Insight into the effect of halogen X in methylammonium lead halide (MAPbX3) spin-coated on zinc oxide film

Herein, we investigated the effect of halogen X in methylammonium lead halide (MAPbX3) where X = (Iodide/Bromide, or Chloride) deposited by spin coating technique on a zinc oxide layer. The ZnO films were first deposited on Fluorine-doped Tin Oxide (FTO) substrates. Then, the perovskite solutions (MAPbI3, MAPbBr3, and MAPbCl3) were deposited on the ZnO layer. The films obtained were characterized by X-ray diffraction (XRD), UV–Visible spectroscopy, and Scanning Electron Microscopy (SEM). The XRD analysis shows characteristic peaks of the ZnO/MAPbX3 heterojunction corresponding to the (100) and (200). The ZnO/MAPbBr3 peaks are more intense than other sample peaks. This analysis also shows the crystalline character of the films produced. SEM images also show the good crystallinity of the films produced. The images show that the grain sizes of the sample ZnO/MAPbBr3 are the largest compared to others. The UV–visible characterization showed that the iodine-based sample absorbed better and had a good band gap (Eg = 1.95 eV). The degradation study was carried out after two weeks of the deposition. The results showed that the iodine-based sample degrades faster compared to another halogen. These findings are helpful in producing stable and efficient perovskite-based solar cells. •ZnO thin films deposited by low-cost technique spin coating showed higher quality.•The iodine-based sample absorbed the best and had a smaller band gap (Eg = 1.95 eV).•The films produced have good crystallinity. The grain size of the sample ZnO/MAPbBr3 is the largest of the grain sizes.•The iodine-based sample degrades faster.