Dispirocycles: Platforms for the Construction of High-Performance Host Materials for Phosphorescent Organic Light-Emitting Diodes.

Spirocyclic compounds such as 9,9'-spirobifluorene (SBF) are becoming more and more attractive for use as host materials in organic optoelectronic devices. Herein, two dispirocycles, namely, dispiro[fluorene-9,9'-anthracene-10',9''-fluorene] and 10,10''-diphenyl-10H,10''H-dispiro[acridine-9,9'-anthracene-10',9''-acridine], were used for the construction of host materials 1-4. The attached triphenylamino group determines the thermal, photophysical, electrochemical, and charge-transport properties, and therefore they have different electroluminescent performances. The device based on dispiro[fluorene-9,9'-anthracene-10',9''-fluorene] (2) and 10,10''-diphenyl-10H,10''H-dispiro[acridine-9,9'-anthracene-10',9''-acridine] (3) molecular platforms exhibited external quantum efficiencies of greater than 21 % with a very high power efficiency (≈100 lm W-1 ). These results demonstrate the potential of extending the application of dispirocyclic molecular platforms with inherent rigidity for developing highly efficient host materials for organic light-emitting diodes.