| As the society developing, the demand for energy is increasing. It has been estimatedthat the conventional energy sources (fossil energy) can only satisfy our demand in20-30 years. So developing new energy sources, especially which have no pollution andcan be used for a long time, is very urgent and necessary. Solar energy is a promisingnew energy source. It can not be exhausted, its storage is very large and it does notpollute the environment. Exploiting solar energy has several ways; solar cell is a veryimportant way. But conventional solar cells are expensive; its cost limited itspopularization. To decrease the cost of solar cells, researchers did a lot of works. By theachievement of Nanometer Science and Technology in the last decade, the research ofdye-sensitized nano-network electrode photoelectrochemical cell has been driven.Dye-sensitized nano-crystalline solar cell is a kind of photoelectrochemical cells, whichcan convert solar energy into electrical energy. Before the several breakthroughs in the90s, most of the dye-sensitized solar cells had relative low efficiency. In 1991 Dr.Gratzel made a solar cell which has the efficiency of 7.1% and IPCE>=80%. In thissolar cell Dr Gratzel adopted nanometer porous TiO2 film as electrode, Ru- metalorganic compound as dye and LiI/I2 as redox electrolyte. From then, the research area ofdye-sensitized nano-crystalline solar cell became flourished.And the dye-sensitized nanometer TiO2 solar cell became a promising substitute of theconventional solar cells.Up to now, the knowledge of dye-sensitized TiO2 nano-crystalline solar cell is far frommature. And there are a lot of problems waiting to solve, especially the problems aboutthe basic processes in the cell and how the cell works. To study these problems we mustknow the relations between the internal parameters and the external properties. But themeasurement of internal parameters is a very difficult task. So studying these problemsby computer simulation is a good idea.Up to now, a few works have been done in the area of computer simulatingdye-sensitized TiO2 nano-crystalline solar cell. These works are mainly in two aspects:1) electrochemical modeling, 2) light flux transfer modeling. These works has veryimportant instruction effect, and increase our knowledge about this kind of solar cell.But these works also have some shortages. For example, they do not calculate the effectof solar cell's internal parameters on the basic processes in the cell; and they can notgive a quantitative relation between the optical process and the electrochemical processin the cell. This thesis will focus on these shortages. 3In this thesis we set up a quasi-one dimensional model, this model includes both theelectrochemical process and the optical process. In this quasi-one dimensional model,we adopt the diffuse-draft model to describe the transport of carriers, adopt ohmiccontact model to describe the anode, adopt the current-overpotential model to describethe cathode, adopt the Four-flux transfer model to describe the transfer of light, adoptthe Mie scattering theory to describe the light scattering process. This quasi-onedimensional model can calculate the carrier density distribution in the cell, the carrierflux density distribution in the cell, the electrical field distribution in the cell and thelight intensity distribution in the cell. It can also be used to research the effect of thecell's internal parameters on the cell's basic process.Computer simulation was performed by this quasi-one dimensional model, there aresome main conclusions:1) The potential drop in the cell was very little; the effect of electrical field on the carrier's transport and cell's output voltage can be neglected. The main power for carrier's transport is the grads of density. The light to electricity process is mainly determined by the dynamics-process in the cell.2) The electron density distribution... |
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