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Molecular Materials (molecular + material)
Selected AbstractsHigh-Performance Organic Photovoltaic Devices Using a New Amorphous Molecular Material with High Hole Drift Mobility, Tris[4-(5-phenylthiophen-2-yl)phenyl]amineADVANCED FUNCTIONAL MATERIALS, Issue 24 2009Hiroshi Kageyama Abstract A new amorphous molecular material, tris[4-(5-phenylthiophen-2-yl)phenyl]amine (TPTPA), is synthesized and characterized. TPTPA forms a stable amorphous glass with a glass-transition temperature of 83,°C when the melt sample is cooled. It also forms amorphous thin films by a thermal deposition technique. TPTPA exhibits a hole drift mobility of 1.0,×,10,2,cm2 V,1 s,1 at an electric field of 1.0,×,105,V cm,1 and at 293,K, as determined by the time-of-flight method, which is of the highest level among those of amorphous molecular materials. pn-Heterojunction organic photovoltaic devices (OPVs) using TPTPA as an electron donor and C60 or C70 as an electron acceptor exhibit high performance with fill factors of 0.66,0.71 and power conversion efficiencies of 1.7,2.2% under air-mass (AM) 1.5G illumination at an intensity of 100,mW cm,2, which are of the highest level ever reported for OPVs using amorphous molecular materials. [source] Bicolor Pixels from a Single Active Molecular Material by Surface-Tension-Driven Deposition,ADVANCED MATERIALS, Issue 12 2007I. Viola The fabrication of a green- and red-emitting pixel structure (see figure, scale bar 10,,m) by the single-step, surface-tension-driven assembly of a single luminescent thiophene-based molecular material is reported. The solid-state organization of the selected thiophene-based oligomer is controlled by exploiting the molecular structural arrangement, induced during a dewetting process and facilitated by the great conformational flexibility of the oligomer, typical of several substituted oligothiophenes. [source] Concerted Spin Crossover and Symmetry Breaking Yield Three Thermally and One Light-Induced Crystallographic Phases of a Molecular Material,ANGEWANDTE CHEMIE, Issue 49 2009Nicolas Bréfuel Vier Kristallphasen des neuartigen molekularen Materials [FeIIH2L2MeH2L2Me](PF6)2 sind durch licht- und thermisch induzierten Spin-Crossover unter Symmetriebruch zugänglich (H2L2Me ist eine acyclische sechszähnige N6 -Schiff-Base). Die ausgerichteten Anordnungen der FeII -Komplexkationen (High-Spin: rote Dreiecke; Low-Spin: blaue Dreiecke) sind durch Schichten der Gegenanionen (grüne Zickzacklinien) voneinander getrennt. [source] [{Zn(enMe)2}2 (enMe)2{Zn2As8V12O40 (H2O)}]× 4H2O: A Hybrid Molecular Material Based on Covalently Linked Inorganic Zn,As,V Clusters and Transition Metal Complexes via enMe Ligands.CHEMINFORM, Issue 30 2004Shou-Tian Zheng Abstract For Abstract see ChemInform Abstract in Full Text. [source] Nanocomposite Hybrid Molecular Materials for Application in Solid-State Electrochemical Supercapacitors,ADVANCED FUNCTIONAL MATERIALS, Issue 7 2005K. Cuentas-Gallegos Abstract Molecular hybrid materials formed from polyoxometalates dispersed in conducting polymers represent an innovative concept in energy storage. This work reports in detail the first practical realization of electrodes based on these materials for energy storage in electrochemical supercapacitors. The molecular hybrids PAni/H4SiW12O40, PAni/H3PW12O40, and PAni/H3PMo12O40 (PAni: polyaniline) have been prepared electrochemically on platinum or carbon substrates, with PAni/H3PMo12O40 being the prototypical example presenting the best energy-storage performance in the series. This hybrid displays the combined activity of its organic and inorganic components to store and release charge in solid-state electrochemical capacitor cells, leading to a promising value of 120,F,g,1 and good cyclability beyond 1000,cycles. [source] Molecular Materials with Contrasting Optical Responses from a Single-Pot Reaction and Fluorescence Switching in a Carbon AcidCHEMISTRY - A EUROPEAN JOURNAL, Issue 12 2009A. Patra Abstract Three for the price of one: The reaction of tetracyanoquinodimethane with an aromatic amine is shown to follow an unusual course leading to three products in a single pot. The product molecules