CdS quantum dots-sensitized TiO₂ nanotube arrays for solar cells

Abstract

CdS quantum dots(QDs) sensitized TiO₂ nanotube arrays photoelectrodes were investigated for their photovoltaic performance of quantum dots-sensitized solar cells. The highly ordered TiO₂ nanotube arrays(TNAs) were synthesized on Ti foils by anodic oxidation method. Then CdS quantum dots were deposited onto the TiO₂ nanotube arrays by successive ionic layer absorption and reaction(SILAR) method to serve as the sensitizers. Cd(NO₃)₂ and Na₂S were used as the precursor materials of Cd⁺ and S²⁻ ions, respectively. It is found that the CdS QDs sensitizer may significantly increase the light response of TiO₂ nanotube arrays. With increasing CdS QDs deposition cycles, the visible light response increases. Maximum photocurrent was obtained for the QDs that have an absorption peak at about 500 nm. Under AM 1.5 G illuminations(100 mW cm⁻²), a 4.85 mA/cm² short circuit current density was achieved, and the maximium energy conversion efficiency of the asprepared CdS QDs-sensitized TNAs solar cells was obtained as high as 0.81 % at five SILAR cycles.

Keywords

quantum dots sensitized solar cell / successive ionic layer adsorption and reaction / TiO₂ nanotube arrays

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