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Molecular Glasses (molecular + glasses)
Selected AbstractsElectroluminescence and Laser Emission of Soluble Pure Red Fluorescent Molecular Glasses Based on DithienylbenzothiadiazoleADVANCED FUNCTIONAL MATERIALS, Issue 18 2009Ju Huang Abstract Soluble molecular red emitters 1a/1b are synthesized by Stille coupling from 2-(3,5-di(1-naphthyl)phenyl)thiophene precursors. The compounds show emission maxima at ca. 610,nm in CH2Cl2 solution and 620,nm in solid films. Replacing the n -hexyl substituent by 4- sec -butoxyphenyl produces a marked increase of glass transition temperature (Tg) from 82,°C to 137,°C and increases the solubility in toluene and p -xylene, thus improving the film-forming properties. Cyclic voltammetry shows that the compounds can be reversibly oxidized and reduced around +1.10 and ,1.20,V, respectively. A two-layered electroluminescent device based on 1b produces a pure red light emission with CIE coordinates (0.646, 0.350) and a maximal luminous efficiency of 2.1,cd A,1. Furthermore, when used as a solution-processed red emitter in optically pumped laser devices, compound 1b successfully produces a lasing emission at ca. 650,nm. [source] Synthesis and Structure,Property Relations of a Series of Photochromic Molecular Glasses for Controlled and Efficient Formation of Surface Relief NanostructuresADVANCED FUNCTIONAL MATERIALS, Issue 16 2009Roland Walker Abstract This paper reports on the synthesis and properties of a new series of photochromic molecular glasses and their structure,property relations with respect to a controlled and efficient formation of surface relief nanostructures. The aim of the paper is to establish a correlation between molecular structure, optical susceptibility, and the achievable surface relief heights. The molecular glasses consist of a triphenylamine core and three azobenzene side groups attached via an ester linkage. Structural variations are performed with respect to the substitution at the azobenzene moiety in order to promote a formation of a stable amorphous phase and to tune absorption properties and molecular dynamics. Surface relief gratings (SRGs) and complex surface patterns can easily be inscribed via holographic techniques. The modulation heights are determined with an equation adapted from the theory for thin gratings, and the values are confirmed with AFM measurements. Temperature-dependent holographic measurements allow for monitoring of SRG build-up and decay and the stability at elevated temperatures, as well as determination of the glass transition temperature. SRG modulation heights of above 600,nm are achieved. These are the highest values reported for molecular glasses to date. The surface patterns of the molecular glasses are stable enough to be copied in a replica molding process. It is demonstrated that the replica can be used to transfer the surface pattern onto a common thermoplastic polymer. [source] Supramolecular Self-Assembled Dendritic Nonlinear Optical Chromophores: Fine-Tuning of Arene,Perfluoroarene Interactions for Ultralarge Electro-Optic Activity and Enhanced Thermal StabilityADVANCED MATERIALS, Issue 19 2009Xing-Hua Zhou Unprecedented electro-optic (EO) activity and excellent alignment stability at 85,°C are demonstrated through rational design of a new series of dendronized polyenic chromophores capable of supramolecular self-assembly directed by fine-tuned arene,perfluoroarene interactions. Analysis of the EO properties showed exceptional poling efficiency for these molecular glasses at high chromophore number density. [source] | ||||||||||