Synergistic Photosensitization of Mixed Dye Extracts from Gumamela (Hibiscus rosa-sinensis L.) Flowers and Banana (Musa acuminata L.) Leaves in a Dye-Sensitized Solar Cell

Abstract

INTRODUCTION

Dye-sensitized solar cells (DSCs) "photovoltaic cells with a dye photosensitizer anchored on a semiconductor” are known for their ease of manufacture, design simplicity, and adaptability in lighting conditions. Recent studies suggest that organic pigments, in replacement for costly synthetic dyes, show remarkable potential in DSCs. in this study, the illuminated current –density-voltage (J-V) characteristics of DSCs with ethanolic dyes from gumamela (H. rosa-sinensis L.) flowers, banana (M. acuminata L.) leaves, and a 1:1 mixture were determined.

METHODS

The electrodes were prepared by screen-printing titanium nanoxide (anode) and a platinum precursor (cathode) on fluorine tin oxide doped glass. The DSCs, after soaking the sintered photoanode layer in the dye solutions (1g: 6 mL concentration) for twelve (12) hours at a temperature of 30 °C, were injected with an iodide-triiodide liquid electrolyte. All setups were subjected under 50 mW LED (4.5 lumens) illumination at an ambient temperature of 30°C. The corresponding J-V and power-voltage curves (P-V) were constructed across varying resistances.

RESULTS

The DSC with 1:1 mixture of gumamela flower and banana leaf dyes exhibited J-V parameters (JSC = 22.5 μA/cm2, VOC = 228 mV, FF = 0.693, and Ε = 0.11%) higher than the gumamela flower (JSC = 4.75 μA/cm2, VOC = 183 mV, FF = 0.513, and Ε = 0.014%) and banana leaf (JSC = 16.4 μA/cm2, VOC = 205 mV, FF = 0.577, and Ε = 0.062%) solar cells' alone.

DISCUSSIONS

The results of the study show that the mixture dye exhibited higher efficiency and better J-V parameters over the unmixed dyes alone, which may be attributed to the superimposition of the absorption peaks of the single dyes in the mixed dye. Hence, photosensitizers of relatively higher efficiencies can be prepared by suitably mixing dye sensitizers in order to absorb light over a wider range of frequencies.