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emitter must have a high oscillator strength and a high exciton binding energy, such as the electronic excitations (excitons) in quantum dots [ 45 ], [ 46 ], [ 47 ] and two-dimensional monolayer transition mental dichalcogenides [ 37 ], [ 39 ], [ 40 ], [ 48 ], [ 49 ], [ 50 ], for the realization of SC. The molecular excitation of J-aggregates represents an ideal platform for the formation of exciton polaritons because of their exceptionally high oscillator strength and narrow resonances even at room temperature and in the liquid phase [ 26 ], [ 27 ]. Herein, we use the

J-aggregate structures in crystals of three bisazomethine dyes Shinya Matsumoto*, I, Kazuko Shirai I, Kimiko Kobayashi II, Tatsuo Wada III and Motoo Shiro IV I Department of Environmental Sciences, Faculty of Education and Human Sciences, Yokohama National University, 79-2 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan II Molecular Characterization Team, RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan III Supramolecular Science Laboratory, RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa

40 Zeitschrift für Kristallographie 210, 40-43 © by R. Oldenbourg Verlag, München 1995 One-dimensional J-aggregates in crystals of l,7-bis-(dimethylamino)-heptamethinium Perchlorate L. Därme* Freie Universität Berlin, Institute of Physical Chemistry, Takustr. 3, D-14195 Berlin, Germany and G. Reck Bundesanstalt für Materialforschung und -prüfung, Rudower Chaussee 5, D-12489 Berlin, Germany Received December 20, 1993; accepted April 18, 1994 Polymethine dye / J-aggregate / Crystal structure / Heptamethinium Perchlorate Abstract. The simple polymethine dye l,7-bis

Abstract

We report the photobehaviour of a series of eight structurally related arylacetylene derivatives, in solution as well as in pristine and PC61BM blended thin-_lms. The formation of both H- and J-aggregates in the solid state have been demonstrated, and, interestingly, an energy transfer from H-aggregates or/and from residual "unstacked" molecules to J-aggregates has been found, the latter being the only emitting species. The fuorescence quenching by PC61BM at di_erent loadings has been studied in blend films, and it has been found particularly effcient in the case of a symmetrical peripheral substitution of the acetylene derivative core. Preliminary time-resolved measurements in emission (ns resolution) and in absorption (fs resolution) con_rmed the H⟶J energy transfer and underlined the presence of delayed fuorescence from Jaggregates, formed by energy transfer from the long-lived first excited singlet state of H-aggregates. In all cases, a homogeneous surface morphology of thin films

Chemistry Division, and Institute for Nanoscience, Naval Research Laboratory, Washington, DC 20375, USA Abstract: We recently found that certain cyanines form tight complexes with carboxymethyl- amylose (CMA) in aqueous solutions and that in these complexes the cyanine exists as a strongly fluorescent and stable J-aggregate. Cyanine dyes are characterized by their ability to form J-aggregates showing very narrow absorption and fluorescence spectra relative to the monomer. Although they have found uses in sensing applications, the practicability has been limited in many

silver/dye nanoparticles in colloidal solutions. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2008,326, 204-209. [5] Lim, I.I.S., Goroleski, F., Mott, D., Kariuki, N., Ip, W., Luo, J. and Zhong, C. J., Adsorption of Cyanine Dyes on Gold Nanoparticles and Formation of J-Aggregates in the Nanoparticle Assembly, J. Phys. Chem. B, 2006,110, 6673-6682. [6] Kometani, N., Nakajima, H., Asami, K., Yonezawa, Y., Scheblykin, I. G. and Vitukhnovsky, A. G., Luminescence properties of the J-aggregate of cyanine dyes in multilayer assemblies,J. Luminesc., 2000

-order nonlinear absorption coefficient I 0 The intensity at focal point ( z = 0) L eff Effective thickness Z 0 Rayleigh range S 1 Singlet excited state T 1 Triplet excited state E T (30) Reichardt solvent polarity parameter M Monomer D Dimer K Equilibrium constant υ M Maximum absorption position of monomer (in cm −1 ) υ H Maximum absorption position of H aggregate (in cm −1 ) υ J Maximum absorption position of J aggregate (in cm −1 ) In general, under influence of a continuous wave laser irradiation, a five-level system can be considered as an approximate model for studying

crystallizes in the monoclinic space group P2Jn with a = 778.9(3) pm, b = 1349.4(3) pm, c = 1950.7(3) pm, ß = 101.10(2)°,Z = 4and£>x = 1.345 g • cm-3.R = 0.076 for 2458 unique reflections with I > 2a(I) at 294 K. The 7r-system of the dye cation is polarized by intermolecular interactions resulting in a bond length alternation. Stacks of dye molecules, which corresponds to J-aggregate structures could not be found. Introduction Polymethine dyes are typically characterized by a com- pletely delocalized 7t-electron system, leading to equaliza- tion of the single and double bond

. So a further progress was achieved by using the /-aggregates: com peting nonradiative desactivation processes (o f the excited dye mole­ cules) were diminished in J-aggregates. 1. Einleitung Die Grundlage jeder photochemischen Speiche­ rung von Lichtenergie basiert auf der (lichtindu­ zierten) Energieübertragung und der Ladungstren­ nung. Die Anforderung an eine erfolgreiche Licht­ speicherung sind ein schneller Elektronentransfer sowie eine effiziente Ladungstrennung. In der Ver­ gangenheit wurden viele Versuche unternommen, durch kovalente Verknüpfung von

conditions, J-aggregating molecules [ 17 ], [ 18 ], [ 19 ], dyes [ 20 ], quantum dots [ 21 ], or two-dimensional materials [ 22 ], [ 23 ] placed nearby resonant metallic nanoparticles or nanoparticle arrays, have been shown to give rise to strong plasmon-exciton coupling. More importantly, many interesting effects have been predicted and observed in these systems, including coherent emission [ 17 ], lasing in nanoparticle arrays [ 24 ], [ 25 ], [ 26 ], ultrafast Rabi oscillations [ 27 ], chemical dynamics tuning [ 28 ], coupling with dark excitonic states [ 29 ], and few