title: Organized assemblies of single wall carbon nanotubes and porphyrin for photochemical solar cells: charge injection from excited porphyrin into single-walled carbon nanotubes.
abstract: Photochemical solar cells have been constructed from organized assemblies of single-walled carbon nanotubes (SWCNT) and protonated porphyrin on nanostructured SnO2 electrodes. The protonated form of porphyrin (H4P2+) and SWCNT composites form 0.5-3.0 microm-sized rodlike structures and they can be assembled onto nanostructured SnO2 films [optically transparent electrode OTE/SnO2] by an electrophoretic deposition method. These organized assemblies are photoactive and absorb strongly in the entire visible region. The incident photon to photocurrent efficiency (IPCE) of OTE/SnO2/SWCNT-H4P2+ is approximately 13% at an applied potential of 0.2 V versus saturated calomel electrode. Femtosecond pump-probe spectroscopy experiments confirm the decay of the excited porphyrin in the SWCNT-H4P2+ assembly as it injects electrons into SWCNT. The dual role of SWCNT in promoting photoinduced charge separation and facilitating charge transport is presented.
authors.affiliation: Radiation Laboratory and Department of Chemistry & Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA.
authors.forename: Taku
authors.initials: T
authors.lastname: Hasobe
authors.forename: Shunichi
authors.initials: S
authors.lastname: Fukuzumi
authors.forename: Prashant V
authors.initials: PV
authors.lastname: Kamat
mesh_terms: D004566:Electrodes; D008027:Light; D015394:Molecular Structure; D049329:Nanostructures / Q000737:chemistry; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000528:radiation effects; D010316:Particle Size; D010777:Photochemistry; D011166:Porphyrins / Q000737:chemistry* / Q000528:radiation effects; D013499:Surface Properties; D013997:Time Factors; D017971:Tin Compounds / Q000737:chemistry
chemical_list: D037742:Nanotubes, Carbon; D011166:Porphyrins; D017971:Tin Compounds; C045358:stannic oxide