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 (T2/T-) redox couple, and reached an efficiency of 1.03?%. QDSSCs based on I-/I3-, T2/T-, and S2-/Sx2- 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 JSC in three QDSSCs based on I-/I3-, T2/T-, and S2-/Sx2- redox couples. The catalytic selectivity of TiC and Pt towards T2/T- and I-/I3- 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-/I3-. However, TiC possesses better catalytic activity for T2/T- than for I-/I3-. These results indicate the great potential of transition metal carbide materials and organic redox couples used in QDSSCs.