Synthesis and Characterization of Red-Emitting Poly(aryleneethynylene)s Based on 2,5-Bis(2-ethylhexyl)-3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (DPP)

Synthesis and characterization of a series of PAEs containing DPP units in the main chain are described. (M) over bar (w) of the polymers was in the range 10 800-111 900. The polymers formed a deep blue solution in chloroform with absorption maxima between 589 and 645 nm and optical band gaps ranging from 1.61 to 1.74 eV. When excited at the absorption maxima, the polymer solutions showed red fluorescence with emission maxima between 656 and 676 nm. The polymers exhibited quasi-reversible oxidation process with HOMO energy levels between -5.60 and -6.17 eV. EL properties of three polymers were investigated with device configuration ITO/PEDOT:PSS/Polymer/LiF/Al. When appropriate bias voltage was applied, a red EL with a maximum brightness of 17.5-24 cd . m(-2) could observe from the devices.