Dual functionality anti-reflection and biocidal coatings

A thin film combination of anti-reflection (AR) and biocidal properties would be of particular interest to reduce the transfer of infection and improve readability of public high use touch screens. In this paper we describe the development of a dual functionality film of silica (AR) and copper oxide (biocidal). Deposition was via flame assisted chemical vapour deposition (FACVD) which has the advantages of being a cost efficient atmospheric pressure technique enabling use of non-volatile precursors and that no closed reaction cell is required so making it ideal for integration into industrial production lines. The resulting films were characterized by a range of techniques including optical spectroscopy, electron microscope and X-ray fluorescence. Biocidal behavior was tested by determining the kill rate of Escherichia coli. A 3 layer stack on glass of silica/copper oxide/silica had better adhesion and lower reflection than a comparable 2 layer stack. This multilayer film led to a > 2% drop in reflection from that of uncoated glass, similar to that of silica only film. In addition, showed a > 6 log10 kill between 6 and 24 h for as deposited and annealed samples

VO2/TiO2 bilayer films for energy efficient windows with multifunctional properties

Vanadium dioxide/titanium dioxide bilayer films have been investigated as a thermochromic coating for application as intelligent window glazings for buildings. The nanostructured VO2 and TiO2 films were deposited on fluorine doped tin oxide coated glass substrates using electric field assisted aerosol assisted chemical vapour deposition (ElFi-AACVD) and sol-gel spin coating, respectively. Their thermochromic properties were investigated using scanning electron microscopy, X-ray diffraction, variable temperature UV/Vis/NIR and X-ray photoelectron spectroscopies. Compared to bare VO2 films, the VO2/TiO2 bilayer films exhibit an increase in visible light transmittance of up to 30%, an increase in integrated luminous transmisttance, with values up to 66%, and a higher transmittance modulation in the near infrared of up to 20% at the thermochromic transition temperature. The TiO2 top layer not only enhances visible light transmittance, but also serves to protect the VO2 bottom layer from oxidation. The bilayer films are shown to exhibit photo-induced super-hydrophilicity. These properties are affected by the morphology of the VO2 under-layer

Aerosol assisted chemical vapour deposition of conformal ZnO compact layers for efficient electron transport in perovskite solar cells

Ultrathin and compact ZnO films were firstly deposited on textured fluorine-doped tin oxide (FTO) electrodes via aerosol assisted chemical vapour deposition (AACVD). Planar CH3NH3PbI3 perovskite solar cells (PSCs) were fabricated under ambient conditions and a best power conversion efficiency (PCE) of 11.75% was achieved

Is the meiofauna a good indicator for climate change and anthropogenic impacts?

Our planet is changing, and one of the most pressing challenges facing the scientific community revolves around understanding how ecological communities respond to global changes. From coastal to deep-sea ecosystems, ecologists are exploring new areas of research to find model organisms that help predict the future of life on our planet. Among the different categories of organisms, meiofauna offer several advantages for the study of marine benthic ecosystems. This paper reviews the advances in the study of meiofauna with regard to climate change and anthropogenic impacts. Four taxonomic groups are valuable for predicting global changes: foraminifers (especially calcareous forms), nematodes, copepods and ostracods. Environmental variables are fundamental in the interpretation of meiofaunal patterns and multistressor experiments are more informative than single stressor ones, revealing complex ecological and biological interactions. Global change has a general negative effect on meiofauna, with important consequences on benthic food webs. However, some meiofaunal species can be favoured by the extreme conditions induced by global change, as they can exhibit remarkable physiological adaptations. This review highlights the need to incorporate studies on taxonomy, genetics and function of meiofaunal taxa into global change impact research

New cvd methods for energy efficient glazing

This work studies the use of the novel electric field assisted chemical vapour deposition (EACVD) process in the production of thermochromic thin films of vanadium dioxide on glass substrates. The investigation studies the effects an applied electric field has on both aerosol assisted chemical vapour deposition (AACVD) and atmospheric pressure chemical vapour deposition (APCVD) reactions of vanadyl acetylacetonate. The electric field was generated by applying a potential difference between two transparent conducting oxide coated glass substrates. The electric field was varied between 0 – 3000 Vm-1. The deposited films were analysed and characterized using scanning electron microscopy, Raman spectroscopy, X-ray diffraction, atomic force microscopy and contact angle measurements. It was found that applying an electric field led to large changes in film microstructure, preferential orientation and changes in the film growth rate. This led to significant changes in materials properties such as increased surface roughness and enhanced wetting behaviour. Electric field assisted chemical vapour deposition shows great promise as a method for nano-structuring and tailoring the properties of metal oxide thin films. Further to the work carried out depositing thermochromic materials a computation building study is carried out to assess the energy saving potential of thermochromic thin films in as intelligent glazing. The building simulation is used to examine the effect of the thermochromic transition, hysteresis width and hysteresis gradient on the energy demand characteristics of a model system in a variety of climates. The results are also compared against current industry standard glazing products. The results suggest that ideal thermochromic systems can give potential savings between 20 – 50 % depending on the specific climate. The building model is also used to asses the energy saving potential of VO2 thin films prepared by electric field assisted atmospheric pressure chemical vapour deposition

On the Effects of Electric Fields in Aerosol Assisted Chemical Vapour Deposition Reactions of Vanadyl Acetylacetonate Solutions in Ethanol

Thin films of thermochromic vanadium dioxide have been deposited on glass substrates at 530 degrees C from the aerosol assisted chemical vapour deposition of vanadyl acetylacetonate solutions in ethanol under the influence of electric fields. Electric fields were generated by applying a potential difference between the top plate and the substrate of the reactor. The deposited films were analysed and characterised using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy and variable temperature UV/Visible spectroscopy. The application of an electric field led to significant changes in the deposited films microstructure and functional properties. It was found that an increase in electric field strength caused a decrease in crystallite size and in an increase in the change in transmission in the near infrared when compared to films grown without the use of an electric field

Fluorine doped vanadium dioxide thin films for smart windows

Thermochromic fluorine doped thin films of vanadium dioxide were deposited from the aerosol assisted chemical vapour deposition reaction of vanadyl acetylacetonate, ethanol and trifluoroacetic acid on glass substrates. The films were characterised with scanning electron microscopy, variable temperature Raman spectroscopy and variable temperature UV/Vis spectroscopy. The incorporation of fluorine in the films led to an increase in the visible transmittance of the films whilst retaining the thermochromic properties. This approach shows promise for improving the aesthetic properties of vanadium dioxide thin films

Electric field assisted chemical vapour deposition - a new method for the preparation of highly porous supercapacitor electrodes

Nanostructured thin films of vanadium oxides were deposited using electric field assisted chemical vapour deposition. The films were characterised using scanning electron microscopy, X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy. It was found that the films had open and porous morphologies with extremely small (5 nm) surface features. The films were made into supercapacitor cells and tested using cyclic voltammetry. It was found that stable asymptotic values specific capacitance values as high as 3700 μF cm−2 could be obtained with good cycling behaviour. Electrodes synthesized in this way show promise for applications in fields such as supercapacitors