Optical Properties and Nanocavity Response of CsPbCl₃Nanowires: Implications for Light-Emitting Devices

Advanced photochemical stability, excellent lasing response, and multifold higher nonlinear optical magnitude of all-inorganic CsPbX₃ (X = Cl, Br, and I) perovskites made them superior to their organic–inorganic hybrid halide counterparts and other conventional semiconducting materials. Herein, in addition to basic material properties, various aspects of the photoluminescence (PL) behaviors along with the highest ever Q-factor nanocavity response of CsPbX₃ (X = Cl) perovskite nanowires (NWs) are reported. The high-quality, single-crystalline CsPbCl₃ NWs were grown by the noncatalytic chemical vapor deposition (NC–CVD) approach. Strong violet-blue (∼415 nm) PL emission, excellent response to multiphoton absorption (MPA), and harmonic generation suggest that these NWs are suitable for light manipulation and detection-related miniaturized device applications. Temperature- and power-dependent PL measurements reveal that the PL emissions from the CsPbCl₃ NWs originate from excitonic transitions. Further, excitation fluence-dependent PL measurements on typical CsPbCl₃ NW demonstrate excellent single-mode lasing at P_Th ∼ 130 μJ/cm² with a nanocavity response quality factor, Q ∼ 4500, higher than most reported values for similar materials and nanostructures. We believe that, in addition to device miniaturization, these findings will surely advance and promote the one- and multiphoton absorption (OPA and MPA)-related optoelectronic applications of CsPbX₃ perovskites. Moreover, the insights of the photophysical transitions revealed here for large bandgap (E_g ∼ 2.99 eV) CsPbCl₃ NWs may also facilitate the understanding of the photophysics of other wide bandgap semiconductors.