title: Construction of nanocrystalline film on nanowire array via swelling electrospun polyvinylpyrrolidone-hosted nanofibers for use in dye-sensitized solar cells.
abstract: A 74% enrichment of the efficiency of ZnO nanowire (NW) dye-sensitized solar cells (DSSCs) is achieved by the addition of a novel light-scattering nanocrystalline film (nanofilm). The 100 nm thick nanofilm is derived from the polyvinylpyrrolidone-hosted SnO(2)/ZnO nanofibers electrospun on the top of ZnO NW arrays via methanol vapor treatment followed by high-temperature calcination. Structural characterizations show that the film is composed of SnO(2) and ZnO nanocrystals with a diameter of ∼10 nm. Short-circuit current, open-circuit voltage, and fill factor of the nanofilm/ZnO NW DSSCs are all superior to those of the ZnO NW DSSCs. The mechanism of photocurrent enhancement in the nanofilm/ZnO NW DSSCs has been investigated using optical modulation spectroscopy. Intensity modulation photocurrent spectroscopy (IMPS) measurements reveal that the dye-sensitized nanofilm does not contribute significant photocurrent in the nanofilm/ZnO NW DSSCs. The significant enhancement of the efficiency of the ZnO NW DSSCs is achieved by reflecting unabsorbed photons back into the NW anode using the novel light-scattering layer of nanofilm.
authors.affiliation: Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan. wujj@mail.ncku.edu.tw
authors.forename: Jih-Jen
authors.initials: JJ
authors.lastname: Wu
authors.forename: Yan-Ru
authors.initials: YR
authors.lastname: Chen
authors.forename: Wen-Pin
authors.initials: WP
authors.lastname: Liao
authors.forename: Chun-Te
authors.initials: CT
authors.lastname: Wu
authors.forename: Chuh-Yung
authors.initials: CY
authors.lastname: Chen