We report on the fabrication of shellac thin films on silicon substrates by matrix-assisted pulsed laser evaporation (MAPLE) using methanol as matrix. Very adherent, dense, and smooth films were obtained by MAPLE with optimized deposition parameters, such as laser wavelength and laser fluence. Films with a root mean square (RMS) roughness of 11 nm measured on 40 × 40 µm² were obtained for a 2000-nm-thick shellac film deposited with 0.6 J/cm² fluence at a laser wavelength of 266 nm. The MAPLE films were tested in simulated gastric fluid in order to assess their capabilities as an enteric coating. The chemical, morphological, and optical properties of shellac samples were investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM).

In the current study, bulk tungsten material surfaces are exposed to hydrogen, deuterium, and helium plasmas in the radiofrequency domain (13.56 MHz) at an input power of 250 W using the hollow-cathode configuration. The ejected material is collected on titanium substrates at various distances (from 6 mm up to 40 mm). Therefore, the exposed tungsten materials are investigated for surface changes (blister occurrence, dust formation, or nano-structuration), along with the crystallinity, depending on the plasma’s exposure times (from 30 min up to 120 min for each plasma type). Also, the collected materials are analyzed (morphological, structural, and statistical investigations) for dust and dust film-like appearance. Plasma discharges are analyzed using two methods: optical emission spectroscopy, and single Langmuir probes, to emphasize the nature of the used plasmas (cold discharges, ~2 eV), along with the presence of tungsten emission (e.g., WI 406.31 nm, WI 421.31 nm) during the plasma lifetime. By using a dedicated protocol, a method was established for obtaining fusion-relevant tungsten surfaces in the hydrogen and deuterium plasma discharges. By using the implemented method, the current paper introduces the possibility of obtaining a new tungsten morphology, i.e., the dandelion-like shape, by using helium plasma, in which the W₁₈O₄₉ compound can be found.

A highly sensitive ammonia-gas sensor based on a tungsten trioxide and polypyrrole (WO₃/PPy) nanocomposite synthesized using pulsed-laser deposition (PLD) and matrix-assisted pulsed-laser evaporation (MAPLE) is presented in this study. The WO₃/PPy nanocomposite is prepared through a layer-by-layer alternate deposition of the PPy thin layer on the WO₃ mesoporous layer. Extensive characterization using X-ray diffraction, FTIR and Raman spectroscopy, scanning electron microscopy, atomic force microscopy, and water contact angle are carried out on the as-prepared layers. The gas-sensing properties of the WO₃/PPy nanocomposite layers are systematically investigated upon exposure to ammonia gas. The results demonstrate that the WO₃/PPy nanocomposite sensor exhibits a lower detection limit, higher response, faster response/recovery time, and exceptional repeatability compared to the pure PPy and WO₃ counterparts. The significant improvement in gas-sensing properties observed in the WO₃/PPy nanocomposite layer can be attributed to the distinctive interactions occurring at the p–n heterojunction established between the n-type WO₃ and p-type PPy. Additionally, the enhanced surface area of the WO₃/PPy nanocomposite, achieved through the PLD and MAPLE synthesis techniques, contributes to its exceptional gas-sensing performance.

This study investigates the influence of nanostructured tungsten trioxide (WO ₃ ) films on the surface properties of transparent electrodes used in organic photovoltaics, specifically indium tin oxide (ITO) and fluorine-doped tin oxide (FTO). The aim is to improve their compatibility with the conductive polymer PEDOT: PSS used as a hole-transport layer (HTL). We show that pulsed laser deposition (PLD) parameters, particularly the number of laser pulses, influence surface architecture, wettability, and optical behaviour of WO₃. The X-ray diffraction investigation reveals that thicker layers adopt a monoclinic structure. The integration of PEDOT: PSS with nanostructured WO₃ layers could help mitigate degradation caused by PEDOT: PSS acidity, creating interfacial conditions that have been associated in the literature with improved device stability and performance. Optical measurements show that thicker WO₃ films enhance absorption in the ultraviolet and near-infrared regions while maintaining high transmittance in the visible range. Additionally, the surface morphology of the WO₃ layer significantly improves electrode hydrophilicity, reducing the water contact angle and enabling uniform PEDOT: PSS deposition without changing HTL thickness. The nanostructured WO₃ film acts as an interfacial modifier that preserves HTL thickness, an important parameter for organic photovoltaic cells and other optoelectronic devices, requiring stable interfaces and efficient charge transport. These insights contribute to the optimization of transparent electrodes for enhanced efficiency in organic photovoltaic applications.