Sensitized Solar Cells Based On TiO₂ Nanostructure

Dye sensitized solar cell (DSSC) has important research and application value in the field of renewable energy due to their excellent properties of simple technology, low cost and stable performance. Perovskite solar cell (PSC) was developed from DSSC and its rapid development of efficiency has aroused a lot of attention from the energy field. After several years of development, the efficiency of PSC has exceeded 20%. Titanium dioxide (TiO2) is the most used inorganic semiconductor material in the photovoltaic field. And its morphology and property have important influence on the efficiency of photovoltaic device. The thesis is oriented by the modifications of technology and performance of photovoltaic device. Based on the preparation and application of inorganic nanomaterials, we studied the optimization of materials and devices.Size controlled TiO2 microspheres were synthesized by simple solvothermal reaction. The size effect and nanoparticulate aggregate structure of TiO2 microsphere can contribute to improve the electrical and optical properties of DSSC, which result in the enhancement of device efficiency from 6.81% to 8.20%. The prepared bi-layer anode was further treated with TiCl4 solution containing magnesium ion in order to optimize the dye adsorption capacity and electron transport performance of bi-layer anode. Therefore, the efficiency of DSSC based on bi-layer anode can be optimized to 9.12%.Based on the principle of chemical reaction between metal titanium and alkaline solution, network-like nanoporous structures were synthesized by hydrothermal reaction. We studied the relationship between hydrothermal condition and nanostructure morphology and the controllable synthesis of different three-dimensional (3D) network nanoporous structures. One kind of these nanostructures was used in fiber dye sensitized solar cell (FDSSC) as the interface between Ti wire and TiO2 nanoparticle film. It can improve the deposition of nanoparticle film and electron transport performance of FDSSC. As a result, the efficiency of FDSSC was increased to 4.64% from 2.56%. In addition, we combine hydrothermal reaction with magnetron sputtering to synthesize TiO2 network nanoporous structure consisted of TiO2 nanowires on FTO glass. The one-step sintering for TiO2 can reduce the interface problem. Compared with traditional nanoparticle porous structure,3D network nanoporous structure is more beneficial to the deposition of perovskite film and the transport of carrier. In result, the efficiency of this new mesoporous perovskite solar cell has enhanced to 12.78% from 9.59%.Tin dioxide (SnO2) film with high resistance prepared by low-temperature magnetron sputtering was used in planar perovskite solar cell, which overcomes the high sintering temperature of TiO2 film. Based on the high transmittance and high mobility of SnO2, we obtained excellent planar perovskite solar cell used SnO2 film as hole blocking layer with the optimized efficiency of 13.68%. What's more, we fabricated the hole blocking layer at room temperature, and we achieved the low temperature device preparations.