form a family of materials with contrasting optical responses, in that they exhibit light emission of different colors and emission switching that is sensitively triggered by acidic/basic environments (see scheme). A wide variety of amines are known to react with 7,7,8,8-tetracyanoquinodimethane (TCNQ) to yield push,pull diaminodicyanoquinodimethanes with a strongly zwitterionic structure and significant optical and nonlinear optical properties. A novel course of reaction is observed now with the amine 2-methyl-4-chloroaniline, which leads to three well-defined products, A,C, in a single pot. A and B are formed through the replacement of one cyano group in TCNQ by the amine; A is a carbon acid and B is its corresponding salt. C is the conventional product in which two cyano groups in TCNQ are replaced by the amine. The products are characterized structurally and spectroscopic studies reveal contrasting optical responses. A is nonfluorescent, whereas B and C show red and green emission, respectively, in the solution and solid states. The acid/conjugate-base pair A and B can be interconverted through facile, reversible, and repeated deprotonation/protonation cycles, which are accompanied by instantaneous switching of the fluorescence. The current study illustrates an interesting case of a single-pot reaction yielding different optical materials with attributes that can be switched through simple approaches such as protonation or tuned through modification of the push,pull characteristics. [source] High-Performance Organic Photovoltaic Devices Using a New Amorphous Molecular Material with High Hole Drift Mobility, Tris[4-(5-phenylthiophen-2-yl)phenyl]amineADVANCED FUNCTIONAL MATERIALS, Issue 24 2009Hiroshi Kageyama Abstract A new amorphous molecular material, tris[4-(5-phenylthiophen-2-yl)phenyl]amine (TPTPA), is synthesized and characterized. TPTPA forms a stable amorphous glass with a glass-transition temperature of 83,°C when the melt sample is cooled. It also forms amorphous thin films by a thermal deposition technique. TPTPA exhibits a hole drift mobility of 1.0,×,10,2,cm2 V,1 s,1 at an electric field of 1.0,×,105,V cm,1 and at 293,K, as determined by the time-of-flight method, which is of the highest level among those of amorphous molecular materials. pn-Heterojunction organic photovoltaic devices (OPVs) using TPTPA as an electron donor and C60 or C70 as an electron acceptor exhibit high performance with fill factors of 0.66,0.71 and power conversion efficiencies of 1.7,2.2% under air-mass (AM) 1.5G illumination at an intensity of 100,mW cm,2, which are of the highest level ever reported for OPVs using amorphous molecular materials. [source] Tris(4-cyanophenyl)amine: Simple Synthesis via Self-assembly; Strong Fluorescence in Solution, Nano/microcrystals, and Solid,ADVANCED FUNCTIONAL MATERIALS, Issue 13 2007A. Patra Abstract The threefold symmetric molecule, tris(4-cyanophenyl)amine (TCPA) is synthesized from 4-fluorocyanobenzene by treatment with potassium carbonate in dimethylsulfoxide; the occurrence of the reaction without any amine reagent suggests the involvement of a novel self-assembly process. A reprecipitation strategy provides stable colloids containing highly monodisperse nano/microcrystals with well-defined cubic morphology and sizes tunable from 250 to 500,nm. The solution, colloid, and solid states of TCPA exhibit strong blue fluorescence; the colloid shows dual emission with an unusually small Stokes shift. Computational investigations are carried out on the molecule and supramolecular assemblies derived from the crystal structure. Coupled with detailed spectroscopic studies, they show that the emission in the colloidal and solid states can be attributed to energy levels resulting from the intermolecular interactions within different aggregation motifs in the condensed phase and energy cascades between them. The computations also reveal the presence of cooperative interactions in the molecular crystal contributing to its high thermal stability. The strong light emission exhibited by TCPA, concurrently in the solution, nano/microcrystal, and solid states establishes it as a novel molecular material of potential practical utility; it