The preparation of ultra-thin semi-transparent solar cells with potential applications in windows or transparent roofs entails several challenges due to the very small thickness of the layers involved. In particular, problems related to undesired inter-diffusion or inhomogeneities originated by incomplete coverage of the growing surfaces must be prevented. In this paper, undoped SnO₂, CdS, and CdTe thin films with thickness suitable for use in ultra-thin solar cells were deposited with a radiofrequency (RF) magnetron sputtering technique onto conductive glass. Preparation conditions were found for depositing the individual layers with good surface coverage, absence of pin holes and with a relatively small growth rate adapted for the control of very small thickness. After a careful growth calibration procedure, heterostructured solar cells devices were fabricated. The influence of an additional undoped SnO₂ buffer layer deposited between the conductive glass and the CdS window was studied. The incorporation of this layer led to an enhancement of both short circuit current and open circuit voltage (by 19 and 32%, respectively) without appreciable changes of other parameters. After the analysis of the cell parameters extracted from the current-voltage (I-V) curves, possible origins of these effects were found to be: Passivation effects of the SnO₂/CdS interface, blocking of impurities diffusion or improvement of the band alignment.

In the present work, various experimental and theoretical methods were combined to study in detail the modifying effect of differences in the order of deposition of components on the state of silver in bimetallic iron–silver samples based on mordenite. In each of the silver-containing samples, the formation of large (≥2 nm in diameter) varieties of silver was observed, which differed from the varieties in the other samples, and in varying degrees. The formation of large Ag NPs on the outer surface of mordenite is explained by the redox interaction of Ag⁺-Fe²⁺ and the selectivity of ion exchange. The local surrounding of Ag in the studied samples is different: for AgMOR—monatomic species dominate, FeAgMOR—silver dimers and AgFeMOR—metal particles. In all investigated samples, the partially charged intra-channel Ag_n^δ+ clusters (~0.7 nm in size) were formed due to partial Ag⁺ reduction and subsequent Ag⁰ agglomeration into the mordenite channel. Most of the silver in the bulk of the zeolite is represented in the cationic state attached to the mordenite framework by differently coordinated electrostatic forces, which can be Ag-O, Ag-Si or Ag-Al, with variations in interatomic distances and do not depend on the order of metal deposition. In addition, the arrangement of the cations in the side pockets means that the transport channels of mordenite are free, which is favorable for the application of the materials under study in catalysis and adsorption.

Silica nanostructures are attractive platforms for hybrid nanomaterials because of their chemical stability and versatile surface functionalization. Here, spherical SiO₂ nanoparticles were synthesized by a modified Stöber method, functionalized with (3-aminopropyl)triethoxysilane (APTES), and decorated with gold nanoparticles (AuNPs) formed using an inorganic stabilization strategy involving OH⁻ and Cl⁻ ions, without conventional organic AuNP capping agents. Complementary characterization by Fourier-transform infrared spectroscopy (FTIR), ultraviolet–visible diffuse reflectance spectroscopy (UV–VIS DRS), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) supported the sequential surface modification and formation of the SiO₂–APTES–AuNPs hybrid material. TEM yielded average diameters of 100.81 ± 1.74 nm for SiO₂ nanoparticles (n = 50) and 2.00 ± 0.31 nm for supported AuNPs (n = 80). Methylene blue (MB) was subsequently used for a proof-of-concept Raman evaluation. At 10⁻³ and 10⁻⁴ M MB, relative Raman signal-amplification ratios of approximately 7.5 and 3.5, respectively, were obtained from the integrated response near 1620 cm⁻¹; these values are not conventional surface-enhanced Raman scattering (SERS) enhancement factors. At 10⁻⁶ M, a fluorescence-like background was observed without establishing metal-enhanced fluorescence. Density functional theory calculations using an Au₃₂ cluster provided qualitative insight into local S···Au and π···Au interactions. Overall, these results establish an inorganic SiO₂-AuNPs as a physicochemically characterized hybrid nanomaterial prepared through an inorganic AuNP-stabilization strategy and support its further investigation in Raman-based applications.

The identification of natural yellow dyes in ancient textiles is complicated, regardless of whether destructive or non-destructive techniques are used. The main limitation is the need for sampling, followed by deterioration and interference by the materials used in consolidation and restoration processes. In addition, different yellow dye sources share the same main fluorophores or components such as luteolin, kaempferol, and quercetin-based chromophores. We propose a minimally invasive methodology to identify sweet-scented marigold (Tagetes lucida), zacatlaxcalli (Cuscuta tinctoria), and weld (Reseda luteola). This methodology was tested on yellow wool samples that were dyed in an artisan workshop in the last 3 to 10 years. Another two samples of yellow wool fibres were obtained from the textile collection of the Franz Mayer Museum in Mexico City. Confocal scanning laser microscopy (CSLM), micro-Raman spectroscopy, attenuated total reflectance Fourier transformed infrared spectroscopy (ATR-FTIR), and variable pressure environmental scanning electron microscopy (VP-ESEM) were used to analyse the samples. The CLSM results showed that dyes are absorbed into the matrix of the fibres. The wool and dyes presented different emission spectra, which can be associated with the main groups of autofluorescent compounds in plants. The FTIR-ATR results supported the proteinaceous origin of the fibres, and the chemical composition and molecular structure of the autofluorescence phytocompounds were identified by micro-Raman spectroscopy. The findings indicate that the proposed methodology is adequate for identifying natural yellow dyes in wool fibres and can be applied to cultural heritage textiles.