Yh. Kim et al., A novel bright blue electroluminescent polymer: Poly[4,4 '-biphenylene-alpha-(9 '',9 '')dihexyl-3-fluorenyl) vinylene], MACRO SYMP, 154, 2000, pp. 171-176
Poly[4,4'-biphenylene-alpha-(9",9"-dihexyl-2-fluorenyl)vinylene] (PBPHFV) w
as synthesized by nickel catalyzed coupling reaction of 1,2-bis(bromophenyl
)-1-(9",9"-dihexyl-2-fluorenyl)ethene and characterized by spectroscopic me
thods and elemental analysis. PBPHFV is soluble in common organic solvents.
The weight average molecular weight (Mw) of PBPHFV is about 15000. PBPHFV
showed good thermal stability as weight loss was less than 5 % on heating t
o 420 C under nitrogen atmosphere. The polymer film showed maximum absorpti
on and emission at 370 nm and 485 nm, respectively. A bright blue electrolu
minescence (lambda(max) = 465nm, maximum intensity = 4116 cd/m(2)) was obta
ined when the device was fabricated with the structure of ITO/PEDOT/PBPHFV/
LiF/Al. The turn on voltage of the device was 4.3 V and the maximum efficie
ncy was 0.22 Im/W. When the blend with PVK (PBPHFV: PVK = 1:5) was used as
an emitting layer, the maximum brightness and efficiency of the device were
9342 cd/m(2) and 1.66 Im/W, respectively.