两种烷基取代喹吖啶酮衍生物LB膜的荧光特性

制备了两种烷基取代喹吖啶酮衍生物C6DHQA和C16DMQA的X型Langmuir-Blodgett(LB)膜,采用紫外-可见吸收、稳态荧光和时间分辨荧光的方法研究其溶液及LB的光学特性。研究结果表明,C16DMQA比C6DHQA的吸收谱整体红移,说明烷基链加长减小了分子的能级间隔;两者LB膜的吸收谱较溶液整体红移,说明在LB膜中形成了"J-聚集体"。两种材料的溶液及LB膜都有较强的荧光发射,溶液的荧光谱与吸收谱有很好的镜像对称关系,形成LB膜后,镜像对称关系被打破,两者第三个荧光峰相对强度差别很大。C6DHQA溶液中的荧光寿命为21ns左右,C16DMQA溶液中的荧光寿命为22ns左右,形成LB膜后,荧光寿命明显较少,两者第三个荧光峰对应的荧光寿命差别较大。其原因应归于C16DMQA分子在基板上的排列更密,分子间的相互作用力强,从而对能级结构的影响更大。

Fluorenscence Spectra of Two Kinds of Alkyl Substitution Quinacridone Derivative Langmuir-Blodgett Films

Two kinds of alkyl substitution quinacridone derivative C6DHQA and C16DMQA X-type Langmuir-Blodgett (LB) films are prepared. The optical characteristics are studied by UV-visual spectrum, steady state and time resolved fluorescence. The experimental results show that the absorption spectrum of the C16DMQA has a whole red shift compared with C6DHQA′s. It shows that the energy level is lower with the added alkyl chain. The absorption spectrum of their LB films has a whole red shift compared with their solution. It shows that the two kinds molecule formed J-aggregation in LB films. The two kinds of material in chloroform solution and LB films both have strong flourescence emission. The absorption spectrum and the flourescence spetrum of the two kinds of material solution have mirror symmetry. But their LB films′s are asymmetrical. The third peak relative intensity of C6DHQA and C16DMQA LB films has a larger difference. The fluorescence lifetime at three fluorescenct emission peaks of C6DHQA solution is about 21 ns and C16DMQA′s is about 22 ns. It is obviously reduced as in LB films. And it is obviously diffrerent at the third peaks of C6DHQA compared with C16DMQA. All these differences are due to closer-arrangement of C16DMQA molecule on the substrate, the intermolecular interactions stronger and has a bigger influence on its energy level structure than C6DHQA molecule.