Flexible fiber-shaped liquid/quasi-solid-state quantum dot-sensitized solar cells based on different metal sulfide counter electrodes

Flexible fiber-shaped quantum dot-sensitized solar cells (QDSSCs) were fabricated by assembling the CdS/CdSe quantum dot deposited TiO2 nanotube photoanodes and different metal sulfide (i.e., NiCo2S4, Ni9S8, and Co3S4) counter electrodes (CEs) all grown on Ti wires with a liquid or gel polysulfide electrolyte. Using the NiCo2S4 CEs, the best power conversion efficiencies of 3.41% and 2.76% were obtained for the resultant fiber-shaped QDSSCs with the liquid and gel polysulfide electrolytes, respectively. Impressively, all the metal sulfide electrodes showed considerable stability under electrochemical cycling tests.