螺芴氧杂蒽LB膜的制备及光谱特性研究

为了研究聚芴材料DSFX-SFX分子在气液两相表面的行为,分子处于溶液、LB膜及粉末状态的光学特性,以及分子有序排列对其发光特性的影响,制备了聚芴材料DSFX-SFX的X型LB膜,研究了π-A等温曲线,测量了其紫外-可见吸收谱和稳态荧光光谱。结果表明,分子以face-on形式平躺在亚相表面,单分子面积为4.78 nm2。在氯仿溶液中吸收峰位在354 nm,归属于分子中三聚氧杂蒽部分与芴环间π-π*电子跃迁;荧光发射峰位在396,419,445 nm(肩峰),归属于发色团三聚氧杂蒽,是芴环与氧杂蒽环之间的电荷转移。在LB膜中,吸收谱和荧光光谱与其溶液光谱相比,整体红移6 nm。结果表明:在LB膜中,两个分子形成激基缔合物,与单分子状态相比,激基缔合物的HOMO升高而LUMO降低。与粉末状态相比,该材料在LB膜中有很强的荧光发射,表明该材料形成有序排列超薄膜有利于荧光发射。

Preparation and Spectral Properties of Spirofluorene Oxygen Complex LB Films

In order to study the behavior of polyfluorene DSFX-SFX molecule in the air-water inter-face, the spectroscopic characteristics, and the effect of the orderly arrangement of molecular on the luminescence properties, Langmuir-Blodgett( LB) films of the polyfluorene DSFX-SFX were prepared. The π-A isothermal curve was studied, and the UV-Vis absorption and steady-state fluorescence spec-tra were measured. The experimental results show that the molecules lie flat on the subphase surface in the form of face-on. The single molecular area is 4. 78 nm2 . In chloroform solution, the absorption peak is at 354 nm, which belongs to π-π* electronic transition of the oxygen mixing into fluorene ring. The fluorescent emission peaks are at 396, 419, and 445 nm (shoulder), respectively. This is due to the emission of trimeric oxa anthracene, and the charge transfer between the fluorene ring and oxygen impurity anthracene ring. In LB film, the fluorescence spectra have an overall red-shifted of 6 nm. This is due to formation of an excimer, leading to the elevated HOMO and the reduction of LU-MO. The orderly arrangement in ultra-thin film is propitious to blue fluorescence emission.