H‑Aggregates Granting Crystallization-Induced Emissive Behavior and Ultralong Phosphorescence from a Pure Organic Molecule

• Published in: The journal of physical chemistry letters Vol. 8; no. 8; pp. 1894 - 1898
• Main Authors: Lucenti, Elena, Forni, Alessandra, Botta, Chiara, Carlucci, Lucia, Giannini, Clelia, Marinotto, Daniele, Previtali, Andrea, Righetto, Stefania, Cariati, Elena
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 20-04-2017
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/acs.jpclett.7b00503

Solid-state luminescent materials with long lifetimes are the subject of ever-growing interest from both a scientific and a technological point of view. However, when dealing with organic compounds, the achievement of highly efficient materials is limited by aggregation-caused quenching (ACQ) phenomena on one side and by ultrafast deactivation of the excited states on the other. Here, we report on a simple organic molecule, namely, cyclic triimidazole (C9H6N6), 1, showing crystallization-induced emissive (CIE) behavior and, in particular, ultralong phosphorescence due to strong coupling in H-aggregated molecules. Our experimental data reveal that luminescence lifetimes up to 1 s, which are several orders of magnitude longer than those of conventional organic fluorophores, can be realized under ambient conditions, thus expanding the class of organic materials for phosphorescence applications.