Self-nanostructured ZnO center dot Al conductive layers consisting of [11 (2) over bar0] oriented domains were coated by a conformal TiO2 thin film and sensitized by 5, 10, 15, 20-tetrakis-(4-carboxyphenyl)porphyrin (TCPP) to be used as transparent conductive electrodes in dye-sensitized solar cells. In addition to the higher surface availability due to the nanopatterning, the TCPP surface density increases by 330% (UV-vis) with respect to a flat conventional substrate thanks to a more sense molecular arrangement, as evidenced by combining high-resolution X-ray photoelectron spectroscopy and atomic force microscopy. Furthermore, the presence of zinc atoms in the TiO2 overlayer (Ti(:Zn)O-2) crucially influences the electronic properties of the assembled TCPP. As a consequence of the orbitals rearrangement attributed to the presence of zinc, a significant quenching of luminescence is observed in the emission spectra of TCPP-sensitized Ti(:Zn)O-2,O- suggesting that electrons could be more effectively injected from the molecular orbitals to the conduction band of the semiconductor.
Dye-Sensitizing of Self-Nanostructured Ti(:Zn)O-2/AZO Transparent Electrodes by Self-Assembly of 5,10,15,20-Tetrakis(4-carboxyphenyl)porphyrin
CONDORELLI, Guglielmo Guido;
2011-01-01
Abstract
Self-nanostructured ZnO center dot Al conductive layers consisting of [11 (2) over bar0] oriented domains were coated by a conformal TiO2 thin film and sensitized by 5, 10, 15, 20-tetrakis-(4-carboxyphenyl)porphyrin (TCPP) to be used as transparent conductive electrodes in dye-sensitized solar cells. In addition to the higher surface availability due to the nanopatterning, the TCPP surface density increases by 330% (UV-vis) with respect to a flat conventional substrate thanks to a more sense molecular arrangement, as evidenced by combining high-resolution X-ray photoelectron spectroscopy and atomic force microscopy. Furthermore, the presence of zinc atoms in the TiO2 overlayer (Ti(:Zn)O-2) crucially influences the electronic properties of the assembled TCPP. As a consequence of the orbitals rearrangement attributed to the presence of zinc, a significant quenching of luminescence is observed in the emission spectra of TCPP-sensitized Ti(:Zn)O-2,O- suggesting that electrons could be more effectively injected from the molecular orbitals to the conduction band of the semiconductor.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
