Three-dimensional ZnO Nanorods Research Articles

Quantitative modeling, optimization, and verification of 63Ni-powered betavoltaic cells based on three-dimensional ZnO nanorod arrays

Quantitative modeling, optimization, and verification of 63Ni-powered betavoltaic cells based on three-dimensional ZnO nanorod arrays

Visible Light-Induced Room-Temperature Formaldehyde Gas Sensor Based on Porous Three-Dimensional ZnO Nanorod Clusters with Rich Oxygen Vacancies.

Oxygen vacancy (VO) is a kind of primary point defect that extensively exists in semiconductor metal oxides (SMOs). Owing to some of its inherent qualities, an artificial manipulation of VO content in one material has evolved into a hot research field, which is deemed to be capable of modulating band structures and surface characteristics of SMOs. Specific to the gas-sensing area, VO engineering of sensing materials has become an effective means in enhancing sensor response and inducing light-enhanced sensing. In this work, a high-efficiency microwave hydrothermal treatment was utilized to prepare a VO-rich ZnO sample without additional reagents. The X-ray photoelectron spectroscopy test revealed a significant increase in VO proportion, which was from 9.21% in commercial ZnO to 36.27% in synthesized VO-rich ZnO possessing three-dimensional and air-permeable microstructures. The subsequent UV–vis–NIR absorption and photoluminescence spectroscopy indicated an extension absorption in the visible region and band gap reduction of VO-rich ZnO. It turned out that the VO-rich ZnO-based sensor exhibited a considerable response of 63% toward 1 ppm HCHO at room temperature (RT, 25 °C) under visible light irradiation. Particularly, the response/recovery time was only 32/20 s for 1 ppm HCHO and further shortened to 10/5 s for 10 ppm HCHO, which was an excellent performance and comparable to most sensors working at high temperatures. The results in this work strongly suggested the availability of VO engineering and also provided a meaningful candidate for researchers to develop high-performance RT sensors detecting volatile organic compounds.

Three-dimensional ZnO nanorods growth on ZnO nanorods seed layer for high responsivity UV photodetector

Three-dimensional ZnO nanorods (NRs) were synthesized by hydrothermal method on ZnO seed layer including horizontal ZnO NRs. The ZnO seed layers consist of different values of NRs were synthesized by spin-coating. The different seed layers and ZnO nanorods arrays were characterized using field emission scanning electron microscopy, X-ray diffraction. Horizontally dispersed NRs on the substrate formed an overlapping junction structure into seed layer as ZnO NRs network. NRs grown on the seed layer including horizontal NRs were oriented in different directions to form three-dimensional ZnO NRs in flower shape. The electrical resistance of sensors based NRs array decreased dramatically with increasing NRs added to ZnO seed layer. Results show that ultraviolet photocurrent increased from 1.7 to 23 μA which is suitable for fabrication of practical photodevices.

A hybrid ZnO/Si/porous-carbon anode for high performance lithium ion battery

In this work, we report an anode material consisting of three-dimensional porous-carbon, nanometer-sized ZnO and Si nanoparticles to realize the high-performance lithium ion batteries. The composite powders are prepared following the processes of fabricating ZnO precursor by co-precipitation, hydrothermal reaction of mixed ZnO/SiO/porous-carbon powders, and subsequent neutralization and roast treatments. Using the hybrid anode material, the enhanced capacity performance (more than 900 mA h g−1 at 0.2 C after 300 cycles) and remarkable long-term cycle stability (more than 500 mA h g−1 at 2 C after 300 cycles) are achieved, which are significantly higher than that of using ZnO or graphite alone as anode. The improvement is ascribed to the synergistic effect of the highly conductive and large surface area porous-carbon, three-dimensional ZnO nanorods, and high adsorption of Li+ of Si particles.

