Recent advancements in perovskite-type hybrid solar cells (PSCs) have driven significant interest due to their promising photovoltaic properties and potential to replace conventional silicon-based solar cells. In this work, we explore the use of N-[(3-dimethylamino) propyl] methacrylamide as an ionic additive in MAPbI3 PSCs with the structure fluorine-doped tin oxide/TiO2/perovskite/spiro-OMeTAD/Ag. This additive aims to enhance device stability by reducing surface defects and mitigating degradation under environmental conditions. Structural characterization through x-ray diffraction and x-ray photoelectron spectroscopy demonstrates that the incorporation of methacrylamide improves the moisture resistance and structural integrity of the perovskite layer. Devices containing the additive exhibit reduced formation of PbI2, even after prolonged exposure to ambient conditions, significantly enhancing stability. These findings underscore the role of ionic additive engineering in passivating defects and preserving photovoltaic performance. This work highlights a practical approach to improving the durability of perovskite solar cells, contributing to the advancement of stable and efficient next-generation photovoltaic technologies.

In this mini-review, we address the properties of graphitic carbon nitride (g-C ₃ N ₄ ) hybrid thin films and their application, with particular attention to the modification of their photocatalytic or photovoltaic properties by the addition of chalcogenide materials, layered semiconductors, or perovskites. The defect states that give rise to active sites for photocatalysis are studied and related to the modification with the different materials. Bulk defects provided by some configurations are also studied. Moreover, the appropriate changes with perovskite materials, or the addition of carbon nitride to perovskites, boost the efficiency and stability of the devices, a subject that is studied in this work. Specific mechanisms of passivation provided by carbon nitride on photovoltaic devices are explained.

The electrocatalytic reduction of nitric oxide and nitrogen dioxide (NOx) remains a significant challenge due to the need for stable, efficient, and cost-effective materials. This study presents a novel support system for NOx reduction in alkaline media, composed of ZrO₂-WO₃-C (ZWC), synthesized via coprecipitation. Platinum nanoparticles (10 wt.%) were loaded onto ZWC and Vulcan carbon support, using similar methods for comparison. Comprehensive physicochemical and electrochemical analyses (N₂ physisorption, XRD, XPS, SEM, TEM, and cyclic and linear voltammetry) revealed that PtZWC outperformed PtC and commercial PtEtek in NOx electrocatalysis. Notably, PtZWC exhibited the highest total electric charge for NOx reduction. At the same time, the hydrogen evolution reaction (HER) was shifted to more negative cathodic potentials, indicating reduced hydrogen coverage and a modified dissociative Tafel mechanism on platinum. Additionally, the combination of WO₃ and ZrO₂ in ZWC enhanced electron transfer and suppressed HER by reducing NO and hydrogen atom adsorption competition. While the incorporation of WO₃ and ZrO₂ lowered the surface area to 96 m²/g, it significantly improved pore properties, facilitating better Pt nanoparticle dispersion (3.06 ± 0.85 nm, as confirmed by SEM and TEM). XRD analysis identified graphite and Pt phases, with monoclinic WO₃ broadening PtZWC peaks (20–25°). At the same time, XPS confirmed oxidation states of Pt, W, and Zr and tungsten-related oxygen vacancies, ensuring chemical stability and enhanced catalytic activity.

In this work, we report the fabrication of CuI@g-C₃N₄/MoS₂ thin films by the thermal evaporation of Cu films and their conversion into hybrid films by a simple wet chemical method. Compared to pure CuI, CuI@g-C₃N₄/MoS₂ shows enhanced absorption near the UV region, which improves its DC photoconductivity. The conductivity of the films is enhanced by the addition of g-C₃N₄/MoS₂, which is distributed on the surface of the CuI film. The band gap of the films red-shifts upon adding g-C₃N₄/MoS₂. We evaluate this material’s potential application as a photodetector and in photocatalysis by evaluating its photoelectrochemical properties using impedance spectroscopy measurements, cyclic voltammetry, and DC photoresponse measurements. We find that upon the addition of g-C₃N₄/MoS₂, the conductivity of the films is increased, as evidenced by the time-dependent photo amperometry measurements. Also, a higher DC photoresponse is observed upon increasing the concentration of MoS₂. This work marks the first time a hybrid CuI@g-C₃N₄/MoS₂ film and its photoelectrochemical characteristics have ever been reported.

Lead-free titanium halide perovskites with the formula Cs2TiClxBr6−x were integrated into an ethylene–vinyl acetate (EVA) matrix to form hybrid perovskite thin films with tunable optoelectronic properties. Importantly, this work goes beyond compositional tuning by demonstrating that the polymer–perovskite hybrid architecture actively governs interfacial charge transport and polarization phenomena. Structural and optical characterization confirmed the formation of vacancy-ordered double perovskites with visible-light absorption and photoluminescence features associated with defect-mediated electronic relaxation. The electrical and photoinduced responses of the composites were investigated using electrochemical impedance spectroscopy with symmetric fluorine-doped tin oxide (FTO)│EVA│FTO configurations. Upon illumination, the films exhibited a marked decrease in impedance, revealing the halide-dependent modulation of charge transport, interfacial polarization, and pseudocapacitive behavior. Mixed-halide compositions displayed improved electrical uniformity and reduced transport resistance compared to pristine EVA, indicating enhanced photoinduced charge dynamics. Hirshfeld surface analysis was employed as a structural descriptor to quantify halide surface exposure, thereby linking composition-dependent electronic localization to the observed photoelectrical response. As a functional demonstration of these charge dynamics, the hybrid films were also evaluated under photocatalytic conditions, where light-driven formate and hydrogen generation corroborated the effective charge separation inferred from impedance measurements.

Nd₂NiO_4+δ was investigated as a Ruddlesden–Popper (RP) cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs), with particular emphasis on its electrochemical performance and oxygen reduction reaction mechanism. The material was synthesized via a polymeric sol–gel route derived from Pechini’s method and evaluated in symmetric cells using Ce_0.9Gd_0.1O_2−δ (GDC) as the electrolyte. X-ray diffraction confirmed the formation of a single RP phase and good chemical compatibility with GDC after thermal treatments at 800 °C. Cathode layers with thicknesses of 8–12 µm were deposited by dip-coating. Electrical conductivity measurements revealed a thermally activated semiconducting behavior governed by Ni²⁺/Ni³⁺ small-polaron hopping, with an activation energy of ~1.08 eV. Electrochemical impedance spectroscopy showed a strong temperature dependence of the area-specific resistance, decreasing from 9.18 Ω·cm² at 600 °C to 0.39 Ω·cm² at 800 °C. Distribution of relaxation times (DRT) analysis enabled the identification of the dominant electrochemical processes, indicating that oxygen surface exchange reactions are more favorable than charge transfer at the cathode–electrolyte interface, which remains the main limiting step. These results demonstrate that Nd₂NiO_4+δ is a promising cathode for IT-SOFC operation, while further optimization of the electrode–electrolyte interface is required to enhance its oxygen reduction kinetics.