Photorechargeable Carbon Dot/Thermoresponsive Polymer Supercapacitor

Abstract

Photorechargeable energy storage devices, including batteries and supercapacitors, have attracted considerable interest as vehicles for efficient harvesting of solar energy. While photovoltaic cell-linked energy storage is widely utilized, reports on direct device photocharging have been rare. Herein, a photorechargeable supercapacitor in which a light-sensitive dielectric medium comprises a thermoresponsive poly(N-isopropylacrylamide) (pNIPAM), stabilized with a dicationic crosslinker, anchoring hydrophilic carbon dots (C-dots), is demonstrated. This design manifests significant photoinduced capacitance linked to the encapsulated C-dots. Specifically, the photothermal properties of the embedded C-dots give rise to a hydrophilic–hydrophobic phase transition of pNIPAM. Consequently, the C-dots are released from the hydrophobic pNIPAM framework, thereby becoming the solvated mobile electrolytes, generating enhanced capacitance and partaking in the redox reactions at the electrode surface. This work demonstrates, for the first time, a role for C-dots as photoactive electrolytes in photorechargeable supercapacitors, charting new avenues for solar charging of energy storage devices.