The oxides of copper (CuxO) are fascinating materials due to their remarkable optical, electrical, thermal and magnetic properties.

No abstract

We demonstrate that a three dimensional (3D) crystalline tungsten trioxide (WO(3)) nanoporous network, directly grown on a transparent conductive oxide (TCO) substrate, is a suitable working electrode material for high performance electrochromic devices. This nanostructure, with achievable thicknesses of up to 2 μm, is prepared at room temperature by the electrochemical anodization of a RF-sputtered tungsten film deposited on a fluoride doped tin oxide (FTO) conductive glass, under low applied anodic voltages and mild chemical dissolution conditions. For the crystalline nanoporous network with thicknesses ranging from 0.6 to 1 μm, impressive coloration efficiencies of up to 141.5 cm(2) C(-1) are achieved by applying a low coloration voltage of -0.25 V. It is also observed that there is no significant degradation of the electrochromic properties of the porous film after 2000 continuous coloration-bleaching cycles. The remarkable electrochromic characteristics of this crystalline and nanoporous WO(3) are mainly ascribed to the combination of a large surface area, facilitating increased intercalation of protons, as well as excellent continuous and directional paths for charge transfer and proton migration in the highly crystalline material.

While layered materials are increasingly investigated for their potential in nanoelectronics, their functionality and efficiency depend on charge injection into the materials via metallic contacts. This work explores the characteristics of different metals (aluminium, tungsten, gold and platinum) deposited on to nanostructured thin films made of two-dimensional (2D) MoS 2 flakes. Metals are chosen based on their work functions relative to the electron affinity of MoS 2. It is observed, and analytically verified, that lower work functions of the contact metals lead to smaller Schottky barrier heights and consequently higher charge carrier injection through the contacts.

In this paper, we present H 2 gas sensors based on hollow and filled, wellaligned electrospun SnO 2 nanofibers, operating at a low temperature of 150 °C. SnO 2 nanofibers with diameters ranging from 80 to 400 nm have been successfully synthesized in which the diameter of the nanofibers can be controlled by adjusting the concentration of polyacrylonitrile in the solution for electrospinning. The presence of this polymer results in the formation of granular walls for the nanofibers. We discussed the correlation between nanofibers morphology, structure, oxygen vacancy contents and the gas sensing performances. X-ray photoelectron spectroscopy analysis revealed that the granular hollow SnO 2 nanofibers, which show the highest responses, contain a significant number of oxygen vacancies, which are favorable for gas sensor operating at low temperatures.

Two-dimensional (2D) molybdenum oxides at their various stoichiometries are promising candidates for generating plasmon resonances in visible light range. Herein, we demonstrate plasmonic 2D molybdenum oxide flakes for gas sensing applications, in which hydrogen (H2) is selected as a model gas. The 2D molybdenum oxide flakes are obtained using a grinding-assisted liquid exfoliation method and exposed to simulated sunlight to acquire its substoichiometric quasi-metallic form. After the exposure to H2 gas molecules, the quasi-metallic molybdenum oxide flakes are partially transformed into semiconducting states, thus gradually losing their plasmonic properties. The novel 2D plasmonic sensing platform is tested using different concentrations of H2 gas at various operating temperatures to comprehensively assess its sensing performance. The presented 2D plasmonic system offers great opportunities for future sensing and optical applications.

No abstract

Fully transparent and flexible electronic substrates that incorporate functional materials are the precursors to realising nextgeneration devices with sensing, self-powering and portable functionalities. Here, we demonstrate a universal process for transferring planar, transparent functional oxide thin films on to elastomeric polydimethylsiloxane (PDMS) substrates. This process overcomes the challenge of incorporating high-temperature-processed crystalline oxide materials with low-temperature organic substrates. The functionality of the process is demonstrated using indium tin oxide (ITO) thin films to realise fully transparent and flexible resistors. The ITO thin films on PDMS are shown to withstand uniaxial strains of 15%, enabled by microstructure tectonics. Furthermore, zinc oxide was transferred to display the versatility of this transfer process. Such a ubiquitous process for the transfer of functional thin films to elastomeric substrates will pave the way for touch sensing and energy harvesting for displays and electronics with flexible and transparent characteristics. INTRODUCTIONNovel micro-and nano-technology applications encompassing plasmonic devices, field effect transistors, light-emitting diodes, sensor networks, electromagnetic components, terahertz metamaterials, energy harvesters and displays are increasingly demonstrated on flexible substrates. 1-7 These applications represent the building blocks of future flexible and transparent device technology incorporating complex circuitry and functionality. In integrating all the applications together to realise powerful and practical technology that is fully transparent, flexible and functional, two major challenges need to be overcome.First, the flexible substrate should ideally be transparent and colourless. A variety of colourless materials such as polyethylene 8 and polydimethylsiloxane (PDMS) 1 and coloured materials such as polyimide (or Kapton) 9 are widely used. The former can withstand only low processing temperatures (o100 1C), while the yellow-brown tinted polyimide can withstand up to B400 1C. The relevance of colourless substrates to flexible device technology is highlighted by the recent research focus on this area. 10,11 Second, functional oxide materials that offer tailored properties need to be integrated. These functional oxides in the form of thin films can be transparent conductive oxides for electrical conduction, ferroelectrics for memories, piezoelectrics for energy harvesting, 12 and semiconductors or dielectrics for high-performance transistors. Almost