Langmuir-Blodgett Films of Squarylium Dye J-Aggregates Exhibiting Femtosecond Optical Responses

1999 ◽  
Vol 561 ◽  
Author(s):  
M. Furuki ◽  
H. Kawashima ◽  
T. Tani ◽  
L. S. Pu
Keyword(s):  
Nonlinear Optical ◽  
Layer Structure ◽  
Molecular Layer ◽  
Optical Microscope ◽  
Langmuir Films ◽  
Lb Films ◽  
Langmuir Blodgett ◽  
Lb Film ◽  
Optical Responses ◽  
J Aggregates

ABSTRACTJ-aggregates of squarylium dyes in Langmuir films have been found to exhibit highly efficient and ultrafast nonlinear optical properties. We established a novel method for making Langmuir- Blodgett (LB) films of J-aggregates with a single absorption band at 784 nm. Deposition of the LB-films was carried out under excess compression of the Langmuir films at a constant speed. Coating the surface of the LB-film with a glassy poly-perfluorocarbon was found to enhance and stabilize the formation of J-aggregates. Characterization of morphology using a near-field scanning optical microscope (NSOM) showed that this LB-film has a highly ordered structure comprising 2- dimensional domains of J-aggregates. We also observed nonlinear-optical responses from this LBfilm. Ultrafast decay of absorption change (250 fs) with quite low saturation energy (3.4 μJ/cm2•pulse) was observed in femtosecond pump-probe measurements. These results suggest highly delocalization of excited states in the J-aggregates of this LB-film with the 2-dimensional mono-molecular layer structure which initially formed in the Langmuir film.

Synthesis, Spectroscopic Characterization and Thin Film Deposition of Three Novel Amphiphilic Porphyrins

1999 ◽  
Vol 03 (07) ◽  
pp. 569-584 ◽  
Author(s):  
COLIN L. HONEYBOURNE ◽  
KEVIN J. BARRELL
Keyword(s):  
Methyl Esters ◽  
Action Spectrum ◽  
Spectroscopic Characterization ◽  
Thin Film Deposition ◽  
Poor Quality ◽  
Film Deposition ◽  
Langmuir Films ◽  
Langmuir Blodgett ◽  
Lb Film ◽  
Cadmium Stearate

The synthesis of three novel porphyrins (that are models for mesoporphyrin) requires the synthesis of eight new pyrroles, one new alkyl-3-oxohexanoate and two new dipyrromethanes. The new porphyrin free bases have hydrophobic substitution patterns different from that in mesoporphyrin. We are seeking amphilic porphyrins that will form Langmuir–Blodgett (LB) multilayers without recourse to either long-chain alkyl substituents or fatty acid additives. In this way the influence of the conjugated tetrapyrrole unit on the properties of the multilayer films can be maximized. We report multilayer deposition for porphyrins having the following substituents: CH 3, C 2 H 5, n- C 3 H 7, ( CH 2)2 COOMe ; no additives such as stearic acid, cadmium stearate or mesitylene are required, Y-type deposition being exhibited by the simply substituted pure methyl esters. The variations in proton NMR chemical shift with concentration are reported and the action spectrum of an LB film of a porphyrinato- Zn (II) complex is described. Our observations and conclusions are in sharp (and optimistic) contrast with those of H. Chou et al. (J. Phys. Chem. 98, 383 (1994)), who found that in the absence of steric constraints from bulky aliphatic chains the Langmuir films are so rigid that either no multilayers or multilayers of poor quality are given. We obtain good-quality multilayers (60 layers) for porphyrins bearing eight small substituents.

scholarly journals Near-Resonant Nonlinear Optical Properties of Pseudoisocyanine J-Aggregates in Langmuir-Blodgett Layers

1997 ◽  
Vol 17 (3) ◽  
pp. 123-137 ◽  
Author(s):  
K.-H. Feller ◽  
R. Gadonas ◽  
A. Pugzlys ◽  
D. Möbius
Keyword(s):  
Optical Properties ◽  
Nonlinear Optical ◽  
Nonlinear Optical Properties ◽  
Third Order ◽  
Langmuir Blodgett ◽  
Langmuir Blodgett Films ◽  
J Aggregates ◽  
Exciton Annihilation ◽  
Dynamical Disorder ◽  
Order Susceptibility

The nonlinear optical properties of pseudoisocyanine J-aggregates in Langmuir-Blodgett films have been investigated by means of degenerate four wave mixing (DFWM) process. The conversion efficiency of the DFWM signal and the estimated third order susceptibility were found to be comparable with those of pseudoisocyanine J-aggregates in solution under comparable resonance conditions. The intensity dependence of the converted (DFWM) signal is interpreted as resulting from different processes including saturation, exciton-exciton annihilation and secondary processes of dynamical disorder.

