Blue 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. 

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... 

The triplet-harvesting mechanism was confirmed by efficiency analysis of the BIY device spectra. A blue fluorescent (BE) device was constructed similarly to the BIY except that the phosphorescent emitter was omitted. The blue portion of the spectrum (380-512 nm) of the BE device exhibits 4.9% EQE, indicating very efficient fluorescence. Figure 14.52 shows that devices B Y and BE have nearly identical spectral radiance for the blue component of the electroluminescence. Thus, fluorescence remained the same while the addition of the phosphorescent dopant to the BE device resulted in the appearance... 

Spectra of blue yellow (B Y) harvesting hybrid and blue fluorescent OLEDs. Blue device has the same structiue as B Y except that the yeUow phosphorescent emitter is omitted. Data are taken at ImA/cm. Inset Structure of the yeUow phosphorescent dopant. 

Thompson, M. E., Li, J., Tamayo, A. et al. 2005. Color tuning dopants for elec-trophosphorescent devices Towards efficient blue phosphorescence from metal complexes. SID Inti. Symp. Dig. Tech. Papers 36 1058. 

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