Organometallic Gold(I) Acetylide/Polyoxometalate Hybrid Langmuir-Blodgett Films: Preparation, Characterization, and Photoelectric Properties

2010 ◽  
Vol 63 (1) ◽  
pp. 103 ◽  
Author(s):  
Li Liu ◽  
Qian Liu ◽  
Ming Chen ◽  
Ming-Jian Li ◽  
Li-Ping Xu ◽  
...  
Keyword(s):  
Pure Water ◽  
Monolayer Films ◽  
Microscopy Imaging ◽  
Lb Films ◽  
Quenching Effect ◽  
Force Microscopy ◽  
Langmuir Blodgett ◽  
Photoelectric Properties ◽  
Langmuir Blodgett Films ◽  
Tunnelling Microscopy

A new series of organometallic/inorganic hybrid Langmuir-Blodgett (LB) films containing an organometallic gold(i) aryleneethynylene metal complex (OMA) as the π-conjugated organometallic molecule and a polyoxometalate (POM, POM = H3BW12O40, H6As2W18O62, or H6P2Mo18O62) of the Keggin and Dawson structure as the inorganic composite, were prepared and characterized by π–A isotherms, UV-vis absorption spectra, photoluminescence spectra, atomic force microscopy imaging, scanning tunnelling microscopy, and surface photovoltage spectroscopy. Our experimental results indicate that stable, well defined and well organized Langmuir and LB films are formed in pure water and polyoxometalate subphases. There is a quenching effect in the luminescence of the gold(i) complex when it is made into the LB films. The OMA/POM hybrid LB films display strong photovoltage effect in the UV-vis region. The photovoltage response of OMA/H6As2W18O62 can be as high as 3338 μV. OMA/POM monolayer films show good electrical conductivity, and the tunnelling current for a OMA/H3BW12O40 monolayer film amounts to 50 to approximately –100 nA when the voltage is set at ±9 V.

Langmuir-Blodgett Films of Dinuclear Mercury(II)-Containing Diethynylcarbazole/Polyoxometalate Hybrids: Film Characterization Studies and Potential Optoelectronic Applications

2010 ◽  
Vol 63 (9) ◽  
pp. 1376 ◽  
Author(s):  
Li Liu ◽  
Ming Chen ◽  
Ling-Xiang Qiao ◽  
Shi-Zhong Liu ◽  
Zu-Liang Du ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Pure Water ◽  
Microscopy Imaging ◽  
Lb Films ◽  
Quenching Effect ◽  
Force Microscopy ◽  
Langmuir Blodgett ◽  
New Family ◽  
Langmuir Blodgett Films ◽  
Tunnelling Microscopy

A new family of organometallic/inorganic hybrid Langmuir-Blodgett (LB) films, consisting of organometallic mercury acetylide (OMA) as the π-conjugated organometallic molecule and polyoxometallate (POM, POM = K5BW12O40 or Na5IMo6O24) of the Keggin and Anderson structures as the inorganic composite and docosanoic acid (DA) as the auxiliary film-forming agent, were prepared and well characterized by π–A isotherms, UV-vis absorption and photoluminescence spectra, atomic force microscopy imaging, scanning tunnelling microscopy, and low-angle X-ray diffraction. Our experimental results indicate that stable and well defined monolayer Langmuir and LB films are formed in pure water and POM subphases. There is a quenching effect in the luminescence intensity of the mercury complex when it is made into the LB films due to the enhanced aggregation phenomenon. These alkynylmercury(ii) based LB films exhibit interesting electrical conductivity behaviour, dependent of the characteristics of the POM used. They all reveal decent electrical conductivity, and the tunnelling current can reach ±100 nA when the voltage is set at –5 to +5 V.

Langmuir-Blodgett Films of Calcium Stearate

1994 ◽  
Vol 351 ◽  
Author(s):  
Necesio Costa ◽  
Mark Aindow ◽  
Peter M. Marquis
Keyword(s):  
Film Surface ◽  
Organic Matrix ◽  
Calcium Stearate ◽  
Contact Mode ◽  
Lb Films ◽  
Force Microscopy ◽  
Langmuir Blodgett ◽  
Atomic Force ◽  
A Value ◽  
Langmuir Blodgett Films

ABSTRACTThe Langmuir Blodgett (LB) Process has been shown to be an appropriate method for use in mimicking of biological processes for producing engineering materials such as bioceramics. The main advantages of this approach are that the layers form at low temperatures, that they are fully dense and that the process of densification is by infiltration rather than by sintering. Moreover, biological hard tissues are self-assembled to perform certain functions; the architecture being controlled by an epitaxial organic matrix. Clearly, if this process can be understood in detail then it is possible that LB films may be used to replicate this architecture for engineering purposes.Atomic Force Microscopy (AFM) and X-ray diffraction (XRD) have been used to study and characterise LB films of calcium stearate obtained by the repeated dipping into and withdrawal of a (001) Si wafer from a subphase containing calcium ions and using stearic acid as the surfactant. Contact-mode AFM images of the film surface have been used to measure the thickness of the LB layers and to reveal the nature and distribution of defects in the film. The measured thickness of the calcium stearate layers is about 2.5 nm; a value consistent with that obtained by XRD, but smaller than the length of an individual calcium stearate molecules.

