Abstracts

Considering the growing need for alternative energy sources or even the improvement of those already developed researchers today have invested in the search for alternative materials that contribute to generating energy in a more efficient and economically viable way. Among the countless potential solutions, solar energy stands out, but it requires strategies to overcome the limitations of the solar cells in use in relation to the low conversion of certain regions of the electromagnetic spectrum, such as ultraviolet and infrared. To face this challenge, the most viable alternative is the combination of solar cells with systems capable of absorbing radiation from these segments, increasing their effectiveness and performance. In this context, coordination compounds containing Eu³⁺ ions are efficient converters of UV radiation into energy suitable for the absorption region of solar cells. However, their fragility from a structural point of view requires them to be embedded in a material that increases their photostability, thus giving rise to the so-called luminescent solar concentrators. In this case, an alternative material to support such luminescent complexes and contribute to the production of efficient solar concentrators is the castor oil as a precursor to the films, a natural compound that is easy to obtain, cheap, and non-toxic for the environment. In this study, different mass percentages, in the range from 0.25% to 3.00% of the synthesized complex [Eu(tta)₃(PIB)] were embedded in castor oil derivative (SiCO) to produce luminescent films by drop casting and their stability against the incidence of radiation were investigated. FTIR, mass spectrometry, elemental analysis and UV-vis spectroscopy data indicated the successful preparation of the Eu³⁺ complex, confirming the stoichiometry. Through photoluminescence spectroscopy, it was observed that the increase in complex concentration leads to a gradual modification of the band profile assigned to the ⁵D₀ → ⁷F₂ transition (hypersensitive transition), which may be related to a smaller spacing between complex units in the film. In concentrations above 1.50%, the ⁵D₀ → ⁷F₂ behavior in the films is similar to that of the powder complex, suggesting that above this concentration the bulk complex behavior prevails. Data regarding the degree of asymmetry of the systems (R₂₁) also suggest greater similarity with the powder structure. Finally, the luminescent films exhibited stabilities close to 50% after 7 hours of direct exposure to radiation from a solar simulator, values slightly below those observed for the same system, produced with the PMMA as matrix. Thus, it can be suggested that the SiCO-based system can be used with the [Eu(tta)₃(PIB)] complex, although it produces less stable systems than those produced with PMMA.