The Synthesis Of Sulfides And Their Application In Dye-sensitized Solar Cell

The most common used catalytic material of counter electrodes (CEs), one of the three crucial components of dye-sensitized solar cells (DSCs), is Pt. However, as an expensive noble metal, Pt can be easily corroded in I3-/I-electrolyte, limiting the DSC commercialization process of Pt used as the CE greatly. Therefore, it is important to develop Pt-free CE catalytic materials which is low-cost and high efficient to cut down the DSC cost as well as to improve its stability.In recent years, the sulfide materials have been widely used on the catalysis of petroleum products, lubricating materials, high temperature materials and other fields because of its abundant resources, security, environmental friendliness and stable chemical properties. However, there are few reports regarding sulfides used on CE materials of DSC. In this study, several sulfides were synthesized and introduced into the DSC as CE catalytic material, as well as several composite materials doped three kinds of carbon. The DSC was fabricated and the performances were evaluated.First, we have obtained shape-controlled ZnS and MoS2particles by improving synthesis methods, which are used as the counter electrode materials of DSC. The efficiency of DSC is1.40%while the ZnS is used as the CE catalytic material. And the efficiency of DSC is6.44%while the MoS2is used as the CE catalytic material.Second, ZnS and MoS2were doped by three kinds of carbon respectively in different mass ratios, which included activated carbon (Ca), conductive carbon (Cc) and nanotubes carbon (CNTs). Among of them, DSC efficiencies of ZnS doped Ca, Cc, and CNTs as electrode material were3.30%,5.33%and4.82%, respectively. DSC efficiencies of MoS2doped with Ca, Cc, and CNTs as electrode material were6.84%,4.96%and7.29%, respectively. Activated carbon, conductive carbon powder and carbon nanotubes have good corrosion resistance and electrical conductivity, improving the performance of sulfide catalyst material greatly. And they have high catalytic performance on the catalysis of the I3-/I-redox couple’s cycle reaction.Finally, studies were carried out on catalytic mechanism of the conventional redox couple (I3-/I-) by Tafel polarization curves (Tafel), cyclic voltammetry (CV) and electrochemical impedance (EIS) experiments. ZnS and MoS2as well as its carbon-doped composite materials exhibit high catalytic performance on the reduction reaction of conventional redox (I3-/I-). In summary, two kinds of catalytic material of sulfide were synthesized in this study. And composite materials were synthesized by sul fides doped with Ca. Cc and CNTs. Sulfides and their composite materials are used as counter electrode materials of DSC. We have obtained higher energy conversion efficiency, reducing the costs of DSC.