Abstract

CdSe quantum dot (QD) sensitized TiO₂ nanotube arrays (TiO₂ NTAs) were successfully prepared by successive ionic layer adsorption and reaction (SILAR) technique. Their composition, structure and photoelectrochemical property were characterized by X-ray diffractometer (XRD), field emission scanning electron microscope (FESEM), UV-vis diffuse reflectance spectroscope and electrochemical workstation. The results indicate that CdSe QDs can expand the photo-response range of TiO₂ NTAs from ultraviolet region to visible region up to 736 nm with increasing SILAR cycles. The photocurrent density for the CdSe QD sensitized TiO₂ NTAs dramatically increases with SILAR cycles and exhibits the highest visible photocurrent density of 11.8 mA / cm² for 6 cycles. More SILAR cycles induce a decrease of photocurrent density. The open circuit potential of CdSe QD sensitized TiO₂ NTAs decrease slowly up to 0.93 eV with increasing SILAR cycles. A model is proposed to explain the influences of SILAR cycles on the visible photocurrent density of CdSe QD sensitized TiO₂ NTAs.

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