Ricerc@Sapienza

Mesoporous NiO films were deposited by means of a screen printing technique onto fluorine-doped tin oxide transparent electrodes and consequently sensitized with Erythrosin B (EryB) dye. The obtained colored NiO material was used as a working electrode in a three-electrode cell to study the evolution of the triple semiconductor/dye/electrolyte interface upon electrochemical polarization in dark conditions. The electrolyte was a solution of I3 -/I- in acetonitrile, with the redox couple representing the typical redox shuttle of dye-sensitized solar cells (DSCs).

In the framework of the research on dye-sensitized solar cells of p-type (p-DSCs) the definition and optimization of the electrolyte have been a crucial aspect for the reach of the recent records of photo-conversion for these devices. At the basis of this progress there was the replacement of the redox shuttle of reference I-3(-)/I- with opportune redox mediators which deliver higher photocurrents and produce larger open circuit photovoltages.

Thin films of cobalt sulfide (CoS) of thickness l < 10m have been employed as anodes of p-type dye-sensitized solar cells (p-DSCs) when P1-sensitized nickel oxide (NiO) was the photoactive cathode and /I - constituted the redox mediator. In the role of counter electrode for p-DSCs, CoS was preferred over traditional platinized fluorine-doped indium oxide (Pt-FTO) due to the lower cost of the starting materials (Co salts) and the easier procedure of deposition onto large area substrates. The latter process was carried out via direct precipitation of CoS from aqueous solutions.

A new series of KuQuinones (KuQs) have been synthesized and employed as dye-sensitizers for NiO-based p-type dye-sensitized solar cells (p-DSSCs). KuQs are pentacyclic quinoid compounds which are characterized by a fully conjugated structure that is responsible for the strong and broad absorption in the visible spectrum. The HOMO/LUMO states of KuQs considered here have matching energy levels with the upper edge of the NiO valence band and I?/I3 ? redox potential energy. These features render such compounds suitable for NiO sensitization in p-DSSCs.

Nanostructured nickel oxide (NiO) was deposited in the configuration of thin film (thickness, l = 2–6 m)
onto fluorine-doped tin oxide (FTO) substrates via plasma-assisted rapid discharge sintering (RDS). Electrochemical
cycling of RDS NiO in 3-methoxy-propionitrile (3-MPN) revealed two characteristic peaks
of NiO oxidation which were associated to the surface-confined redox processes Ni(II) ? Ni(III) and