Blue Luminescence of Facial Tris(quinolin‐8‐olato)aluminum(III) in Solution, Crystals, and Thin Films

Abstract

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 (γ‐ and δ‐Alq3; see Figure) via a solid‐to‐solid reaction, opening the route to the development of blue‐light‐emitting Alq3‐based OLEDs.

Alq3 Nanorods: Promising Building Blocks for Optical Devices

“…[6][7][8][9][10][11][12][13][14][15] Tris-(8-hydroxyquinoline) aluminum (Alq 3 ), a complex first used in 1987 by Tang and Van Slyke for efficient organic light emitting diodes (OLEDs) that required low driving voltages, [10] has since become one of the most powerful emitting materials for OLED devices. There has been abundant progress in its optical properties, such as color tuning, [16][17][18] enhancement of electroluminescence (EL) and photoluminescence (PL) efficiency, [19,20] and white light emission. [21,22] But more recently, alongside the fast development of nanoscience and nanotechnology, increased effort was put into the controlled synthesis of Alq 3 nanostructures, particularly one-dimensional (1D) nanostructures, in order to find potential applications in nano-optoelectronic devices.…”

Formation of Flower-Like Crystals of Tris(8-hydroxyquinoline)aluminum from 8-Hydroxyquinoline on Anodic Porous Alumina

“…To date, five crystalline phases ( , , , , and ) have been identified for Alq 3 [8][9][10]. To the best of our knowledge, -, -, and -Alq 3 are formed by meridional isomers, whileand -Alq 3 are formed by facial isomers [2,[5][6][7][10][11][12][13].…”

“…The preparation and characterization of Alq 3 have been widely studied [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Because of the bidentate ligand, Alq 3 complexes form two isomers, as shown in Figure 1: meridional and facial.…”

“…Because of the bidentate ligand, Alq 3 complexes form two isomers, as shown in Figure 1: meridional and facial. Interestingly, the two isomers exhibit different types of photoluminescence (PL): specifically, green [2,3] in the case of the meridional isomer and blue [4][5][6][7] for the facial isomer. To date, five crystalline phases ( , , , , and ) have been identified for Alq 3 [8][9][10].…”

Photoconduction in Alq3

“…[24][25][26][27][28] These isomers have different optical properties. The percentage of these isomers present in the film cannot be controlled easily.…”