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1.
《Journal of Polymer Science.Polymer Physics》2018,56(13):965-969
Interchain interactions can play a positive role in reaching amplified spontaneous emission in an interesting core–polymer system where the donor (side chains) and the acceptor (core) are chemically linked together. Different degree of interchain interactions modifies the photophysical characteristics of the polymer. By means of transient absorption spectroscopy we show that the stimulated emission from the core decreases passing from solid state to concentrated solution and it is almost absent in the diluted solution. The conformational rearrangements of the core–polymer chain in solution limits the efficiency of the intrachain Förster energy transfer mechanism. The free chain rotations decrease the exciton hopping along the conjugated chains, the ratio between donor and acceptor moieties in the polymer, and change the relative orientation of the transition dipoles of the donor and acceptor causing a strong decrease of energy transfer efficiency and subsequently of the gain. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 965–969 相似文献
2.
We present general analytical expression for two and three-dimensional cases of static energy transfer kinetics in doped nanoparticles (of round, spherical and cylindrical shape). A series of numerical experiments has been performed using Monte-Carlo simulation. The analytical expressions have shown very good coincidence with the computer simulation. 相似文献
3.
Ann M. Hentschel 《Physics in Perspective (PIP)》2005,7(1):107-129
This tour of significant scientific sites in Bern uses the local legacy of its most illustrious scientists, Albert Einstein (1879–1955) and Fritz Houtermans (1903–1966), as its guiding thread through the old town and the university district.Ann M.Hentschel is translator of the correspondence volumes of The Collected Papers of Albert Einstein and is currently employed by the Institute for the History and Philosophy of Science at the University of Bern to write the guide for a city tour of Einsteins old haunts in Bern for the coming jubilee of special relativity in 2005. For the historical companion guidebook, see Hentschel and Grasshoff, Albert Einstein (ref. 4) and the website <. 相似文献
4.
S. L. Yefimova G. Ya. Gural’chuk A. V. Sorokin Yu. V. Malyukin I. A. Borovoy A. S. Lubyanaya 《Journal of Applied Spectroscopy》2008,75(5):658-663
Interactions between the cationic polymethine dyes 3,3′-diethyloxacarbocyanaine iodide (DiOC2), 3,3′-dioctadecyloxacarbocyanine iodide (DiOC18), and 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (DiI) in the nano-scale volume of anionic sodium
dodecylsulfate (SDS) micelles have been studied using optical spectroscopy techniques. The solubilization of pairs of dye
molecules (DiOC18/DiI or DiOC2/DiI) within SDS micelles was monitored by Forster resonance energy transfer (FRET) between the dyes in each pair. The influence
of the hydrophobicity of the dyes DiOC2 and DiOC18 on the efficiency of their binding to SDS micelles and, consequently, on the efficiency of FRET between DiOC18 and DiI or DiOC2 and DiI fluorophors has been analyzed. It has been shown that hydrophobic interactions in addition to electrostatic interactions
are of key importance for the binding between the positively charged dyes and negatively charged surfactant micelles.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 5, pp. 646–652, September–October, 2008. 相似文献
5.
《Analytical letters》2012,45(8):1997-2009
Abstract Excitation energy transfer from micellar BDHC and TX-405 to micellized naphthacene and pyrene. respectively, has been shown to occur. In the case of pyrene, the variation of the I1/I3 ratio indicates that sensitization also occurs in premicelar aggregates. In micelles, an energy transfer efficiency of 0.50 was found for BDHC/naphthacene and 0.24 for TX-405/pyrene. the respective donor/acceptor separations are 61.6 A? and 78.6 A?. 相似文献
6.
Piotr Dobryszycki Dorota Krzyzanowska Marian Kochman 《Journal of Chemical Sciences》1991,103(3):435-440
The range of flexibility of the rabbit muscle aldolase molecule was studied using fluorescent labelled aldolase. The protein
molecule was specifically labelled on the opposite sites of the enzyme subunit with the fluorescence energy donor and acceptor
residues. Labelled aldolase with full enzymatic activity was used as a tool in the FRET studies between IAEDANS — donor or
Cys-289 and IAF — acceptor on Cys-239. A range of Forster distance (R) was obtained by collisional quenching of the donor emission. The experiments of donor fluorescence quenching with wide range
of acrylamide concentrations have shown the changes of donor-acceptor distances. In the absence of quencher the D-A distance
distribution in characterized by an average value of 40.4 ?, and a half-width of 0.13 ?. A dramatic increase in half-width
to 17.7? is observed after expositions of the enzyme to high acrylamide concentrations (0.13 M-0.68 M). 相似文献
7.
