Saturated deep blue organic electrophosphorescence using a fluorine-free emitter

• Published in: Applied physics letters 2005-12, Vol.87 (24), p.243507-243507-3
• Main Authors: Holmes, R. J., Forrest, S. R., Sajoto, T., Tamayo, A., Djurovich, P. I., Thompson, M. E., Brooks, J., Tung, Y.-J., D'Andrade, B. W., Weaver, M. S., Kwong, R. C., Brown, J. J.
• Format: Article
• Language: English
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.2143128

We demonstrate saturated, deep blue organic electrophosphorescence using the facial - and meridianal - isomers of the fluorine-free emitter tris (phenyl-methyl-benzimidazolyl)iridium(III) ( f - Ir ( pmb ) 3 and m - Ir ( pmb ) 3 , respectively) doped into the wide energy gap host, p - bis (triphenylsilyly)benzene (UGH2). The highest energy electrophosphorescent transition occurs at a wavelength of λ = 389 nm for the fac - isomer and λ = 395 nm for the mer - isomer. The emission chromaticity is characterized by Commission Internationale de l'Eclairage coordinates of ( x = 0.17 , y = 0.06 ) for both isomers. Peak quantum and power efficiencies of ( 2.6 ± 0.3 ) % and ( 0.5 ± 0.1 ) lm ∕ W and ( 5.8 ± 0.6 ) % and ( 1.7 ± 0.2 ) lm ∕ W are obtained using f - Ir ( pmb ) 3 and m - Ir ( pmb ) 3 respectively. This work represents a departure from previously explored, fluorinated blue phosphors, and demonstrates an efficient deep blue/near ultraviolet electrophosphorescent device.