Ricerc@Sapienza

Electrodeposition of NiOOH is an attracting route toward nanosized films of NiO, a p-type semiconductor used in many advanced applications. In this paper, the deposition mechanism is thoroughly investigated aiming at the clarification of the deposition dynamics and the chemical nature of the deposit. We focused on initial stages of the potentiostatic deposition on ITO, which yields a nanostructured film. In the potential range investigated the process is mass transport controlled and strongly overlaps with oxygen evolution reaction.

For the first time it is shown that the NiO films operating as
photocathodes in dye-sensitized solar cells (DSCs), alter their Xray
diffraction (XRD) pattern upon occurrence of the photoelectrochemical
reaction of reduction. In particular, it has been
observed that mesoporous NiO sensitized with Fast Green (FG)
presents splitting and broadening of its characteristic XRD
peaks after device operation in p-type DSC (p-DSC) and tandem
DSC (t-DSC). The nature of the changes in the diffraction

Perovskite (CH3NH3PbI3) solar cells (PSCs) were produced in the inverted architecture employing transparent nickel oxide (NiO) as hole transporting layer (HTL). The different functional layers of the photoconversion device were solution processed in ambient conditions the HTL of NiO being prepared via sol-gel and successively deposited by spin-coating. The conditions of preparation of the transparent HTL were optimized through the stabilization of the nickel-containing sol with bulky alcohols and strong inorganic acids.

The present contribution reports on the analysis of the electrochemical properties of screen-printed nickel oxide (NiO) in aqueous electrolyte when NiO is in the configuration of thin film (thickness, l ≤ 7 μm). This type of NiO samples presents mesoscopic morphology. The latter characteristic combined to the intrinsic electroactivity of the oxide leads to the observation of proportionality between NiO thickness and current density. In particular, NiO undergoes two distinct processes of oxidation with reversible features in aqueous media.

Squaraines are full-organic dyes employed as sensitizers in ptype dye-sensitized solar cells (p-DSSC). Their absorption spectrum shows a wide tunability that ranges from visible to NIR. Sensitization in the NIR region is crucial for exploiting a particularly intense portion of the solar spectrum. In this work three squaraines will be presented and tested as sensitizers in NiO-based p-type DSSC O4_C2, O4_C4 and O4_C12). The structures of the dyes differ for the length of the alkyl side chain (C2, C4 and C12).

Nanostructured NiO as hole selective contact for perovskite solar cells is deposited on ITO from the potentiostatic anodic electrodeposition of NiOOH. Along with the large surface extension due to the honeycomb-like morphology, the electrodeposition route imparts different electrochemical features in respect to the classic sol-gel!derived NiO, which are two interesting features for optoelectronic applications.

The effect of the conditions of sensitization on the photoelectrochemical performance of p-type dye-sensitized solar cells (p-DSCs)
with screen-printed nickel oxide (NiO) photocathodes is analyzed. The dye-sensitizers employed in the present study are asymmetric
squaraines. The conditions of sensitization differ for the relative concentration of the anti-aggregating agentCDCA(chenideoxycholic
acid) with respect to the concentration of the dye-sensitizer. The co-adsorption of CDCA onto NiO electrode brings about a decrease

The design and the synthesis of three unsymmetrical squaraines, DS_34, DS_45, and DS_47, have been achieved for their utilization as sensitizers of screen-printed NiO cathodes in p-type dye-sensitized solar cells (p-DSCs). DS_34, DS_45, and DS_47 are bidentate dyes, each bearing two carboxylic anchoring groups, which differ solely in the length of alkyl chain attached to the nitrogen atom of the condensed pyrrole ring (ethyl, butyl, and dodecyl for DS_45, DS_34, and DS_47, respectively).

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.