Preparation Of AgNO₃-fullerene Composite Crystal Material And Application Of C₆₀/C₇₀ In Situ Separation

Fullerenes,as a new optical material,has important research value,and has been used in solar cells,biosensors,optical signal processing and control,etc.However,the performance of fullerenes is closely related to the purity of fullerenes.At present,there are two main problem s in synthesis and industrial production of fullerenes:low yield and low purity of fullerenes.E specially,the latterwhich directly determines the physical,chemical and optoelectronic proper ties of fullerenes,plays a key role in the application of fullerene materials.However,the proc ess of purifying fullerenes（especially high-purity）is complex and expensive in cost,which ha s seriously hindered the application and promotion of high-purity fullerene materials.Therefor e,the separation and purification of fullerenes has always been the focus of scientific research.In our research,we found that Ag⁺in the metal complex had a strong interaction with full erenes,and in turn the interaction can be used to extract C₆₀ from the fullerene mixture(C₆₀,C₇₀)to purify C₇₀.Research of characterization and interaction was implemented by mass spectr ometry,Raman spectroscopy,ultraviolet-visible absorption spectroscopy,X-ray diffraction an d density functional calculations.The main research contents of this paper are as follows:1.Synthesis of Ag⁺-fullerene.Ag⁺-fullerenes were respectively synthesized at two interfa ces of liquid-liquid and solid-liquid respectively.Comparison was made on morphology and el ement composition of crystals synthesized by the two aforementioned intercalation methods.T he results of SEM,Raman spectroscopy and XRD showed that the crystals synthesized at the l iquid-liquid interface were homogeneous and the conversion rate was high.2.We studied the interaction between AgNO₃ and fullerene C₆₀ molecules.By combining Raman survey and numerical calculation,the binding nature of Ag⁺-fullerene was revealed to be partial covalent bond,and the binding of Ag⁺in C₆₀ at the positions of η¹ and η² greatly r educes the symmetry and polarisability of the molecule,resulting in charge transfer and overla pping orbitals between Ag⁺and C₆₀,resulting in a broadened and weakened Raman peak.3.Separation and purification of fullerenes.In the process of seperating mixed fulle renes(C₆₀/C₇₀:1:1,3:7,1:9),specific C₆₀ organometallic crystallites were formed between Ag⁺and C₆₀.In this way,C₆₀ was successfully extracted,And C₇₀ with high purity was obtaine d.In addition,its morphology and structure were characterized by SEM,Raman spectroscopy and XRD spectroscopy,in order to study its potential separation mechanism.