Search results for "optoelectronic"
showing 10 items of 2328 documents
Electrochemical pH Control at Gold Nanowires
2018
In this work, interdigitated arrays of nanowire electrodes are used with one array acting as the working electrode while the other is used to generate the required protons. Finite element simulations of the pH control electrodes were performed to provide insight on the generation and subsequent diffusion of protons. This informed the inter-tine spacing of the electrodes used.. This electrochemical pH control method was then used to enable the detection of analytes of interest.
New n-type molecular semiconductor–doped insulator (MSDI) heterojunctions combining a triphenodioxazine (TPDO) and the lutetium bisphthalocyanine (Lu…
2018
International audience; Molecular semiconductor–doped insulator (MSDI) heterojunctions were designed using a new family of sublayers, namely triphenodioxazines (TPDO). The device obtained by combining the tetracyano triphenodioxazine bearing two triisopropylsilylethynyl moieties as a sublayer with the lutetium bisphthalocyanine (LuPc2) as a top layer showed a nonlinear current–voltage characteristic independent of the sign of the polarization, which is the signature of MSDI heterojunctions. Thus, a TPDO was used in a chemical sensor for the first time. Despite LuPc2 being the only material exposed to the atmosphere, the positive response of the device under ammonia revealed the key role pla…
Photodoping-Inspired Room-Temperature Gas Sensing by Anatase TiO2 Quantum Dots
2021
Detection of volatile organic compounds (VOCs) at room temperature in an ambient environment is highly desired, but still a distant function for gas sensor materials. Here, we are demonstrating a p...
Should TiO2 nanostructures doped with Li+ be used as photoanodes for photoelectrochemical water splitting applications?
2017
[EN] Different TiO2 nanostructures, nanotubes and nanosponges, were obtained by anodization of Ti under stagnant and hydrodynamic conditions. Samples were doped with Li+ before and after annealing at 450 degrees C during 1 h. The nanostructures were characterized by different microscopy techniques: Field Emission Scanning Electron Microscopy (FE-SEM) and Raman Confocal Laser Microscopy. Additionally, Incident Photon-to-electron Conversion Efficiency (IPCE), photoelectrochemical water splitting and stability measurements were also performed. According to the results, TiO2 nanostructures doped before annealing present the worst photocurrent response, even if compared with undoped samples. On …
Lateral Fusion of Chemical Vapor Deposited N = 5 Armchair Graphene Nanoribbons
2017
Bottom-up synthesis of low-bandgap graphene nanoribbons with various widths is of great importance for their applications in electronic and optoelectronic devices. Here we demonstrate a synthesis of N = 5 armchair graphene nanoribbons (5-AGNRs) and their lateral fusion into wider AGNRs, by a chemical vapor deposition method. The efficient formation of 10- and 15- AGNRs is revealed by a combination of different spectroscopic methods, including Raman and UV−visnear-infrared spectroscopy as well as by scanning tunneling microscopy. The degree of fusion and thus the optical and electronic properties of the resulting GNRs can be controlled by the annealing temperature, providing GNR films with o…
Sb-implanted ZnO ultra-thin films
2017
Mild heating of the Zn(C5F6HO2)(2)center dot 2H(2)O center dot CH3(OCH2CH2)(2)OCH3 precursor allowed MOCVD deposition of ZnO films, in a low-pressure horizontal hot-wall reactor, on ITO substrates. The ZnO films were subsequently implanted with Sb ions. XRD measurements provided evidence that they consist of hexagonal, (002) and (101) oriented, crystals. UV-vis spectra showed that the transmittance of these films in the visible region is about 90%. The Sb implanted ZnO film showed a current-voltage characteristic that resembles that of a rectifying diode. This study represents the first example of Sb-implantation in ZnO films obtained by MOCVD.
Gold based plasmonic stripes co-integrated with low loss Si3N4 platform in aqueous environment
2018
We demonstrate a butt-coupled interface between LPCVD Si 3 N 4 and gold based plasmonic waveguides in aqueous environment, exhibiting 2.3dB coupling loss and 75μm propagation length at 1550nm, towards future employment in biosensing applications.
ZnO nanorods covered with a TiO2 layer: simple sol–gel preparation, and optical, photocatalytic and photoelectrochemical properties
2015
In this work, composite core–shell ZnO/TiO2 materials were fabricated by deposition of TiO2 layers via a sol–gel method onto ZnO nanorods hydrothermally grown on an ITO electrode. Two approaches to the sol–gel procedure resulted in strongly different morphologies and thicknesses of the deposited TiO2 layer, as shown in electron microscopy studies. The decrease of the optical band gap energies of the ZnO/TiO2 composites by about 0.2–0.3 eV with respect to the TiO2 nanoparticles and ZnO nanorods was determined from UV-Vis diffuse reflectance spectra. The photocatalytic activities of the systems were determined by investigation of the decolorization of Methylene Blue (MB) in aqueous solution, …
<title>Electrochromism in oxyfluoride thin films</title>
1994
Oxyfluoride films based on W and Ti were prepared by reactive sputtering in plasmas containing O2 + CF4. The deposition rate was large, particularly when chemical sputtering was promoted by heating the target. The films could show large charge insertion/extraction, high coloration efficiency, and good cycling durability.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Early detection of volcanic hazard by lidar measurement of carbon dioxide
2016
Volcanic gases give information on magmatic processes. In particular, anomalous releases of carbon dioxide precede volcanic eruptions. Up to now, this gas has been measured in volcanic plumes with conventional measurements that imply the severe risks of local sampling and can last many hours. For these reasons and for the great advantages of laser sensing, the thorough development of volcanic lidars has been undertaken at ENEA (Italian National Agency for New Technologies, Energy and Sustainable Economic Development). In fact, lidar profiling allows one to scan remotely volcanic plumes in a fast and continuous way, and with high spatial and temporal resolution. A differential absorption lid…