Preparation Of Titanium Dioxide Semiconductor Materials And Their Applications In Thin Film Solar Cells

Since the global warming and serious energy crisis, effective utilization of solar energy has attracted significant attention. Solar cell is an effective way to make full use of solar energy. As a new type of thin film solar cell, dye-sensitized solar cell (DSC) is an alternative to silicon solar cell due to its high photoelectric conversion efficiency, low cost, environmental friendly, and simple manufacture. Recently, the highest photoelectric conversion efficiency of DSC reached12%. However, it is still necessary to further improve the photoelectric conversion efficiency and long-term stability of DSC. Inorganic-organic heterojunction solar cell (HSC) is a new type of thin film solar cell, which can take advantage from inorganic materials such as high electron mobility, large surface area, high molar absorption coefficient, as well as the easy-processing and flexibility of polymer semiconductors. Still, the performance of HSC needs to be further improved compared with other types of thin film solar cells.In this paper, we improved highly efficient DSC by N doping modification and morphology controlling of TiO2. Furthermore, we prepared high-efficiency HSC using SnS-sensitized nanostructured hierarchically spherical TiO2electrodes and organic polymer as both hole transporter and electron donor.We improved the performance of TiO2materials by N-doping. A series of nanocrystalline N-doped TiO2were synthesized using titanium isopropoxide and ammonia as titanium and nitrogen source with varying initial N/Ti molar ratios. The effect of varying amounts of N dopant on the performance of DSC was investigated in detail. The conversion efficiencies of DSCs were significantly enhanced by N-doped TiO2electrodes. The best N-doped DSC yielded an efficiency of7.95%. N-doped DSC shows a higher electron transfer rate, better long-term stability, and shorter electron lifetime than the undoped ones.We synthesized two kinds of mesoporous TiO2spheres using template methods. The conversion. efficiencies of DSCs were significantly enhanced by spherical TiO2electrodes. DSCs based on mesoporous TiO2spheres reached an efficiency of9.52%and10.15%, which are12%and19%higher than the ones based on nanoparticles.We fabricated the HSCs which are composed of inorganic SnS-sensitized nanostruetured hierarchically spherical TiO2electrodes and organic polymer(P3HT). We further investigated the effect of SnS deposition time and different TiO2electrode morphology on the photovoltaic performance of HSCs. When SnS CBD time was3h, a promising efficiency of2.81%was obtained, which is47times higher than that without SnS. We also obtained a significantly high Voc of0.85V, which is0.2V higher than the values reported by other reports. The efficiency of HSC based on spherical TiO2electrodes is22-94times higher than that of other cells based on nanocrystals TiO2electrodes. The results demonstrate the important role of hierarchically TiO2sphere electrode for HSC.