Fig. 4: Cyclic voltammetry measurement.

a Schematic of the QD/ionic liquid/Pt sandwich structure for two-electrode measurement, and b the equivalent circuit. C’EDL is the capacitance formed at the Pt/ionic liquid interface, CIL is the bulk capacitance of the ionic liquid, and CEDL is the capacitance between the ionic liquid and QD layer. CT is the total capacitance obtained in the CV measurement. c Cyclic voltammograms of two-electrode devices that contain a PbS QD assembly deposited by spin-coating (green, dotted line), dip-coating (blue line), and liquid-air interfacial assembly (magenta, dashed line). d Areal capacitance of devices derived from CV measurements.