Self-assembled ultrafine CsPbBr3 perovskite nanowires for polarized light detection

One-dimensional (1D) metal halide perovskite nanowire (NW) arrays with high absorption efficiency, emission yield and dielectric constants, as well as anisotropic optoelectronic properties have found applications in energy harvesting, flexible electronics, and biomedical imaging devices. Here, a modified two-step solvothermal method is developed for the synthesis of self-assembled cubic CsPbBr3 NW arrays. This method provides facile access to continuous and uniform ultrafine perovskite NWs and well-aligned pure perovskite NW arrayed architectures. Under excitation at 365 nm, the CsPbBr3 NWs give a strong blue emission observable to the naked eyes. The CsPbBr3 NWs also exhibit strong two-photon excited luminescence under the irradiation with an 800 nm pulse laser. By rotating the polarization angle of the 800 nm laser, strong polarization dependence with a polarization degree up to ∼0.49 is demonstrated in the self-assembled CsPbBr3 NW array, although the CsPbBr3 NWs have an isotropic cubic structure. Based on density functional theory (DFT) calculations, this polarization-dependent emission is correlated with the anisotropic charge density distribution of the perovskite NWs. These findings suggest that the ultrafine CsPbBr3 NWs with a well-defined self-assembled architecture could be applied as next-generation polarization-sensitive photoelectronic detection materials.