Effect of the electrophoretic deposition of Au {NPs} in the performance CdS {QDs} sensitized solar Cells

By Zaraz
Published in Electrochimica Acta NULL 2016

Abstract

Abstract Solution-processed mesoscopic oxide semiconductor-based materials offer potentially low-cost and high stability alternative for next generation of solar cells, and metallic nanoparticles had shown to be a good alternative to improve specific parameters in such kind of devices. In the present work, it is showed the systematic study of the effect of electrophoretic gold nanospheres (Au NPs) with cadmium sulfide Quantum Dots (CdS QDs) sensitized TiO2 solar cells. Au {NPs} were added by electrophoretic deposition at several times (0.5, 2.5 and 7.5 minutes) and CdS {QDs} were deposited by a Successive Ionic Layer Absorption and Reaction (SILAR) method. Electrophoretic deposition allowed to significantly decrease the Au {NPs} deposition times respect previously reported methods. The results show that Au {NPs} reduce the photocurrent (from 9.85 to 9.44 mA/cm2) at the same time that increase the open circuit voltage (Voc) (from 575 to 618 mV) and the Fill Factor (FF) (from 46 to 51%) which result in a final increase of the photoconversion efficiency (?) (from 2.63 to 2.96% for 0.5 min of deposit). A systematic characterization permitted to identify the origin of the variations observed in the solar cell parameters with and without Au NPs. Incident Photon to Current conversion efficiency (IPCE) demonstrate that the Au {NPs} reduces the amount of light that reach the CdS {QDs} and Impedance Spectroscopy (IS) analysis, indicates a downshift in the TiO2 conduction band (CB) and decreases the recombination processes, resulting in the observed increase in the {FF} and Voc.

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