Comparison of the effects of ZnS and Al2O3 blocking layers on the efficiency of quantum dot-sensitized solar cell photo-anode

The study of previous reported works on the role of blocking layer in quantum dot-sensitized solar cells (QDSSCs) shows a multiplier boost of efficiency. So, the investigation in this regard would be very important. In this way, we planned to examine the effects of two commonly used blocking layers, ZnS and Al2O3, located on photo-anode of a QDSSC, on the efficiency of the cell. The structure is formed of ZnOnanorods grown on FTO that are sensitized by CdS quantum dots. It should be noted that, the two mentioned blocking layers are deposited after the sensitization process. We obtained the efficiency for the combinations ZnO/CdS/ZnS and ZnO/CdS/Al2O3 equal to 1.28% and 1.24%, respectively. These results show the better behavior for ZnS blocking layer than Al2O3 in a similar structure.