8-羟基喹啉铝的荧光老化机制

FLUORESCENT DEGRADATION MECHANISM OF 8 HYDROXYQUINOLINE ALUMINIUM

报导了８－羟基喹啉铝（Ａｌｑ３）在紫外光照射下发生荧光猝灭的机制， 测量了Ａｌｑ３ 在光照射前后的紫外－可见吸收光谱、荧光光谱、红外吸收光谱和Ｘ－射线光电子能谱（ＸＰＳ）， 分析了紫外光照射后Ａｌｑ３ 分子结构变化， 证明了产生结构变化的根源是空气中水与Ａｌｑ３ 发生了化学反应， 对Ａｌｑ３ 的荧光老化机制提出了可能的解释．

We have investigated the physical and chemical characteristics of 8 hydroxyquinoline aluminium (Alq 3), which has been used most widely as the electron transporting and emitting layer in organic light emitting diodes. The fluorescent stability of Alq 3 is reported when the film was irradiated by an ultraviolet (UV) lamp. Thin film was analyzed in situ by using UV Vis absorption spectrophotometer, fluorescence spectrometer, X ray photoelectron spectroscopy (XPS) and nano second fluorescence spectrophotometer. We observed that the PL intensities and absorbance decreased with increasing the irradiated times, the fluorescent decays were rapid after irradiation, and the X ray photoemission spectra of the irradiated films changed. Degradation in photoluminescence properties was significant in the presence of atmospheric moisture. The photodegradation reaction was a hydrisis process involving water in air to yield the fluorescent quenchers. The results indicated that reaction between H 2O in the air and Alq 3 to liberate one or more 8 hydroxyquinoline at first and then undergoes a condensation reaction to generate a non emissive compound, which plays a role as luminescence quenching center. The photodagradation of Alq 3 may seriously effect on the performance of LEDs. Therefore, it is important to keep the devices from the moisture in air for protection photodegradation, resulting in enhancement of the LEDs.