Two different azo molecules functionalized graphene oxide (GO) through an ester linkage have been synthesized for the first time. Chemical structure of the azo-GO hybrids was confirmed by Fourier transform infrared spectroscopy and UV-visible spectroscopy. The GO functionalized with 5-((4-methoxyphenyl)azo)-salicylaldehyde was further characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM). The SEM studies demonstrated that the morphology of the azo-GO hybrid was found to be similar to the GO sheets but slightly more wrinkled. Further, TEM image of azo-GO indicates some dark spots on the GO sheets due to azo functionalization. AFM results also reveal that the azo functionalization increases the thickness of GO sheet to 4–5 nm from 1.2–1.8 nm. Both the azo-hybrids show absorption band around 379 nm due to the π–π* transition of the trans azo units. Photoluminescence spectra of azo-GO hybrids show a strong quenching compared with azo molecules due to the photoinduced electron or energy transfer from the azo chromophore to the GO sheets. It also reveals strong electronic interaction between azo and GO sheets.
首次合成了两种通过酯键功能化的不同偶氮分子修饰的氧化
石墨烯(GO)。偶氮-GO杂化物的
化学结构通过傅里叶变换红外光谱和紫外可见光谱得到了证实。功能化了5-((4-
甲氧基苯基)偶氮)-
水杨醛的GO进一步通过扫描电子显微镜(
SEM)、透射电子显微镜(
TEM)和原子力显微镜(A
FM)进行了表征。
SEM研究表明,偶氮-GO杂化物的形态与GO薄片相似,但稍微更皱折。此外,偶氮-GO的
TEM图像显示,GO薄片上由于偶氮功能化而出现了一些暗点。A
FM结果还显示,偶氮功能化使GO薄片的厚度从1.2–1.8纳米增加到4–5纳米。两种偶氮杂化物在约379纳米处显示出吸收带,这是由于反式偶氮单元的π–π*跃迁。与偶氮分子相比,偶氮-GO杂化物的光致发光光谱显示出强烈的淬灭现象,这主要是由于光诱导的电子或能量转移发生在偶氮发色团与GO薄片之间。它还揭示了偶氮与GO薄片之间的强电子相互作用。