In this work, combination of halides and MA, FA, Cesium -Cs- and Sodium -Na- cations were considered. The main structure of the cell absorbing layers was NaCsMAFAPb -IBr-3. The formulation of CsMAFAPb-IBr-3 without Na was used as a reference -control-. Compositional cell cation by the mixture of MA0.2FA0.7Na0.05Cs0.05Pb -I5/6Br1/6-3 was used for comparison. Different characterization scheme such as IV measurements, Scanning Electron Microscopy, and X-ray Diffraction -XRD- were prepared to compare the performance of these two types of perovskite cell structures. SEM patterns showed the samples containing combined Na-Cs cations have a more compact surface with fewer pinholes. Also they exhibited higher efficiency compared to the reference sample. This was mainly due to the less defects of the interface surface. Moreover, better crystallinity was observed for the perovskite samples having Na-Cs combined cations from XRD pattern, which resulted in increase in charge transfer and also cell efficiency.

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