Effects of silicon-nanoparticles in suppression of electron recombination in TiO2 based dye-sensitized solar cell
Idriss Bedja*, Ravindra Kumar Gupta
Using electrochemical etching of silicon wafers, silicon nanoparticles (Si-np) with average size of 13 nm were synthesized and coated on mesoporous TiO2 surface. We present, here, for the first time, preliminary results of nanosecond transient absorption spectroscopy, a suppression of electron recombination at the interface Si-np/TiO2 and dye (N719) by slowing down the recombination lifetime from 0.17 ms to 3.7 ms. In the other side, nanosecond transient emission spectroscopy has proved that ultrafast injection of excited electrons to TiO2 has not been affected with a measurement of 30 ns fast relaxation time of excited state of the dye. The transport of the injected electron in the Si-np layer to the TiO2 conduction band should only be occurred by tunneling effect since 13 nm Si-np were aggregated from less than 3-4 nm as exhibited by red luminescence.
Keywords: Nanoparticles, Spectroscopy, Dye-sensitized solar cells