Blue luminescence of facial tris(quinolin-8-olato)aluminum(III) in solution, crystals, and thin films

Isolation, mass production, and characterization in solution and in the solid state of the facial stereoisomer of tris(quinolin-8-olato)aluminum(III) (Alq3) is reported. A phase- transformation diagram shows how to selectively produce the two blue-emitting polymorphs of the fac isomer (?- and ?-Alq3; see Figure) via a solid-to-solid reaction, opening the route to the development of blue-light-emitting Alq3-based OLEDs.