Pure blue light-emitting fluorene-based conjugated polymer with excellent thermal, photophysical, and electroluminescent properties

A functionalized polyfluorene (FPF) with dendritic carbazole and oxadiazole side chains have been successfully designed, synthesized, and characterized. The weight-average molecular weight (M (w)) and number-average molecular weight (M (n)) were measured by gel permeation chromatography (GPC) to be 71280 and 31185, respectively. The FPF is thermally stable with high decomposition temperature (T (d) = 495 A degrees C) and glass transition temperature (T (g) = 160 A degrees C), and show good solubility in organic solvents, such as N,N-dimethyl formamide, tetrahydrofuran, CHCl3, and toluene. The photoluminescent and electroluminescent (EL) emissions and Commission Internationale de L'Eclairage coordinates indicated pure blue light emission of FPF and its device. The luminance-voltage (L-V) and current density-voltage (J-V) characteristics of the devices based on FPF indicated typical diode characteristics with a maximum luminance of 980 cd/m(2) at a drive voltage of 13.0 V, a maximum current density of 726 mA/cm(2), and a turn-on voltage of 8.54 V. The maximum EL efficiency of the device based on FPF was measured to be 0.46 % at the current density of 12.5 mA/cm(2). These results indicate that the FPF polymer could be a promising candidate for pure blue light-emitting polymer with excellent thermal, photophysical, and electroluminescent properties.