New potential materials for polymer solar cells : polymeric ruthenium bipyridine complexes

New potential materials for polymer solar cells contg. ruthenium bipyridine complexes as photosensitizing dyes were synthesized. The 4'- Me functionality of 4,4'-Dimethyl-2,2'-bipyridine was derivatized to form 3-hydroxypropyl, which was then reacted with methacryloyl chloride to add an acrylate functionality, then co-polymd. with Me methacrylate monomer to leave a polymeric dangling group on the bipyridine. This was then added into dimethoxy Ruthenium bipyridine complexes and dimethoxy Ruthenium di(1,10)-phenanthroline complexes. Proton NMR was used to verify structure of some intermediates, and UV-VIS spectroscopy was used to verify incorporation into the ruthenium complexes. Cyclic voltammetry was performed and current-potential relationships of the copolymers are presented in graphical form. This overall approach led to polymers that display favorable absorption and luminescence as well as electrochem. properties for photovoltaic device application

New trends in the use of transition metal-ligand complexes for applications in electroluminescent devices

The advantage of using phosphorescent transition metal-ligand complexes in optoelectronic applications such as organic light-emitting diodes (OLEDs) and light-emitting electrochemical cells (LECs) are described and evaluated. Additionally, different device constructions utilizing phosphorescent transition-metal complexes like iridium(III) mixed-ligand complexes and ruthenium(II) systems are reviewed and specified. Diverse host materials in which the phosphorescent emitters can be placed are discussed, such as small organic molecules and a few polymeric systems, and alternative processing technologies are briefly compared. Recent developments in the synthesis of iridium(III) triplet emitters are discussed. Different device architectures require different kinds of metal-ligand complexes. The different synthetic routes leading to charged and non-charged complexes are briefly discussed

Synthesis of 2,2'-bipyridines : from versatile building blocks to sexy architectures and functional (nano)materials

The latest synthetic strategies to prepare 2,2-bipyridine and its mono-substituted, symmetrical and unsymmetrical 3,3-, 4,4-, 5,5-, and 6,6-disubstituted derivatives are critically discussed and evaluated. Different coupling procedures to achieve new symmetrical and unsymmetrical functionalized 2,2-bipyridines, such as Stille-type, Negishi-type, and Suzuki-type cross-coupling reactions are discussed in detail. Moreover, condensation procedures that allow further variations are presented. The application of functional group transformations for access to additional groups is examined

Film thickness dependency of the emission colors of PPE-PPVs in inkjet printed libraries

The influence of side chains, film thickness, and thermal treatment of .pi.-conjugated polymers on emission colors, was studied. The resp. thickness libraries of six alkoxy-substituted poly(p-phenylene ethynylene)-alt-poly(p-phenylene vinylene)s (PPE-PPVs) were prepd. by inkjet printing. The optical properties of the printed libraries were screened utilizing high-throughput methods. The emission colors of the studied polymers strongly depend on the inter-chain interactions which are increased with increasing film thickness and influenced by the side chains. Upon annealing at 70, white emission was obsd. from the printed films

Iridium(III) complexes with PEO and PS polymer macroligands and light-emitting properties : synthesis and characterization

On the basis of terpyridine functionalized poly(ethylene oxide) (PEO) and poly(styrene) (PS), a series of light-emitting iridium(III) compounds was effectively synthesized. The respective iridium(III) target compounds were prepared by grafting chloro-bridged precursor complexes [Ir(ppy)2--Cl]2 (ppy = phenylpyridine) and [Ir(ppy-CHO)2--Cl]2 (ppy-CHO = 4-(2-pyridyl)benzaldehyde) onto terpyridine functionalized PEO and PS tails. 1D and 2D NMR characterization was performed revealing the expected resonances. Gel permeation chromatography (GPC) proved the stability and purity of the targeted materials. Preliminary investigations of the light-emitting properties were carried out by standard methods such as UV-vis and steady-state luminescence spectroscopy. The morphology and the quality of films of these iridium(III) compounds were furthermore investigated using AFM. Improved stability on the electrode surface was illustrated using cyclic voltammetry. One of the polymer materials was compared to the neat complex, which showed quick degradation