Exciton behaviours in doped tris (8‐hydroxyquinoline) aluminum (Alq₃) films

Abstract

Abstract The doping effect on exciton behaviours in amorphous tris (8‐hydroxyquinolinato) aluminum (Alq 3 ) were studied for the first time by transient photoluminescence (PL) measurements at room temperature. The dopants 4‐(diacynomethylene)‐2‐methyl‐6‐(p‐dimethylaminostyryl)‐4H‐pyan (DCM) and 5,6,11,12‐tetraphenylnaphthacene (rubrene) were used into Alq 3 films at various concentration from 0.5 to 24 wt.% for this study. The exciton recombination rate was found sharply increased with doping concentration in Alq 3 films. The exciton lifetime in pure Alq 3 was found as ∼ 20 ns and it was reduced up to ∼8 ns with doping concentration. The exciton diffusion coefficient and diffusion length in doped films was found as 0.5 – 1.4 × 10 –6 cm 2 s –1 and 18–35 Å, respectively (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)