Study On Carbon Nanotube Counter Electrode And Titanium Dioxide Photoanode Of Dye-Sensitized Solar Cells

Dye-sensitized solar cells（DSSCs） have attracted extensive attention in industrial and academic fields since their discovery in the early 1990 s, owing to their low cost, environmental friendliness, good performance in weak light conditions, and simple manufacturing processes. The electrocatalytic activity of counter electrode for reducing electrolyte, photoanode structure, and dye adsorption amount are the keys to affect cells efficiency in dye sensitized solar cells. In the paper, carbon nanotube counter electrode and titanium dioxide photoanode of dye-sensitized solar cells were studied to improve the efficiency of dye sensitized solar cells and decrease the cost of device, the main research content of the paper is as follows:1. Carbon nanotubes（CNTs） with different morphologies were introduced dye sensitized solar cells（DSSCs） as low-cost substitutes for Pt counter electrode（CE）. The study found that the long carbon nanotubes possess better electrocatalytic activity than short carbon nanotubes, and the dye sensitized solar cells with long carbon nanotube as counter electrode obtained the photoelectric conversion efficiency of 2.42%, which was improved 19.8% compared with the DSSCs using short carbon nanotubes as counter electrode; the electrocatalytic activity of aligned multi-walled carbon nanotubes（AMWCNTs） were superior to the long carbon nanotubes, and the cells achieved a high photoelectric conversion efficiency of 2.95%.However, CNTs have a very high tendency to form agglomerates, thus reducing the electrochemical properties of CNTs. Therefore, CNTs were functionalized noncovalently by lysozyme（LZ）, cetyl pyridinium chloride（CPC）, deoxycholate sodium（NaDC） and polyethylene glycol octylphenol ether（Triton X-100） to improve its dispersion and introduced DSSCs as counter electrode. The study found that the Triton X-100 functionalized carbon nanotubes possessed relatively good dispersion and electrocatalytic activity after functionalization of carbon nanotubes, and the corresponding cells had relatively high efficiency.2. Two different TiO₂ microspheres were synthesized by hydrothermal method from titanium sulfate and employed into DSSCs as photoanode. The research found that Ti O₂ microsphere with loose construction and rough surfaces was applied on photoanode, the cells exhibited better photoelectric performance than the cells with dense TiO₂ microsphere photoanode.In order to further increase the adhesion of photoanode, TiO₂ nanoflowers were growth directly on the FTO conductive glass substrate through hydrothermal method under different temperature using different amount of tetra n-butyl titanate as precursor, HCl solution as solvent. When the amount of the butyl titanate was 1.5 ml, TiO₂ nanoflowers with uniform morphology were obtained and the corresponding DSSCs obtained the highest photoelectric conversion efficiency（1.83%）. And then, it was found by adjusting temperature: when the growth temperature of TiO₂ nano-membrane rose from 150 °C to 165 °C, the efficiency of the cells increased from 0.14% to 0.39%; when the growth temperature drops to 135 °C, the efficiency of corresponding DSSCs was also reduced, which indicated that the growth temperature of TiO₂ nano-membrane is helpful to improve the performance of dye sensitized solar cells.