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Regulation Of Luminescence Properties Of Small Particle Nanomaterials

Posted on:2022-02-11Degree:MasterType:Thesis
Country:ChinaCandidate:S M DuFull Text:PDF
GTID:2481306479473064Subject:Applied Chemistry
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Graphene quantum dots(GQDs)and black phosphorous quantum dots(BPQDs)are both zero-dimensional(0D)fluorescent nanomaterials.This paper mainly discusses the fluorescent properties of these two types of 0D nanomaterials,and will use GQDs as luminous bodies to construct Fluorescence quenching sensor of heavy metal Hg2+.GQDs are 0D luminescent nanomaterials with a particle size of less than 10 nm,sp2 and sp3 hybridized carbon atoms as the skeleton,and rich oxygen-containing functional groups on the surface.They have the advantages of small particle size,large specific surface area,tunable photoluminescence,etc.,but Most GQDs exhibit short-wave radiation with low quantum yield,and their applications are limited.N-doping is a method that can effectively improve the luminescence performance of GQDs and can enhance the interaction between GQDs and metal ions.Therefore,N-doped GQDs(N-GQDs)have received widespread attention as candidate materials for biosensing applications.BPQDs are single-layer or several-layer light-emitting nanomaterials with unique electronic and optical properties prepared by destroying the van der Waals forces between black phosphorous(BP)layers.They have received extensive attention in recent years,and currently there are few reports on their light-emitting mechanism.Based on the above background,this paper has launched the following work:(1)At room temperature,BPQDs are prepared by ultrasonic stripping in ultrapure water,and three sets of different sizes are obtained by ultrafiltration separation,which are respectively denoted as BPQDs@(<3K),BPQDs@(3-10K)and BPQDs@(10-30K).The morphology and structure of BPQDs@(<3K)BPQDs@(3-10K)and BPQDs@(10-30K)were characterized,and the influence of size on the fluorescence performance of BPQDs was explored.The experimental results show that the fluorescence emission of BPQDs is independent of size.Influences.(2)The effect of oxygen content on the surface of BPQDs on its luminescence performance was discussed.In this chapter,BPQDs@(<3K)is chemically oxidized and reduced to obtain BPQDs@(<3K)-Oxi and BPQDs@(<3K)-Red.Compared with BPQDs@(<3K),the oxygen content on the surface of BPQDs@(<3K)-Oxi increases,which leads to a red shift of the fluorescence maximum emission wavelength;the oxygen content on the surface of BPQDs@(<3K)-Red decreases,which leads to fluorescence The blue shift of the maximum emission wavelength indicates that the fluorescence performance of BPQDs is directly related to the oxygen content on the surface.The research in this chapter provides a feasible method for regulating the fluorescence properties of BPQDs,and provides a feasible idea for exploring the fluorescence emission mechanism of BPQDs.(3)This chapter discusses the influence of N-doping on the fluorescence emission performance of GQDs.The morphology and structure of GQDs before and after doping were characterized,and the fluorescence spectra were measured.The experimental results show that,compared with GQDs,the optimal fluorescence emission of N-GQDs will appear red-shifted,and the quantum yield will also be greatly improved.Using N-GQDs as the luminescent agent and glutathione as the masking agent,a Hg2+-related quenching photoluminescence(PL)sensor was prepared to detect Hg2+in tap water.The sensor shows a linear relationship between0.5 and 110 nM,and the detection limit is 0.08 nM(S/N=3).The sensor has been successfully applied to the detection of actual samples.
Keywords/Search Tags:Graphene quantum dots, Black phosphorous quantum dots, Fluorescence, Luminescence mechanism, Regulation
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