Tandem organic dye-sensitized solar cells: Looking for higher performance and durability

Abstract

High-performance dye-sensitized solar cells (DSSCs) are the result of state-of-the-art blend of knowledge and experience; but finding accurate sensitizers from one side and explicit demonstration of the effects of material parameters on the power conversion efficiency (PCE) from the other side are direct challenges to the manufacture of DSSCs. Tandem DSSCs (T-DSSCs) is a young member of such family which allows one to attain higher power conversion efficiencies (PCE), but complications beyond T-DSSC manufacture has urged researchers to make use of Edisonian approach. Response Surface Methodology (RSM) and Desirability Function (DF) approaches are used to optimize T-DSSCs manufacture. Thickness of TiO2 layer, time required for TiCl4 treatment, and the concentration of anti-aggregation agent are explanatory variables changed to manufacture T-DSSCs with optimized photocurrent (Jsc), photovoltage (Voc) and Durability. The concentration of anti-aggregation agent was the key factor in attaining high-performance T-DSSCs. By the combined use of RSM and DF and through multi-objective optimization, it was found that under anti-aggregation agent concentration of 0.012 mM, thickness of TiO2 of 24.2 μm, and TiCl4 treatment time of ca. 78 min, T-DSSC having the highest possible performance with Jsc (13.37 mA/cm2), Voc (1.054 V), and Durability (1388 h) can be achieved.