Optimization of Solar Energy Conversion and Inherent Storage Capacity: Allura Red–NaLS–EDTA Photogalvanic System

Photogalvanic (PG) cells enable incident light to be converted into electrical energy and allow a portion of the generated energy to be retained within the electrolyte system. This study examined an alkaline Allura Red–sodium lauryl sulphate (NaLS)–ethylenediaminetetraacetic acid (EDTA) electrolyte, with Allura Red as photosensitiser, EDTA as reductant and NaLS as surfactant. Measurements were made in an H-shaped glass cell containing 25 mL of electrolyte, a platinum working electrode and a saturated calomel electrode. The platinum-electrode compartment was illuminated after the potential had stabilised in darkness; the second compartment remained shielded from illumination, and a water filter was used to reduce infrared heating. Photopotential and photocurrent were monitored, and current–voltage characteristics were obtained by varying the external resistance. The effects of dye, surfactant and reductant concentrations, pH, illumination intensity and electrode area were assessed. The reported optimum concentrations were 3.7 × 10⁻⁵ M Allura Red and 2 × 10⁻³ M each of NaLS and EDTA at pH 12.65; an incident intensity of 10.4 mW cm⁻² was specified for the concentration-dependent measurements. The reported photopotential and photocurrent were 545 mV and 414 µA, respectively, with a fill factor of 0.3671 and conversion efficiency of 1.32%. The power output declined to half its initial dark value after 80 min. These results describe measurable photoelectrical output and post-illumination power retention under the investigated conditions, while the detailed charge-transfer pathway remains a proposed interpretation.