W Tungsten

The ring-fused thiophene derivatives benzo[c]thiophene and its precursor bicyclo[2.2.2]octadiene (BCOD) have been introduced as π-conjugated spacers for organic push–pull sensitizers with dihexyloxy-substituted triphenylamine as donor and cyanoacrylic acid as acceptor (OL1–OL6). The effects of the fused ring on the spectroscopic and electrochemical properties of these sensitizers and their photovoltaic performance in dye-sensitized solar cells have been evaluated. Introduction of a binary benzo[c]thiophene and ethylenedioxy thiophene as π bridge caused a significant red shift of the characteristic intramolecular charge-transfer band to 642 nm. It is found that the sensitizer OL3, which contains one benzo[c]thiophene unit as π linker, gives the highest overall conversion efficiency of 5.03 % among all these dyes.

Sensitive souls: A series of sensitizers for dye-sensitized solar cells features ring-fused thiophene bridges between donor and acceptor moieties. The absorption spectra of the push–pull sensitizers all exhibit intense intramolecular charge transfer bands in the visible region (see picture), and solar cells based on the dyes show good incident photon to current conversion efficiencies.