A novel PbS/TiO2 composite counter electrode for CdS quantum dot-sensitized ZnO nanorods solar cells

•PbS/TiO2 nanotubes were fabricated as counter electrode (CE) for the first time.•PbS/TiO2 CE showed excellent electrocatalytic activity in polysulfide electrolyte.•The efficiency with the PbS(6)/TiO2 CE was enhanced by 440.8% that with Pt CE.

A series of novel PbS/TiO2 nanotubes was fabricated as counter electrodes (CEs) through a combination of anodic oxidation and successive ionic-layer adsorption and reaction methods. The photovoltaic-conversion efficiency of ZnO nanorods sensitized with CdS quantum dots using the optimized PbS(6)/TiO2 CE increased by nearly 440.8% and 227.5% compared with the efficiency of nanorods using planar Pt and bare TiO2 CE, respectively. Thus, the novel PbS/TiO2 composite CE was a promising catalytic electrode with excellent electrocatalytic activity for the reduction of charge carriers in polysulfide electrolyte.

Graphical abstractSchematic diagram of CdS QD-sensitized ZnO NRs with PbS/TiO2 composite CE.Figure optionsDownload full-size imageDownload as PowerPoint slide