Search results for "efficiency"
showing 10 items of 1430 documents
Evaluation of interfacial stress transfer efficiency by coating fragmentation test
2007
Probabilistic model of coating fragmentation under uniaxial tensile loading is developed. Analytical expressions of the crack spacing evolution are obtained for small-strain and large-strain fragmentation regimes. The model is applied for coating and interface property identification of several thin brittle coating/polymer substrate systems. An estimate of the stress transfer length, derived from the fragmentation data, is found to correlate with the interfacial shear strength thus suggesting that both parameters reflect an intrinsic property related to the mechanical efficiency of coating/substrate interface.
Multifunctional derivatives of dimethoxy-substituted triphenylamine containing different acceptor moieties
2020
This project has received funding from the Research Council of Lithuania (LMTLT), Agreement No. [S-LZ-19-2]. This research was funded by the Région Centre, the Tunisian ministry of research, University of Monastir and the French ministry of Higher Education and Research. J. Bouclé would like to thank the Sigma-Lim LabEx environment for financial supports, and the PLATINOM facility at XLIM laboratory regarding device fabrication and characterizations. DG acknowledges the Lithuanian Academy of Sciences for the financial support.
Recombination in Perovskite Solar Cells
2017
Trap-assisted recombination, despite being lower as compared with traditional inorganic solar cells, is still the dominant recombination mechanism in perovskite solar cells (PSCs) and limits their efficiency. We investigate the attributes of the primary trap assisted recombination channels (grain boundaries and interfaces) and their correlation to defect ions in PSCs. We achieve this by using a validated device model to fit the simulations to the experimental data of efficient vacuum-deposited p-i-n and n-i-p CH3NH3PbI3 solar cells, including the light intensity dependence of the open circuit voltage and fill factor. We find that, despite the presence of traps at interfaces and grain bounda…
Europium(III)-doped A(2)Hf(2)O(7) (A = Y, Gd, Lu) nanoparticles: Influence of annealing temperature, europium(III) concentration and host cation on t…
2016
The detailed analyses of structure and luminescence of europium(III)-doped A(2)Hf(2)O(7) (A = Y, Gd, Lu) nanoparticles is presented. Samples were prepared by time and cost effective combustion method that utilize polyethylene glycol both as a chelating agent and as a fuel, with different europium(III) concentrations (from 1 to 12 at.%), annealed at temperatures ranging from 800 to 1400 degrees C, and with alternating A(3+) cation in the A(2)Hf(2)O(7) host. Then, structural variations between materials were analysed by Xray diffraction and structural refinement, while the changes in the luminescence were assessed from the Judd-Ofelt analyses of emission spectra. Nanoparticles prepared at the…
Quantum dot-block copolymer hybrids with improved properties and their application to quantum dot light-emitting devices.
2009
To combine the optical properties of CdSe@ZnS quantum dots (QDs) with the electrical properties of semiconducting polymers, we prepared QD/polymer hybrids by grafting a block copolymer (BCP) containing thiol-anchoring moieties (poly(para-methyl triphenylamine-b-cysteamine acrylamide)) onto the surfaces of QDs through the ligand exchange procedure. The prepared QD/polymer hybrids possess improved processability such as enhanced solubility in various organic solvents as well as the film formation properties along with the improved colloidal stability derived from the grafted polymer shells. We also demonstrated light-emitting diodes based on QD/polymer hybrids, exhibiting the improved device …
Methoxycarbazolyl-disubstituted dibenzofuranes as holes- and electrons-transporting hosts for phosphorescent and TADF-based OLEDs
2020
This research was funded by European Social Fund (Project No 09.3.3-LMT-K-712-02-0105). DG acknowledges to the ERDF PostDoc grant No. 1.1.1.2/VIAA/1/16/177.
Self-assembled silver nanoparticles for plasmon-enhanced solar cell back reflectors: correlation between structural and optical properties
2013
The spectra of localized surface plasmon resonances (LSPRs) in self-assembled silver nanoparticles (NPs), prepared by solid-state dewetting of thin films, are discussed in terms of their structural properties. We summarize the dependences of size and shape of NPs on the fabrication conditions with a proposed structural-phase diagram. It was found that the surface coverage distribution and the mean surface coverage (SC) size were the most appropriate statistical parameters to describe the correlation between the morphology and the optical properties of the nanostructures. The results are interpreted with theoretical predictions based on Mie theory. The broadband scattering efficiency of LSPR…
Performance data of optically stimulable irradiated materials (doped alkali halides) oriented for imaging and dosimetry purposes
1997
Performance characteristics of a doped alkali halide (KBr:In)-based imaging plate (IP) and dosemeter (D) both the devices utilizing optically stimulated luminescence (OSL) and suitable for UV-light and x-ray energy recording are described. By exploiting (silicon) photodiode array as a photodetector, the detective quantum efficiency of 0.1 for IP (KBr:In) can be achieved. A very wide dynamic range, 1010:1 for UV (6.35 eV) and 1011:1 for x-ray (44 kV tube voltage) OSL recording at the spatial resolution of 1 mm2, is favorable for digital imaging and considerably improves image quality. These possibilities are illustrated by presenting available information capacities, energy consumption per b…
3D photonic crystal intermediate reflectors for enhanced light-trapping in tandem solar cells
2012
The concept of 3D photonic crystals embedded in tandem solar cells as intermediate reflective layers is investigated. Numerical as well as experimental results will be presented.
A bacteriochlorin-diketopyrrolopyrrole triad as a donor for solution-processed bulk heterojunction organic solar cells
2019
We have designed an A–π–D–π–A small-molecule triad consisting of a bacteriochlorin (BC) donor central core linked with two diketopyrrolopyrrole (DPP) acceptors via ethynyl bridges (BC-DPP-1). BC-DPP-1 has a narrow optical bandgap of 1.38 eV with highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels of −4.93 eV and −3.40 eV, respectively, and it was used as an electron donor along with [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as an acceptor for solution-processed small-molecule organic solar cells. After optimizing the weight ratio between BC-DPP-1 and PC71BM and pyridine as a solvent additive and subsequent solvent vapor annealing using THF, an …