Effect of small-size co-sensitizer on acid-base co-sensitization system of dye-sensitized solar cells

Inhibition of electron recombination and dye aggregation is a crucial strategy to enhance the power conversion efficiency (PCE) of co-sensitized solar cells. Here, large-size organic dyes TA, TP containing triphenylamine donor, cyanoacetic acid and pyridine acceptor are prepared. Different molar ratios are used to explore the optimal acid-base co-sensitization systems, different concentrations of small-size co-sensitizer (coded EA) are added to the optimal acid-base co-sensitization system non-competitive adsorption, and the effect of EA on acid-base co-sensitization system was studied. The results show that the addition of EA greatly improves the molar absorbance of dye molecules, and the introduction of oxyalkyl chains in the triphenylamine donor effectively inhibits the interfacial charge recombination and dye aggregation, so that the short-circuit current density (Jsc) of ternary co-sensitization system increased from 10.81 mA cm–2 to 13.70 mA cm–2. At the same time, PCE based on [email protected](3:2)@EA(100%) devices improved by 30.61% (from 4.9% to 6.4%). The electron-rich EDOT of EA fills the adsorption gap of acid-base dye on the TiO2 surface, increases the overall dye load and photogenerated electron density, and thus increases the open-circuit voltage (Voc) and Jsc of the devices. This ternary co-sensitization provides more options for improving the PCE of dye-sensitized solar cells (DSSCs).