Morphology-Dependent Optical Properties and Exciton Dynamics of CsPbBr ₃ Nanowires and Nanoplatelets

Lead halide perovskites have emerged as promising candidates for next-generation optoelectronic devices owing to their tunable bandgaps, high photoluminescence efficiency, and excellent carrier transport characteristics. Low-dimensional nanostructures, particularly nanowires (NWs) and nanoplatelets (NPLs), further enhance these properties through anisotropic charge transport and strong quantum confinement; however, direct morphology-dependent comparisons remain limited. Herein, CsPbBr3 NWs and NPLs were synthesized via a ligand-regulated hot-injection strategy that enables precise dimensional control by tuning ligand ratios. The NWs exhibit uniform one-dimensional (1D) geometry (∼9 nm diameter), whereas NPLs form ∼5 nm-thick two-dimensional (2D) structures. Structural and optical analyses reveal morphology-dependent spectral responses in which NWs show exciton absorption and emission at 505/520 nm, while NPLs display pronounced blue-shifts (465/480 nm) due to enhanced vertical confinement. Time-resolved photoluminescence reveals significantly longer exciton lifetimes in NWs (88.06 ns) than NPLs (32.20 ns), indicating reduced defect density and superior radiative recombination characteristics. Femtosecond transient absorption confirms slower carrier trapping and prolonged hot-carrier relaxation in NWs. This comparative study establishes a direct structure–property relationship between 1D and 2D CsPbBr3 nanostructures, offering insight into morphology-guided design for lasers, single-photon emitters, and blue optoelectronic devices.