Halochromic effect/transitions and their role in the efficiency of chromotrope 2B-based photo-galvanic cells

Abstract

The present research study investigates photo-galvanic cells by leveraging the halochromic effect of the water-soluble chromotrope 2B dye. Exploitation of the pH-induced structural transitions of this photo-sensitizer in a photo-galvanic system containing a sodium thiosulphate pentahydrate reductant and a sulfamic acid surfactant achieves encouraging solar energy conversion. Experimental results reveal a robust electrical output, including a power of 1195.04 µW, current of 8.27 mA, and potential of 738 mV. The system demonstrated a remarkable conversion efficiency of 3.55% and fill factor of 0.19. Statistical analysis further validated the stability of the system, noting a negative alloy electrode potential (i.e., −830.51 mV). By correlating the halochromic color-shifting properties of chromotrope 2B with cell performance, this study provides critical insights into how pH-sensitive molecular transitions can be strategically exploited for more efficient and sustainable solar energy storage and generation in the future.