一种蓝光发射材料的表征及发光性能研究

Characterization and Photoluminescence Properties of a Blue-Light-Emitting Material

8-羟基喹啉铝类有机金属配合物作为一类重要的发光材料广受关注。文章合成并通过真空升华提纯得到了一种高纯度的8-羟基喹啉铝的衍生物-三(2-甲基-8-羟基喹啉)铝,通过红外光谱、核磁共振谱以及元素分析确定了三(2-甲基-8-羟基喹啉)铝的分子结构。通过热重和差示扫描量热分析研究了三(2-甲基-8-羟基喹啉)铝的热稳定性,试验结果表明:此衍生物的结晶转变温度可达158℃,分解温度为357℃;并进一步通过紫外可见吸收光谱和荧光光谱表征了材料的带隙以及能带结构。将吸收边的线性关系延伸到与能量轴相交所得禁带宽度2.85eV,三(2-甲基-8-羟基喹啉)铝在365nm紫外光的激发下,在乙醇溶液体系中的荧光发射峰在479nm处,为蓝色荧光,荧光量子效率高,是一种蓝光发射的优选材料。

Tris （2-methyl-8-hydroxyquinoline）aluminum （AlMeq3）was synthesized and purified by vacuum sublimation. The structure of the complex was characterized by ^1 H NMR, FTIR spectra and elemental analysis techniques. AlMeq3 consists of three 2-methyl-8-hydroxyquinoline ligands and one aluminum atom. Its thermal stability was studied by TG and DSC analysis and the result shows that AlMeq3 is a thermally stable material, with decomposition and crystalline transition temperature being 357 and 158 ℃, respectively. Energy band structure was investigated by UV-Vis absorption spectra and fluorescence emission spectra. Experimental results show that its UV absorption bands were at about 246 and 390 nm, and the absorption band at about 246 nm can be assigned to π-π＊ of phenyl ring. AlMeqs displays 8-hydroxyquinoline-oriented photophysieal properties. The optical gap of AlMeq3 was about 2.85 eV, as determined by intrinsic absorption band edge of the complex in ethanol solution. Under UV excitation at 365 nm, the complex in ethanol solution emitted intensive blue fluorescence with the maximum emission peak at 479 nm, while the effective energy-transfer from the ligand to the central Al^3＋ ion occurred in the complex. AlMeq3 with bright blue photoluminescence can be applied as luminescent material in OLEDs.