Impact of FeS on the TiO₂ Layer As Support System in QDSCs

We report on the passivation of titanium oxide with FeS from three molecular precursors with tin sulfide (SnS) photon absorbers that were fabricated and assembled to increase the performance of quantum dot sensitized solar cells (QDSSCs). FeS was loaded on the TiO₂ surfaces, and then, SnS photosensitizer was deposited to form a ternary modified device. The morphology, structural structure, size distribution, chemical composition, and conversion efficiency were explored by FE-SEM, XRD, TEM, UV-vis, EDS, EIS, and J-V analysis. The CV, LSV, and stability state were also investigated for migration and separation of photogenerated charge carriers in the as-prepared cells labeled F-S-1, F-S-2, and F-S-3. The FE-SEM image of the F-S-2 cell is composed of FeS interconnected with SnS and FeS, which provided paths for electron movement compared with the F-S-1 and F-S-3 devices. The semicircle for the F/S-1 and F/S-3 solar device diameters illustrates that the high-medium frequency regain is greater than that of the F/S-2 device, implying that both cells have charge-transfer impedances and lower contact. Apparently, the F/S-2 device shows superior catalytic activity, which can be linked to the hybridization of TiO₂/FeS/SnS due to the synergistic effect. The F/S-2/S-2l has a maximum efficiency η of 6.73% in comparison to F/S-1 and F/S-3, which have the same conversion efficiency of 3.82%. The results of the F/S-2 device follow a similar trend to the chronoamperometry analysis, CV, and LSV results from this study.