4,4′-Diaminodiphenylsulfone; an efficient co-additive in dye-sensitized nanocrystalline TiO2 solar cells

The effect of 4,4′-diaminodiphenylsulfone (DADPS) as a co-additives in iodide/triiodide redox electrolyte on the performance of dye-sensitized solar cell based on the 2-cyano-3-(4-(diphenylamino)phenyl)acrylic acid (TPA) and 2-cyano-3-(2΄-(5΄,10΄,15΄,20΄- tetraphenylporphyrinato Zinc (II)yl) acrylic acid (Zn-1) dyes have been investigated. Compared withstandard electrolyte (0.1 M LiI, 0.05 M I₂, 0.6 M 1-butyl-2,3-dimethylimidazolium iodide (BDMII) and TBP (0.5, 1 M)), adding 0.5 M of DADPS, as a co-additive, into the electrolyte system has caused increasing short current density (J_sc) and open-circuit potential (V_oc) consequently the energy conversion (η) improved. Electrochemical impedance results indicate adsorbing of DADPS on the titanium dioxide surface leads to an increase in the lifetime (τ). Adsorbing of DADPS on the semiconductor surface retards the interfacial charge recombination that has a beneficial effect on the V_oc and J_sc. The results showed that amine groups of DADPS attach to the conduction band (CB) of TiO₂ film and suppress the electron recombination process and as a result, it can be applied as a promising co-additive in DSSCs.