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.