Structure and Photoelectrochemical Characterization of Electrochemical Deposited CdSe Quantum Dots Sensitized TiO_2 Nanorod Arrays Photoelectrodes

摘要

The convenient electrochemical deposition method has been adopted to synthesis CdSe quantum dots on TiO_2 nanorod which provide a direct current pathway for electron with few grain boundaries. This electrodeposition method is not only quick, simple, and low cost, but also can prepare QDs with favorable performance as well as high surface coverage. By adjusting the total charge quantity applied during deposition, the entire TiO_2 nanorods were covered by dense and uniform CdSe quantum dots to form a core-shell structure. The structure and photoelectrochemical properties of CdSe with different deposited electrical quantity have been studied. It was found that the CdSe quantum dots exhibit a zinc-blende structure after annealing and the absorption spectra shows red-shift for absorption edge as the deposited quantity of CdSe increasing. When the deposited electrical quantity was 0.9 coulomb, the electrode yielded a largest saturated current density of 8.57 mA/cm~2 under the irradiation of AM1.5G simulated sunlight at 100 mW/cm~2, and it exhibited the relatively lower resistance resulted in the superior ability for charge transfer.