Ternary ZnxCd1-xSe QDs sensitized TiO2 photoelectrodes on FTO substrates have been prepared using an ion-exchange route and they were further assembled to solar cells. Lattice parameters and band gaps of ZnxCd1-xSe QDs were found to have linear and quadratic relationships with the Zn content (x) respectively. In these fabricated QDSSCs, QDs with the composition of x=0.6 produced the highest photocurrent and photoconversion efficiency. Furthermore, the model sensitizer of three semiconductor QDs layers, ZnSe/CdS/CdSe, was prepared successively by a series of SILAR procedures in reproducible and controllable ways, and further used as photoelectrodes for QDSSCs. The results show that the performance of QDSSCs is strongly dependent on the order of QDs with respect to TiO2. The pre-assembled ZnSe QD layer acts as a seed layer in the following SILAR process, inducing the nucleation and growth of CdS QDs, while CdS and CdSe QDs have a complementary effect in the light harvest. A high efficiency of 4.94% and a long electron lifetime of 87.4 ms are achieved by TiO2/ZnSe/CdS/CdSe electrode. Both ternary and multilayered QD-sensitizers have been demonstrated to be promising photoelectrodes for solar cells, which is a consequence of the following facts: The higher intensity and red shift of light absorption in the region of 400−700 nm increase the electron concentration in TiO2 substrate; the effective band alignment among QDs with the different compositions forms a stepwise structure of band-edge levels, which would directly accelerate the transport of both electron and hole across the photoelectrode, enhancing the photovoltaic performance of solar cells.