White Light Emission from a Zero-Dimensional Lead Chloride Hybrid Material

Organic–inorganic hybrid (OIH) materials have emerged as a high-performance class of light emitters, which can be used as phosphors for optically pumped white-light-emitting diodes (WLEDs). Here, we report a new example of broadband white light (WL) emission from zero-dimensional lead chloride-based OIH material, namely, (TAE)₂[Pb₂Cl₁₀]­(Cl)₂ (TAE = tris­(2aminoethyl)­ammonium (C₆N₄H₂₂)). Single crystals of this compound and its corresponding ammonium salt TAE·HCl have been synthesized by a slow solvent evaporation method at room temperature and were characterized by X-ray diffraction, optical absorption, and photoluminescence measurements. The crystal structure shows an isolated lead chloride edge sharing bioctahedra [Pb₂Cl₁₀]^6– interacting with two [TAE]⁴⁺ cations and two Cl^– chlorine ions through multiple hydrogen bonds in a triclinic unit cell, which confers to this system its 0D character. Upon UV irradiation at 3.81 eV, (TAE)₂[Pb₂Cl₁₀]­(Cl)₂ shows a very broadband WL emission resulting from the overlapping of two peaks located at 2.07 and 2.83 eV, attributed to photoinduced free excitons confined in Pb₂Cl₁₀ inorganic bioctahedra and the organic cations, respectively. When excited with a 4.66 eV laser, the full width at half-maximum of WL band luminescence reaches the unprecedented value of 1.25 eV (247 nm) and exhibits the highest CRI value with 96 and chromaticity coordinates closer to the reference white light. This was mainly attributed to light emission originating from some self-trapped excitonic states caused by a structurally highly distorted inorganic subnetwork. The present results enrich the restricted family of hybrid perovskite WL emitters and highlight the importance of the 0D OIH materials for solid-state lighting applications.