An innovative and versatile set-up for in situ and real time measures in an electrochemical cell is described. An original coupling between micro-Raman spectroscopy and atomic force microscopy enables one to collect data on opaque electrodes. This system allows for the correlation of topographic images with chemical maps during the charge exchange occurring in oxidation/reduction processes. The proposed set-up plays a crucial role when reactions, both reversible and non-reversible, are studied step by step during electrochemical reactions and/or when local chemical analysis is required.

The drive for the development of systems that can simultaneously investigate chemical and morphological information comes from the requisite to fully understand the structure and chemical reactivity relationships of materials. This is particularly relevant in photocatalysis, a field ruled by surface interactions. An in-depth understanding of these complex interactions could lead to significant improvements in materials design, and consequently, in photocatalytic performances. Here, we present a first approach to a combined atomic force microscopy (AFM) and Raman spectroscopy characterization of anodic TiO₂ nanotubes arrays decorated with Ag nanoparticle electrodeposition from either the same anodizing organic electrolyte or from an aqueous one. Photocatalytic substrates were used in up to 15 consecutive photocatalysis tests to prove their possible deterioration with reuse. Sample aging can, in principle, produce changes in both the morphology and the chemical compounds that characterize the photocatalyst surface. Adopting multiple characterization techniques, such as a combination of AFM and Raman spectroscopy in an original setup, can profitably enable the observation of surface contamination. A significant drop in photocatalytic activity was observed after 10 cycles on samples where silver was deposited from the organic electrolyte, while the others remained stable. Such a drop was ascribed to photocatalyst deactivation. While in other cases, a simple recovery treatment allowed the initial photoactivity to be restored, this deactivation was not restored even after chemical and thermal cleaning treatments.

Next-generation flexible, soft, and stretchable sensors and electronic devices are conquering the technological scene due to their extremely innovative applications. Especially when produced via innovative technologies like additive manufacturing (AM) and/or inkjet printing (IJP), they represent an undeniable strategic asset for Industry 5.0. Within the growing sensor market, they offer advantages in terms of sensitivity and maximum sensing range. In addition, the use of AM/IJP reduces material waste, enhances scalability, and lowers cost production. In the present work, the design and fabrication of a highly flexible inkjet-printed piezoelectric sensor on top of a thin highly flexible polyimide substrate are presented. The silver top and bottom electrodes were inkjet-printed together with a P(VDF-TrFE) active layer with a nominal thickness of 3 μm which is located between them. The experimental results demonstrate that, even in extreme bending conditions and at different bending speeds, the fabricated sensors are able to maintain their performance without mechanical delamination, giving a stable and repeatable output peak-to-peak signal of 850 mV under cyclic bending. The material combination and the IJP-based fabrication technique employed for the first time in this work to produce highly flexible sensors represent a promising novelty in terms of both sensor performance and customization possibilities.

Electrochemically induced blisters in highly oriented pyrolytic graphite (HOPG) are nanometre- to micrometre-sized swollen graphitic regions generated during anion intercalation, when gaseous species become trapped beneath the upper layers. Although usually recognized from topography, these structures also carry a local spectroscopic signature associated with finite thickness of the graphitic blister skin, strain, and intercalation-induced heterogeneity. Here, we combine correlated AFM–Raman spectroscopy and STM–TERS to connect blister morphology with local vibrational response from the micrometre to nanometre scale. Analysis of 23 blisters shows that blistered regions differ from the adjacent intercalated basal plane by enhanced Raman intensity and shifts of the G and 2D bands toward lower wavenumbers, consistent with tensile strain in the swollen graphitic layers. The G-band downshift follows the blister topography, reaches its maximum near the centre, and, when correlated with AFM-derived strain through a spherical-cap approximation, yields a shift rate of −39.3 cm−1/ε% strain; the two 2D components shift at −83.2 and −98.8 cm−1/ε% strain. TERS further resolves local heterogeneity: the D band is localized at intercalated graphite steps, whereas blister borders show a progressive G-band downshift from the flat basal plane into the swollen region, without the appearance of the defect-related D band. These results support the description of HOPG blisters as internally pressurized, strained few-layer graphitic structures and highlight AFM–Raman/TERS correlation as a suitable approach for guiding strain engineering and nanoscale interface studies in layered carbon materials.