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 CsPbI${}_3$:EuI${}_2$. The ETL used in this work is a transparent mesoporous TiO${}_2$ 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 TiO${}_2$ 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 TiO${}_2$ 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.

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.

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.

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.

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%.