Synergetic effect of Leucophyllum frutescens and Ehretia microphylla dyes in enhancing the photovoltaic performance of dye-sensitized solar cells

The use of new natural dyes derived from Leucophyllum frutescens and Ehretia microphylla as well as their combination in dye-sensitized solar cells (DSSCs) has been explored for the first time in the current work. The primary pigments that sensitize the semiconductor TiO₂ films were found to be carotenoid, anthocyanin, and chlorophyll. Pigments from Leucophyllum frutescens and Ehretia microphylla were designated as LF and EM, and their mixture blended at volume percent of 50:50, 75:25, and 25:75 were labeled as LE1, LE2, and LE3, respectively. The absorption range, emission intensities, and the functional groups of the dyes and dye-loaded TiO₂ photo-anode films were analyzed using ultraviolet-visible, photoluminescence and Fourier transform infrared spectroscopy. The surface morphology of bare and sensitized TiO₂ films was identified through scanning electron microscopy (SEM). To evaluate the photovoltaic performance of the fabricated devices, the current-voltage characteristics, electrochemical impedance spectroscopy analysis and incident photon-to-current conversion efficiency measurements were performed. The study found that the co-sensitized cell LE2 outperformed both single and mixed dye-based cells, achieving a maximum conversion efficiency of 1.33% with a V_oc of 516 mV and a J_sc of 2.55 mA cm^-2. This synergetic effect of natural dyes proved the superior performance of DSSCs with co-sensitization.

Essential oils from the leaves and flowers of Leucophyllum frutescens (Scrophulariaceae): phytochemical analysis and inhibitory effects against elastase and collagenase in vitro

Leucophyllum frutescens (Scrophulariaceae) is a medicinal plant of Mexican traditional medicine. The aim of this study was to analyse the volatile components from the leaves and flowers by GC/MS and to assess their anti-aging activity for the first time. A total of 30 compounds were identified where 1-octen-3-ol (73.56%) and D-limonene (11.12%) represented the major ingredients in the leaves, while n-heneicosane (32.30%) and dehydroepingaione (15.15%) were the major components in the flowers. In vitro anti-aging activity was measured via assessing collagenase and elastase inhibition. Essential oils from the leaves and flowers showed potential collagenase inhibitory activity with IC₅₀ of 55.7 and 47.4 µg/mL. However, the oils from the leaves and flowers showed moderate anti-elastase activity with IC₅₀ of 60.8 and 97.7 µg/mL. Therefore, the oil of Leucophyllum frutescens could afford a promising natural anti-aging drug.