Super-capacitors interfaced with quantum dots at the electrolyte/electrode interface: capacitance gain and fluorescence line-width narrowing

TL;DR

This study demonstrates that embedding quantum dots at the electrolyte/electrode interface in supercapacitors significantly enhances capacitance and fluorescence properties, revealing new insights into interface effects and potential for light-sensitive energy storage devices.

Contribution

It introduces a novel approach of integrating quantum dots at the electrolyte/electrode interface to enhance supercapacitor performance and fluorescence characteristics.

Findings

Capacitance amplification up to 2.5 times at specific QD concentrations

Fluorescence line narrowing indicating fluorescence gain

Enhanced interface understanding through fluorescence and capacitance measurements

Abstract

Quantum dots (QDs), embedded in supercapacitors (S-C) cells exhibited capacitance amplification that peaked at certain QD concentration. More than 2.5 peak amplification was demonstrated with cyclic voltammetry (C-V) at a scan rate of 0.1 V/s. The mass ratio of the dots to that of the active-carbon electrode (A-C) was less than 1:5000. Fluorescence signals from dry (without electrolyte) and wet (with electrolyte) samples, exhibited a correlated, substantial peak enhancement vs QD concentration, as well. In the case of wet samples, fluorescence line narrowing was demonstrated, which indicates a substantial fluorescence gain. Both effects are attributed to local field effects through formation of a colloidal array at the electrode/electrolyte interface. Embedding QDs at the electrolyte/electrode interface has an added value that it may be further enhanced by white light and indeed this is the case here. Probing the electrolyte/electrode interface with fluorescing materials adds to our basic knowledge of the interface and could be useful for light-sensitive S-C cells.