Enhancing Power Conversion Efficiency of Natural Dye-Sensitized Solar Cells Through Pigment Interaction Analysis of Delonix regia Extracts

Dye-sensitized solar cells (DSSCs) represent a promising low-cost photovoltaic technology with relatively high conversion efficiency and a simple fabrication process. Natural dyes have drawn growing interest compared to ruthenium-based dyes since they are greener. However, the power conversion efficiency (PCE) of natural dyes is generally low. In this study, we investigated novel approaches to improve the PCE of DSSCs using Delonix regia extracts by polarity-based separation using preparative thin-layer chromatography (PTLC). Our study indicated that polarity-based separation can significantly enhance the PCE, with one fraction achieving a PCE of 1.13%, which is high compared to most natural dye-based DSSCs, and is also 1.85 times that of the crude methanol extract. The major compounds in the highest-efficiency layer were flavanol-based dyes. Our study demonstrates the potential antagonistic effects within Delonix regia extracts in DSSC applications, which play a critical role in improving PCE. The study is expected to support future efforts to enhance the PCE of natural compound-based DSSCs, especially those using flavanol-based natural dyes.