Search results for "quenching"
showing 10 items of 275 documents
Partitioning of Pyrene-Labeled Phospho- and Sphingolipids between Ordered and Disordered Bilayer Domains
2004
AbstractHere we have studied how the length of the pyrene-labeled acyl chain (n) of a phosphatidylcholine, sphingomyelin, or galactosylceramide affects the partitioning of these lipids between 1), gel and fluid domains coexisting in bovine brain sphingomyelin (BB-SM) or BB-SM/spin-labeled phosphatidylcholine (PC) bilayers or 2), between liquid-disordered and liquid-ordered domains in BB-SM/spin-labeled PC/cholesterol bilayers. The partitioning behavior was deduced either from modeling of pyrene excimer/monomer ratio versus temperature plots, or from quenching of the pyrene monomer fluorescence by spin-labeled PC. New methods were developed to model excimer formation and pyrene lipid quenchi…
Thiophene pyrenyl derivatives for the supramolecular processability of single-walled carbon nanotubes in thin film heterojunction
2017
Abstract A major problem for the use of single-wall carbon nanotubes (SWCNTs) in electronic devices relates to their poor processability. Chemical modification inevitably introduces defects in the nanotube lattice, resulting in a loss of electronic properties. In this contest, we report on a supramolecular approach with the aim of increasing the dispersion of SWCNTs in solution and in organic semiconductor matrices by ensuring the optoelectronic properties. In particular, new pyrenyl derivatives of thiophene have been synthesized and used to improve the solubility of SWCNTs for electron transfer in thin film heterojunction with poly(3-hexylthiophene) (P3HT) as donor system. Photoinduced ele…
Influence of pressure on ultrasonic cavitation activity in room temperature ionic liquids: An electrochemical study
2019
Abstract This paper provides proofs of the respective contributions of dissolved gases and solvent vapor on cavitation activity in sonoreactors. This activity can be detected by electrochemistry because the fluctuating events measured at the electrode surface are only linked to physical effects of cavitation. As ionic liquids present very low volatilities, their vaporization is reduced, and cavitation bubbles only depend on the presence of gases. Then, cavitation activity may be trigged by reactor atmosphere control. Applying severe depression within an irradiated ionic liquid medium contributes to removing dissolved gases, thus quenching cavitation activity. A specific sonoelectrochemical …
Large area perovskite light-emitting diodes by gas-assisted crystallization:
2019
Halide perovskites have been gaining considerable attention recently for use in light-emitting applications, due to their bandgap tunability, color purity and low cost fabrication methods. However, current fabrication techniques limit the processing to small-area devices. Here, we show that a facile N 2 gas-quenching technique can be used to make methylammonium lead bromide-based perovskite light-emitting diodes (PeLEDs) with a peak luminance of 6600 cd m −2 and a current efficiency of 7.0 cd A −1 . We use this strategy to upscale PeLEDs to large-area substrates (230 cm 2 ) by developing a protocol for slot-die coating combined with gas-quenching. The resulting large area devices (9 device…
Ultrafast luminescence of Ga- and In-doped ZnO ceramics
2021
The work of authors (a-c) was financially supported by Russian Foundation for Basic Research (RFBR, Russia) and the work of the last author (d) had financial support from State Education Development Agency (VIAA, Latvia) . All of that was approved as a result of ERA.Net RUS PLUS 2017 joint call for proposals. Here is the link for the joint call for reference: https://www.eranet-rus.eu/en/196.php .
Inverse simulated annealing: Improvements and application to amorphous InSb
2014
An improved inverse simulated annealing method is presented to determine the structure of complex disordered systems from first principles in agreement with available experimental data or desired predetermined target properties. The effectiveness of this method is demonstrated by revisiting the structure of amorphous InSb. The resulting network is mostly tetrahedral and in excellent agreement with available experimental data.
Effect of surface impurities on downconversion luminescence of Pr3+, Yb3+ activated SrF2 nanoparticles
2020
Abstract Pr3+,Yb3+ activated SrF2 nanoparticles synthesized by low-temperature hydrothermal method were studied. The composition and size of nanoparticles were intentionally changed by controlling synthesis conditions. After structural and morphological characterization, the spectroscopic properties of the nanoparticles were analyzed in the visible and near infrared spectra ranges. The results show correlation between the gradual change of the amount of carboxylate and hydroxyl moieties on the nanoparticle surface, varied by the size nanoparticles and the quenching of the luminescence. The size-related amount of surface quenchers is strongly connected to the decrease of the downconversion e…
Light-responsive hybrid material based on luminescent core-shell quantum dots and steroidal organogel
2016
We report the synthesis of a smart novel hybrid with reversible photoswitchable luminescence properties modulated by light. The combination of a low molecular weight organogelator (LMOG) and CdSe/ZnS core-shell semiconductor nanoparticles capped with trioctylphosphine oxide ligands produces a luminescent, stable and transparent material. Modulation of the luminescence properties was successfully achieved using a diarylethene photochromic compound, with good resistance to fatigue ca. 22 cycles. Interestingly, the morphology of the organogel fibers was preserved in the hybrid, while a partial luminescence quenching of the nanoparticle was observed. This material could have implication for on-…
Insight into the defect-molecule interaction through the molecular-like photoluminescence of SiO2 nanoparticles
2016
Luminescence properties due to surface defects in SiO2 are the main keystone with particles that have nanoscale dimensions, thus motivating their investigation for many emission related applications in the last few decades. A critical issue is the role played by the atmosphere that, by quenching mechanisms, weakens both the efficiency and stability of the defects. A deep knowledge of these factors is mandatory in order to properly limit any detrimental effects and, ultimately, to offer new advantageous possibilities for their exploitation. Up to now, quenching effects have been interpreted as general defect conversion processes due to the difficulty in disentangling the emission kinetics by…
Luminescence of natural α-quartz crystal with aluminum, alkali and noble ions impurities
2019
This work was supported by the Latvian Science Council Grant No lzp-2018/1–0289 .