Photoluminescence spectra of 8-hydroxyquinoline aluminum embedded in porous alumina

Alq(3) is the key electroluminescent material currently used in organic light-emitting devices (OLEDs) based on "small molecules '. In the study of OLEDs Alq(3) was used as the active layer, and significant fluorescent degradation of Alq(3) was found in a room ambient. In order to extend the periods of time of OLEDs, at the present time, researchers try to encapsulate it in special environments with cooling equipment, thus to make the capacity larger and the cost higher. As the optical properties of anodic alumina is good, and the pore of anodic alumina is much larger than the molecular diameter of Alq(3), Alq(3) can be successfully embedded in the porous alumina. To clarify the optical properties of the embedded films, we have done a series of experiments to study the photoluminescence(PL) of the embedded films. It was shown that the peak of PL of the compound film was at about 490 nm, blue shifted a lot compared with that of the solid matter, and the PL was correlative with the quantity and the degree of conglomeration of the molecule of Alq(3) embedded in the porous alumina. With the number increasing, the peak of PL exhibited a red shift, and the intensity enhanced; but the intensity decreased unexpectedly when the conglomeration was too large. As most of the molecules of Alq(3) existed in Van der Waals binding when the number was high, the peak shifted a little. The broad full width at half maximum(FWHM) of the PL and the stability of Alq(3) in the porous alumina may make the embedded film a new application in the tunable solid laser. At the same time, for the similarity in the mechanism of PL and EL, the experimental results suggest the properties of embedded film in EL devices and provide a base for application in electroluminescence.