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In this work we present the electrochemical and photoelectrochemical characterization of NiO thin films [thickness (l) range: 2 <= l <= 4 mu m], which have been obtained from screen-printing of three precursor-pastes. All three pastes contained preformed NiO nanoparticles [diameter ((MT SET)) range: 20 < ((MT SET)) < 50 nm], but differed for the content and nature of the acidic component. The resulting NiO samples were employed as photoactive cathodes of p-type dye-sensitized solar cells (p-DSCs). The temperature of sintering was kept below 450 degrees C to warrant mesoporosity and electrical connectivity between the nanostructured domains while maintaining a good level of adhesion on the substrate. The photoelectrochemical properties of bare and erythrosine b (ERY)-sensitized NiO in p-DSCs depended on the composition of the screen-printing paste. The NiO samples obtained from the pastes with the lowest amount of acidic component or containing the acid with the stronger character, namely HCl, gave the best performances in the corresponding p-DSCs. In the series of ERY-based p-DSCs here tested the most performing screen-printed electrode gave the largest overall conversion efficiency (eta > 0.04%) and highest external quantum efficiency (EQE > 9% at 830 nm) with respect to the p-DSCs with NiO photocathodes of similar thickness, which have been prepared via different methods of deposition. (C) 2017 The Electrochemical Society.All rights reserved

In this study, we have investigated for the first time the use of isoindigo derivatives as sensitizers in NiObased\ud dye-sensitized solar cells (DSSCs). For this purpose, two indigo sensitizers were prepared and their\ud electronic properties were characterized by UV/visible spectroscopy, cyclic voltammetry and timedependent\ud density functional theory (TD-DFT). The first dye contains a N,N-di(4-benzoic acid)\ud phenylamine moiety acting as anchoring/donor group, and the isoindigo acting as the acceptor, while\ud the second compound is a dyad which is based on the same structure, but is additionally\ud functionalized with a naphthalene imide unit, acting as a secondary electron acceptor. The electronic\ud properties were also modeled by TD-DFT quantum chemistry calculations and they revealed that\ud a charge transfer band is present between the trisarylamine donor part and the isoindigo moiety. The\ud photovoltaic performances of these new dyes were evaluated in NiO-based DSSCs with both iodide/\ud triiodide and cobalt electrolytes. It turned out that they perform well since the photocurrent was\ud generated up to the wavelength of 700 nm. Altogether, these results underscore the viability of\ud isoindigo dyes for p-DSSCs

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