Biphenyl기를 포함하는 공액 공중합체의 합성 및 전계발광 특성

Abstract

Poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene)(MEH-PPV) 및 주쇄에 서로 다른 조성비의 biphenylrl를 포함하는 poly(2-methoxy-5-(2-ethylhexyl-oxy)-1,4-phenylene vinylene-co-1,1''-biphenyl-4,4''-ylene vinylene) [poly(MEHPV-co-BPV)] 공중합체를 α-elimination 법으로 합성하였다. 또한 교대 공중합체인 Poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene-alt-1,1''-biphenyl-4,4''-ylene vinylene) [poly(MEHPV-alt-BPV)] 및 고분자 주쇄내에 공액 영역과 비공액 영역이 교대로 배열된 poly(1,8-octanedioxy-2-methoxy-1,4-phenylene-1,2-ethenylene-1,1''-biphenyl-4,4''-ylene-1,2-ethenylene-3-methoxy-1,4-phenylene) [poly(BFMP8-BPV)]와 poly(1,12-dodecaedioxy-s-methoxy-1,4-phenylene-1,2-ethenylene-1,1''-biphenyl4,4''-ylene-1,2-ethenylene-3-methoxy-1,4-phenylene)[poly(BFMP12-BPV)]를 Honer~ Emmons 반응으로 각각 합성하였다. 합성된 고분자를 발광층으로 하는 단일 EL 소자를 제작하여 이들의 광전기적인 특성을 비교, 평가하였다. Poly(MEHPV-co-BPV)의 경우 BPV기가 도입됨에 따라 용해도가 현저히 감소하였으며 MEHPV 반복단위에 의한 발광 (586nm)과 BPV 반복단위에 의한 발광(469, 495nm)이 동시에 관찰되었고, poly(MEHPV-alt-BPV)의 경우 두 반복단위의 중간지점 (544 nm)에서 최대 발광이 나타났다.

Poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene)(MEH-PPV) and poly(2-methoxy-5-(2-ethylhexyl-oxy)-1,4-phenylene vinylene-co-1,1''-biphenyl-4,4''-ylene vinylene) [poly(MEHPV-co-BPV)] with a different feed ratio of biphenyl group in the main chain were synthesized by α-elimination reaction. Poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene-alt-1,1''-biphenyl-4,4''-ylene vinylene) [poly(MEHPV-alt-BPV)], which has alternating repeat unit, and poly(1,8-octanedioxy-2-methoxy-1,4-phenylene-1,2-ethenylene-1,1''-biphenyl-4,4''-ylene-1,2-ethenylene-3-methoxy-1,4-phenylene) [poly(BFMP8-BPV)] and poly(1,12-dodecaedioxy-s-methoxy-1,4-phenylene-1,2-ethenylene-1,1''-biphenyl4,4''-ylene-1,2-ethenylene-3-methoxy-1,4-phenylene)[poly(BFMP12-BPV)] containing both conjugated and non-conjugated group in the main chain were synthesized by the Honer-Emmons were examined. The solubility of poly(MEHPV-co-BPV)s in common organic solvents decreased rapidly with the increasing amount of BPV units in the copolymer. Emission spectrum of poly(MEHPV-co-BPV)s had two peaks corresponding to MEPHV(586 nm) and BPV(469, 495 nm) moiety, respctively. However, LED fabricated with poly(MEHPV-alt-BPV)showed relatively sharp single peak(544 nm) in the middle of the two peaks.