A simulation study of polarization characteristics of ultrathin CsPbBr ₃ nanowires with different cross-section shapes and sizes

The polarization characteristics of ultrathin CsPbBr ₃ nanowires are investigated. Especially, for the height of cross-section of nanowires between 2 nm and 25 nm, the normalized intensity and polarization ratio ρ of CsPbBr ₃ nanowires with triangular, square and hexagonal cross-section shapes are compared. The results show that, along with the increase of the height of cross-section, the polarization ratios of these three nanowires decrease until T = 15 nm, and increase afterwards. Also, along with the increase of the cross-section area up to 100 nm ², the polarization ratios of these three nanowires increase too. In general, for the same height or area, the polarization ratio ρ of these nanowires follows ρ _hexagon > ρ _square > ρ _triangle. Therefore, the nanowire with the hexagonal cross-section should be chosen, where for a cross-section height of 2 nm and a length-height ratio of 20:1, the maximal polarization ratio is 0.951 at the longitudinal center of the NW. Further, for the hexagonal NW with a cross-section height of 10 nm, the hexagonal NW with a length-height ratio of 45:1 exhibits the maximal polarization ratio at the longitudinal center of the NW. These simulation results predict the feasible size and shape of CsPbBr ₃ nanowire devices with high polarization ratios.