Development of Cu2S/carbon composite electrode for CdS/CdSe quantum dot sensitized solar cell modules

•A stable Cu2S/carbon composite counter electrode was developed.•Good catalytic activity toward S2−/S22−S22− redox couple was achieved.•CdS/CdSe co-sensitized solar cells (QDSCs) can be well sealed.•CdS/CdSe QDSC module with over 12 cm2 aperture area was first fabricated.•The QDSC module can exhibit 2.31% efficiency.

A new composite counter electrode consisting of Cu2S nanoparticles (NPs) and active carbon/carbon black has been developed for CdS/CdSe co-sensitized solar cells (CdS/CdSe QDSCs). This kind of composite photocathode is suitable for screen printing, and exhibits good catalytic activity toward S22−S22−/S2− redox couple. Based on this Cu2S/carbon composite electrode, sealed CdS/CdSe QDSCs were fabricated, which can present up to 3.87% of light-to-electricity conversion efficiency. Besides, our newly developed Cu2S/carbon composite electrode was primarily stable in 1 M polysulfide electrolyte after the QDSCs with this counter electrode were sealed, kept in the dark at room temperature and tested every two or three days for 30 days. On the basis of the above results, CdS/CdSe QDSC modules consisting of four paralleled sub-cells with the aperture area of over 12 cm2 have been designed and prepared for the first time. Up to 2.31% of light-to-electricity conversion efficiency of CdS/CdSe QDSC module was achieved. This Cu2S/carbon composite electrode exhibits good potential application for further investigation.

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