Solution-Processible Small Molecular Organic Light-Emitting Diode Material and Devices Based on the Substituted Aluminum Quinolate

We have discovered a new type of small molecular host material based on aluminum(III) 8-hydroxyquinolates, Al(Saq) 3, which was synthesized with three 5-( N -ethylanilinesulfonamide)-8- quinolinoline as bidentate ligands. By X-ray diffraction crystallographic analysis, the crystals of meridional Al(Saq) 3 are monoclinic, space group P 2 1 / c, a = 17.952(3) Å, b = 17.716(3) Å, c = 17.080(3) Å, β = 99.895(4)°. Its peak photoluminescence in solid phase appears at 488 nm. Its LUMO/HOMO (−3.13/−6.04 eV) and optical band gap ( E g 2.91 eV) were determined by cyclic voltammetry . In solid thin film morphological investigation, it shows good thermal properties and high quantum efficiency. When doped with 0.7 wt % of the high fluorescent green dopant 10-(2-benzothiazolyl)-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1 H,5 H,11 H -benzo-[ l ]pyrano[6,7,8-ij]quinolizin-11-one (C-545T), energy transfer from Al(Saq) 3 to dopant will occur and high green light emission can be achieved. For fabrication of OLEDs using spin-coating techniques, its electroluminescence is at 1931 CIE x,y (0.21, 0.41).