Unlocking the potential of chlorophyll-based carbon dots towards water-splitting, white-light LED and encryption applications

Abstract

The versatile traits of carbon dots (CD) have positioned them as a compelling subject of study across various burgeoning fields. This work has successfully sourced CD from a porphyrin-containing compound, chlorophyll, which boasts outstanding light-harvesting and energy transfer capabilities. CD with excellent physicochemical properties were synthesized using a low-cost solvothermal method. The optical properties of CD have been harnessed for water-splitting applications with ZnO, resulting in significantly improved current efficiency of the photoanodes. When irradiated with AM1.5 G illumination, ZnO/CD heterojunction provided the highest photocurrent efficiency (0.225 mA/cm2 at 1.23 V vs RHE) as a result of enhanced light absorption across the UV to the visible region and improved interfacial charge transfer kinetics in comparison to the pristine ZnO. Additionally, the nanocomposite prepared of CD and boric acid (BACD) evinced promising naked eye phosphorescence for 10 s with an average phosphorescence lifetime of 1.5 s. The BACD nanocomposite was used as a free-standing thin film phosphor material for white light LED preparation and as an ink for data encryption. The results demonstrate that the acquired CD hold substantial promise for a variety of applications.