has led to the exploration of the underlying mechanism that describes the phenomena observed in the different physical states. [source] Design of Hole Blocking Layer with Electron Transport Channels for High Performance Polymer Light-Emitting Diodes,ADVANCED MATERIALS, Issue 10 2008Chung-Chin Hsiao A novel dual-functional composite layer composed of a high ionization potential nonconjugated polymer or conjugated molecular material and an inorganic salt of a low work function metal is demonstrated. The composite provides superior hole blocking along with promising electron transport capability and results in good device performance for two model electroluminescent polymers, PFO and MEH-PPV. [source] Bicolor Pixels from a Single Active Molecular Material by Surface-Tension-Driven Deposition,ADVANCED MATERIALS, Issue 12 2007I. Viola The fabrication of a green- and red-emitting pixel structure (see figure, scale bar 10,,m) by the single-step, surface-tension-driven assembly of a single luminescent thiophene-based molecular material is reported. The solid-state organization of the selected thiophene-based oligomer is controlled by exploiting the molecular structural arrangement, induced during a dewetting process and facilitated by the great conformational flexibility of the oligomer, typical of several substituted oligothiophenes. [source] High-Performance Organic Photovoltaic Devices Using a New Amorphous Molecular Material with High Hole Drift Mobility, Tris[4-(5-phenylthiophen-2-yl)phenyl]amineADVANCED FUNCTIONAL MATERIALS, Issue 24 2009Hiroshi Kageyama Abstract A new amorphous molecular material, tris[4-(5-phenylthiophen-2-yl)phenyl]amine (TPTPA), is synthesized and characterized. TPTPA forms a stable amorphous glass with a glass-transition temperature of 83,°C when the melt sample is cooled. It also forms amorphous thin films by a thermal deposition technique. TPTPA exhibits a hole drift mobility of 1.0,×,10,2,cm2 V,1 s,1 at an electric field of 1.0,×,105,V cm,1 and at 293,K, as determined by the time-of-flight method, which is of the highest level among those of amorphous molecular materials. pn-Heterojunction organic photovoltaic devices (OPVs) using TPTPA as an electron donor and C60 or C70 as an electron acceptor exhibit high performance with fill factors of 0.66,0.71 and power conversion efficiencies of 1.7,2.2% under air-mass (AM) 1.5G illumination at an intensity of 100,mW cm,2, which are of the highest level ever reported for OPVs using amorphous molecular materials. [source] Spatial Patterning of the , -Phase in Poly(9,9-dioctylfluorene): A Metamaterials-Inspired Molecular Conformation Approach to the Fabrication of Polymer Semiconductor Optical StructuresADVANCED FUNCTIONAL MATERIALS, Issue 20 2009Gihan Ryu Abstract Materials in which sub-wavelength physical structures, rather than variations in chemical composition, are used to modify the nature of their interaction with electromagnetic radiation form the promising new class of metamaterials. For molecular materials one has an intriguing alternative, namely structuring the conformation or physical geometry of the molecule. In order for this to be an effective methodology one needs the change in conformation i) to engender a significant change in electromagnetic properties and ii) to be spatially controllable to allow patterning of practical structures. In this paper the potential of such an approach is demonstrated through spatial patterning, via masked solvent vapor exposure, of the , -phase conformation in poly(9,9-dioctylfluorene) (PFO). Significantly the conformation change approach preserves a planar film format and is found not to negatively impact on optical gain properties, both very attractive features for optoelectronic and photonic lightwave circuit applications. As a specific demonstration the ability to spatially control the lasing wavelength for samples in which a , -phase conformation is selectively patterned in a glassy PFO film spin coated atop a one-dimensional distributed-feedback grating etched into a spectrosil substrate is shown. [source] PSSP, a computer program for the crystal structure solution of molecular materials from X-ray powder diffraction dataJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2010Silvina Pagola This work describes the computer program PSSP (powder structure solution program) for the crystal structure solution of molecular solids from X-ray powder diffraction data. This direct-space structure solution program uses the simulated annealing global optimization algorithm to minimize the difference between integrated intensities calculated from trial models and those extracted in a Le Bail fit of the experimental pattern, using a cost function for dealing with peak overlap through defined intensity correlation coefficients, computationally faster to calculate than Rwp. The methodology outlined is applicable to organic solids composed of moderately complex rigid and flexible molecules, using diffraction data up to relatively low resolution. PSSP performance tests using 11 molecular solids with six to 20 degrees of freedom are analyzed. [source] Lessons learned from research on photorefractive polymers and molecular materialsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2001Luping Yu Abstract Organic photorefractive (PR) materials are a new kind of electrooptic substance that emerged 10 years ago. These are very complicated materials that possess both electrooptic effects and photoconductivity. It is challenging to integrate these properties into a single polymer system that will exhibit this PR effect. This article highlights our efforts in the past nine years in synthesizing and characterizing fully functionalized organic PR materials. I emphasize the lessons we have learned from this research, which may be more valuable to those who are interested in this area. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2557,2564, 2001 [source] 5-Oxatricyclo[5.1.0.01,3]octan-4-one, containing an enantiomorph and a racemate and not two polymorphs, is another example of a composite crystalACTA CRYSTALLOGRAPHICA SECTION B, Issue 2 2003Frank H. Herbstein This new example of a composite crystal adds to the small number previously reported among inorganic and molecular materials. Revision of the nomenclature used allows more fruitful comparison with the precedents. [source] Multichromophores for Nonlinear Optics: Designing the Material Properties by Electrostatic Interactions,CHEMPHYSCHEM, Issue 17 2007Francesca Terenziani Dr. Abstract To fully exploit the promise of molecular materials for NLO applications, inter- and supramolecular interactions must be accounted for. We review our recent work on electrostatic interchromophore interactions in multichromophores for NLO applications. The discussion is based on a bottom-up modeling strategy: each chromophore is described in terms of an essential state model, validated and parameterized against spectroscopic data for solvated chromophores. The relevant information is then used to build a model for clusters of chromophores interacting through electrostatic forces. Exact NLO responses and spectra calculated within this model fully account for collective and cooperative interchromophore interactions, which can either amplify or suppress NLO responses; supramolecular engineering of multichromophores is a powerful tool for the design of NLO materials. Moreover, new features emerge in multichromophores with no counterpart at the single-chromophore level, offering new exciting opportunities for applications. [source] Pyridinium Conjugated Ferrocenes with Thien and Bithien Bridges: Synthesis and Electrochemical PropertiesCHINESE JOURNAL OF CHEMISTRY, Issue 8 2009Yonghua GONG Abstract Three di- and tri-branched pyridinium salts with ferrocene ends and thienyl or bithienyl bridges, (E,E)- N -methyl-2,4,6-tris{2-[5-(2-ferrocenylvinyl)thien-2-yl]vinyl} pyridinium iodide, (E,E)- N -methyl-2,6-bis- {2-[5,-(2-ferrocenylvinyl)-2,2,-bithien-5-yl]vinyl} pyridinium iodide, and (E,E)- N -methyl-2,4,6-tris-{2-[5,-(2-ferrocenylvinyl)-2,2,-bithien-5-yl]vinyl}pyridinium iodide, were designed and successfully synthesized. The electrochemical properties of these compounds were primarily investigated, showing that most of these multiferrocenyl pyridinium salts are potential electrochemical molecular materials with good oxidation-reduction reversibility. [source] | |||||||||||||