The band-edge levels of CdS-, CdSe-, and CdS/CdSe-sensitized TiO 2 electrodes were determined by ultraviolet photoelectron spectroscopy (UPS) to explore the reason leading to the high performance of the TiO2 /CdS/CdSe electrode. The obtained UPS results show the stepwise energy level in the TiO2 /CdS/CdSe electrode, indicating energy level alignment occurrence between CdS and CdSe in the TiO2 /CdS/CdSe. Time-resolved photoluminescence and open-circuit photovoltage decay experiments reveal that the photogenerated electrons in the TiO2 /CdS/CdSe have higher injection efficiency, but lower recombination rate to the electrolyte, attributable to the stepwise structure of band-edge levels constructed by the effect of the energy level alignment.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)