Highly efficient interfacial layer using SILAR-derived Ag2S quantum dots for solid-state bifacial dye-sensitized solar cells

Ag2S quantum dots (QDs) were employed as an interfacial layer between polymer electrolyte and transparent polyaniline counter electrode (PANI CE) in bifacial dye-sensitized solar cells (DSSCs). The Ag2S QDs film, which was prepared by successive ionic layer adsorption and reaction (SILAR) could deliver an extra visible light harvesting and enhance the catalytic performance of PANI CE, leading to increased photo-generated electrons and suppressed interfacial recombination. The device performances have been significantly improved as compared to the controlled DSSC without Ag2S QDs interfacial layer (QDIL). An optimal power conversion efficiency of 6.50% was achieved in the Ag2S QDILs based solid-state bifacial DSSC with 2 SILAR cycles, which was comparable to the highest reported efficiency of 7-8% for solid-state DSSCs, and was almost 130% of the conventional structured DSSC without Ag2S QDIL (5.02%). Electrochemical and electron transport/recombination performances have also been demonstrated for this type of device. The results also highlight the general importance of light-active QDs interfacial layer in transparent cathode for other kind of devices. (C) 2017 Elsevier Ltd. All rights reserved.