Research Progress on Counter Electrodes of Quantum Dot-sensitized Solar Cells

Quantum dots sensitized solar cells (QDSCs) play a key role in the new generation photovoltaic devices due to their low cost and easy fabrication process. The absorption spectrum of quantum dots can be tailored by controlling grain size, and multi-exaction generation. QDSCs using inorganic compound QDs replaces the dye as a sensitizer, which is able to solve the stability of the dye sensitized solar cells. However, further improvement of the conversion efficiency of QDSCs is still a major issue for their application. Recently, tailoring electronic properties of the counter electrode(CE) in QDSCs using different materials has been considered as a promising way to improve photovoltaic performance of QDSCs. This article reviewed the quite recent progress of CE in QDSCs based on synthesis method, surface microtopography and crystal structure. This review gave a panorama of metal chalcogenides, composite materials, hybrid materials, muti-component metal chalcogenides, conductive polymers, and carbon CE materials for QDSCs, while the influence of CE materials on the charge transfer impedance, the electron transport process, catalytic properties, and I-V characteristics was stressed in detail. Finally, an outlook on the future challenges and pros- 33 pects of novel materials as the CE for QDSCs were also briefly put forward.