Polyfluorene-Based Polyelectrolytes

FIGURE 2.24 The plot of brightness (dashed line) and current density (dotted line) vs. applied voltage for PLEDs (a) ITO/PEDOT/366/Ca/Ag and (b) ITO/132/366/Ca/Ag. (From Herguth, P., Jiang, X., Liu, M.S., and Jen, A.K.-Y., Macromolecules, 35, 6094, 2002. With permission.) 

A series of fluorene copolymers with amino-functionalized side chains 373 and 374 has been prepared by the same group (Chart 2.92). Upon quaternization, they gave copolymers 375 and 376, which were soluble in polar solvents (methanol, DMF, DMSO) [439]. Devices from the 

SCHEME 2.57 Suzuki synthesis of multicomponent copolymers for RGB PLED display. (From Muller, C.D., Falcou, A., Reckefuss, N., Rojahn, M., Widerhirn, V., Rudati, P., Frohne, H., Nuyken, O., 

When an electron-deficient BT unit was incorporated into the backbone of these polymers, an efficient energy transfer resulted in complete fluorescence quenching from the fluorene sites already at BT concentrations as low as 1% (for both neutral and quaternized copolymers, 377 and 378) [440] (Chart 2.93). These macromolecules emit green (544-550 nm, 377) to yellow (555-580 nm, 378) light and can be processed from environment-friendly solvents such as alcohols. The PLED fabricated with these polymers showed high 4 (]over 3 and 1% for 377 and 378, respectively (A1 cathode). 

Whereas all above water-soluble PFs are tetra-alkylammonium-based salts, Burrows et al. [443] reported on anionic fluorene-based copolymer 381 that showed a blue shift in PL (from 424 to 411 nm) as well as a dramatic increase in the fluorescence quantum yield (from 10-15 to 60%) when incorporated into w-dodecylpentaoxyethylene glycol ether micelles [443], 

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Huang, R, L.T. Hou, H.L. Shen, J.X. Jiang, F. Wang, H.Y. Zhen, and Y. Cao. 2005. Synthesis, photophysics, and electroluminescence of high-efficiency saturated red light-emitting polyfluorene-based polyelectrolytes and their neutral precursors. J Mater Chem 15 (25) 2499-2507. 

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