Phosphorescent emitter

PLEDs contain polymeric emissive materials that are almost exclusively processed by solution coating (spin coating or inkjetting). This has been discussed in Chapter 2. While most polymer work uses fluorescent emissive materials, there are a few examples of phosphorescent materials being incorporated into a polymer chain and being used as phosphorescent emitters. This part of the materials discussion will be covered in Chapter 4. 

C. Yang, C. Tai, and I. Sun, Synthesis of a high-efficiency red phosphorescent emitter for organic light emitting diodes, J. Mater. Chem., 14 947-950 (2004). 

Another efficient material introduced by the same group is the green emitting /ac-tris(2-phenylpyridine)iridium [Ir(ppy)3, 67] [38], A suitable host for this phosphorescent emitter is CBP (10). The triplet lifetime is rather short, the experimentally determined value being 500 ns in the CBP matrix. Another iridium complex was shown to emit in the red with high efficiency due to the short phosphorescence lifetime in comparison with PtOEP [165]. 

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. 

Yellow and Red Dopants Phosphorescent Emitters Creating White Light Creating Polarized Light... 

Emissive dopants, for OLED efficiency characteristics, 12, 141 organometallics emitters, 12, 143 phosphor-doped OLEDs, 12, 142 phosphorescent emitters, 12, 142 Emitters, in OLEDs, 12, 158 Enallenes, in Alder-ene reactions, 10, 591 a,/3-Enals, via propargylic alcohol isomerization, 10, 96 Enamides... 

In this work, we will review the optical, and to some extent, the electrochemical properties, of selected subfamilies of Ir(III) complexes. This will be done having in mind mainly (i) the actual interest in the manipulation and tuning of the photophysical properties of complexes playing as phosphorescence emitters, (ii) the possible use of Ir(III) centers as templating units for multicomponent arrays, particularly in view of charge separation (CS) schemes for the interconversion of light and chemical energy. 

The PL spectrum of a thin film of poly(3,6-dibenzosilole) 31 at 77 K exhibited a 0-0 transition at 3.5 eV and a second maximum at 3.3 eV (excitation at 4.4 eV) [41]. The phosphorescence emission spectrum at 77K consists of a broad band exhibiting vibronic structure (excitation at 3.9 eV). The polymer triplet energy level was taken to be the onset of triplet emission at 2.55 eV. This is considerably higher than the triplet energy of commonly used polyfluorenes (2.1 eV) [10,46] making it a host for phosphorescent emitters without the risk of energy back-transfer onto the polymer. 

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