Interchromophoric Excitonic Coupling Controls Phosphorescence in Thermomorphs of Carbazole Dimer

Abstract

A rigid carbazole dimer exhibits temperature-dependent phosphorescence governed by thermomorphically modulated excitonic coupling, displaying red-shifted emission at 298 K (513 nm) and blue-shifted emission at 77 K (460 nm). Variable temperature crystallography reveals intramolecular reorientation enhances Coulombic coupling despite increased intermolecular separation, enabling unconventional control over triplet-state energetics.