Second harmonic generation from alternate-layer LB films: quadratic enhancement with film thickness

1994 ◽  
Vol 445 (1924) ◽  
pp. 385-398 ◽  
Keyword(s):  
Optical Properties ◽  
Second Harmonic Generation ◽  
Film Thickness ◽  
Harmonic Generation ◽  
Nonlinear Optical ◽  
Second Harmonic ◽  
Lb Films ◽  
Langmuir Blodgett ◽  
Alternate Layer ◽  
Order Susceptibility

The second harmonic generation (SHG) from alternate-layer Langmuir-Blodgett (LB) films of stilbazolium dyes and 4, 4'-dioctadecyl-3, 5, 3', 5'-tetramethyldipyrryl-methene hydrobromide increases as I 2ω(N) = l 2ω(1) N 2 for N ≥ 2 bilayers, but the equivalent monolayer signal ( I 2ω(1) ) is significantly less than the intensity from LB monolayers of the corresponding dye on glass. This is attributed, in part, to the different molecular tilts and, in part, to the position of the anion which influences the charge distribution within the chromophore. For alternate-layer films of E-N-octadecyl-4-[2-(4-dimethylaminophenyl)ethenyl]pyridinium octadecylsulphate (dye I) the second-order susceptibility and chromophore tilt angle are χ (2) zzz = 45 pm V -1 and ϕ = 30° respectively, whereas the methoxy congener, E-N-octadecyl-4-[2-(4-methoxyphenyl)ethenyl]pyridinium octadecylsulphate (dye II), has χ (2) zzz = 11 Pm V -1 and ϕ = 35°. The nonlinear optical properties of such films are dependent upon the compatibility of the dye and spacer.

SECOND ORDER NONLINEAR OPTICAL PROPERTIES OF LANGMUIR–BLODGETT FILMS CONSISTING OF NON-AMPHIPHILIC POLAR MOLECULES

2004 ◽  
Vol 13 (03n04) ◽  
pp. 355-358 ◽  
Author(s):  
JUN KAWAMATA ◽  
SHOICHIRO HIRAKAWA ◽  
SEIJI TANI ◽  
YUICHIRO OGATA ◽  
AKIHIKO YAMAGISHI
Keyword(s):  
Optical Properties ◽  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Nonlinear Optical ◽  
Second Harmonic ◽  
Single Layer ◽  
Lb Films ◽  
Langmuir Blodgett ◽  
Solid Substrates ◽  
Langmuir Blodgett Films

We have prepared hybrid Langmuir–Blodgett (LB) films consisting of a clay single layer and a non-amphiphilic polar molecule, 2,5-bis(p-dimethylaminocinnamylidene)-cyclopentanone. LB films deposited on solid substrates were characterized by means of UV-vis absorption spectroscopy and optical second-harmonic generation (SHG) measurements.

Intermolecular interactions in Langmuir-Blodget films of liquid crystalline perylene derivatives

2008 ◽  
Vol 16 (3) ◽  
Author(s):  
R. Hertmanowski ◽  
T. Martyński ◽  
R. Stolarski ◽  
D. Bauman
Keyword(s):  
Liquid Crystalline ◽  
Fluorescence Spectra ◽  
Solid Substrate ◽  
Discotic Liquid Crystals ◽  
Dye Molecules ◽  
Lb Films ◽  
Langmuir Blodgett ◽  
Alkyl Chains ◽  
Perylene Derivatives ◽  
J Aggregates

AbstractLangmuir-Blodgett (LB) films formed of some discotic liquid crystals, namely 3,4,9,10-tetra-(n-alkoxy-carbonyl)-perylenes, mixed with arachid acid have been studied. The absorption and fluorescence spectra were recorded. The results obtained have led to conclusions about formation of self-aggregates of dye molecules both in ground and excited states at the air-solid substrate interface. It was found that some fraction of J-aggregates can be created in the ground state. In the excited state, mostly excimers appear and the number of this kind of aggregates depends on the length of the alkyl chains substituted to the perylene core, as well as on the dye concentration and the number of layers in LB films.