A novel multifunctional electrochemical platform for simultaneous detection, elimination, and inactivation of pathogenic bacteria based on the Vancomycin-functionalised AgNPs/3D-ZnO nanorod arrays

A novel fast, sensitive, and specific multifunctional electrochemical platform has been proposed for simultaneous detection, elimination, and inactivation of pathogenic bacteria for the first time. The platform is constituted with three-dimensional ZnO nanorod arrays (3D-ZnO) decorated with sliver nanoparticles (AgNPs) and functionalized with vancomycin (Van). Based on the specific recognition of Van for Gram-positive bacteria, the fabricated electrochemical platform has presented high detection sensitivity to Staphylococcus aureus with a low detection limit of 330cfu/mL and adaptable bacterial-elimination efficiency (50%) at low concentrations (1000–2000cfu/mL). Moreover, the platform has shown high antibacterial activity (99.99%) arising from the synergistic germicidal effect of the composited antibacterial AgNPs and Van units. The current work could provide new strategies to construct advanced platforms for simultaneous detection, elimination, and inactivation of various pathogenic bacteria.

3D micro-structured arrays of Zn\u039f nanorods

The fabrication of nanostructures with controlled assembly and architecture is very important for the development of novel nanomaterial-based devices. We demonstrate that laser techniques coupled with low-temperature hydrothermal growth enable complex three-dimensional ZnO nanorod patterning on various types of substrates and geometries. This methodology is based on a procedure involving the 3D scaffold fabrication using Multi-Photon Lithography of a photosensitive material, followed by Zn seeded Aqueous Chemical Growth of ZnO nanorods. 3D, uniformly aligned ZnO nanorods are produced. The increase in active surface area, up to 4.4 times in the cases presented here, provides a dramatic increase in photocatalytic performance, while other applications are also proposed.

Three-dimensional carbon cloth-supported ZnO nanorod arrays as a binder-free anode for lithium-ion batteries

Three-dimensional ZnO nanorod arrays on flexible high surface area carbon cloth were successfully synthesized and directly used as negative electrodes for lithium-ion batteries without using any binder additive. The structure and morphology of the as-prepared hybrid ZnO electrode were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM). When tested as anodes in a lithium cell, the hybrid electrode demonstrated a high discharge capacity along with excellent rate capability and good cycling stability, delivering a reversible capacity of 891 mAh g−1 at the second cycle and retaining a capacity of 469 mAh g−1 after 100 cycles.

Growth of three-dimensional ZnO nanorods by electrochemical method for quantum dots-sensitized solar cells

There-dimensional (3D) superstructure was expected to fabricate high performance photoelectrodes of quantum dot-sensitized solar cells (QDSCs). In this paper, the ZnO 3D superstructure with multi-layer structure (3D ZnO nanorods) was grown on ITO glass by a novel electrochemical method at low temperature (60–90 °C). The 3D ZnO nanorods were composed of close-packed ZnO nanorod bundles with wide dimension distribution ranging from hundreds of nanometers to several micrometers. The effects of some important parameters, such as concentration of Zn(NO 3) 2, deposition temperature and concentration of ZnO nanoparticles (served as growth seeds for ZnO nanorods), on the morphology of 3D ZnO nanorods were also studied by scanning electron microscopy. Once being applied in QDSCs, the 3D ZnO nanorods showed more superior photoelectrochemical performance to ZnO nanorod array. The conversion efficiency of 1.42% achieved by the QDSC based on 3D ZnO nanorods was a very promising value for the QDSCs based on ZnO electrodes.

Thermal oxidation of Cu nanofilm on three-dimensional ZnO nanorod arrays

Three-dimensional (3D) ZnO–CuO core-shell nanorod arrays have been synthesized by a three-step process on silicon (100) substrates. A hydrothermal method was used to grow 3D ZnO nanorod arrays, followed by deposition of Cu nanofilm using sputtering, which was oxidized subsequently at 400 °C to form CuO shell surrounding ZnO nanorod core. The control over oxygen flow and pressure during the Cu nanofilm oxidation was found to improve the uniformity and intactness of CuO shell surrounding ZnO nanorod core. With higher oxygen flow, more conformal CuO thin film coating was achieved on the 3D ZnO nanorods array as a result of more sufficient oxygen access at the bottom portion of ZnO nanorods array. Higher pressure during thermal oxidation favored the formation of non-conformal ZnO–CuO core-shell nanorods and impurity Zn2SiO4 possibly at the interface of ZnO and Si substrate. UV-vis absorption spectroscopy revealed higher absorption efficiency in the visible region in ZnO–CuO core-shell nanorods than in pure ZnO nanorods. The fabricated ZnO–CuO core-shell nanorods could be useful nanoscale building blocks in solar cells and light emitting devices.