High photo-currents with a zwitterionic thiocyanate-free dye in aqueous-based dye sensitized solar cells

Abstract

We report a new water soluble and stable thiolate/disulfide redox couple (T⁻/DS) and its use with a new zwitterionic and thiocyanate-free dye (T169) in a 100% aqueous electrolyte system. A DSSC incorporating T169 and the T⁻/DS showed the highest photocurrents (J_sc = 13.30 mA cm⁻²) and IPCE% (84%) values reported to date. In addition, a 2000 h long-term stability measurement was performed, where J_sc and V_oc of the above mentioned DSSC stayed somehow the same except for the fill factor (FF) which decreased from 0.62 to 0.48 and consequently lowered the total efficiency (from η = 4.5% on day 1 to η = 3.3% after 2000 h).