title: Hyperbranched quasi-1D TiO2 nanostructure for hybrid organic-inorganic solar cells.
abstract: The performance of hybrid solar cells is strongly affected by the device morphology. In this work, we demonstrate a poly(3-hexylthiophene-2,5-diyl)/TiO2 hybrid solar cell where the TiO2 photoanode comprises an array of tree-like hyperbranched quasi-1D nanostructures self-assembled from the gas phase. This advanced architecture enables us to increase the power conversion efficiency to over 1%, doubling the efficiency with respect to state of the art devices employing standard mesoporous titania photoanodes. This improvement is attributed to several peculiar features of this array of nanostructures: high interfacial area; increased optical density thanks to the enhanced light scattering; and enhanced crystallization of poly(3-hexylthiophene-2,5-diyl) inside the quasi-1D nanostructure.
authors.affiliation: †Center for Nanoscience and Technology @PoliMi, Istituto Italiano di Tecnologia, Via Giovanni Pascoli 70/3, 20133 Milano, Italy.|‡Dipartimento di Energia, Politecnico di Milano, Via Ponzio, 20133 Milano, Italy.
authors.forename: Ali
authors.initials: A
authors.lastname: Ghadirzadeh
authors.affiliation: †Center for Nanoscience and Technology @PoliMi, Istituto Italiano di Tecnologia, Via Giovanni Pascoli 70/3, 20133 Milano, Italy.|§Dipartimento di Fisica, Politecnico di Milano, Piazza L. Da Vinci 32, 20133 Milano, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Passoni
authors.affiliation: †Center for Nanoscience and Technology @PoliMi, Istituto Italiano di Tecnologia, Via Giovanni Pascoli 70/3, 20133 Milano, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Grancini
authors.affiliation: ∥Laboratory of Nanostructured Fluorinated Materials (NFMLab), Department of Chemistry, Materials, and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy.
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Terraneo
authors.affiliation: †Center for Nanoscience and Technology @PoliMi, Istituto Italiano di Tecnologia, Via Giovanni Pascoli 70/3, 20133 Milano, Italy.|‡Dipartimento di Energia, Politecnico di Milano, Via Ponzio, 20133 Milano, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Li Bassi
authors.affiliation: †Center for Nanoscience and Technology @PoliMi, Istituto Italiano di Tecnologia, Via Giovanni Pascoli 70/3, 20133 Milano, Italy.
authors.forename: Annamaria
authors.initials: A
authors.lastname: Petrozza
authors.affiliation: †Center for Nanoscience and Technology @PoliMi, Istituto Italiano di Tecnologia, Via Giovanni Pascoli 70/3, 20133 Milano, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Di Fonzo
keywords: 1D nanostructures; P3HT; hybrid solar cells; hyperbranched nanostructures; pulsed laser deposition; self-assembled