NH₃-induced morphological evolution of organohalide perovskites from three-dimensional microcubes to one-dimensional nanorod aggregates and their electrochemical performance

Sensitive nature of organic-inorganic hybrid perovskite material provides an opportunity to turn its electrochemical property. Herein, the conversion process from three-dimensional (3D) CH₃NH₃PbI₃ (MAPbI₃) microcubes to one-dimensional (1D) nanorod aggregates was reported by NH₃ post-treatment for 30 min, which enhanced the carrier mobility (36.91 cm²/V) and Li-ion diffusion coefficient (5.26 × 10⁻⁹ cm² s⁻¹) and narrowed the optical band gap (1.385 eV) of MAPbI₃ nanorod aggregates. The morphology evolution of 3D MAPbI₃ crystals and 1D MAPbI₃ nanorod rebuilding mechanism induced by NH₃ have been investigated and proposed. In addition, compared with samples without NH₃ treatment, 1D nanorod aggregates exhibited the improved electrochemical performances including capacity (from 53 mA h g⁻¹ to 243 mA h g⁻¹) and cycle stability (132 mA h g⁻¹, 300th cycle) which are ascribed to the improved electronic properties and special 1D microstructure.