Understanding how different surface ligands can influence the efficiency of conversion of ZCIS and ZCIS/ZnS sensitized solar cells

ZCIS and ZCIS/ZnS quantum dots (QDs) stand out for their high optical absorption coefficients, high quantum yields , greater stability, reduced surface defects , and lower toxicity, making them the most widely used QDs in technological applications such as energy conversion. In this work, high-quality ZCIS and ZCIS/ZnS QDs were synthesized under ideal conditions in an organic medium, with their surface ligands (SL) subsequently replaced by 3-mercaptopropionic acid (MPA) and thioglycolic acid (TGA) ligands, to obtain the dispersion of materials in an aqueous medium, allowing efficient loading of QDs onto the photoanode . The influence of SL on the devices was evaluated by applying QDs in the manufacture of sensitized solar cells. QDs with core-shell structure (ZCIS/ZnS) exhibit charge transfer hindered by the ZnS shell when applied to solar cells. TGA enabled greater loading of QDs into the solar cell and was more efficient than MPA in providing better-absorbing substrates. The best response of the solar cells was obtained when TGA was used as a ligand in ZCIS QDs. This SL not only enhances the light absorption capability of the photoanode but also significantly affects the charge recombination and electron injection efficiency at the QDs/TiO 2 interface, as revealed in our detailed study using electrochemical impedance spectroscopy .