GOSs-稀土配合物紫外增强材料的光谱分析与稳定性研究

氧化石墨烯薄片(GOSs)作为一种新型的二维片状材料,具有较高的比表面积、丰富的表面含氧官能团以及良好的光热稳定性。而稀土配合物通过无机稀土元素与有机配体的结合表现出优异的荧光特性。为了将两类材料具有的物化特性结合起来应用于紫外光谱探测领域。选取了合适的有机配体啉菲罗啉(1,10-邻二氮杂菲,phen)、2’2-联嘧啶(bpm)作为桥联分子,把氧化石墨烯(GOSs)与稀土配合物通过氢键自组装作用进行复合,制备了高效稳定可调的GOSs-稀土配合物复合荧光材料GOSs-Eu(BA)3phen和GOSs-Eu(TTA)3bpm,并且制备了相应的聚乙烯醇(PVA)共混紫外增强薄膜,对其光谱特性与稳定性进行了深入的研究。采用红外光谱、扫描电镜和金相显微镜等方法,对紫外增强材料进行了性能表征。采用吸收光谱,荧光光谱等方法,对紫外增强薄膜进行了性能表征。此外,通过热重测试(TGA)表征了GOSs氢键复合前后紫外增强材料的热稳定性,通过荧光强度-紫外光照次数表征了GOSs氢键复合前后紫外增强薄膜的光稳定性。红外光谱分析发现,进行配位前后有机配体的特征峰产生了频移,表明稀土配合物中Eu 3+与配体之间存在着明显的配位作用。在进行复合之后,桥联配体的特征峰也产生了偏移,表明GOSs与稀土配合物通过桥联分子的氢键作用进行了进行复合。吸收光谱与荧光光谱测定结果表明增强薄膜吸收峰在200~400 nm,荧光主峰在612 nm左右,为Eu 3+特征红色荧光峰,且不同配体可以实现不同范围的吸收产生差异化的荧光表现。扫描电镜和金相显微镜清晰地展示了稀土配合物复合前后的微观形貌,即颗粒状稀土配合物附着在石墨烯薄片上。光稳定性测试表明经过GOSs氢键复合之后,Eu(BA)3phen和Eu(TTA)3bpm稀土配合物荧光材料在进行25次荧光强度测试后光漂白程度分别下降了4.26%和6.41%,提高了其光稳定性。热重测试也表明在经过GOSs氢键复合之后,稀土配合物的热稳定性有了很大提高。总之,得益于GOSs和稀土配合物的特性结合,所制备的紫外增强材料表现出优异的荧光特性与稳定性,必将在紫外探测方面有着广阔的应用前景。

Research on the Spectral Analysis and Stability of Ultraviolet-Enhanced Thin Films with Stable and Tunable Graphene Oxide-Rare Earth Complexes

As a new two-dimensional sheet material,graphene oxide sheets(GOSs)offers many advantages,such as high specific surface area,abundant surface oxygen-containing functional groups and good photothermal stability.In particular,rare earth complexes formed with GOSs exhibit excellent fluorescent characteristics from the combination of the inorganic rare earth element and the organic ligand.In order to combine the physicochemical properties of the two types of materials for applications in the field of ultraviolet(UV)spectroscopy,GOSs was compounded with rare earth complexes through means of hydrogen bond self-assembly,with appropriate organic ligands,namely phenanthroline(phen)and 2’2-bipyrimidine(bpm),being used as bridging molecules.This method was used to prepare the highly stable and tunable GOSs-rare earth complex fluorescent materials GOSs-Eu(BA)3phen and GOSs-Eu(TTA)3bpm.A corresponding poly vinyl alcohol(PVA)mixed UV enhanced film was also prepared for each GOSs-rare earth complex,respectively.The properties of the materials were studied using infrared(IR)spectroscopy,scanning electron microscopy(SEM),and metallographic microscopy.The films were also characterized by their absorption and fluorescence spectra.In addition,the thermal stability of the UV-enhanced materials was tested using thermogravimetric analysis(TGA),and the photostability of the UV-enhanced film before and after reacting with the hydrogen bonds of the GOSs was tested using fluorescence intensity experiments.IR spectroscopy results showed that the characteristic absorption peaks of the organic ligands shifted after the complex formation,indicating that there is significant coordination between Eu 3+and the ligands in the rare earth complex.In addition,the characteristic chemical shift peaks of the bridging ligands also shifted,showing that the GOSs and the rare earth complexes were combined through hydrogen bonding of the bridging molecules.The absorption and fluorescence spectra results indicated that the absorption peak of the enhanced film was in the range of 200~400 nm,and that the main fluorescence peak was at about 612 nm,which is the characteristic red fluorescent peak of Eu 3+.Different ligands achieved different absorption ranges,thus leading to differences in fluorescence behavior.The pictures from SEM and metallographic microscopy clearly showed that the rare earth complex particles adhered to the graphene sheet after the compositing process.The photostability test further showed that,following the compositing process,the photobleaching degree of Eu(BA)3phen and Eu(TAA)3bpm rare earth complex fluorescent materials decreased by 4.26%and 6.41%respectively,after 25 fluorescence intensity tests.The TGA results showed that the thermal stability of the rare earth complexes was greatly improved after the formation of hydrogen bonds with GOSs.In summary,the prepared UV-enhanced materials were shown to exhibit excellent fluorescent characteristics and stability,and will have broad applications in UV detection,especially in the field of narrow-band differential detection.