含多苯環取代之聚(1,4-仲苯基乙炔)及共聚物之合成及其在高分子電激發光元件上之應用

Abstract

本研究合成出五種DP-PPV衍生物的單體1,4-Bis(chloromethyl) - 2,3,5-triphenyl-6-[p-(2-ethylhexoxy)phenyl]benzene (M1)，1,4-Bis (chloromethyl) -2,3,5-triphenyl-6-butyl benzene(M2)，1,4-Bis(chloromethyl)-2,3-diphenyl-5,6-dipentylbenzene(M3)1,4-Bis(chloromethyl)-2,3-diphenyl-5-(9,9-dihexylfluoren-2-yl)benzene(M4)1,4-Bis(bromomethyl)-2-[-p-(3,7-dimethyloctoxy) phenyl]-3-phenyl benzene (M5)，成功的利用Gilch route聚合法，以t-BuOK當作鹼合成出四種聚合物(P1~P4)。M3是唯一無法得到任何聚合物的單體。在主鏈苯環上有四個苯環基團取代的聚合物P1，其PL最大放射峰在384 nm的位置。應該是它的分子量太低及四個苯環取代基龐大的立體阻礙所造成。在主鏈苯環上有三個苯環基團取代的聚合物P2，其PL最大放射峰在483 nm的位置。在主鏈苯環上有兩個苯環基團以及一個芴基取代的聚合物P3，其PL最大放射峰在506 nm的位置。聚合物P2,P3分別為藍光及藍綠光的發光材料。P4的主鏈上只有兩個苯環取代，為一最大放射峰在498 nm的藍綠光的材料。 在本研究的第二部份，單體M5與1,4-bis(chloromethyl)-2,5- diphenylbenzene, 1,4-bis(bromomethyl)-2,5-dimethoxybenzene,以及1,4-bis (bromomethyl)-2-(2-ethylhexoxy)-5- methoxybenzene 等，進行共聚反應，分別合成出共聚物P5~P14，這些聚合物的最大放射峰皆介於500∼570 nm的範圍之間，屬於藍綠光到黃綠光的發光材料。本研究亦製作了結構為ITO/PEDOT/Polymer/Ca(Al)的雙層有機電激發光二極體元件，並探討其發光特性。結果顯示大多數的發光材料皆有很高的EL效率，其中又以聚合物P11表現出最高的效率，達到了6.14cd/A。

In this study, five kinds of monomer, i.e. 1,4-bis(chloromethyl)- 2,3,5-triphenyl-6-[p-(2-ethylhexoxy)phenyl]benzene (M1), 1,4-bis(chloro- methyl)-2,3,5-triphenyl-6-butylbenzene (M2), 1,4-bis(chloromethyl)-2,3- diphenyl-5,6-dipentylbenzene (M3), 1,4-bis(chloromethyl)-2,3-diphenyl-5- (9,9-dihexylfluoren-2-yl)benzene (M4), and 1,4-bis(bromomethyl)-2-[-p- (3,7-dimethyloctoxy)phenyl]-3-phenylbenzene (M5) were synthesized, Five monomers were polymerized via Gilch route using t-BuoK as base to yield substituted PPV derivatives (P1~P4). Monomer M3 was the only one which did not yield any polymer. Polymer P1 which contains four phenyl substituents on the phenylene ring (QP-PPV) shows a photoluminescence (PL) peak at 384 nm. The reason could be due to its low molecular weight and large steric hindrance of four phenyl substituents on the phenylene ring. Polymer P2 which contain three phenyl substituents on the phenylene ring (TP-PPV), shows a PL peak at 483 nm while polymer P3 which contains two phenyl and one fluorenyl substituents show a PL peak at 506 nm. Polymer P2 emits blue light while polymer P3 emits blue-green light. Polymer P4 which contains two phenyl substituents on the phenylene ring emits also blue green light at 498 nm. In the second part of this study , monomer (M5) was copolymerized with 1,4-bis(chloromethyl)-2,5-diphenylbenzene , 1,4-bis(bromomethyl)- 2,5-dimethoxybenzene , 1,4-bis(bromomethyl)-2-(2-ethylhexoxy)-5- methoxybenzene to form copolymers (P5~P14) . All copolymers emit blue green to yellow green light from 500 to 570 nm .Double-layer light-emitting devices with a simple ITO/PEDOT/Polymer/Ca(Al) configuration were fabricated and characterized. Most of the polymers exhibited a very high EL efficiency . A double layer device using copolymer P11 as the emissive layer revealed the highest EL efficiency of 6.14 cd/A.