Photoanodes for Aqueous Solar Cells: Exploring Additives and Formulations Starting from a Commercial TiO2 Paste

Whereas the commercialization of dye‐sensitized solar cells (DSSCs) is finally proceeding taking advantage of their low cost and tunable optical features, such as colour and transparency for both indoor and building‐integrated applications, the corresponding aqueous counterpart is still at its infancy. As the TiO2 electrode is a fundamental component for hybrid solar cells, this work investigates the effect of different molecular (α‐terpineol, propylene carbonate) and polymeric (polyethylene oxide, polyethylene glycol, carboxymethyl cellulose and xanthan gum) additives that can be introduced into a commercial TiO2 paste for for screen‐printing (or doctor blade). Among all, the addition of polyethylene glycol leads to the best cell performances, with markedly increased short‐circuit current density (+18 %) and power conversion efficiency (+48 %) with respect to the pristine (commercial) counterpart. When further explored at different concentration levels, electrodes fabricated from polyethylene glycol‐based pastes show different morphologies, thicknesses and performances, which are investigated through (photo)electrochemical, structural, physical‐chemical and microscopic techniques.