Search results for "Toe"
showing 10 items of 3824 documents
Asymmetric Dual-Grating Micro-Slit Configuration for Broadband Solid State Coherent Detection of THz Pulses
2016
We demonstrated solid-state broadband coherent Terahertz characterization based on the Terahertz Field Induced Second Harmonic effect in Silica. The THz detector consists of an asymmetric micro-slit array which can be operated at 200V applied bias.
Fullerene imposed high open-circuit voltage in efficient perovskite based solar cells
2016
Five different commercially available fullerenes are evaluated as hole blocking/electron transporting materials in p–i–n methylammonium lead iodide perovskite solar cells using a vacuum deposited perovskite absorber layer. A significant enhancement of the solar cell performance can be obtained by selecting a suitable fullerene derivative. Open-circuit voltages as high as 1.11 volts are obtained leading to a power conversion efficiency of 14.6%.
Meniscus coated high open-circuit voltage bi-layer solar cells
2012
Neat bi-layer solar cells of a fullerene acceptor and a cyanine dye donor were prepared using meniscus coating. Meniscus coating is very material efficient and leads to high quality pinhole-free films. The cells exhibit high open circuit voltages of 1 volt, only 0.8 eV below the band gap of the cyanine dye. This is one of the smallest differences reported for organic solar cells and illustrates an almost optimal donor-acceptor energy level alignment.
Bending Sensors Based on Thin Films of Semitransparent Bithiophene-Fulleropyrrolidine Bisadducts
2020
In this study, a novel bithiophene‐fulleropyrrolidine bisadducts system (bis‐Th2PC 60 ) was synthesized and electropolymerized by chronoamperometry onto flexible ITO/PET substrates. The resulting semitransparent thin film was characterized by XPS, FT‐IR, cyclic voltammetry and optical techniques, confirming the good outcome of the electropolymerization process. AFM investigations permitted to highlight an inherent disordered granular morphology, in which the grain‐to‐grain separation depends upon the application of bending. The electrical resistance of the thin film was characterized as function of bending (in the range 0°‐90°), showing promising responsivity to low bending angles (10°‐30°)…
Ultra-broad spectral photo-response in FePS3 air-stable devices
2021
Van der Waals materials with narrow energy gaps and efficient response over a broadband optical spectral range are key to widen the energy window of nanoscale optoelectronic devices. Here, we characterize FePS as an appealing narrow-gap p-type semiconductor with an efficient broadband photo-response, a high refractive index, and a remarkable resilience against air and light exposure. To enable fast prototyping, we provide a straightforward guideline to determine the thickness of few-layered FePS nanosheets extracted from the optical transmission characteristics of several flakes. The analysis of the electrical photo-response of FePS devices as a function of the excitation energy confirms a …
In-situ electrochemical atomic force microscopy study of aging of magnetron sputtered Pt-Co nanoalloy thin films during accelerated degradation test
2016
Abstract A Pt-Co nanoalloy thin film catalyst was prepared by using simultaneous magnetron sputtering of Pt and Co. The catalyst was characterized during accelerated degradation test using in-situ electrochemical atomic force microscopy complemented with ex-situ techniques such as energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and synchrotron radiation photoelectron spectroscopy. The combined results gave the full step-by-step picture of the catalyst behavior during the aging test.
Supramolecular control of liquid crystals by doping with halogen-bonding dyes
2017
Introducing photochromic or polymeric dopants into nematic liquid crystals is a well-established method to create stimuli-responsive photonic materials with the ability to "control light with light". Herein, we demonstrate a new material design concept by showing that specific supramolecular interactions between the host liquid crystal and the guest dopants enhance the optical performance of the doped liquid crystals. By varying the type and strength of the dopant-host interaction, the phase-transition temperature, the order parameter of the guest molecules, and the diffraction signal in response to interference irradiation, can be accurately engineered. Our concept points out the potential…
Magnesium(II) polyporphine: The first electron-conducting polymer with directly linked unsubstituted porphyrin units obtained by electrooxidation at …
2010
Abstract Electrooxidation of magnesium(II) porphine, a totally unsubstituted porphyrin, in acetonitrile solution under potentiostatic or potentiodynamic regime leads to a polymer film at the electrode surface. Polymer deposition takes place at extremely low potential, several hundred mV less positive even compared to the deposition potential for pyrrole or EDOT (at identical monomer concentrations) in the same solvent. Film thickness can be controlled by the passed deposition charge. This material and its THF-soluble fraction have been characterized by various electrochemical methods as well as by UV–visible and IR spectroscopies, XPS, XRD and MALDI-TOF techniques. This analysis has allowed…
Structure and the metal-support interaction of the Au/Mn oxide catalysts
2010
Gold catalysts with loading 1 and 10 wt % were-prepared by deposition precipitation method with urea over mesoporous manganese oxide, obtained through a surfactant-assisted procedure by using cetyltrimethylammonium bromide (CTAB), followed by treatment with sulphuric acid. For comparison, Au(10 wt %) was also deposited over commercial CeO2 and SiO2 supports. The materials were characterized by XRD and EXAFS at the Mn K and Au L-III edges and XPS. Moreover, the analyses were performed on the samples treated under 1%CO/He, at 250 degrees C for 90 min. The structural and surface results of the as prepared manganese oxide confirmed the formation of gamma-MnO2 along with some amorphous Mn3O4 upo…
Influence of Nitrogen Doping on Device Operation for TiO 2 -Based Solid-State Dye-Sensitized Solar Cells: Photo-Physics from Materials to Devices
2016
International audience; Solid-state dye-sensitized solar cells (ssDSSC) constitute a major approach to photovoltaic energy conversion with efficiencies over 8% reported thanks to the rational design of efficient porous metal oxide electrodes, organic chromophores, and hole transporters. Among the various strategies used to push the performance ahead, doping of the nanocrystalline titanium dioxide (TiO 2) electrode is regularly proposed to extend the photo-activity of the materials into the visible range. However, although various beneficial effects for device performance have been observed in the literature, they remain strongly dependent on the method used for the production of the metal o…