Vanadium oxide intercalated with polyelectrolytes: novel layered hybrids with anion exchange properties.

Novel anion exchange hybrid materials were developed by the insertion of poly(diallymethylammonium chloride) (PDDACl) and poly(allylamine hydrochloride) (PAHCl) polyelectrolytes into V(2)O(5) interlayer spaces using hydrothermal treatment and were used to host an anionic cyanine dye. A systematic study of the hybrid material synthesis by direct in situ reaction of PDDACl and PAHCl polycations with V(2)O(5) powders showed that the interlayer space of V(2)O(5) expands from 0.44 nm to 1.40 nm and 1.80 nm upon intercalation of PDDACl and PAHCl polyelectrolytes, respectively. X-ray photoelectron spectroscopy and DR UV-Vis-NIR spectroscopy revealed that some V(5+) sites were reduced to V(4+) during the intercalation of the polyelectrolytes, these acted as both charge balancing entities for the negative oxide sheets and carriers for exchange sites located in the V(2)O(5) interlayer space. The interlayer separation is consistent with the existence of coiled conformation of the polycations. The hybrid materials produced [PDDACl](0.24)[PDDA](0.29)V(2)O(5) and [PAHCl](0.28)[PAH](0.47)V(2)O(5), exhibited approximately 45.0% and 37.0% of chloride ions still available for anionic exchange, respectively. These materials were used to encapsulate a cyanine anionic dye. The presence of the dye was evidenced in the [PDDACl](0.24)[PDDA](0.29)V(2)O(5) by significant fluorescence, with emission peak centered at 617 nm.

Single-wall carbon nanotubes chemically modified with cysteamine and their application in polymer solar cells: influence of the chemical modification on device performance.

In order to improve the dispersion of single-wall carbon nanotubes in a matrix of poly(3-hexylthiophene), this paper reports the modification of single-wall carbon nanotubes with COOH groups followed by reaction with cysteamine that introduced thiol groups along the tubes. The resulting modified single-wall carbon nanotubes were characterized by high resolution transmission electron microscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy and Raman spectroscopy. The modified carbon nanotubes were applied, in combination with poly(3-hexylthiophene), in a bulk heterojunction solar cell. After passing through a post-treatment process to obtain debundied modified single-wall carbon nanotubes, solar cells with improved performance were obtained. After the treatment sequence, both the open circuit voltage and short-circuit current increased in comparison to the non-treated modified single-wall carbon nanotubes polymer solar cells.