Poly OLEDs

None-the-less, a number of thorough studies of cross-linking in high poly(ole-tin)s have been reported. In early work, Randall et a/. - studied irradiated high-density poly(ethylene)s (HOPE) using - C NMR, and identified a number of new structures, including internal double bonds and Y-type cross-links. The materials under consideration contained initially a high concentration of vinyl end... 

The polyaddition of diisocyanates with di-oles or poly-oles (e.g. polyalkylenglykol ether) formes polyurethanes, the properties of which can be varied in a very wide range by the combination of the reaction components (see Fig. 94). 

In preparing the compatible blend, the compatibilizer is reac-tively blended with PC and a blending partner in the presence of a transesterification catalyst. The blending partner can be a poly(ole-fin), styrene acrylonitrile copolymer, acrylonitrile-butadiene-styrene, poly (methyl methacrylate), or poly (styrene). Suitable transesterification catalysts include tetraphenyl phosphonium benzoate, tetraphenyl phosphonium acetate, and tetraphenyl phosphonium... 

Single layer OLEDs have been fabricated with a variety of emitter molecules and conjugated polymers such as poly(phenylene vinylene) (PPV). 

Since multiple electrical and optical functionality must be combined in the fabrication of an OLED, many workers have turned to the techniques of molecular self-assembly in order to optimize the microstructure of the materials used. In turn, such approaches necessitate the incorporation of additional chemical functionality into the molecules. For example, the successive dipping of a substrate into solutions of polyanion and polycation leads to the deposition of poly-ionic bilayers [59, 60]. Since the precursor form of PPV is cationic, this is a very appealing way to tailor its properties. Anionic polymers that have been studied include sulfonatcd polystyrene [59] and sulfonatcd polyanilinc 159, 60]. Thermal conversion of the precursor PPV then results in an electroluminescent blended polymer film. 

An alternative approach utilizes polymeric analogs of PBD. The oxadiazole unit may be in the polymer main chain or attached as a side chain. A reasonable device performance has been demonstrated in poly(aromatic oxadia/ole)s [71—74. ... 

Poly-(acetylene)s are widely used in different fields, such as organic light-emitting diodes (OLEDS), solar cells, and lasers.135 Synthesis... 

ErQ3 gives both PL and EL emission at 1,500 nm.207-209 Red light (614 nm) is emitted by [Eu(TTFA)3(phen)] (Figure 2(a)) doped in a poly(A-vinylcarbazole) layer.210 The complex [Eu(TTFA)3(TPPO)2] (TPPO = triphenylphosphine oxide, see Figure 2(f)) emits in the red when incorporated in OLEDs,211,212 behavior which is enhanced when the material is heat treated.204 Near-IR EL and PL emission was observed from blends of polyfp-phenylene-vinylene) with [Yb(TPP)(ACAC)] and [Er(TPP)(ACAC)] (H2TPP is 5,10,15,20-tetraphenylporphyrin) by both EL and PL 213... 

Grubbs group reported a series of cross-linkable triarylamine-containing poly(norbor-nenes) (51) and investigated them as the HTMs in a bilayer OLED (Scheme 3.19) [94]. However, cross-linking was found to decrease the device performance due to the low Ts of the polymers and the poor film quality after UV irradiation. 

In this chapter, we describe mainly a-Si H TFTs AM-OLEDs technology, developed at the University of Michigan within Kanicki s group since 1999, that one day may be able to compete not only with the poly-Si TFT AM-OLEDs but also with the a-Si H TFT AM-LCDs. The a-Si H TFT AM-OLEDs developed by others are only briefly described in this chapter. 

CDT, based in Cambridge, U.K., was founded after initial work done at the Cambridge University. Researchers in Cambridge discovered that poly(/>-phenylenevinylene) (PPV, Figure 11.16) and its derivatives can be used as emitters to construct OLEDs, which were the first examples of PLEDs [4], The invention has brought flat-panel displays to the verge of commercialization. 

DuPont is an active player in OLED technology. Polymers used in devices as emitting materials are poly(p-phenylenevinylene), poly(arylenevinylene)s, poly(p-phenylene), poly(arylene)s, polyquinolines, and polyfluorenes. In some cases, an anionic surfactant such as lithium nonylphenoxy ether sulfate was added to the above-mentioned polymeric emitters... 

Wu et al. [31] have recently presented a novel concept of designing oxygen nanosensors. They used the precipitation method to obtain polyfluorene beads (0 25 nm) doped with the oxygen indicator platinum(II) octaethylporphyrin. Poly (9,9-dihexylfluorene) belongs to materials widely used in OLEDs and has a bright blue emission when excited in the UV region. In beads, FRET-mediated red emission... 

Light-emitting polymers [46,48] are a more recent development and may eventually prove superior to small-molecule OLED. Typical polymers are the green poly(para-phenylene vinylene) (PPV 53), the orange-red dialkoxy derivatives (54), and the blue polyfluorene (55) [48],... 

---