Bifunctional One-Dimensional Hierarchical Nanostructures Composed of Cobalt Sulfide Nanoclusters on Carbon Nanotubes Backbone for Dye-Sensitized Solar Cells and Supercapacitors

Abstract

One-dimensional (1D) hierarchical nanostructures composed of CoS1.097 nanoclusters directly grown on carbon nanotube (CNT) backbone (CNT@CoS1.097) were successfully synthesized by a facile glucose-assisted hydrothermal method. It was found that glucose acted as a binder to assist the hierarchical CoS1.097 nanoclusters grown on the surfaces of CNTs with uniform coverage along the longitudinal axis. The extensive electrochemical measurements confirmed that the CNT@CoS1.097 nanocomposite indeed provided simultaneously enhanced electrical conductivity and superior electrochemical activity as electrode materials for dye-sensitized solar cells (DSCs) and supercapacitors (SCs). The DSC assembled with the CNT@CoS1.097 nanocomposite counter electrode (CE) achieved an enhanced photovoltaic conversion of 7.18% to those of DSCs based on the Pt, CNT, and CoS1.097 CEs. Additionally, serving as a SC electrode, this nanocomposite delivered a remarkable specific capacitance of 541 F g–1 at 32 A g–1 and a stable reversible specific capacitance of 640 F g–1 after consecutive 3000 charge/discharge at 8 A g–1. These results demonstrate that the CNT@CoS1.097 nanocomposite electrode is quite promising to be considered for high-performance DSCs and high-rate SCs.