A Study on the Performance of CdTe/CdS Quantum Dot-Sensitized Solar Cells Incorporating Carbon Nanotubes

Abstract

Cadmium sulfide (CdS) and cadmium telluride (CdTe) quantum dots (QDs) were used as sensitizers to create quantum dot-sensitized solar cells (QDSSCs). CdS QDs were deposited onto the mesoporous titanium dioxide (TiO2) layer by a successive ionic layer adsorption and reaction (SILAR) method. Pre-synthesized CdTe QDs were deposited onto a layer of CdS QDs using a direct adsorption (DA) technique. CdTe/CdS QDSSCs had higher the light harvesting ability compared with CdS or CdTe QDSSCs. Single-walled carbon nanotubes (SWNTs) were incorporated with CdTe/CdS QDSSCs by spraying them onto the substrate before deposition of the next layer to apply p-type properties of SWNTs or mixing them with TiO2 nanoparticles. In addition, chemical modified SWNTs also were incorporated with QDSSCs by mixing them with CdTe QDs solution. QDSSCs incorporating SWNTs mostly exhibited enhanced photo-current conversion efficiency (PCE) compared with the pristine cell. In particular, a maximum rate increase of 24% was obtained with the solar cell containing a TiO2 layer mixed with SWNTs. It was expected that various applications of SWNTs could affect future energy technology.