title: Phosphonic anchoring groups in organic dyes for solid-state solar cells.
abstract: We report the synthesis and the optoelectronic characterization of three new 4H-pyran-4-ylidene and thiazole derivatives (pyt) as metal-free organic dyes for solid-state dye-sensitized solar cells (DSSCs). We investigate the performance and the long-term stability of devices employing pyt dyes functionalized with carboxylic and phosphonic acids as TiO2 anchoring groups. In contrast to reports on liquid electrolyte DSSCs, we show that solid-state DSSCs prepared with phosphoric pyt derivatives can achieve similar power conversion efficiency to their carboxyl analogues. We make use of the Mott-Schottky analysis and equivalent circuit models to demonstrate that a phosphonic group induces a significant increase in built-in voltage at the TiO2-hole transporter interface, which results in a higher open circuit voltage.
authors.affiliation: Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, UK. antonioabate83@gmail.com h.snaith1@physics.ox.ac.uk.
authors.forename: Antonio
authors.initials: A
authors.lastname: Abate
authors.forename: Raquel
authors.initials: R
authors.lastname: Pérez-Tejada
authors.forename: Konrad
authors.initials: K
authors.lastname: Wojciechowski
authors.forename: Jamie M
authors.initials: JM
authors.lastname: Foster
authors.forename: Aditya
authors.initials: A
authors.lastname: Sadhanala
authors.forename: Ullrich
authors.initials: U
authors.lastname: Steiner
authors.forename: Henry J
authors.initials: HJ
authors.lastname: Snaith
authors.forename: Santiago
authors.initials: S
authors.lastname: Franco
authors.forename: Jesús
authors.initials: J
authors.lastname: Orduna