Xanthene

About: Xanthene is a research topic. Over the lifetime, 2132 publications have been published within this topic receiving 34803 citations. The topic is also known as: Xanthene & dibenzo[a,e]pyran.

Photophysics and photochemistry of xanthene dyes in polymer solutions and films

Abstract: The singlet and triplet lifetimes of erythrosin B and rose bengal, two representative xanthene dyes, are significantly increased by enclosing the dye in a cage of poly(4-vinylpyridine) (PVP). The fluorescence yield, controlled by the rate of intersystem crossing, is also increased by such encapsulation. Parallel effects are observed upon adding the polymer to an ethanolic solution of the xanthene or upon loading the dye into a polymer matrix dispersed on a metal oxide surface. The effect of the polymer on static quenching of the excited dye and the implications of dye-loaded polymer films in solar energy conversion are discussed.

Chitosan synergistically enhanced by successive Fe3O4 and silver nanoparticles as a novel green catalyst in one-pot, three-component synthesis of tetrahydrobenzo[α]xanthene-11-ones

Abstract: Chitosan (CS) is modified with Fe 3 O 4 nanoparticles composite through in situ co-precipitation of Fe 3+ and Fe 2+ ions via NH 4 OH in an aqueous solution, resulting in magnetic Fe 3 O 4 /CS NPs. Adsorption of Ag + ions on the surface of the latter, followed by green reduction of Ag + via ascorbic acid, renders Fe 3 O 4 /CS-Ag NPs which shows an excellent catalytic activity toward one-pot, three-component synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[ α ]xanthene-11-one derivatives. The composition of the nanocatalyst is analyzed by FT-IR, XRD, TGA, VSM, ICP, SEM and TEM. Hence unique heterogeneous Fe 3 O 4 /CS-Ag NPs acts as an excellent green catalyst giving high yield product with good recyclability and without significant loss of the activity.

Quasi solid state dye sensitized solar cells employing a polymer electrolyte and xanthene dyes

Abstract: A series of organic dyes in the xanthene class namely Rose Bengal (RB), Eosin Y (EY) and Fluorescein sodium (FLU) were used as photo-sensitizer for nano-crystalline TiO2, for the application of quasi solid state dye sensitized solar cells. These dyes have same backbone with different number of electron acceptor groups. The dye with the highest number of electron acceptor group, i.e. 8 namely RB shows highest power conversion efficiency due the lower band gap and higher light harvesting efficiency (LHE). The ionic conductivity of polymer electrolyte used in quasi solid state DSSC was examined in terms of polymer content and redox couple concentration. The dependence of photovoltaic performance of the solar cell on the polymer content in the electrolyte used in DSSC, was studied by current–voltage characteristics under illumination and electrochemical impedance spectroscopy (EIS). The result indicates the charge transfer behavior occurred at nano-crystalline TiO2/electrolyte and PEDOT:PSS/electrolyte interface plays an important role in influencing the photovoltaic performance of the device. The quasi solid state dye sensitized solar cell posseses a good long-term stability and power conversion efficiency is almost equal to that of DSSCs with liquid electrolyte.