Comparison of Trap-State Distribution and Carrier Transport in TiO2 Nanotubular and Nanoparticular Electrodes of Dye Sensitized Solar Cells

In this paper we have studied the performance of dye-sensitized solar cells (DSCs) based on nanotube arrays of TiO2 with different lengths and compared them to nanoparticular films. By measuring electron transport time and lifetime using transient photocurrent and photovoltage techniques we found out the electron transport is quit comparable in these two morphologies however the electron lifetime is much longer in nanotubular structure so we have much larger electron diffusion length and charge collection efficiencies in nanotubular electrodes. By measuring extracted charges at open circuit condition we found that nanotubular structure have higher density of traps in deeper levels that make it difficult for electrons to transport through these one-dimensional ordered nanostructures, so in spite of high degree of order we have quit comparable transport time similar to nanoparticulate electrodes.

کلیدواژه ها:

TiO2 nanotube arrays ، Dye sensitized solar cell ، Electron lifetime ، Electron trapping