Synthesis and Electroluminescence Properties of White-Light Single Polyfluorenes with High-Molecular Weight by Click Reaction

We reported a new way to synthesize single-chain white light-emitting polyfluorene (WPF) with an increased molecular weight using azide-alkyne click reaction. Four basic polymers with specific end-capping, which exhibited high-glass transition temperatures (T-g > 100 degrees C) and excellent thermal stability, were used as foundations of the WPF's synthesis; a blue-light polymer (PFB2) end-capped with azide groups can easily react with acetylene end-capped polymers (PFB1, PFG1, and PFR1, which are emitting blue-, green- and red-light, respectively) to form triazole-ring linkages in polar solvents such as N,N-dimethylforamide/toluene co-solvent at moderate temperature of 100 degrees C, even without metal-catalyst. Several WPFs that consist of these four basic polymers in certain ratios were derived, and the polymer light-emitting diode device based on the high-molecular weight WPF was achieved and demonstrated a maximum brightness of 7551 cd/m(2) (at 12.5 V) and a maximum yield of 5.5 cd/A with Commission Internationale de l'Eclairage coordinates of (0.30, 0.33) using fine-tuned WPF5 as emitting material. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 3355-3365, 2011