Preparation of 8‐hydroxyquinoline aluminum nanomaterials to enhance properties for green organic light‐emitting diode devices

Abstract

Tris(8-hydroquinoline) aluminum (Alq3) plays an important role in the applications of green organic light-emitting diodes (OLEDs). In this paper, Alq3 nanofilms were prepared on glass substrates by physical vapor deposition system with different surface states. The structures and morphologies of Alq3 nanofilms were characterized by X-ray diffractometer and scanning electron microscope. Alq3 nanomaterials were used as the main luminescent material for green OLED devices. The structure of the green OLED is Mo/2-TNATA (20 nm)/NPB (10 nm)/Alq3 (25 nm):Ir(ppy) 3 (5%)/Bphen (10 nm)/LiF (5 nm)/ Mg:Ag (10%) (10 nm). The photoelectric properties of green OLED devices were characterized by the system of Photo Research PR655 spectrometer. The results show that the weak interactions among Alq3 molecules such as π-π bond interactions and van der Waals forces caused molecules self-assembling into nanospheres, nanospherical chains, nanowires, or nanotubes in physical vapor deposition system. Precise surface state control of Alq3 nanomaterials can be realized by controlling the deposition temperature, thus, to enhance properties for green OLED displays. It is found that among different morphologies, Alq3 nanotubes have been proved to be the best green OLED devices with the brightness of 11,490 cd/m 2 , CIE (3358, 0.6302) at 5 V, and the current efficiency is 20.24 cd/A.

p-Type Doping of Gold Nanoparticles on Ellagic Acid Noncovalently Modified Single-Walled Carbon Nanotubes Compositing with PEDOT:PSS Bilayer Films for Organic Light-Emitting Diodes

“…The fundamental design of the OLED devices resembles a sandwich, as shown in Figure a. It includes a thin and transparent anode with semiconductor properties, a metal cathode, a hole transport layer (HTL), an emission layer, and an electron transport layer (ETL) . The fundamental design of OLEDs determines the following order of evaporation, in sequence, for molybdenum oxide (MoO 3 ) (hole injection layer), NPB (( N , N ′-di-[(1-naphthalenyl)- N , N ′-diphenyl]-1,1′-biphenyl)-4,4′-diamine) (HTL), C545T (2-phenyl-9,10-di­(naphthalen-2-yl)-anthracene):Alq 3 (light-emitting layer), 8-hydroxyquinoline aluminum (Alq 3 ) (ETL), lithium fluoride (LiF) (cathode modification layer), and high-purity aluminum (Al) (cathode).…”

Tris(8-hydroxyquinoline)aluminium in a polymer matrix as an active layer for green OLED applications

“…The HOMO (π orbitals) states are found on the phenoxide (O) ring of quinoline, while the LUMO (π* orbitals) is located mainly on the pyridyl (N) side [23]. Alq3 has strong stability in a dry environment because the electronic structure of Al 3+ (1s 2 2s 2 2p 6 ) is similar to the atomic structure of the corresponding inert gas [24]. Alq3 is thermally stable.…”