- Series of Quinoidal Methyl-Dioxocyano-Pyridine Based π-Extended Narrow-Bandgap Oligomers for Solution-Processed Small-Molecule Organic Solar Cells
-
Small molecules with narrow bandgap of 71BM, showing the higher hole mobility and promising electric performance. (Graph Presented).
- Tang, Ailing,Zhan, Chuanlang,Yao, Jiannian
-
p. 4719 - 4730
(2015/07/27)
-
- Dimerization of merocyanine dyes. Structural and energetic characterization of dipolar dye aggregates and implications for nonlinear optical materials
-
Aggregation of polar merocyanine dyes has been identified as an important problem in the fabrication of organic materials for photonic applications. In this work, a series of merocyanine dyes is synthesized, and their aggregation is investigated by a combination of several experimental techniques to reveal structure-property relationships. These studies provide clear evidence for the formation of centrosymmetric dimers for all investigated merocyanines in concentrated solution and in the solid state. The thermodynamics of dimerization in liquid solution is studied by concentration-dependent permittivity measurements, UV-vis spectroscopy, and electrooptical absorption experiments. A centrosymmetric dimer structure with antiparallel ordering of the dipole moments is observed in solution by 2D NMR spectroscopy as well as in the solid state by x-ray crystallography and interpreted in terms of dipolar and π-π interactions. The optical properties of the dimer aggregates are satisfactorily explained by an excitonic coupling model. The effect of an external electric field on the dimerization equilibrium is considered and quantitatively determined by electrooptical absorption measurements. Implications of the observed findings on the design of nonlinear optical and photorefractive materials are discussed.
- Wuerthner, Frank,Yao, Sheng,Debaerdemaeker, Tony,Wortmann, Ruediger
-
p. 9431 - 9447
(2007/10/03)
-
- Azo pyridone dyestuffs containing at least one reactive phosphoric or phosphonic acid group
-
Azo pyridone dyestuffs containing at least one reactive phosphoric or phosphonic acid group. The dyestuffs are characterized by the formula: wherein A is an aromatic radical containing at least one phosphoric or phosphonic acid group and R is a monovalent radical derived from a pyridone coupling component by removing a hydrogen atom attached to a ring carbon atom of the pyridone ring. The aromatic radical A is preferably a phenyl or naphthyl group. In addition to its phosphonic or phosphoric acid group or groups, radical A may be substituted with one or more halogen, alkyl, alkoxy, nitro, sulfonic acid or carboxylic acid groups. Cellulosic textiles, e.g., cotton or cotton/polyester blends, may be reactively dyed with these dyestuffs in an acid, neutral or alkaline bath using dicyandiamide or the equivalent. The phosphoric or phosphonic acid groups and the cellulosic material react to fix the dye through an ester linkage. Examples of suitable dyestuffs include those having the formula: STR1 and STR2
- -
-
-