Novel semiconducting CdSe quantum dot based electrochemical capacitors

For the first time, we report on novel electrochemical capacitors using semiconducting CdSe quantum dots (QDs) as electrodes. Semiconducting QDs with two colors (red, orange) possessing high quantum yield were deposited on transparent ITO substrates to form electrodes of the electrochemical supercapacitors. The two kinds of QDs demonstrated typical capacitive cyclic voltammetry behavior in 2 M H2SO4 aqueous solution. Red QDs demonstrated higher mass-specific capacitance (over 10-fold) compared to orange QDs. Red QDs exhibited stable cycle stability and low internal resistance. Our study demonstrated semiconductor CdSe QDs can be incorporated to high-performance supercapacitors. These novel electrode materials of QDs can pave new way to QD-based energy storage devices or electrochemical sensors.