一种新型的蓝光发射材料δ-Alq_3的制备与光谱分析

Preparation and Spectral Analysis of a New Type of Blue Light-Emitting Material δ-Alq_3

制备了一种新型的蓝光发射材料-δAlq3,测试了其红外吸收光谱、X射线衍射谱、紫外-可见光吸收光谱、光致发光光谱和电致发光光谱,并通过与-αAlq3的光谱性能的比较,研究了Alq3分子空间结构与光谱性能之间的关系。结果表明:-αAlq3分子空间结构经过真空加热发生变化,生成对称性较差的-δAlq3;分子空间结构的改变引起Alq3分子中酚环电子云密度的降低和相邻分子间的共轭效应的减弱,导致在紫外-可见吸收光谱中-δAlq3长波段的π—π*电子跃迁吸收峰向短波方向的移动,在光致发光光谱中-δAlq3的最大发射峰波长为480 nm,比-αAlq3的最大发射峰波长(515 nm)蓝移35 nm,在电致发光光谱中-αAlq3和-δAlq3的最大发射峰波长都为520 nm。

In the present article,δ-Alq3, a new type of blue light-emitting material, was synthesized and investigated by IR spectra, XRD spectra, UV-Vis absorption spectra, photoluminescence （PL） spectra, and electroluminescence （EL） spectra. The relationship between molecular spatial structure and spectral characteristics was studied by the spectral analysis of δ-Alq3 and α-Alq3. Results show that a new phase of Alq3 （δ-Alq3） can be obtained by vacuum heating α-Alq3, and the molecular spatial structure of α-Alq3 changes during the vacuum heating. The molecular spatial structure of δ-Alq3 lacks symmetry compared to α-Alq3. This transformation can reduce the electron cloud density on phenoxide of Alq3 and weaken the intermolecular conjugated interaction between adjacent Alq3 molecules. Hence, the π-π electron transition absorption peak of δ-Alq3 shifts toward short wave- length in UV-Vis absorption spectra, and the maximum emission peak of δ-Alq3 （λmax=480 nm） blue-shifts by 35 nm compared with that of α-Alq3 （λmax=515 nm） in PL spectra. The maximum emission peaks of δ-Alq3 and a-Alqa are all at 520 nm in EL spectra.