1H-Pyrazolo[3,4-b]quinolines and Their Performance in Electroluminescent Devices

A series of highly luminescent pyrazolo[3,4-b]quinolines were prepared and used as luminophores in fabrication of three-layer electroluminescent devices. The devices were fabricated using the basic structure of indium tinoxide (ITO)/TPD/Pyrazoloquinoline/ ALQ/Mg:Ag, where TPD (3-methylphenyl)-1,1_-biphenyl-4,4_-diamine was used as a hole transport layer and AlQ (8-hydroxyquinoline) as an electron transport layer. Bright blue-green and blue emissions were obtained from all the devices with such configurations. The devices with 6d and 6f pyrazoloquinoline derivatives achieved Lmax = 20800 cd/m2 and 8550 cd/m2 at a current density of 30 mA/4 mm2. The luminance efficiency was 3.38 and 1.70 lm/W respectively.