Herein, we investigate the influence of aspect ratio and quantum confinement on the single-photon (σ1) and two-photon absorption cross-section (σ2) for perovskite CsPbI3 nanorod (NR). Notably, experimentally measured data show extremely high σ2 for CsPbI3 NR (10.8 × 107 GM) which is five orders of magnitude higher than organic chromophores, and two order of magnitude higher than CsPbBr3 nanocrystals. Moreover, σ2 for NRs can be enhanced by two-orders of magnitude by varying the aspect ratio and σ1 enhances linearly with aspect ratios. Furthermore, experimental data show moderate quantum confinement effect on the volume-normalized σ1 and σ2 for nanorods.
Keywords: NLO for halide perovskites; perovskite CsPbI3 nanorods with different aspect ratios; quantum confinement effect; single and two-photon absorption cross-section.