Background: In QDs-based solar cell devices, the PbS QDs layer was mainly focused
to optimize. The ZnO electron acceptor layer attracts less attention whereas it shows the key
roles in extracting and transporting charge carriers in heterojunction. The utilization of 1-D ZnO
structures has been demonstrated to be large interface areas and good carrier pathways for efficient
carrier collection. However, the influences of the morphology of metal oxide nanostructures
on the photovoltaic performance of QD-based solar cells have been few in-depth reports.
Objective: In this work, ZnO NRs/PbS QD based solar cells were fabricated. The influences of
the ZnO NRs array structures on characteristics of ZnO NRs/PbS QD based solar cells were investigated.
Method: ZnO NRs/PbS QD based solar cells were fabricated via spin coating method. XRD,
SEM, UV-VIS-NIR spectrophotometer, I-V and EQE measurement systems were utilized to investigate
the fabricated samples.
Results: We have found optimum combinations of the linked parameters of ZnO NRs, their
length of (230 ± 5) nm and density of (1.50 ± 5)x1010 # of rods.cm-2, that exhibit maximum efficiency
of ∼2.5% for the ZnO NR/PbS QDs based solar cell.
Conclusion: The influences the ZnO NRs structures on the solar cell characteristics, including
the absorption, external quantum efficiency, and current density-voltage curves, were investigated.
There seems to be an optimum between NR length and their density for resulting in maximum
efficiency. This could be due the interplay of solar flux absorption and junction area controlled
by these two parameters of ZnO NR morphology.