Electrolyte for quantum dot-sensitized solar cells assessed with cyclic voltammetry

Abstract

An intuitive method was designed to measure the performance of various electrolytes for quantum dot-sensitized solar cells (QDSSCs). Cyclic voltammetry (CV) measurements were used to evaluate the electrolyte performance using a standard three-electrode system composed of a working electrode, counter electrode, and reference electrode. CV measurements were carried out over the potential range of −0.7 to −0.1 V at a scan rate of 50 mV s−1 in five different polysulfide electrolytes. A higher reduction peak current in the CV curve indicated a faster rate of the redox reaction (S 2− to S2−) in the electrolyte. The QDSSCs were assembled into a sandwich structure consisting of a CdS/CdSe co-sensitized photoanode, a PbSe counter electrode, and a polysulfide electrolyte. Photocurrent density vs. voltage curves were measured for the assembled cells. The resulting energy conversion efficiency measurements were consistent with the CV results. An energy conversion efficiency of 5.14% was obtained for QDSSCs using an electrolyte containing 0.05 M 1,2-dimethyl-3-propylimidazolium iodide.