Unveiling Clusterization-Triggered Emission Mechanism Through a Small-Molecule Clusteroluminogen with Color Tunable...

Clusterization-triggered emission (CTE) is a photophysical phenomenon where clusteroluminogens (CLgens) generate efficient luminescence through supramolecular self-assembly in the solid state. This phenomenon offers unique photophysical properties, distinguishing it from traditional chromophores. In the context of light-emitting devices, there is growing interest in single-component white-light (SCWL) emission, where a single material produces broad emission. However, SCWL emission based on CLgens has been rarely reported, particularly in single crystals, and fabricating SCWL emitters from small-molecule, nonconjugated luminogens remains a significant challenge. The underlying mechanism of CTE is still not fully understood, prompting investigations into small-molecule CLgens to explore their structure-property relationships. In this study, a novel organic salt, TET.Br₄ (TET = N,N'-bis-(2-aminoethyl)-1,3-propanediamine), is synthesized, consisting of saturated TET cations connected by a hydrogen-bonded network of bromine anions in the crystalline state. The photophysical properties of TET.Br₄ are characterized through optical absorption, photoluminescence measurements, and density functional theory (DFT) calculations. The results demonstrate color-tunable CTE and near-white-light emission, highlighting the synergetic role of through-space conjugation, energy/charge transfer, and halogen atoms in the CTE mechanism. This study aims to unravel the mechanism of CTE in small-molecule CLgens and address the scarcity of reports on SCWL emission from nonconjugated luminogens, contributing to advancements in this field.