CuS/brass based counter electrode in quantum dot-sensitized solar cells (QDSCs) with considerable efficiency and good stability

Quantum dot-sensitized solar cells (QDSCs) have attracted much attention for its convenient fabrication, low-cost and great theoretical conversion efficiency of 44%, which are considered to be good alternative to new generation of photovoltaic. However, the conversion efficiency of QDSCs is still low for poor charger transfer to the oxidized redox polysulfide species (S-n(2)) on counter electrode (CE). Besides, the stability of CE is also a serious problem. Therefore, much attention has been focused on improving the efficiency and stability of CE. In this study, brass substrate with flower-like CuO/Cu(OH)(2) nanorods film was first applied in QDSCs as the CE, which exhibited an excellent performance. The flower-like CuO/Cu(OH)(2) nanorods were obtained on brass substrate by a facile alternate current (AC) etching method. A possible formation mechanism of the flower-like CuO/Cu(OH)(2) nanorods was proposed. The CuO/Cu(OH)(2) converted to CuS quickly after immersing in polysulfide electrolyte. A CE of QDSCs based on the prepared CuS/brass was constructed and a promising efficiency (mu) of 3.82% was obtained. Due to the excellent stability of brass, the stability of the prepared CE was greatly improved. Compared to those Pt CEs and directly immersing Cu2S CEs, CuS/brass CEs present superior conversion efficiency and stability. (C) 2015 Elsevier Ltd. All rights reserved.