Anish Cyriac S. R. Amrutha M. Jayakannan 《Journal of polymer science. Part A, Polymer chemistry》2008,46(10):3241-3256
We report a novel poly (m‐phenylenevinylene)s and their copolymers based on renewable resource starting material 3‐pentadecylphenol to trace the Forster energy transfer process and molecular aggregation in the π‐conjugated polymers. The new bisylide monomer was polymerized with bisaldehyde (or benzaldehyde) under Wittig‐Horner reaction conditions to prepare poly [(4‐methoxy‐6‐pentadecyl‐1, 3‐phenylenevinylene)‐alt‐(1, 3‐phenylenevinylene)] (m‐PPV) and its para‐counterpart poly [(4‐methoxy‐6‐pentadecyl‐1, 3‐phenylenevinylene)‐alt‐(1, 4‐phenylenevinylene)] (p‐PPV) and oligo‐phenylenevinylene model compound 4‐methoxy‐6‐pentadecyl‐1, 3‐distyrylbenzene (OPV). A series of with m‐ or p‐conjugated segments were also prepared by varying the m‐ and p‐content from 0 to 100% in the feed. The selective excitation of m‐conjugated segments in the copolymer by 310 nm light showed emission properties of pure p‐conjugated segments indicating the efficient Forster energy transfer process in segmented copolymers. Both solution quantum yields and the emission intensities increase up to 75% of para‐content in the copolymers. In the solid state, the increase in the p‐incorporation in the copolymer decreases the photoluminescent intensity almost by four times as compared to that of pure meta‐substituted PPV. The excitation spectra of the polymers confirmed a new peak at 400 nm corresponding to the aggregated polymer chains in the film, which is absent in the solution. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3241–3256, 2008 相似文献
8.
A strong red fluorescent nanocomposite, consisting of graphite-like carbon nitride nanosheets (g-C3N4 NSs) and serum albumin-capped Au nanoclusters (AuNCs), was synthesized. Dopamine (DA) can quench the red fluorescence of the nanocomposite, based on the Forster resonance energy transfer (FRET) mechanism. In this quenching process, the energy is transferred from the fluorescent g-C3N4 NSs-AuNCs to the oxidized DA quinine molecules (DA is easily oxidated to form DA quinine in air). The red fluorescence emission at 420 nm decreases dramatically and the quenching ratio (F0 – F)/F0 is linearly related to the concentration of DA in the range of 0.05–8.0 μmol L−1 with a detection limit of 0.018 μmol L−1 (S/N = 3). Additionally, this sensor has a potential of application to assay the DA in the real samples, such as human serum and human urine. 相似文献
9.
使用中位-四(1-苯基吡唑-4-基)卟啉(TPPyPH2)掺杂空穴传输材料N,N′-二苯基-N,N′-双(4-甲苯基)-1,1′-二苯基-4,4′-二胺(TPD)制备了红色有机电致发光器件.因为TPD的发射光谱与TPPyPH2的吸收光谱具有更大的光谱重叠,为了得到更为有效的从主体材料TPD向红光染料TPPyPH2的能量传递,我们使用TPD代替传统的8-羟基喹啉铝(Alq3)作为主体发光材料.器件在680nm处具有纯的红光发射峰;通过使用Alq3电子传输层以及使用Alq3共掺杂发光层的方法,使器件的发光性能得到了改善,结构为ITO/Alq3+TPPyPH2+TPD(50nm)/Alq3(30nm)/Al的器件的最大发光亮度为177cd/m2. 相似文献
10.
Ahmad S. Shawali Ibrahim F. Zeid Mahmoud H. Abdelkader Alsayed A. Elsherbini Farag M. A. Altalbawy 《中国化学会会志》2001,48(1):65-72
7‐Arylhydrazono[1,2,4]triazolo[3,4‐b][1,3,4]thiadiazines 4 were synthesized from the reactions of 4‐amino‐5‐phenyl‐4H‐[1,2,4]triazole‐3‐thiol 2 and 2‐(2‐naphthyl)‐2‐oxoethanehydrazonoyl bromides 1 and their acid dissociation constants pK and pK*, in the ground and excited states, respectively, were determined. Both pK and pK* constants were correlated by Hammett equation. The pK and the spectral data presented indicate that the title compounds exist predominantly in the hydrazone tautomeric form. 相似文献