Details

Autor(en) / Beteiligte

• Wu, Ya‐Hang
• Xiao, Hongyan
• Chen, Bin
• Weiss, Richard G.
• Chen, Yu‐Zhe
• Tung, Chen‐Ho
• Wu, Li‐Zhu

Titel

Multiple‐State Emissions from Neat, Single‐Component Molecular Solids: Suppression of Kasha's Rule

Ist Teil von

• Angewandte Chemie (International ed.), 2020-06, Vol.59 (25), p.10173-10178

Auflage

International ed. in English

Ort / Verlag

Germany: Wiley Subscription Services, Inc

Erscheinungsjahr

2020

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Three rigid and structurally simple heterocyclic stilbene derivatives, (E)‐3H,3′H‐[1,1′‐biisobenzofuranylidene]‐3,3′‐dione, (E)‐3‐(3‐oxobenzo[c] thiophen‐1(3H)‐ylidene)isobenzofuran‐1(3H)‐one, and (E)‐3H,3′H‐[1,1′‐bibenzo[c] thiophenylidene]‐3,3′‐dione, are found to fluoresce in their neat solid phases, from upper (S2) and lowest (S1) singlet excited states, even at room temperature in air. Photophysical studies, single‐crystal structures, and theoretical calculations indicate that large energy gaps between S2 and S1 states (T2 and T1 states) as well as an abundance of intra and intermolecular hydrogen bonds suppress internal conversions of the upper excited states in the solids and make possible the fluorescence from S2 excited states (phosphorescence from T2 excited states). These results, including unprecedented fluorescence quantum yields (2.3–9.6 %) from the S2 states in the neat solids, establish a unique molecular skeleton for achieving multi‐colored emissions from upper excited states by “suppressing” Kasha's rule. A unique molecular skeleton that exhibits multiple‐state emissions as neat, single‐component molecular solids at room temperature in air is reported. Mechanistic studies revealed that large energy gaps between S2 and S1 states, and an abundance of intramolecular/intermolecular hydrogen bonds, suppress internal conversions of the upper excited states in the solids and enable unprecedented fluorescence quantum yields (2.3–9.6 %) from the S2 states.