A series of 6-substituted-3-methyl-1-phenyl-4-(4-methoxyphenyl)-1H-pyrazolo
[3,4-b]quinolines, MeOPAQ-X (X = t-Bu, OMe, H, F, Cl, Br), were synthesized
and assessed as potential emitters in electroluminescent (EL) devices. All
derivatives emitted in the blue region with an emission lambda (max) rangi
ng from 448 nm to 460 nm and a quantum yield between 0.55 and 0.20. EL devi
ces with a configuration of ITO/NPB/CBP/TPBI:MeOPAQ-X/TPBI/Mg:Ag were fabri
cated, where ITO, NPB, CBP, TPBI and Mg:Ag are indium tin oxide, 4,4'-bis[N
-(1-naphthyl)-N-phenylamino]biphenyl, 4,4'-dicarbazolyl-1,1'-biphenyl, 2,2'
,2 "-(benzene-1,3,5-triyl)tris[1-phenyl-1H-benzimidazole] and magnesium : s
ilver alloy (similar to 10 : 1) respectively. Light emission from the dopan
t was observed. An external quantum efficiency around 3% could be obtained
for all substituted derivatives. In particular, brightness around 13 000 cd
m(-2) was achieved for the device based on MeOPAQ-H. The performances were
comparable to the best available materials in the blue organic light-emitt
ing diodes.