title: An Integrated Experimental/Theoretical Study of Structurally Related Poly-Thiophenes Used in Photovoltaic Systems.
abstract: In this work, a series of eight thiophene-based polymers (exploited as "donors" in bulk heterojunction photovoltaics cells), whose structures were designed to be suitably tuned with the electronic characteristics of the [6,6]-Phenyl C61 butyric acid methyl ester (PCBM), is considered,. The electronic properties of the mono-, di-, trimeric oligomers are reckoned (at the Hartree-Fock and DFT level of the theory) and compared to experimental spectroscopic and electrochemical results. Indeed, electrochemical and spectroscopic results show a systematic difference whose physical nature is assessed and related to the exciton (electron-hole) binding energy ( J e , h ). The critical comparison of the experimental and theoretical band gaps, i.e., the HOMO-LUMO energy difference, suggests that electrochemical and DFT values are the most suited to being used in the design of a polythiophene-based p-n junction for photovoltaics.
authors.affiliation: Department of Geological and Chemical Sciences, University of Modena and Reggio Emilia, Via G. Campi 183, Modena 41125, Italy. davide.vanossi@unimore.it.
authors.forename: Davide
authors.initials: D
authors.lastname: Vanossi
authors.affiliation: Department of Physics, University of Modena and Reggio Emilia, Via G. Campi 213, Modena 41125, Italy. luigi.cigarini@unimore.it.
authors.forename: Luigi
authors.initials: L
authors.lastname: Cigarini
authors.affiliation: Department of Chemistry, University of Florence, Via della Lastruccia 3, Sesto Fiorentino 50019, Italy. andrea.giaccherini@unifi.it.
authors.forename: Andrea
authors.initials: A
authors.lastname: Giaccherini
authors.affiliation: Department of Physics, University of Bath, Claverton Down Bath BA2 7AY, UK. E.Da.Como@bath.ac.uk.
authors.forename: Enrico
authors.initials: E
authors.lastname: da Como
authors.affiliation: Department of Physics, University of Bath, Claverton Down Bath BA2 7AY, UK. claudio.fontanesi@unimore.it.|Department of Engineering "Enzo Ferrari", University of Modena and Reggio Emilia, Via Vivarelli 10, Modena 41125, Italy. claudio.fontanesi@unimore.it.
authors.forename: Claudio
authors.initials: C
authors.lastname: Fontanesi
mesh_terms: D000465:Algorithms; D008962:Models, Theoretical; D015394:Molecular Structure; D011108:Polymers / Q000737:chemistry*; D012666:Semiconductors; D013876:Thiophenes / Q000737:chemistry*
chemical_list: D011108:Polymers; D013876:Thiophenes; C066730:polythiophene
keywords: DFT; HF; band gap; exciton; polythiophenes