A polyfluorene derivative containing a monomer with bis-aldehyde functional group was synthesized according to Suzuki coupling reaction.Then

a small amount of oligo(phenylenevinylene with two triphenylamine side group) (MOPV) with bis-phosphonate functional groups was grafted to the polyfluorene derivative with bis-aldehyde functional groups by using WittigHorner method.The structures

thermal

optical and electrochemical properties of MOPV

pre-grafted polymer P1 and the grafted polymer PF;g-MOPV were characterized by 1H\|NMR

GPC

DSC

TGA

UV-Vis

photoluminescence (PL) spectroscopy and cyclic voltammetry (CV)

respectively.The grafted polymer exhibited better thermal properties than the pre-grafted polymer P1.The grafted polymer exihibited two PL emission bands ascribed to polyfluorene and MOPV segments

which indicated that F-rster energy transfer from polyfluorene host to MOPV guest was efficient.This is the main mechanism in the PL process.To investigate the electroluminescent (EL) characteristics of the grafted polymer

a singlelayer PLEDs device with a configuration of indium tin oxide (ITO)/poly-(ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT∶PSS)/polymer/Ca/Al was fabricated.The grafted polymer emitted yellowish-green light with the international commission on illumination(CIE) coordinates of (0.30

0.57) and the maximum brightness of 1550 cd/m2.The MOPV segments serve as effective sites for charge trapping

which can trap both electron and hole from the polyfluorene backbone.Charge trapping rather than Frster energy transfer is the main mechanism in the EL process.