Broad-Band Emission in a Zero-Dimensional Hybrid Organic [PbBr₆] Trimer with Intrinsic Vacancies

The understanding of broad-band emission mechanisms on low-dimensional metal halides is an urgent need for the design principle of these materials and their photoluminescence tuning. Herein, a new zero-dimensional (0D) organic-inorganic hybrid material (C₉NH₂₀)₆Pb₃Br₁₂ has been discovered, in which face-sharing PbBr₆ trimer clusters crystallize with organic cations (C₉NH₂₀⁺), forming periodic structure with 0D blocks. Broad-band green emission peaking at about 522 nm was observed for this material, with a full width at half-maximum (fwhm) of 134 nm. The emission was attributed to excitons trapped at controlled intrinsic vacancies, and this is the new example in 0D metal halides, also confirmed by spectroscopy analysis and first-principles calculations. Discovery of the single-crystalline hybrid material and observation of defect-induced luminescence extend the scope of bulk 0D materials and understanding of photophysical properties for optoelectronic applications.