Titanium Substrate Photoanode And New Style Counter Electrode For Dye-sensitized Solar Cells

Due to the global energy crisis, the development and utilization of solar energy has become a hot topic. As a new kind of resource-saving and environment-friendly solar cell, dye-sensitized solar cell (DSSC), which becomes the focal point in the field of new energy, has aroused a great attention among the engineering and academic domain. Traditional DSSCs use expensive and fragile FTO glass as substrate and noble platinum as catalyst for the reduction of the redox species. The fragility and high cost of FTO limits the development and application of DSSCs. Moreover, the noble platinum remarkably increases the cost of the DSSC. Thus, many alternative flexible substrates and cheap materials have been investigated for DSSCs.Based on the limitation of the conventional DSSC technology, the main research contents and work of this paper include three parts.Firstly, porous nano-crystalline TiO2film was prepared on titanium substrate using the screen printing process and its morphology and property was studied for the application in DSSC as photo-anode. It was found that the cell current density, fill factor and photoelectric conversion efficiency reached optimum values when the thickness of the TiO2film is14μm.Secondly, three kinds of different surface treatment methods for titanium substrate have been developed, including mechanical treatment, chemical treatment and anodic oxidation treatment. The treated titanium substrates were utilized for preparation of DSSC. It was found that these three pretreatment methods were able to increase the surface roughness and the surface area of the titanium substrate, leading to improvement of the performance in DSSCs.Thirdly, a simple and hydrazine-free solution-based approach for depositing Cu2ZnSnS4(CZTS) and Cu2ZnSn(S,Se)4(CZTSSe) layers is reported. The process involved incorporating metal salts (Cu(CH3COO)2, Zn(CH3COO)2, SnCl2) and thiourea into a single pyridine-based solution, spin-coating a precursor film, and selenizing using Se pellets in an inert atmosphere, to form the desired CZTSSe films. The formed CZTSSe films on FTO were used as counter electrodes for DSSCs. Compared with the case of the unselenided copper-zinc-tin-sulfur electrode and platinum counter electrode for DSSC, CZTSSe electrode showed improved crystallinity and catalytic performance in DSSCs.