Quantum Dot-Sensitized Solar Cells Featuring CuS/CoS Electrodes Provide 4.1% Efficiency

CuS, CoS, and CuS/CoS onto fluorine-doped tin oxide glass substrates were deposited to function as counter electrodes for polysulfide redox reactions in CdS/CdSe quantum dot-sensitized solar cells (QDSSCs). Relative to a Pt electrode, the CuS, CoS, and CuS/CoS electrodes provide greater electrocatalytic activity, higher reflectivity, and lower charge-transfer resistance. Measurements of fill factor and short-current density reveal that the electrocatalytic activities, reflectivity, and internal resistance of counter electrodes play strong roles in determining the energy-conversion efficiency (.) of the QDSSCs. Because the CuS/CoS electrode has a smaller internal resistance and higher reflectivity relative to those of the CuS and CoS electrodes, it exhibits a higher fill factor and short-circuit current density. As a result, the QDSSC featuring a CuS/CoS electrode provides a higher value of.. Under illumination of one sun (100 mW cm(-2)), the QDSSCs incorporating Pt, CuS, CoS, and CuS/CoS counter electrodes provide values of eta of 3.0 +/- 0.1, 3.3 +/- 0.3, 3.8 +/- 0.2, and 4.1 +/- 0.2%, respectively.