2-十八烷基-7,7,8,8-四氰基对醌二甲烷和3,3′,5,5′-四甲基联苯胺电荷转移配合物LB膜的制备和表征

Preparation and Characterization of Langmuir-Blodgett Film of Charge-transfer Complex of 2-Octadecyl-7,7,8,8-tetracyanoquino-dimethane and 3,3′,5,5′-Tetramethylbenzidine

利用LB技术制备了2-十八烷基-7,7,8,8-四氰基对醌二甲烷(C18TCNQ)和3,3,′5,5′-四甲基联苯胺(TMB)的电荷转移配合物(CT comp lex)薄膜,即TMB.C18TCNQ LB膜.利用红外(IR)光谱、紫外-可见-近红外(UV-V is-NIR)光谱以及原子力显微镜(AFM)研究了TMB.C18TCNQ在LB膜中的分子取向、结构及表面形貌.结果表明,配合物为混合堆积类型,LB膜中电子给体TMB和电子受体C18TCNQ的环面分别垂直于固体基板表面,而且给体和受体以面对面的方式堆积.5层TMB.C18TCNQ LB膜的AFM照片显示,其表面形貌是由许多堆积在一起的六边形片状微晶组成的,微晶的宽度约为180 nm.与通过LB技术和掺杂技术制备的TMB.C18TCNQ掺杂膜比较,TMB.C18TCNQ LB膜具有明显不同的结构,其长的脂肪烃链有向垂直于基板表面方向变化的趋势,LB膜与掺杂膜的表面形貌也有明显不同.这表明不同的制备方法可以影响薄膜的结构和形貌.

Langmuir-Blodgett（LB） films of the mixed-stack charge-transfer（CT） complex of 2-octadecyl-7, 7,8,8-tetracyanoquinodimethane （ C18 TCNQ） and 3,3＇, 5,5 ＇-tetramethylbenzidine （ TMB ） were prepared. The structures, molecular orientation and morphology of TMB · C18 TCNQ in LB films were characterized by infra- red（IR）, uhraviolet-visible-near infrared（UV-Vis-NIR） spectroscopies and atomic force microscopy（AFM）. From the UV-Vis-NIR and IR spectra, it could be concluded that the TMB· C18 TCNQ complex is in a mixedstacked arrangement style, and the chromophore planes of both C18 TCNQ and TMB are nearly perpendicular to the substrate surface. AFM image shows that the morphology of five-layer LB film of the complex consists of many two-dimensional hexagonal flake microcrystals. The width of these flake microcrystals is about 180 nm.