Current Organizations / Institutes

The organizations/institutes from the scholar's latest article


Valentina Arena has a total of 49 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    AVA‐MAPbI 3 Cap‐and‐Root Islands on Mesoporous TiO 2 Toward Neutral‐Color Semi‐Transparent Perovskite Solar Cells in Agrivoltaics

    by Salvatore Valastro, Gaetano Calogero, Emanuele Smecca, Giovanni Mannino, Valentina Arena, Ioannis Deretzis, Corrado Bongiorno, Salvatore Ethan Panasci, Filippo Giannazzo, Miriam Distefano, et al.

    Semi‐transparent perovskite solar cells offer a route to agrivoltaics, combining electricity generation with controlled light transmission for crop cultivation. However, conventional perovskite films preferentially absorb blue photons, producing redshifted transmitted spectra that can affect plant photophysiology. This work presents quasi‐neutral‐color semi‐transparent perovskite films based on AVA‐MAPbI 3 islands rooted in mesoporous TiO 2 (mp‐TiO 2 ). This architecture localizes absorption within the islands while ensuring spectrally balanced, visually neutral transmitted light and efficient charge extraction via the extended perovskite/mp‐TiO 2 interface. Films are fabricated through a one‐step, antisolvent‐free process where controlled de‐wetting and crystallization form islands anchored to the mp‐TiO 2 scaffold. Island coverage and size are tuned via spin‐coating speed and annealing temperature. Using HTL‐free carbon‐based architecture as a testbed, perovskite coverage is identified as the main factor governing the transmittance‐efficiency trade‐off. Photocurrent scaling with coverage and conductive AFM measurements suggest that each island behaves as an independent photogeneration unit. Year‐long outdoor simulations at 37.3°N project that a device with an ideal transparent cathode can reach 4.50% efficiency and generate 116.38 kWh m −2 year −1 , sufficient to power energy‐intensive greenhouses. Lettuce grown under an LED‐simulated perovskite spectrum showed uncompromised biomass, pigments, leaf nitrogen‐carbon content, and carbon/nitrogen ratio, supporting perovskite island‐based photovoltaics for agrivoltaic applications.

  • Open Access

    A Sputtered Gig-Lox TiO2 Sponge Integrated with CsPbI3:EuI2 for Semitransparent Perovskite Solar Cells

    by C. Spampinato, G. Calogero, G. Mannino, S. Valastro, E. Smecca, V. Arena, P. La Magna, C. Bongiorno, E. Fazio, A. Alberti

    In this study, we propose a novel approach where in an innovative porous grazing incidence atomic flux coupled with local oxidation (gig-lox) TiO2 electron transport layer (ETL), deposited by sputtering, is integrated with a fully inorganic CsPbI3:EuI2 perovskite. This combination is used as a photoactive layer in semitransparent perovskite solar cells (ST-PSC). The solvent-free, scalable porous oxide sponge-like in structure, is produced via a grazing-incidence Ti flux that undergoes localized progressive oxidation. The sponge offers ≈50% volume porosity that is available for perovskite infiltration. The result of the oxide-perovskite integration is a double-layer struc made of a perovskite-filled sponge covered by a cap of pure perovskite. The material has unique optical properties and structure as attested by spectroscopic ellipsometry and X-ray diffraction analyses. The double-layer structure exhibits semitransparency, and its reduced photoluminescence (PL) intensity relative to that of a single perovskite layer indicates efficient charge carrier injection into the porous TiO2. In perspective, the layer can be used in PSC as demonstrated by simulations.


  • Open Access

    Engineering GO-pAmOx: A Polyoxazoline-Functionalized Graphene Oxide Composite for Selective Removal of NSAIDs and Organic Pollutants from Water

    by Luca Stefanuto, Agnese Ricci, Elisa Fardelli, Sara Del Galdo, Simone Pepi, Valerio Graziani, Luca Tortora, Claudio Rossi, Valentina Arena, Corrado Bongiorno, et al.

