Two dimensional layered electron transport bridges in mesoscopic TiO2 for dye sensitized solar cell applications

The present work demonstrates the possibility of facilitating electron transport in mesoscopic titanium dioxide (TiO₂) by incorporating nanoflakes of layered molybdenum disulfide (MoS₂) as an alternate electron transport bridge. Results suggest that performance of dye sensitized solar cells (DSSCs) can be increased up to ∼16% (from 7.39% to 8.55%) by incorporating 0.2 wt % of MoS₂ into the bulk of TiO₂, due to the significant improvement in electron lifetime from 8 ms to 23 ms. The nanoflakes of MoS₂ form alternate electron transport bridges in the bulk TiO₂ nanoparticle film through which photo-injected electrons travel more efficiently to reach transparent electrode compared to DSSCs utilize only TiO₂ without MoS₂. Presence of atomically thin layered MoS₂ nanoflakes in the bulk of TiO₂ assist the photo-electrons to skip electron-hole capture processes occur through TiO₂ surface states to avoid the interfacial recombination. Further increment in the concentration of MoS₂ suppresses the resulting DSSC performance by blocking the porosity which results in less dye adsorption and hence lower photocurrent values.