Influence of a nanostructured ZnO layer on the carrier recombination and dynamics in chalcopyrite solar cells

The influence of the incorporation of a nanostructured ZnO layer on the carrier recombination and dynamics of chalcopyrite solar cells was studied. Intensity-modulated photocurrent and photovoltage spectroscopy (IMPS and IMVS, respectively) were used for the charge carrier dynamics characterization of two ZnO/In2S3/CuInS2-based solar cells. The charge carrier dynamics on a cell with a ZnO nanorod (ZnO-NR) layer was compared with a similar sample without the nanostructured layer. The IMPS and IMVS responses were measured at different continuous light intensities, and a multitrapping behavior was observed. Higher recombination and transport times were obtained for the cell including the NR layer. Moreover, an enhancement in the charge carrier collection efficiency was observed for the cell with the NR additional layer. The increased surface-to-volume ratio of the NR layer and the passivation of defects in the ZnO/In2S3 interface could be associated with the observed charge dynamics enhancement.