3‐(9‐Carbazolyl)carbazoles and 3,6‐Di(9‐carbazolyl)carbazoles as Effective Host Materials for Efficient Blue Organic Electrophosphorescence

Linking topology in oligocarbazoles (see figure) has a strong influence on their electronic properties. 3(6),9′-linked oligocarbazoles exhibit unusual suppression of electronic coupling between units, leading to localized excited states and very small reduction of triplet energies (compared to the monomer). Coupled with their excellent morphological stability, this makes them suitable as host materials for blue electrophosphorescence devices.