arrays are synthesized by chemical vapor deposition. Carbon-nanotube fibers are directly spun from the obtained nanotube arrays and then tested mechanically. A strong correlation between the array morphologies and the mechanical properties of the fibers is observed: well-aligned arrays yield fibers with much higher performance, while wavy and entangled arrays give poor fiber properties.