微波辅助合成色控型CMC-Tb/Eu纳米复合物的荧光性质

Fluorescence Properties of Tunable Luminescence Color CMC-Tb/Eu Nano Complexes Synthesized via Microwave-Assisted Heating

微波辅助下通过共同沉淀法制备了一系列可色控的CMC-Tb/Eu复合物,并通过SEM-EDS、TEM、XPS、UV-Vis,荧光光谱和荧光寿命检测等方法考察了复合物的形貌、结构、荧光性能以及能量转移特征.结果表明:CMC-Tb/Eu复合物的表面与CMC的相比裂痕多,有小粒子集聚于CMC表面,颗粒为实心结构,平均直径为75~98 nm;纳米复合物中金属离子都与CMC分子链上的—OH、—COO^-以及—COC—中O原子发生配位键合和离子;CMC为主要的光能量吸收体,在其与稀土离子的能量传递过程中,传递给Tb^(3+)的效率要远大于传递给Eu^(3+);在激发光为350 nm下,CMCTb/Eu发射光谱中存在~5D_4→~7F_5(544 nm)和~5D_4→~7F_6(489 nm)Tb^(3+)跃迁峰;589 nm和616 nm附近的两个发射峰是由Tb^(3+)的~5D_4→~7F_3和~5D_4→~7F_4跃迁以及Eu^(3+)的~5D_0→~7F_1和~5D_0→~7F_2跃迁叠加所致;实现了荧光光色可控.Tb^(3+)的~5D_4→~7F_5跃迁峰强度变化以及纳米复合物的荧光寿命变化证明了纳米复合物存在Tb(Ⅲ)Eu(Ⅲ)能量转移.

A series of novel tunable luminescence color CMC( Carboxymethyl Cellulose)-Tb/Eu nano complexes were synthesized via the coprecipitation reaction with microwave-assisted heating. Then,the morphology,structure,fluorescence properties and energy transfer characteristic of the synthesized nano complexes were investigated by means of SEM-EDS,TEM,XPS,UV-Vis,PL spectra and decay lifetime. The results show that( 1) as compared with CMC,there exist more cracks on the surface of the synthesized CMC-Tb/Eu nano complexes;( 2) in the nano complexes,small solid particles cluster on the surface of CMC,and the average size of the particles is 75 ~ 98 nm;( 3) the O atoms in —OH,—COO^-and —COC— of the molecular chain of CMC bond with Tb^(3+)or Eu^(3+)in the synthesized nano complexes ionically and covalently;( 4) CMC is the main energy acceptor,and in the energy transfer between CMC and Tb or between CMC and Eu,the efficiency of transferring energy from CMC to Tb^(3+)is higher than that to Eu^(3+);( 5) under a 350 nm excitation,the ~5D_4→~7F_5( 544 nm) and ~5D_4→~7F_6( 489 nm)transitions of Tb^(3+)appear in the emission spectrum of CMC-Tb/Eu;( 6) the two peaks respectively locating at around 589 nm and 616 nm result from the overlapping of the transitions( ~5D_4→~7F_3 and ~5D_4→~7F_4) of Tb^(3+)and the transitions( ~5D_0~7F_1 and ~5D_0~7F_2) of Eu^(3+),respectively; and( 7) the tunable luminescence color is realized. The intensity change of ~5D_4→~7F_5 of Tb^(3+)and the luminescence lifetime change of the synthesize nano complexes demonstrate that the energy transfer of Tb( Ⅲ) Eu( Ⅲ) exists in the synthesized nano complexes.