The New 8 - Hydroxyquinoline Aluminum Compounds Electroluminescent Materials And Devices Research And Development,

Since 1987, organic light emitting diodes have become a new and fascinating area of research. The advantages of organic light emitting diodes over other displays are high luminescence efficiency, wider selection of emission colors, super thin film, light weight, lower driving voltage. Since then, organic light emitting diodes(OLEDs) become one of the hotspots in the flat panel display. OLEDs are regarded as "The third generation of flat panel display".Nowadays, the research purpose for OLEDs is mainly focus on the enhancement of device efficiency and operating life, and looking for new materials with improved properties. In fact, looking for new materials or new synthetic method is the keystone. 8-hydroxyquinoline aluminium(Alq3) is one of the best electroluminescent materials. 8-hydroxyquinoline aluminium in solid state is provided with good film formation and thermal stability, high electron transfer mobility and fluorescence quantum efficiency. Till now, Alq3 is mainly synthesized using traditional method by the reaction of aluminium salts with 8-hydroxyquinoline with sodium hydroxide (NaOH) adjusting the PH value of the solution. The Alq3 is precipitated out when the PH value of the solution reaches about five. To purify the Alq3, vacuum sublimation processes are used and complicated instrument and equipment are needed. In order to simplify the preparation processes and get higher yield of Alq3, a new method is reported in this paper.LiAltLi was added to an ethanol solution of 8-hydroxyquinoline slowly, the reaction take place very rapidly and yellow solid precipitated as the reaction processed. The products were characterized by hydrogen nuclear magnetic resonance (*H NMR), ultraviolet-visible absorption, infrared spectra, element analysis and X-ray crystal structure analysis. The OLEDs were fabricated by using Alq3 as emitter and electron transfer layer with vacuum deposition method.The results show that the quality of Alq3 prepared by this simple method is similar to that of commercial products after sublimation purification.To modify the emitting properties of Alq3, two derivatives of 8-hydroxyquinoline have been synthesized. The complexes of zinc and aluminium with 5-aldehydol-8-hydroxyquinoline were obtained. These two compounds have favorable performance in fluorescence and electroluminescence. The experimental results indicated that all these materials are possibly candidates for organic light emitting diodes applications.