Photocurrent Enhancement of CdSe Quantum-Dot Sensitized Solar Cells Incorporating Single-Walled Carbon Nanotubes

Abstract

We demonstrate quantum-dot sensitized solar cells (QDSSCs) which have colloidal CdSe quantum dots (TOPO-CdSe) as a sensitizer onto mesoporous TiO2 photoanodes. CdS quantum-dot (QD) layer plays a role of buffer layer for direct adsorption of TOPO-CdSe. We incorporate single-walled carbon nanotubes with TiO2 photoanode of our QDSSCs to facilitate efficient charge transfer. Short-circuit current densities (J(sc)) of our QDSSCs are enhanced while other parameters are maintained. Furthermore, we apply inert N-2 pressure onto our sensitized photoanodes and observe 44% of Jsc enhancement with respect to pristine sample. Consequently, light-harvesting efficiency of our QDSSCs are increased. Significant series resistance reduction is observed from electrochemical impedance spectroscopy, indicating better interface contact between TiO2 photoanode and TOPO-CdSe QD sensitizer are achieved.