A broadband Pb-chalcogenide/CdS solar cells with tandem quantum-dots embedded in the bulk matrix (QDiM) absorption layers by using chemical bath deposition

•PbS and PbSe films with quantum dots embedded in matrix morphologies are obtained by using chemical bath deposition.•A PbSe/PbS stacked tandem structure is proposed to enhance the efficiency of PbS/CdS thin films solar cells.•The Introduction of PbSe layer can enhance the spectra absorption both in the visible and near-infrared regions.•An enhancement of power conversion efficiency (PCE) of 4.2% has been achieved with a high short current density of 40 mA/cm2.

In this paper we have presented a power conversion efficiency (PCE) enhanced Pb-chalcogenide/CdS quantum dots (QDs) solar cells with novel tandem absorption layers synthesized by using chemical bath deposition (CBD) method. The tandem absorption layer is assembled by orderly stacking PbS-QDs layer, PbS-QDiM layer and PbSe-QDiM layer. Compared to single layer PbS-QDs/CdS solar cells, the solar cell with double-tandem layers (PbS-QDiM/QDs) shows the highest short current density (Jsc) of 47.5 mA/cm2 due to smoothing of the photo-generated carrier transportation and enhancing the absorption in the visible region 530-800 nm. However, the decreased open circuit voltage (Voc) of 0.14 eV results in a low power conversion efficiency (PCE) of 2.2%. The triple-tandem absorber (PbSe-QDiM/PbS-QDiM/QDs) enhances the spectra absorption both in the visible (500-800 nm) and near-infrared (1000-1700 nm) regions, resulting in a higher short current density (Jsc) of 40 mA/cm2, while keeping a relatively large open circuit voltage (Voc) of 0.28 eV. Through an architectural modification, an enhancement of power conversion efficiency (PCE) of 4.2% has been achieved.

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