High performance CdSe quantum dot sensitized ZnO solar cell fabricated from ion exchange

Highlights: • Efficient CdSe sensitized ZnO QDSSC is fabricated through ion exchanges. • The cell exhibits relative high light harvesting and low charge recombination. • ZnSe overcoating is introduced to enhance the cell efficiency. • High power conversion efficiency of 5.08% is achieved. We report on a facile and efficient way to prepare CdSe/ZnO photoanode for quantum dot sensitized solar cell (QDSSC). CdSe/ZnO is achieved through a two-step ion exchange process in aqueous solution at lower temperature. SEM, light absorption, dark current and impedance spectroscopy analyses revealed that this process of ion exchange can form not only higher amount and larger sized QDs on ZnO that lead to the enhancement of light harvesting, but also full coverage of QDs on ZnO as well as excellent QD/ZnO interfaces that contribute to the suppression of charge recombination. In combination with ZnSe overcoating, QDSSC assembled with the CdSe/ZnO photoanode exhibits high cell efficiency of 5.08%.