Nanocomposite Dye Sensitized Solar Cell (DSSC) Based on Titanium Oxide/Tungsten Oxide Photoelectrode

In the operational process of dye sensitized solar cell (DSSC) photo excitation of the sensitizer is followed by electron injection into the conduction band of the mesoporous oxide semiconductor. The dye molecule is regenerated by the redox system, which itself is restored at the counter electrode by electrons passed through the load. Some electrons in conduction band of the photo-electrode travel back to the electrolyte, which results in a loss of efficiency in the DSSC [1-2]. Therefore, it is important to suppress this recombination reaction and to improve the collection of photo-injected electrons for enhancing the cell performance [3]. Tungsten oxide (WO₃) is a semiconductor oxide material with a band-gap of 2.6–3.0 eV [3], and it is becoming the focus of research attention due to its unique electronic properties. Various WO₃ nanostructures (nanoparticles, nanoplatelets, nanorods, and nanowires) are of special interest as promising candidate [3, 4] as a photo-electrode.

It  is  well  known  that  polyaniline  (PANI)  is  one  of  the most  promising  conducting  polymers.  Due to its high electrochemical activity, environmental stability and low cost, PANI materials have been employed to fabricate efficient counter electrode in DSSCs [5].

Recently, there is a large interest to incorporate carbon nanotubes (CNTs) into organic solar cells because of the unique electrical properties of CNTs. For example, CNTs were used as electron acceptors in the photoactive layer of the solar cells [6]. Also, CNTs were used as transparent anodes in order to replace the prevailed wildly used indium tin oxide (ITO) [7].

In this work nanomaterials for photo- and counter-electrodes are synthesized and investigated. The morphological structures of WO₃ nanorods deposited onto TiO₂ nanoparticles and PANI-CNTs. The electro-catalytic activity of the counter electrode is investigated using cyclic voltammetry technique.

The  CNTs  blended  PANI  base  counter electrode  and  ruthenium  dye  sensitized  WO₃/TiO₂ based photo-electrode  were  assembled  to form DSSC. The electrical properties of the fabricated solar cells were investigated by measuring the current density voltage (J–V) under both darkness and illumination conditions. It was found that there is a significant improvement in the performance of DSSC used WO₃ nanorods.

References

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