title: Highly efficient ZnO/Au Schottky barrier dye-sensitized solar cells: Role of gold nanoparticles on the charge-transfer process.
abstract: Zinc oxide (ZnO) nanorods decorated with gold (Au) nanoparticles have been synthesized and used to fabricate dye-sensitized solar cells (DSSC). The picosecond-resolved, time-correlated single-photon-count (TCSPC) spectroscopy technique was used to explore the charge-transfer mechanism in the ZnO/Au-nanocomposite DSSC. Due to the formation of the Schottky barrier at the ZnO/Au interface and the higher optical absorptions of the ZnO/Au photoelectrodes arising from the surface plasmon absorption of the Au nanoparticles, enhanced power-conversion efficiency (PCE) of 6.49% for small-area (0.1 cm(2)) ZnO/Au-nanocomposite DSSC was achieved compared to the 5.34% efficiency of the bare ZnO nanorod DSSC. The TCSPC studies revealed similar dynamics for the charge transfer from dye molecules to ZnO both in the presence and absence of Au nanoparticles. A slower fluorescence decay associated with the electron recombination process, observed in the presence of Au nanoparticles, confirmed the blocking of the electron transfer from ZnO back to the dye or electrolyte by the Schottky barrier formed at the ZnO/Au interface. For large area DSSC (1 cm(2)), ~130% enhancement in PCE (from 0.50% to 1.16%) was achieved after incorporation of the Au nanoparticles into the ZnO nanorods.
authors: Center of Excellence in Nanotechnology, School of Engineering and Technology, Asian Institute of Technology, P. O. Box 4, Klong Luang, Pathumthani 12120, Thailand.
authors: Tanujjal
authors: T
authors: Bora
authors: Htet H
authors: HH
authors: Kyaw
authors: Soumik
authors: S
authors: Sarkar
authors: Samir K
authors: SK
authors: Pal
authors: Joydeep
authors: J
authors: Dutta