SnS-Quantum Dot Solar Cells Using Novel TiC Counter Electrode and Organic Redox Couples

Low-cost quantum-dot sensitized solar cells (QDSSCs) were fabricated by using the earth-abundant element SnS quantum dot, novel TiC counter electrodes, and the organic disulfide/thiolate (T 2 /T − ) redox couple, and reached an efficiency of 1.03 %. QDSSCs based on I − /I 3 − , T 2 /T − , and S 2− /S x 2− redox couples were assembled to study the role of the redox couples in the regeneration of sensitizers. Charge-extraction results reveal the reasons for the difference in J SC in three QDSSCs based on I − /I 3 − , T 2 /T − , and S 2− /S x 2− redox couples. The catalytic selectivity of TiC and Pt towards T 2 /T − and I − /I 3 − redox couples was investigated using Tafel polarization and electrochemical impedance analysis. These results indicated that Pt and TiC show a similar catalytic selectivity for I − /I 3 − . However, TiC possesses better catalytic activity for T 2 /T − than for I − /I 3 − . These results indicate the great potential of transition metal carbide materials and organic redox couples used in QDSSCs. Graphical Solar cells : Quantum-dot sensitized solar cells (QDSSCs) were fabricated using counter electrodes based on earth-abundant SnS and TiC and the organic disulfide/thiolate (T 2 /T − ) redox couple (see figure). The loss of photocurrent in QDSSCs based on different redox couples (I − /I 3 − , T 2 /T − , and S 2− /S x 2− ) was ascribed to the inability of the redox couples to regenerate the sensitizer.