title: Bandgap modulation in efficient n-thiophene absorbers for dye solar cell sensitization.
abstract: Five new sensitizers for dye sensitized solar cells have been designed consisting of conjugated thienylenevinylene units threaded with alkyl chains to improve solubility and cyanoacetic acid as anchoring group. The conjugation length was increased from 2 to 6 thienylenevinylene units, which resulted in a red-shift of the optical absorption of the dyes from 550 to 750 nm, improving the spectral overlap with the solar spectrum. The photovoltaic performance of these dyes as sensitizers in mesoporous TiO(2) solar cells shows a clear correlation of increasing photocurrent with the extension of the conjugation up to an optimal length. Further extension of the conjugation increases the absorption but additional effects like self-quenching or recombination processes reduce the photocurrent and photovoltages and consequently the overall efficiency of the DSC.
authors: Photovoltaic and Optoelectronic Devices Group, Physics Department, Universitat Jaume I, 12071 Castelló, Spain.
authors: Eva Ma
authors: EM
authors: Barea
authors: Rubén
authors: R
authors: Caballero
authors: Francisco
authors: F
authors: Fabregat-Santiago
authors: Pilar
authors: P
authors: De la Cruz
authors: Fernando
authors: F
authors: Langa
authors: Juan
authors: J
authors: Bisquert