In Situ Growth of PbS Nanocubes as Highly Catalytic Counter Electrodes for Quantum Dot Sensitized Solar Cells

In this work, a face-centered cubic phase of galena PbS nanocubes, directly in situ grown onto conducting substrates, was fabricated by a facile chemical bath deposition method. The as-prepared PbS nanocubes show a highly crystalline structure and a quite uniform rectangular shape with approximate dimensions of 60-80 nm. These PbS nanocubes are demonstrated to act as excellent counter electrode (CE) materials in quantum dot sensitized solar cells (QDSCs) for electrocatalyzing polysulfide electrolyte regeneration. A CdS/CdSe QDSC constructed with a PbS nanocube-based CE yields a considerable power conversion efficiency of 3.49%. Moreover, the performance characterizations reveal that PbS CEs exhibit comparable electrocatalytic activity to the conventional Cu2S CEs while significantly outperforming the noble Pt CEs. Meanwhile, PbS CEs bypass the stability and contamination problems of Cu2S CEs. This work provides an alternative CE with advantages of high catalytic capability and stability as well as the ease of fabrication.