Comparative study on polymer light-emitting devices based on blends of polyfluorene and 4,7-di-2-thienyl-2,1,3-benzothiadiazole with devices based on copolymer of the same composition.
The small molecule 4,7-di-2-thienyl-2,1,3-benzothiadiazole (DBT) dye has been synthesized and blended into blue-emitting polyfluorene as a host. The photophysics of the blend films and electroluminescence device performance was compared with that from polyfluorene-co-4,7-di-2-thienyl-2,1,3-benzothiadiazole (PFO-DBT) copolymer of the same molar composition, with DBT incorporated covalently into the polyfluorene backbone. The role of intra- and interpolymer chain interaction and energy transfer in the polymer light-emitting devices are discussed. On the basis of the direct comparison of blend and copolymer from the same molecular composition, we can draw the conclusion that, in conjugated polymers, intrachain energy transfer along the polymer backbone is more efficient than that via interchain interaction and plays a more important role in polymer light-emitting devices.
Fan
Suqin
S
Lab of Specially Functional Materials, Institute of Polymer Optoelectrionic Materials and Devices, South China University of Technology, Ministry of Education, Guangzhou 510640, China.
Sun
Mingliang
M
Chen
Zhao
Z
Luo
Jie
J
Hou
Qiong
Q
Peng
Junbiao
J
Yang
Hong
H
Zhang
Dengqing
D
Li
Fuyou
F
Cao
Yong
Y