Quantum-dot-sensitized solar cells: Assembly of CdS-quantum-dots coupling techniques of self-assembled monolayer and chemical bath deposition

Two methods, coupling self-assembled monolayer and chemical bath deposition (CBD), were utilized to assemble cadmium sulfide (CdS) quantum dots (QDs) onto mesoporous $\mathrm{Ti}{\mathrm{O}}_2$ films for dye-sensitized solar cell (DSSC) applications. Colloidal CdS QDs were first self-assembled on the $\mathrm{Ti}{\mathrm{O}}_2$ surface. CBD was then introduced to replenish the incorporated amount and increase the coverage ratio of CdS QDs on the $\mathrm{Ti}{\mathrm{O}}_2$ surface. The preassembled CdS QDs act as nucleation sites in the CBD process, forming a CdS nanofilm with an interfacial structure capable of inhibiting the recombination of injected electrons. An efficiency as high as 1.35% for the QD-sensitized DSSC was achieved using the present strategy.