PL and EL properties of a new kind of copolymer DBPPV–co–MEHPPV

The copolymers, DBPPV–co–MEHPPV (4:1, 1:1, 1:4), have been synthesized by the modified Gilch polymerization. For comparison, the homopolymers poly[2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene] (MEHPPV) and poly(2,5-dibutoxy-p-phenylene vinylene) (DBPPV) were synthesized either. The 1H NMR measurements showed a lower concentration of structural defects for DBPPV–co–MEHPPV copolymers. The synthesized polymers showed UV–vis absorbance in the range 460–500 nm. Photoluminescence (PL) and electroluminescence (EL) properties of the copolymers have been studied. The organic light emitting devices with the structure of ITO/polymer/AlQ/LiF/Al have been fabricated based on these polymers, and they showed better EL properties. The highest EL brightness of the DBPPV–co–MEHPPV (1:4) and DBPPV–co–MEHPPV (1:1) devices reached 1130 and 486 cd/m2, respectively.