Aggregation-Induced Modulation of the Optoelectronic Properties of Carbon Dots and Removal of Cd2+ Ions with Sustainable Use in Photocurrent Generation

Abstract

Herein, we report the room-temperature fabrication of carbon dots (C-dots) using UV light irradiation within 15 min. The formation pathway has been investigated by time-dependent mass spectroscopic and transmission electron microscopic (TEM) studies. The inherent insolubility of carbon dots in organic solvents has been overcome by employing the phase-transfer strategy, and the C-dots have been found to remain in aggregated state in organic solvents. Interestingly, aggregation leads to the generation of a considerable amount of current conductivity in carbon dots, as is evident by current–voltage (I–V) measurements. This is not attainable by carbon dots in aqueous solution. However, the aggregates of C-dots do not show any photocurrent response. The phase transfer of C-dots has also been utilized to remove the toxic Cd2+ ions from contaminated water by dragging them into the organic solvents with carbon dots. The C-dots–metal hybrid obtained by the removal of Cd2+ with carbon dots in organic medium shows a very good photoresponsive nature with significant photogain. This suggests proper utilization of the removed (from polluted water) cadmium ions in a sustainable manner for photocurrent generation.