Conformational Landscapes in the Ground and Excited States Dictate Circularly Polarized Excimer Emission: A Thermodynamic–Kinetic Interplay in Carbazole Dimer Systems

Key Points

• This research aims to understand how conformational states in carbazole dimers influence circularly polarized light (CPL) emission.
• Examination of the conformational behavior of chiral carbazole dimers in varying thermal conditions.
• Analysis of CPL intensity and its correlation with conformer types (tt and gauche).
• Comparison of a chiral carbazole dimer and a tert-butyl derivative to assess substituent effects.
• The tt conformer in chiral carbazole dimers produces strong excimer CPL, while gauche conformers result in weak local emission.
• Cooling the sample enhances CPL intensity and leads to red-shifts due to increased tt conformer contribution.
• The tert-butyl derivative reveals weak, temperature-insensitive CPL due to the prevalence of non-CPL-emissive gauche conformers.