Phosphorescence of aluminum tris(quinoline-8-olate)

Phosphorescence from an aluminum tris(quinoline-8-olate) (Alq3)-based organic light-emitting diode was observed by measuring the delayed electroluminescence at low temperatures. The spectra as well as the transient intensities were investigated. Vibronic progressions of the phosphorescence (T1→S0 transition) were resolved and the triplet energy of Alq3 was measured to be 2.05±0.1 eV. The lifetimes of the triplet state were determined from the delayed fluorescence as well as from the phosphorescence decay to be 8.1±0.5, 7.0±0.5, and 5.6±0.5 ms at 30, 50, and 80 K, respectively.