Interplay of Fluorescence and Phosphorescence in Organic Biluminescent Emitters

Abstract

'-diphenyl-(1,1-biphenyl)-4,4-diamine). In the extreme case, the singlet and triplet exciton lifetimes stretch from 3 ns to 300 ms, respectively. Through sample engineering and oxygen quenching experiments, the triplet exciton density can be controlled over several orders of magnitude, allowing us to study exciton interactions between singlet and triplet manifolds. The results show that singlet-triplet annihilation reduces the overall biluminescence efficiency already at moderate excitation levels. Additionally, the presented system represents an illustrative role model to study excitonic effects in organic materials.