Phosphorescent dopants

SCHEME 3.1 Chemical structures of anthracene, a hole transport triarylamine, an electron transport and a green emitter Alq3, and a phosphorescent dopant PtOEP. 

For a triplet emissive guest (phosphorescent) dopant, the triplet energy level of the host normally should be higher than that of the guest. 

SCHEME 3.85 Chemical structure of some orange to red phosphorescent dopants. 

SCHEME 3.89 Chemical structures of some blue-phosphorescent dopants. 

SCHEME 3.90 Chemical structure of blue-phosphorescent dopants. 

PL 414-427 nm PL 390-402 r SCHEME 3.91 Chemical structure of blue-phosphorescent dopants. 

The above strategy, using three primary colors as phosphorescent dopants, has a big problem in controlling the efficiency of the energy transfer, which eventualy will result in... 

FIGURE 3.18 Normalized EL spectra of the white PHOLED at several current densities upper insert Absorption of neat CBP films (100 nm) and lower insert A White PHOLED structure (left) and the chemical structures of phosphorescent dopants (right). (From D Andrade, B.W., Brooks, J., Adamovich, V., Thompson, M.E., and Forrest, S.R., Adv. Mater., 14, 1032, 2002. With permission.)... 

As the EL efficiency is limited by the poor phosphorescent dopant PtOEP, by using a good red phosphorescent iridium complex, Liu et al. demonstrated a very highly efficient PHOLED by applying a HBM [350], The device structure is ITO/NPD/CBP 6% Ir(piq-F)3/BCP/Alq3/Mg Ag. 

Photophysical Parameters of Some Polymer Hosts and Phosphorescent Dopants... 

FIGURE 7.10 Luminous efficiency (open squares) and power efficiency (filled circles) versus luminance for a PHOLED incorporating an improved green phosphorescent dopant. 

FIGURE 7.13 A 2.2" full-color transparent AMOLED display fabricated by Samsung SDI incorporating phosphorescent dopants. 

Phenylquinoxalines (30) turned out to be both fluorescent and phosphorescent emitters [167, 168]. By using these molecules as host, singlet excitons as well as triplet excitons can be transfered by long-range interactions to phosphorescent dopant molecules such as 66. 

Abstract Mononuclear Ir(III)-polyimine complexes show outstanding luminescence properties, i.e., high intensities, lifetimes in the is time range, and emission wavelengths that can be tuned so as to cover a full range of visible colors, from blue to red. We discuss the approaches for the use of ligands that afford control on luminescence features. Emphasis is placed on subfamilies of cyclometalated complexes, whose recent enormous expansion is motivated by their potential for applications, including that as phosphorescent dopants in OLEDs fabrication. The interplay of the different excited states associated... 

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