Xanthan-Based Hydrogel for Stable and Efficient Quasi-Solid Truly Aqueous Dye-Sensitized Solar Cell with Cobalt Mediator

9siAqueous dye-sensitized solar cells (DSSCs) are emerging as a promising alternative to enhance both the lifetime and environmental friendliness of traditional DSSCs. Herein, a cobalt-based, jellified (with xanthan gum) aqueous electrolyte, leading to a valuable efficiency exceeding 4% (VOC = 847 mV, JSC = 6.73 mA cm−2, fill factor =  74%), is reported. Design of experiment is used to precisely and significantly study, at a multivariate level, the effects produced by the Co2+ concentration, Co2+/Co3+ ratio, and xanthan gum amount modifications on the overall photovoltaic parameters of lab-scale solar cells.partially_openopenS. Galliano, F. Bella, M. Bonomo, F. Giordano, M. Grätzel, G. Viscardi, A. Hagfeldt, C. Gerbaldi, C. BaroloGalliano, S.; Bella, F.; Bonomo, M.; Giordano, F.; Grätzel, M.; Viscardi, G.; Hagfeldt, A.; Gerbaldi, C.; Barolo, C

Optimization of distyryl-Bodipy chromophores for efficient panchromatic sensitization in dye sensitized solar cells

Cataloged from PDF version of article.Versatility of Bodipy (4,4-difluoro-4-bora-3a, 4a-diaza-s-indacene) dyes was further expanded in recent dye-sensitized solar cell applications. Here we report a series of derivatives designed to address earlier problems in Bodipy sensitized solar cells. In the best case example, an overall efficiency of a modest 2.46% was achieved, but panchromatic nature of the dyes is quite impressive. This is the best reported efficiency in liquid electrolyte solar cells with Bodipy dyes as photosensitizers

Rose Bengal sensitized bilayered photoanode of nano-crystalline TiO–CeO for dye-sensitized solar cell application

There are two traditional ways to read Kant’s claim that every event necessarily has a cause: the weaker every-event some-cause (WCP) and the stronger same-cause same-effect (SCP) causal principles. The debate on whether and where he subscribes to the SCP has focused on the Analogies in the Critique of Pure Reason (Guyer, Allison, and Watkins) and on the Metaphysical Foundations of Natural Science (Friedman). By analysing the arguments and conclusions of both the Analogies and the Postulates, as well as the two Latin principles non datur casus and non datur fatum that summarise their results, I will argue that the SCP is actually demonstrated in the Postulates section of the First Critique

Optical description of solid-state dye-sensitized solar cells. II. Device optical modeling with implications for improving efficiency

We use the optical transfer-matrix method to quantify the spatial distribution of light in solid-state dye-sensitized solar cells (DSCs), employing material optical properties measured experimentally in the accompanying article (Part I) as input into the optical model. By comparing the optical modeling results with experimental photovoltaic action spectra for solid-state DSCs containing either a ruthenium-based dye or an organic indoline-based dye, we show that the internal quantum efficiency (IQE) of the devices for both dyes is around 60% for almost all wavelengths, substantially lower than the almost 100% IQE measured for liquid DSCs, indicating substantial electrical losses in solid-state DSCs that can account for much of the current factor-of-two difference between the efficiencies of liquid and solid-state DSCs. The model calculations also demonstrate significant optical losses due to absorption by 2, 2′,7, 7′ -tetrakis-(N,N -di- p -methoxyphenyl- amine)-9, 9′ -spirobifluorene (spiro-OMeTAD) and TiO2 in the blue and to a lesser extent throughout the visible. As a consequence, the more absorptive organic dye, D149, should outperform the standard ruthenium complex sensitizer, Z907, for all device thicknesses, underlining the potential benefits of high extinction coefficient dyes optimized for solid-state DSC operation. © 2009 American Institute of Physics.David M. Huang, Henry J. Snaith, Michael Grätzel, Klaus Meerholz and Adam J. Moul

Influence of Iodide Concentration on the Efficiency and Stability of Dye-Sensitized Solar Cell Containing Non-Volatile Electrolyte

Dye-sensitized solar cells based on nanocrystalline TiO2 have been fabricated with an amphiphilic ruthenium sensitizer NaRu(4-carboxylic acid-4'-carboxylate) (4,4'-dinonyl-2,2'-bipyridine)(NCS)2, coded as Z-907Na, and a series of non-volatile 3-methoxyproprionitrile (MPN)-based electrolytes with different concentration of 1-methyl-3-propylimidazolium iodide (PMII). The short-circuit photocurrent density increases with increasing iodide concentration until at 1.5M practically quantitative dye regeneration is achieved as proved by time-resolved laser experiments. Devices containing 1.0M PMII electrolyte show excellent stability during long-time thermal aging at 80 degrees C and under light soaking at 60 degrees C

Electrochemical Properties of Cu(II/I)-Based Redox Mediators for Dye-Sensitized Solar Cells

Three Cu(II/I)-phenanthroline and Cu(II/I)-bipyridine redox mediators are studied on various electrodes and in variety of electrolyte solutions using cyclic voltammetry and impedance spectroscopy on symmetrical dummy cells. Graphene-based catalysts provide comparably high activity to PEDOT, and both catalysts outperform the activity of platinum. The charge-transfer kinetics and the diffusion rate significantly slowdown in the presence 4-tert-butylpyridine. This effect is specific only for Cu-mediators (is missing for Co-mediators), and is ascribed to a sensitivity of the coordination sphere of the Cu(II)-species to structural and substitutional changes. The 'Zombie Cells' made from symmetrical PEDOT/PEDOT devices exhibit enhanced charge-transfer rate and enhanced diffusion resistance. Electrochemically clean Cu(II)-bipyridine species are prepared, for the first time, by electrochemical oxidation of the parent Cu(I) complexes. Our preparative electrolysis brings numerous advantages over the standard chemical syntheses of the Cu(II)-bipyridine complexes. The superior performance of electrochemically grown clean Cu(II)-bipyridine complex is demonstrated on practical dye-sensitized solar cells. (C) 2016 Elsevier Ltd. All rights reserved