Nanostructured LB films developed from poly(p-acryloylaminophenylmethylphosphonic) acid

2016 ◽  
Vol 1819 ◽  
Author(s):  
Rosa E. Lazo-Jiménez ◽  
José A. Chávez-Carvayar ◽  
Ana M. Herrera-González ◽  
Valentin Islas-Pérez ◽  
María P. Carreón-Castro
Keyword(s):  
Multilayer Films ◽  
Molecular Area ◽  
Lb Films ◽  
Force Microscopy ◽  
Langmuir Blodgett ◽  
Glass Substrates ◽  
Atomic Force ◽  
Air Water Interface ◽  
Langmuir Blodgett Films ◽  
Ordered Nanostructures

ABSTRACTIn this paper, the formation of Langmuir-Blodgett films of poly(p-acryloylaminophenylmethylphosphonic) acid polymers, with general formula (C10H12NPO4)n are reported. The Langmuir-Blodgett (LB) technique was used for building ordered nanostructures in molecular assemblies of these polymers, which were able to form stable films. At the air-water interface, these polymers (with low and high molecular weight) formed Langmuir (L) monolayers, which were characterized by surface pressure versus molecular area (π-A) isotherms and Brewster´s Angle Microscopy (BAM). Using the LB method, molecular mono and multilayer films of these polymers were prepared and transferred onto glass substrates forming Z-type multilayers, with a transfer ratio close to unity. These LB films were characterized by Atomic Force Microscopy (AFM).

Nanoparticle assembly following Langmuir–Hinshelwood kinetics on a Langmuir film and chain networks captured in LB films

2015 ◽  
Vol 17 (11) ◽  
pp. 7386-7394 ◽  
Author(s):  
Lasya Maganti ◽  
Madhuri Jash ◽  
Anju Nair ◽  
T. P. Radhakrishnan
Keyword(s):  
Metal Nanoparticles ◽  
Nanoparticle Assembly ◽  
Deposition Pressure ◽  
Langmuir Film ◽  
Lb Films ◽  
Langmuir Blodgett ◽  
Langmuir Blodgett Films ◽  
Positively Charged

Negatively charged metal nanoparticles assemble as chain networks through Langmuir–Hinshelwood kinetics on a Langmuir film of positively charged amphiphiles. The extension of the networks captured in Langmuir–Blodgett films is tuned by the deposition pressure.

Structural and Morphological Characterization of Ultrathin Films of an Asymmetric Polydiacetylene

1996 ◽  
Vol 440 ◽  
Author(s):  
H. C. Wang ◽  
D. W. Cheong ◽  
J. Kumar ◽  
C. Sung ◽  
S. K. Tripathy
Keyword(s):  
Second Harmonic ◽  
Morphological Characterization ◽  
Lb Films ◽  
Force Microscopy ◽  
Langmuir Blodgett ◽  
Glass Substrates ◽  
Atomic Force ◽  
Transmission Electron ◽  
Air Water Interface

AbstractA soluble, asymmetrically substituted polydiacetylene, poly(BPOD), has been reported to form stable monolayers at the air-water interface by the Langmuir-Blodgett (LB) technique [2]. Preformed polydiacetylene has been deposited onto hydrophobic substrates as multilayers to form second order nonlinear optical thin films. Second harmonic generation was found to increase with the number of layers. From previous atomic force microscopy (AFM) studies backbone orientation along the dipping direction with an interchain spacing of about 5 A° was indicated [2].The film morphology and preferential molecular orientation of these LB films are further investigated by transmission electron microscopy (TEM). A specifically tailored sample preparation method for the ultrathin LB films was used. Multilayer films were deposited on hydrophobic collodion covered glass substrates for this purpose. Electron diffraction was employed to study the crystalline organization of mono and multilayers of LB films as well as cast films.

New Strategies for Preparing Electrically Conductive Langmuir-Blodgett Films

1992 ◽  
Vol 247 ◽  
Author(s):  
J. H. Cheung ◽  
R. B. Rosner ◽  
M. F. Rubner
Keyword(s):  
Electrical Properties ◽  
Stearic Acid ◽  
Structural Changes ◽  
Solid State Reactions ◽  
Emeraldine Base ◽  
Structure Property ◽  
Electrically Conductive ◽  
Lb Films ◽  
Langmuir Blodgett ◽  
Langmuir Blodgett Films

ABSTRACTThe fabrication, structure and electrical properties of new electrically conductive Langmuir-Blodgett (LB) films of polyaniline and polypyrrole have been investigated. Polyaniline in its emeraldine-base form was mixed with stearic acid (PAN-B/SA) to produce stable films at the air-water interface (5/1 or 10/1 mole ratio of PAN-B/SA). These films were then transferred into multilayer films which were found to exhibit conductivities of about 1 S/cm upon doping with hydrochloric acid. The alkyl chains of the stearic acid molecules were found to be distributed randomly throughout the LB film thereby exerting a minimal influence on the electrical properties of the polyaniline phase. In addition to this mixed monolayer approach, a novel method of fabricating highly conductive polypyrrole LB films has been developed. This method is based on the sequential exposure of ferric stéarate LB films to hydrogen chloride (HC1) gas and pyrrole vapor. Each of these two solid state reactions was found to impart dramatic chemical and structural changes to the film. Polypyrrole LB films with conductivities as high as 5 S/cm were produced via this process. The electrical and optical properties of films made by both techniques were examined in order to elucidate their structure/property relationships.

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