The Influence of ZnO Nanorod Length and Counter Electrode Material on the Photovoltaic Properties of CdS/CdSe Quantum Dots Cosensitized ZnO Nanorods Solar Cells

In this work, a highly efficient quantum dot-sensitized solar cell (QDSSC) was fabricated using CdS/CdSe cosensitized ZnO nanorod arrays (NRs) as photoelectrode, and the CuS prepared by a microwave-assisted hydrothermal method as counter electrode (CE). For the assembled solar cells, the vertically aligned one-dimensional ZnO NRs offer a large surface area for deposition of quantum dots and serve as direct pathways for fast electron transport. The CuS nanoplate CEs provide high surface area for more active catalytic sites and easy accessibility for polysulfide electrolyte, resulting in superior catalytic activity for the polysulfide electrolyte than conventional Pt CEs. The effects of nanorod length, number of successive ionic layer adsorption and reaction cycles for CdS, and chemical bath deposition time for CdSe on the photovoltaic performance were investigated, and it was found that the QDSSC assembled with CdS(6)/CdSe(4 h)/ZnO(5.4 mu m) and CuS CEs yields a maximum power conversion efficiency of 4.55%, with V-OC, J(SC), and FF of 0.60 V, 14.63 mA.cm(-2), and 0.52, respectively, under one-sun illumination.