Femtosecond Optical Nonlinearity in the Squarylium Dye J-Aggregates

1997 ◽  
Vol 488 ◽  
Author(s):  
M. Furuki ◽  
L. S. Pu ◽  
F. Sasaki ◽  
S. Kobayashi ◽  
T. Tani
Keyword(s):  
Molecular Layer ◽  
Chloroform Solution ◽  
Optical Nonlinearity ◽  
Dimensional Structure ◽  
Two Dimensional ◽  
Dye Molecules ◽  
Optical Responses ◽  
Squarylium Dye ◽  
Air Water Interface ◽  
J Aggregates

AbstractSquarylium dye with two propyl and two hexyl groups forms a mono-molecular layer with domains of J-aggregates by spreading its chloroform solution at an air-water interface. Fluorescence microscopy and an absorbance evaluation which also considers the reflectance suggest that this Langmuir-film has a close packed two-dimensional structure with a complete Jaggregate formation of all dye molecules. Strong and ultrafast nonlinear optical responses, indicating delocalization of excitons over 30 molecules, have been observed at 5 °C from this ideal mono-molecular layer of J-aggregates.

DOUBLE-LAYER ELECTROLUMINESCENT DEVICES BASED ON LANGMUIR-BLODGETT FILMS OF AMPHIPHILIC 8-AMINOQUINOLINE

2006 ◽  
Vol 05 (06) ◽  
pp. 703-707
Author(s):  
SUI-PING DENG ◽  
HUI ZHENG ◽  
JIAN-MING OUYANG
Keyword(s):  
Double Layer ◽  
Layer Structure ◽  
Lb Films ◽  
Electroluminescent Devices ◽  
Langmuir Blodgett ◽  
Double Layer Structure ◽  
Organic Electroluminescent ◽  
Langmuir Blodgett Films

Organic electroluminescent (EL) devices with a double-layer structure, ITO/H 2 A/Alq 3/ Al , were fabricated from powder and 15-layer LB films of a new amphiphilic 8-aminoquinoline ligand, N , N -bis(8-quinolinyl)hexadecyl propanediamide ( H 2 A ), respectively. Their driving voltages were 6.5 and 7.5 V, highest luminances 60 and 28.4 cd/m2.

Preformed polymers for Langmuir—Blodgett films

1990 ◽  
Vol 330 (1610) ◽  
pp. 153-166 ◽  
Keyword(s):  
Second Harmonic ◽  
Layer Structure ◽  
Polymeric Films ◽  
Lb Films ◽  
Langmuir Blodgett ◽  
X Ray Scattering ◽  
Electro Optic ◽  
Langmuir Blodgett Films ◽  
Simple Molecules ◽  
Derivatives Of

Langmuir-Blodgett (LB) films of simple molecules are usually fragile and this has prompted the study of polymeric lb films. Films have been prepared successfully from preformed polymers that are derivatives of various vinyl-maleic anhydride alternating copolymers. By using a computer-controlled trough polymeric films containing several hundred layers have been prepared. Low-angle X-ray scattering studies indicate that the films have a regular layer structure. By using a specially constructed trough, multilayers have been prepared in which alternate layers are polymeric, LB films prepared from polymers containing appropriate vinyl groups can be crosslinked by ultraviolet light or an electron beam (EB). This not only further stabilizes the films and renders them insoluble, but also allows patterns to be ‘ drawn ’ in the films. Films of these polymers have been used as submicrometre EB resists. Films suitable for second harmonic generation and electro-optic modulation have been prepared. Some further applications of polymeric LB films are outlined.

Enhanced Optical and Nonlinear Optical Responses in a Polyelectrolyte Templated Langmuir−Blodgett Film

Langmuir ◽  
2011 ◽  
Vol 27 (3) ◽  
pp. 1064-1069 ◽  
Author(s):  
K. Rajesh ◽  
B. Balaswamy ◽  
K. Yamamoto ◽  
H. Yamaki ◽  
J. Kawamata ◽  
...  
Keyword(s):  
Nonlinear Optical ◽  
Blodgett Film ◽  
Langmuir Blodgett ◽  
Optical Responses ◽  
Langmuir Blodgett Film
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