Carbazole polymers

In the effort to make pure blue-emitting materials Shim and coworkers [146] synthesized a series of PPV-based copolymers containing carbazole (polymers 95 and 96) and fluorene (polymers 97 and 98) units via Wittig polycondensation. The use of trimethylsilyl substituents, instead of alkoxy groups, eliminates the electron donor influence of the latter and leads to chain distortion that bathochromically shifts the emission (Amax = 480 nm for 95 and 495 nm for 97). In addition, a very high PLQY was found for these polymers in the solid state (64 and 81%, respectively). Single-layer PLEDs fabricated with 95 and 97 (ITO/polymer/Al) showed EL efficiencies of 13 and 32 times higher than MEH-PPV, respectively (see also Ref. [147] for synthesis and PLED studies of polymers 99 and 100) (Chart 2.20). 

Thiophene containing carbazole polymers, (V), were prepared by Leclerc (5) and used as light-emitting diodes. 

Charge-transfer polymers were commercialized by IBM Corporation since about 1968 in xerographic copiers A drum covered by trinitro-fluorenone-polyvinyl carbazole polymer mixed with trinitrofluore-none replaced the expensive Se drum. 

Regiogegular fluorcene, (IV), and carbazole polymers, (V), prepared by Heeney [4] and Leclerc [5], respectively, were useful as electroluminescent devices because of their solubility in organic solvents and ease of processability. 

Novel composite carbazole polymer films containing silver and gold nanoparticles and being thiol-stabilized have been fabricated. Optical properties of PEPC films are more sensitive to the nanoparticles incorporation than the properties of PVC films. This can be provided by the formation of additional interaction of particles and -CH2-O-CH2- group presented in the polymer chain. High values of the current density measured and the character of the current-voltage dependence in the composite films can be the consequence of several mechanisms of charge carrier transport in both composite PEPC and PVC films. 

An important difference in photophysical behavior between the naphthalenic and carbazole polymers is the lifetime of the mobile exciton compared with that of the triplet excimer. For PVCA the mobile exciton is much shorter lived than the excimeric species but for PIVN just the reverse is true. In both polymers the primary mode of delayed fluorescence production involves a hetero-annihilation of the type... 

The carbazole polymer poly(iV-vinylcarbazole) functions as a positive electrode material for a secondary lithium battery <85CC553>, and as a memory photoreceptor <91M1 204-0l>. The related poly[3-(3-bromocarbazol-9-yl)propyl]methylsiloxane (18) forms novel electrochromic films <89CC196>. Carbazole anions have b n used to initiate the polymerization of acrylates and methacrylates <95CC275>. The novel polymeric pyrrolocarbazole (19) displays physical properties similar to those of polyanilines. 

Carbazole polymers can be roughly subdivided into polymers that contain the carbazole group as a pendent group and those that have the carhaz-ole group in the backbone. A special variety is a carbazole polymer with conjugated groups. 

The most important class belongs to polymers based on A-vinylcarb-azole (NVK). Carbazole polymers are reviewed in the literature. The interest in poly(A-vinylcarbazole) (PVK) and related polymers originates because these polymers are ... 

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