Two-dimensional organic-inorganic hybrid perovskite quantum-well nanowires enabled by directional noncovalent...

Layered 2D semiconductors, when grown into 1D nanowires, can exhibit excellent optical and electronic properties, promising for nanoscale optoelectronics and photonics. However, rational strategies to grow such nanowires are lacking. Here, we present a large family of quantum-well nanowires made from 2D organic-inorganic hybrid metal halide perovskites with tunable well thickness, organic spacer cations, halide anions, and metal cations, achieved by harnessing directional nonvalent intermolecular interactions present among certain spacer cations. The unusual 1D anisotropic growth within the 2D plane is induced by preferential self-assembly of selected spacer cations along the direction of stronger intermolecular interactions and further promoted by crystal growth engineering. Owing to the intrinsic 2D quantum-well-like crystal structures and 1D photon confinement at the subwavelength scale, these nanowires exhibit robust exciton-photon coupling, with Rabi splitting energies of up to 700 meV, as well as wavelength-tunable and more efficient lasing compared to exfoliated crystals.