Delving into judiciously extracted inexpensive micro-algal dyes for DSSCs: Spectral decipherment and time-oriented extraction systems

Abstract

The temperature and extraction techniques used for natural dye fabrication in dye-sensitized solar cells have significant implications for the future economy, influencing the efficiency and yield of dye extraction. This study analyzes the optical properties of microalgal dyes, examining reflectance and photo-electron energy scans, alongside emission rates in the UV–visible region, using aqueous methanol and ethanol solvents. Different time-oriented extraction methods, involving heating and a combination of sonication and heating, are assessed for their impact on specific and non-specific dye and pigment peaks. Extended heating periods result in dye degradation, while longer sonication proves efficient at 60 °C. The sonication technique's efficiency exponentially increases with Scenedesmus sp. concentration but not as much with Asterarcys quadricellulare at 60 °C. Asterarcys quadricellulare exhibits higher efficiency with ethanol, especially at 80 °C, and performs comparably with Scenedesmus sp. The optimal heating duration ranges from 10 to 25 min, while sonication is more efficient within 25 to 40 min for both temperatures.