title: [1]Benzothieno[3,2-b]benzothiophene-Based Organic Dyes for Dye-Sensitized Solar Cells.
abstract: Three new metal-free organic dyes with the [1]benzothieno[3,2-b]benzothiophene (BTBT) π-bridge, having the structure donor-π-acceptor (D-π-A) and labeled as 19, 20 and 21, have been designed and synthesized for application in dye-sensitized solar cells (DSSC). Once the design of the π-acceptor block was fixed, containing the BTBT as the π-bridge and the cyanoacrylic group as the electron acceptor and anchoring unit, we selected three donor units with different electron-donor capacity, in order to assemble new chromophores with high molar extinction coefficients (ε), whose absorption features well reflect the good performance of the final DSSC devices. Starting with the 19 dye, which shows a molar extinction coefficient ε of over 14,000 M(-1) cm(-1) and takes into account the absorption maximun at the longer wavelength, the substitution of the BFT donor unit with the BFA yields a great enhancement of absorptivity (molar extinction coefficient ε > 42,000 M(-1) cm(-1)), until reaching the higher value (ε > 69,000 M(-1) cm(-1)) with the BFPhz donor unit. The good general photovoltaic performances obtained with the three dyes highlight the suitable properties of electron-transport of the BTBT as the π-bridge in organic chromophore for DSSC, making this very cheap and easy to synthesize molecule particularly attractive for efficient and low-cost photovoltaic devices.
authors.affiliation: Institute of Nanotechnology, NANOTEC, Italian National Council of Research, CNR , Campus Ecotekne, Via Lecce-Monteroni, 73100 Lecce, Italy.
authors.forename: Agostina L
authors.initials: AL
authors.lastname: Capodilupo
authors.affiliation: Euromediterranean Center for Nanomaterial Modelling and Technology (ECMT), Istituto Nanoscienze-CNR , Via per Arnesano 73100 Lecce, Italy.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Fabiano
authors.affiliation: Center for Biomolecular Nanotechnologies (CBN), Fondazione Istituto Italiano di Tecnologia , Energy Platform, Via Barsanti, 73010, Arnesano, Lecce, Italy.
authors.forename: Luisa
authors.initials: L
authors.lastname: De Marco
authors.affiliation: Dipartimento di Scienze e Tecnologie Biologiche e Ambientali, Università del Salento , Via Monteroni, 73100, Lecce, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Ciccarella
authors.affiliation: Institute of Nanotechnology, NANOTEC, Italian National Council of Research, CNR , Campus Ecotekne, Via Lecce-Monteroni, 73100 Lecce, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Gigli
authors.affiliation: Institute of Chemistry of OrganoMetallic Compounds, ICCOM, Italian National Council of Research, CNR , Via Orabona, 4, 70125, Bary, Italy.
authors.forename: Carmela
authors.initials: C
authors.lastname: Martinelli
authors.affiliation: Institute of Chemistry of OrganoMetallic Compounds, ICCOM, Italian National Council of Research, CNR , Via Orabona, 4, 70125, Bary, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Cardone