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/m2, CIE (3358, 0.6302) at 5 V, and the current efficiency is 20.24 cd/A. [ABSTRACT FROM AUTHOR]