Preparation and Characterization of Blue‐Luminescent Tris(8‐hydroxyquinoline)‐aluminum (Alq₃)

Abstract

Abstract Using differential scanning calorimetry (DSC) measurements in combination with structural and optical characterization we have investigated the formation conditions of different phases of tris(8‐hydroxyquinoline)aluminum (Alq 3 ). We have identified the δ‐phase as a high‐temperature phase of Alq 3 being composed of the facial stereoisomer, and report an efficient method to obtain blue luminescent Alq 3 by a simple annealing process. This allows the preparation of large amounts of pure δ‐Alq 3 by choosing appropriate annealing conditions, which is necessary for further characterization of this blue‐luminescent phase, and offers the possibility of fabricating blue organic light‐emitting devices (OLEDs) from this material.