Advances in metal halide perovskite ultrathin nanowires

One-dimensional metal halide perovskite (MHP) nanowires (NWs) have recently emerged as highly promising optoelectronic materials due to their high aspect ratio, anisotropic quantum confinement, nonlinear optical response, unique mechanical flexibility, in addition to the well-known advantageous properties inherent to MHPs. In this review, we discuss the recent advancements in the synthesis, characterization, and properties of MHP NWs, particularly with their diameters below the Bohr radius (referred as ultrathin MHP NWs). Key future directions are highlighted, including refining synthesis methods for atomic-level control, understanding the growth mechanisms, improving stability through surface passivation, exploring lead-free alternatives to mitigate toxicity concerns, and achieving novel and unique properties. These advancements will enable ultrathin MHP NWs to play a pivotal role in advanced applications in various optical, optoelectronic, and photonic technologies.