    Organic wastewater compounds (OWCs) employed in human activities are, nowadays, commonly detected in surface water, groundwater, and drinking water. In particular, pharmaceuticals have caused great concern because after their consumption, traces of metabolites are excreted and reach the water resources either directly or after inefficient treatment. Despite this, these compounds are not regulated in drinking water, and existing toxicity data are inadequate to assess potential risks from chronic low-dose exposure. Considering the necessity to find new efficient, reusable, and biocompatible systems to remove organic pollutants from wastewater, the adsorption process has been found to be the most effective and economical because it is simple, highly efficient, regenerative, and scalable and does not produce intermediates that can increase the toxicity of the parent contaminants. Prompted by these reasons, in this research, an adsorbed medium composed of graphene oxide and an amine-oxazoline-based polymer (poly­(2-(3-(amino)­propyl))-2-oxazoline) was synthesized and employed in several adsorption experiments targeting nonsteroidal anti-inflammatory drugs such as ibuprofen (1), aspirin (2), ketoprofen (3), and benzoic acid (4). The specific interaction between acidic moieties of drugs and basic domains of the polymer has been investigated by targeting both acid compounds and pharmaceutical products free of carboxylic groups. Also, the influence of several parameters, including initial concentration, liquid-phase composition, pH, and reusability, has been investigated. Results show that the maximum adsorption capacity for ibuprofen (1), aspirin (2), ketoprofen (3), and benzoic acid (4) for experiments conducted in water, at the maximum initial concentration explored (90 mg L–1) and at natural pH equilibrium (pH ∼ 4), are, respectively, 37.4, 27.5, 43.5, and 26.0 mg g–1. These findings suggest that the prepared GO-pAmOx material has significant potential for adsorbing these drugs in water and good versatility for all investigated acid compounds and maintains high reusability. Notably, the reduction in adsorption capacity after ten adsorption cycles was only 1%.


  • Open Access

    X-ray Investigation of CsPbI3:EuCl3 Infiltrated into Gig-Lox TiO2 Spongy Layers for Perovskite Solar Cells Applications

    by Paola La Magna, Carlo Spampinato, Salvatore Valastro, Emanuele Smecca, Valentina Arena, Giovanni Mannino, Ioannis Deretzis, Giuseppe Fisicaro, Corrado Bongiorno, Alessandra Alberti

    In this study, we explore the potential of a blended material comprising CsPbI3:EuCl3 perovskite and Gig-Lox TiO2, a unique transparent spongy material known for its multi-branched porous structure, for application in solar cells. The inclusion of EuCl3 in CsPbI3 serves to stabilize the photoactive γ-phase with a bandgap of 1.75 eV, making it suitable for solar energy conversion in tandem solar cells. Our study applies X-ray-based techniques to investigate the structural properties and interfacial behavior within this blended material, in comparison with a reference perovskite layer deposited on glass. In addition, Spectroscopic ellipsometry is complemented with density functional theory calculations and photoluminescence measurements to elucidate the absorption and radiative emission properties of the blend. Notably, our findings reveal a significant quenching of photoluminescence within the blended material, underscoring the pivotal role of the distributed interfaces in facilitating efficient carrier injection from the CsPbI3:EuCl3 perovskite into the Gig-Lox TiO2 sponge. These findings pave the way for the application of the blend as an Electron Transport Layer (ETL) in semi-transparent perovskite solar cells for tandem and building integrated photovoltaics.


  • Open Access

    Infiltration of CsPbI3:EuI2 Perovskites into TiO2 Spongy Layers Deposited by gig-lox Sputtering Processes

    by Carlo Spampinato, Paola La Magna, Salvatore Valastro, Emanuele Smecca, Valentina Arena, Corrado Bongiorno, Giovanni Mannino, Enza Fazio, Carmelo Corsaro, Fortunato Neri, et al.

