Hole transporting agents

Electroluminescent polymeric 1,3,4-oxadiazole-containing agents, (IV), prepared by Roberts [3] were also effective as electron hole transport agents. 

Hole transport agent doped nonlinear optical polymer [17] 70 % bisA-NAS 30 % DEH 298 75 2.5 X 10 16 b... 

Small organic molecules doped into polymer binders have also been employed in DEED devices. Coating is done using inexpensive solution techniques. A commonly used polymer is polyvinylcarbazole [50-52], which is a hole transport material with moderate mobility. Polysilanes have also been used as hole transport agents [53]. Common laser dyes may be employed as the emissive molecular dopant, for example coumarins [50, 51], rhodamines [50] or pyrans [51, 53]. Similar considerations of energetics and concentration apply to doped polymers as to small molecule dopant-host systems the dopant should provide the lowest energy site for the exciton and concentration quenching should be minimized. 

Bacher et al. [15] reported on a series of triphenylene derivatives with one, two or three reactive acrylate units for crosslinking (Fig. 9.8(a)). No influence of the number of acrylate units on the degree of crosslinking was reported. Bi-layer OLEDs with the triphenylene as hole-transport agent and vapor-deposited A1Q3... 

MAJOR APPLICATIONS Hole transport agent in electrophotography, light-emitting diodes, display devices, and printing processes. 

In the recent work [24], the photoreceptor comprised a support with a photosensitive layer containing a binder, a hole-transporting agent containing stilbene derivative I... 

Also, Liphardt et al. deseribe photorefraetive polymers with performanee eompetitive with available erystals. The materials are a mixture of the eleetrooptie polymer based on bisphenol A and 4,4 -nitroaminostilbene with 29 % by weight of benzaldehyde diphenylhydrazone, a hole transporting agent ... 

Doubly doped polymers can be used to enhance two functions. For example, Wu et al. [58] added Alq3 as an election transport agent and nile red as an emitter to hole transporting PVK. 

Levitzki A (2000) Protein Tyrosine Kinase Inhibitors as Therapeutic Agents. 211 1-15 Lewis, FD, Wasielewski MR (2004) Dynamics and Equilibrium for Single Step Hole Transport Processes in Duplex DNA. 236 45-65... 

Many electroluminescent materials have poor charge transport properties. The present invention is directed to polymeric agents containing grafted naphthalene or pyrene, which makes then effective as both hole transport and electroluminescent agents. 

Figure 4.46. Molecular structures of commonly used OLED/PLED materials. Shown are (a) Alq3 (tris(quinoxalinato)Al (III)) used as an electron-transport material (b) DIQA (diisoamylquinacridone) used as an emissive dopant (c) BCP (2,9-dimethyl-4,7-diphenyl-l,10-phenanthroline) used as an exciton/ hole blocking agent (d) NPB (l,4-bis(l-napthylphenyl amino)biphenyl) (e) PFO (9,9-dioctylfluorene) used as an emissive polymer in PLEDs (f) PEDOT-PSS (poly-3,4-ethylenedioxythiophene-polystyrene sulfonate) used as a hole transport material in PLEDs.

Among the electron transport agents, derivatives of oxadiazole [34, 35] have been extensively studied. (Oxadiazoles do emit quite efficiently, but the wavelengths [36] are generally too short to be useful for display applications). By far the most widely used hole transport materials are the aryl-amines, exemplified by TPD [37] (see Table 13-2). Because of their use in electrophotographic photoconductors, dating back to the 1970s, there is an extensive literature [38] on the... 

The photoreceptor has a light-sensitive layer containing a binder resin, a chargegenerating agent, and a positive hole-transporting material of stilbene derivative I. 

---