Search results for "Toe"
showing 10 items of 3824 documents
UV optical record and electron beam lithography in polymer films
2012
Possibility of UV optical record and electron beam lithography in different type of organic polymer films was studied. Mechanisms of molecular structure changes: photoisomerization, destruction, cross-linking and oxidation have been discussed. The results of UV illumination of polyurethanes, polyacrilates, and some block-copolymers are described. The element analysis of polyisoprene block copolymer was performed before and after UV illumination, and the changes in transmission spectra of the polymer film were measured. The resolution of electron beam lithography on polymer films was studied. In the polyisoprene block copolymer film the oxidation polymerization was ascertain at UV-illuminati…
Low-dimensional iodide perovskite nanocrystals enable efficient red emission
2019
We report herein a simple ligand-assisted reprecipitation method at room temperature to synthesize mixed-cation hybrid organic–inorganic perovskite nanocrystals with low structural dimensionality.
<title>Effect of light exposure on dislocation mobility in fullerite C60 crystals</title>
2001
The illumination-time evolution and the wavelength dependence of the photoinduced changes in dislocation mobility on the (111) face of C60 single crystals in air for the wavelength range 150 - 900 nm and power densities 0.2 - 2 mW/cm2 has been investigated. The results show that the light exposure in air leads to the decrease of the dislocation mobility. The magnitude of the effect as a function of the illumination time was investigated and a two-stage relationship was obtained. The ultraviolet light was found to be more effective than the visible light in the photoinduced reduction of dislocation mobility and solubility. In the wavelength range of 150 - 700 nm, the reduction of dislocation…
Side-chain conjugated polymers for use in the active layers of hybrid semiconducting polymer/quantum dot light emitting diodes
2016
Three monomers, M1–M3, with modified carbazole cores and styrene functionality were prepared for use in the active layers of hybrid polymer/quantum dot light emitting diodes. Utilizing reversible addition fragmentation chain transfer polymerization, side-chain conjugated polymers, P1–P3, with narrow polydispersities and disulfide end groups were obtained. The thermal, optical, and electrochemical properties of the polymers varied depending on the substituents of the carbazole cores. Through the disulfide end groups the polymers were chemically blended with quantum dots to obtain QD/polymer hybrids, which were further used as active layers in light emitting diodes. The fabricated devices ret…
Switching of Polymer Brushes
1999
Polymer coatings of brushlike monolayers composed of two different polymers, polystyrene and poly(2-vinylpyridine), are grafted by radical polymerization on the surface of silicon wafers. Thickness, grafting density, molecular weight of grafted chains, and the composition of the coatings were regulated by grafting time, monomer concentration, and additional initiator in solution. A typical dry film thickness is between 10 and 100 nm, and the molecular weights of the components range from 100 to 300 kg/mol. The fabricated coatings turn out to be sensitive to the composition of the environment. For instance after exposition to toluene the layer becomes hydrophobic and the top of the layer is …
Magneto-Transport Results in SAM Based MTJs
2015
This chapter is dedicated to the description of the magneto-transport results obtained in LSMO/SAM/Co magnetic tunnel nanojunctions fabricated by nanoindentation lithography technique. We started by focusing on the study of LSMO/C12P/Co MTJs. This because C12P is a medium size alkyl chain: long enough to avoid short-circuits in the junction but short enough to give a device resistance in the order of few tens of MO and thus easier to measure. Next, we started to tune the molecule thickness from C10P to C18P (from 10 carbon atoms in the alkyl chain to 18). This allowed on one hand to validate our system by comparing the exponential increase of the junction resistance to the one reported in t…
Fully Vacuum-Processed Wide Band Gap Mixed-Halide Perovskite Solar Cells
2017
Methylammonium lead mixed-halide perovskites MAPb(BrxI1–x)3 are promising materials for the preparation of tandem devices. When exposed to light, MAPb(BrxI1–x)3 segregates in iodide- and bromide-rich phases, limiting the achievable photovoltage and hence the attainable device efficiency. To date only solution-processed mixed-halide perovskites have been demonstrated. We present fully vacuum-deposited mixed-halide perovskite thin films with band gap of 1.72 and 1.87 eV, prepared by controlling the deposition rates of the different halide precursors. When used in thin-film devices, these materials lead to power conversion efficiencies of 15.9 and 10.5%, respectively, which are among the highe…
Combined thermal evaporated and solution processed organic light emitting diodes
2011
Abstract Highly efficient, partly solution processed phosphorescent red, green and white organic light emitting diodes with small molecular weight host materials are prepared from commercially available starting compounds. Starting from an evaporated reference device, layers are stepwise replaced by solution processed layers. Replacing the evaporated hole transport layer by a solution processed polymer interlayer does not affect the performance and allows spincoating of the emissive layer after annealing of the polymer. Devices with, next to the spincoated hole injection and transport layer, a solution processed emission layer show similar characteristics and efficiencies as the reference d…
A new cross-linkable 9,10-diphenylanthracene derivative as a wide bandgap host for solution-processed organic light-emitting diodes
2018
Efficient organic light-emitting diodes (OLEDs) can be obtained using multilayered architectures where the processes of charge injection, transport and recombination are separated and optimized in each layer. Processing these structures from solution requires strategies to avoid redissolution or damage of the previously deposited layers. Several reports have demonstrated the development of cross-linkable hole transport materials, while less literature describes the synthesis and applications of such wide bandgap host materials for multilayered OLEDs. In this work we introduce a cross-linkable derivative of 9-(4-(10-phenylanthracene-9-yl)phenyl)-9H-carbazole incorporating styrene moieties (S…
Ionic iridium complex and conjugated polymer used to solution-process a bilayer white light-emitting diode.
2013
Bilayer white light-emitting devices are prepared from solution, using an ionic orange phosphorescent organometallic complex and a neutral fluorescent conjugated polymer. Because of the very different polarity of the two components, they dissolve in orthogonal solvents, allowing for the direct deposition of the blue emitter on top of the orange emitter without the need of cross-linking or special coating methodology. Fine tuning of the layer thickness of both light-emitting layers allows for the color tuning of different types of white light.