    Perovskite solar cells have become a popular alternative to traditional silicon solar cells due to their potential to provide high-efficiency, low-cost, and lightweight solar energy harvesting solutions. However, the multilayer architecture of perovskite solar cells demands careful investigation of the interaction and interfacing between the various layers, as they play a crucial role in determining the overall performance of the cell. In this context, the present work aims at analyzing the coupling between a spongy transparent electron-transporting layer (ETL) and perovskite in a formulation CsPbI3:EuI2. The ETL used in this work is a transparent mesoporous TiO2 layer called “gig-lox” (grazing incidence angle geometry–local oxidation), which has been optimized to boost the interfacing with the perovskite for achieving a highly interconnected blend of materials. The gig-lox TiO2 ETL shows a high surface wettability with respect to the perovskite solution, especially after pre-annealing at 500 °C, and this enables the perovskite material to deeply infiltrate throughout it. The surface wettability of the gig-lox TiO2 has been estimated by contact angle measurements, while the deep infiltration of the perovskite material has been demonstrated through X-ray diffraction and transmission electron microscopy analyses. Thanks to the achieved deep infiltration, the photo-generated charge injection from the perovskite into the mesoporous oxide is enhanced with respect to the use of a planar compact oxide, as shown by the photoluminescence measurements. The mainstay of the approach resides in the ETL that is deposited by a solvent-free sputtering method and is up-scalable for high industrial throughput.


  • Preventing lead leakage in perovskite solar cells with a sustainable titanium dioxide sponge

    by Salvatore Valastro, Emanuele Smecca, Giovanni Mannino, Corrado Bongiorno, Giuseppe Fisicaro, Stefan Goedecker, Valentina Arena, Carlo Spampinato, Ioannis Deretzis, Sandro Dattilo, et al.


  • Open Access

    Lead Detection in a Gig-Lox TiO2 Sponge by X-ray Reflectivity

    by Valentina Arena, Emanuele Smecca, Salvatore Valastro, Corrado Bongiorno, Giuseppe Fisicaro, Ioannis Deretzis, Carlo Spampinato, Giovanni Mannino, Sandro Dattilo, Andrea Antonino Scamporrino, et al.

    The importance of lead analysis in environmental matrices becomes increasingly relevant due to the anthropogenic spread of toxic species in nature. Alongside the existing analytical methods to detect lead in a liquid environment, we propose a new dry approach for lead detection and measurement based on its capture from a liquid solution by a solid sponge and subsequent quantification based on X-ray analyses. The detection method exploits the relationship between the electronic density of the solid sponge, which depends on the captured lead, and the critical angle for total reflection of the X-rays. For this purpose, gig-lox TiO2 layers, grown by modified sputtering physical deposition, were implemented for their branched multi-porosity spongy structure that is ideal for capturing lead atoms or other metallic ionic species in a liquid environment. The gig-lox TiO2 layers grown on glass substrates were soaked into aqueous solutions containing different concentrations of Pb, dried after soaking, and finally probed through X-ray reflectivity analyses. It has been found that lead atoms are chemisorbed onto the many available surfaces within the gig-lox TiO2 sponge by establishing stable oxygen bonding. The infiltration of lead into the structure causes an increase in the overall electronic density of the layer and, thus, an increment of its critical angle. Based on the established linear relationship between the amount of lead adsorbed and the augmented critical angle, a standardized quantitative procedure to detect Pb is proposed. The method can be, in principle, applied to other capturing spongy oxides and toxic species.


  • Spongy TiO2 layers deposited by gig-lox sputtering processes: Contact angle measurements

    by C. Spampinato, S. Valastro, E. Smecca, V. Arena, G. Mannino, A. La Magna, C. Corsaro, F. Neri, E. Fazio, A. Alberti

    The use of nanostructured materials is increasingly widespread thanks to their particular properties that can improve the performance of devices in various scientific applications. One of them is in the architecture of perovskite solar cells characterized by high photoconversion efficiency values that make them able to compete with silicon solar cells. In this framework, we deposited TiO2 sponges by reactive sputtering based on a grazing-incidence geometry combined with the local oxidation of species. The deposited material gains 50% porosity in volume through depths of hundreds of nanometers and consists of a forest of uniform rods separated by mesopores (pipelines) arising from the grazing geometry. Many previous studies showed how TiO2 can improve the efficiency of perovskite solar cells. In this article, we investigated the change of the wettability values of the TiO2 samples before and after a postdeposition thermal annealing treatment. For comparison, the influence of the annealing on the wettability of the glass substrate is also reported.