Search results for "ELECTROLUMINESCENCE"

Efficient Polymer Light‐Emitting Diode Using Air‐Stable Metal Oxides as Electrodes

2009

Poly(phenylenevinylene)‐based organic light‐emitting diodes (OLEDs) are fabricated using air‐stable metal oxides as electrodes, producing very efficient and bright electroluminescent devices. Efficiencies of 8 cd A−1 and luminances above 20000 cd m−2 are obtained, comparable to the values reported for classic OLED structures using reactive metals as cathodes.

Electrical excitation of surface plasmons by an individual carbon nanotube transistor.

2013

We demonstrate here the realization of an integrated, electrically driven, source of surface plasmon polaritons. Light-emitting individual single-walled carbon nanotube field effect transistors were fabricated in a plasmonic-ready platform. The devices were operated at ambient conditions to act as an electroluminescence source localized near the contacting gold electrodes. We show that photon emission from the semiconducting channel can couple to propagating surface plasmons developing in the electrical terminals. Our results show that a common functional element can be operated for two different platforms emphasizing thus the high degree of compatibility between state-of-the-art nano-optoe…

Light-emitting fabrics

2015

Light-emitting fibres that suit integration with textiles are prepared by dip-coating a steel wire with an electroluminescent material and then cleverly wrapping the structure with a carbon nanotube sheet that functions as a transparent electrode.

Irradiance Dependent Temperature Coefficients for MC Solar Cells from Elkem Solar Grade Silicon in Comparison with Reference Polysilicon

2014

Abstract An increase in sun intensity enhances the output power of the solar cells, but at the same time the rise of cell temperature affects its electrical performance negatively. The present authors have made a comparative study on temperature coefficients at various irradiances of multicrystalline solar cells made from the standard Siemens process and from material produced by a metallurgical route – the Elkem Solar Silicon (ESS®) process. Such temperature coefficients measured while exposed to various irradiance levels are essential to build a better understanding and prediction of field performance of solar cells manufactured from various feedstock types. In the current experiment, the…

Star-Shaped Conjugated Systems

2010

The present review deals with the preparation and the properties of star-shaped conjugated compounds. Three, four or six conjugated arms are attached to cross-conjugated cores, which consist of single atoms (B, C+, N), benzene or azine rings or polycyclic ring systems, as for example triphenylene or tristriazolotriazine. Many of these shape-persistent [n]star compounds tend to π-stacking and self-organization, and exhibit interesting properties in materials science: Linear and non-linear optics, electrical conductivity, electroluminescence, formation of liquid crystalline phases, etc.

Contrôle de nano-antennes optiques par une commande électrique : tuner plasmonique et transduction

2011

Optical nano-antennae are the new class of components to control light/matterinteraction at the nanoscale. These devices are operating in the visible to near infraredpart of the spectrum. The properties of these nano objects are controlled by theform, the size and the material.In the radio frequency domain, the tuner changes dynamically the operatingwavelength of the antenna. In this thesis work, we search to transfer this conceptto the nanoscale. The principle is to change the load impedance of the antenna, i.e.changing the optical index of the dielectric medium around the nano-object. Forthat we used anisotropic liquid cristal molecules. The value of the optical index iscontrolled by appl…

Radiative efficiency of lead iodide based perovskite solar cells

2014

The maximum efficiency of any solar cell can be evaluated in terms of its corresponding ability to emit light. We herein determine the important figure of merit of radiative efficiency for Methylammonium Lead Iodide perovskite solar cells and, to put in context, relate it to an organic photovoltaic (OPV) model device. We evaluate the reciprocity relation between electroluminescence and photovoltaic quantum efficiency and conclude that the emission from the perovskite devices is dominated by a sharp band-to-band transition that has a radiative efficiency much higher than that of an average OPV device. As a consequence, the perovskite have the benefit of retaining an open circuit voltage ~0.1…

2015

AbstractThe synthesis, characterization and evaluation in solid-state devices of a series of 8 cationic iridium complexes bearing different numbers of methoxy groups on the cyclometallating ligands are reported. The optoelectronic characterization showed a dramatic red shift in the absorption and the emission and a reduction of the electrochemical gap of the complexes when a methoxy group was introduced para to the Ir-C bond. The addition of a second or third methoxy group did not lead to a significant further red shift in these spectra. Emission maxima over the series ranged from 595 to 730 nm. All complexes possessing a motif with a methoxy group at the 3-position of the cyclometalating l…

Low-diffusion Xe-He gas mixtures for rare-event detection: electroluminescence yield

2020

[EN] High pressure xenon Time Projection Chambers (TPC) based on secondary scintillation (electroluminescence) signal amplification are being proposed for rare event detection such as directional dark matter, double electron capture and double beta decay detection. The discrimination of the rare event through the topological signature of primary ionisation trails is a major asset for this type of TPC when compared to single liquid or double-phase TPCs, limited mainly by the high electron diffusion in pure xenon. Helium admixtures with xenon can be an attractive solution to reduce the electron diffu- sion significantly, improving the discrimination efficiency of these optical TPCs. We have m…

Dumbbell-Shaped Dinuclear Iridium Complexes and Their Application to Light-Emitting Electrochemical Cells

2010

A novel family of dumbbell- shaped dinuclear complexes in which an oligophenyleneethynylene spacer is linked to two heteroleptic iridiumA complexes is presented. The synthesis, as well as the electrochemical and pho- tophysical characterization of the new complexes, is reported. The experimen- tal results are interpreted with the help of density functional theory calcula- tions. From these studies we conclude that the lowest triplet excited state cor- responds to a 3 p-p* state located on the conjugated spacer. The presence of this state below the 3 MLCT/ 3 LLCT emitting states of the end-capping Ir III complexes explains the low quantum yields observed for the dinuclear com- plexes (one or…