Broadband white-light emission from a novel two-dimensional metal halide assembled by Pb–Cl hendecahedrons

Abstract

The abundant selection of organic molecules and inorganic units has allowed for the fabrication of organic–inorganic hybrid metal halides (OIMHs) of various morphologies and crystal structures with controllable molecular dimensions and unique photoelectric properties. This work reports a unique two-dimensional (2D) OIMH, C₆H₁₀N₂Pb₂Cl₆, which comprises distinctive lead chloride hendecahedrons, (Pb₂Cl₆)²⁻, and p-phenylenediamium cations. The extremely large lattice distortion endows this 2D OIMH with strong electron–phonon coupling and an abundance of self-trapped excitons (STEs), which contribute to its broadband “cold” white-light emission with a large Stokes shift (∼200 nm) and a remarkable photoluminescence quantum efficiency (PLQE) of over 17% in 2D OIMHs.