Organic molecule controlled synthesis of three-dimensional rhododendron-like cobalt sulfide hierarchitectures as counter electrodes for dye-sensitized solar cells

Abstract

Three-dimensional rhododendron-like cobalt sulfide (CoS) hierarchitectures have been prepared via a simple hydrothermal approach based on an organic molecule directing method. The growth of the CoS nanostructure is described in detail and the performance of the dye-sensitized solar cell based on the CoS counter electrode is evaluated. The hierarchitectures are constructed with two-dimensional nanosheets. The growth of the nanosheet is induced by cysteine and ethylenediamine, and the thickness of the nanosheet is found to be dependent on the reaction time. Electrochemical measurements reveal that the rhododendron-like CoS is a superior catalyst towards the reduction of triiodide (I₃⁻). When it is used as a counter electrode for dye-sensitized solar cells, the power conversion efficiency is up to 3.53%, which is comparable to the efficiency of the cell with a Pt counter electrode (3.93%).