Four silane-containing Schiff base oligomers (o-SBNs and o-SBBs) were synthesized by high-temperature polycondensation reactions using silicon-based dialdehydes with naphthalene and 1,1’-binaphthalene diamine derivates. The samples showed a moderate solubility in common organic solvents, where the incorporation of TPS cores into o-SBN2 allows the formation of highly soluble material in non-polar solvents with higher molecular weights (11.58 kDa) and polydispersity. All oligo-SBs displayed high thermal resistance (above 450 °C), showing enhanced thermal stability for TPS-containing oligomers, with the degradation temperature exceeding 530 °C (o-SBB2) and high T_g values due to the higher aromatic content granted by TPS and 1,1’-binaphthalene moieties. Optical results of the oligo-SBs showed broad absorption and emission behavior in the visible spectrum, ranging from deep blue (o-SBN1 and o-SBB1) to blue (o-SBN2 and o-SBB2). The structure promotes a clear bathochromic shift for TPS-based oligomers, attributed to an extended π-conjugation across the backbone. In addition, the π-π overlap effect highlights larger Stokes shifts for the DMS core oligomers o-SN2 (133 nm) and o-SBB1 (195 nm). The oligo-SBs were found to be wide-bandgap materials, with E_g^opt values in the range of 2.60 eV to 3.67 eV. The higher molecular weight of o-SBN2, which provided an extended π-conjugation, allows the lowest value of E_g^opt (2.60 eV) to be achieved. In addition, DFT, TDDFT and EDDM calculations were performed on trimeric oligo-SBs, revealing that HOMOs are localized in the amine-terminal fraction, while LUMOs are localized over the terminal aldehyde groups. These findings highlight the used DMS and TPS cores in Schiff base materials, providing valuable insights into fine-tuning physicochemical properties through the use of suitable building blocks and their potential as optoelectronic materials.

In this study, we aimed to evaluate the evaporating fractions of a polymeric material by thermal evaporation to scale up polymer-based organic photovoltaic (OPV) devices. Due to its high thermal stability and suitable optoelectronic properties, we used a poly(azomethine)-based material (PAZ2ThA2) as the donor layer. The control and reproducibility of our methodology were confirmed through two specific analyses: size exclusion chromatography, which allowed us to separate and measure the size of the deposited material, and UV–visible absorption spectroscopy, which provided information about the light absorption of the evaporated fractions. Our deposition rates reached a maximum of 1.4 Å·s−1. We fabricated bilayer OPV devices to evaluate the thickness dependence of the deposited fractions and achieved a maximum short-circuit current density of 1.60 mA·cm−2 at 9 nm thickness. These results confirm the feasibility of obtaining reproducible vacuum-processed polymer-based OPV devices, a significant step toward their scalability.

A polymeric support based on a poly(azomethine) (PAM) structure was synthesized using mechanochemical polymerization (PAM@M) and compared with its counterpart prepared via conventional high-temperature solution-phase polycondensation (PAM@T). The mechanochemical approach not only significantly reduced the synthesis time (1 hour versus 24 hours), but also resulted in a polymer with amorphous character while the one synthesized via conventional heating exhibits some crystalline peaks. FePAM@M demonstrated superior catalytic performance with complete conversion of glycerol to solketal with 100% selectivity in only 1 hour at room temperature, exhibiting an impressive environmental factor (E-factor = 3.49). The conversion of glycerol into value-added products is essential due to its large-scale generation as a by-product of biodiesel, so the results of this work highlight FePAM@M as a highly efficient and sustainable catalyst for this valorisation.