Characteristic of (Pb_1-xZn_x)S tandem structured quantum dot-sensitized solar cell having wide light absorbance

A quantum dot-sensitized solar cell (QD-SSC) is one of these new type solar cells because of their advantages such as the inverse Auger effect, the tuning the particle size. Many quantum dot semiconductors such as CdS, CdSe, PbS and PbSe are used as the sensitizers instead of the ruthenium dye molecules in the QD-SSC. The light absorbance of the quantum dot materials is changed as the dipping cycle and the amount of the materials. Therefore, the light absorbance and the efficiency of the QD-SSC can be increased by using these characteristics. In this study, we tried to widen the light absorbance of the QD-SSC by changing the doping amounts of Pb and Zn in the (Pb_1-xZn_x)S material. Finally, we fabricated the (Pb_1-xZn_x)S tandem structured QD-SSC. When the tandem structure multilayer as the layer which contains less Zn amount is placed on the bottom and the layer which contains more Pb amount is placed on the top side, the light absorbance is broaden effectively by using this tandem structure. As a result, we got the I-V characteristics of (Pb_1-xZn_x)S QD-SSC with 3 multilayer, 0.38 V, 3.219 mA/cm², 0.39 of FF, 0.48%.