阅读说明：本技术 一种稀土配合物/氧化石墨烯荧光材料及其制备方法和应用 (Rare earth complex/graphene oxide fluorescent material and preparation method and application thereof ) 是由 王政芳 臧国凤 李善吉 温华文 于 2021-08-27 设计创作，主要内容包括：本发明公开了一种稀土配合物/氧化石墨烯荧光材料及其制备方法和应用,所述制备方法包括如下步骤：包括如下步骤：使化合物1与化合物2反应,得到长共轭配体；将所述长共轭配体与稀土金属盐、含氨基邻菲罗啉混合,反应得到稀土配合物；将所述稀土配合物与环氧硅烷偶联剂改性氧化石墨烯混合,反应得到稀土配合物/氧化石墨烯荧光材料。本发明的氧化石墨烯与稀土配合物通过化学键连接,有效地解决了掺杂方法中氧化石墨烯与铕配合物的相分离现象。同时,稀土配合物的配体含有柔性的长共轭链段,具有很好的共轭性和共平面性,空间位阻小,可以使得稀土配合物的激发态需要的能量更低,大大增加了激发态的分子数,从而提高氧化石墨烯的荧光性能。(The invention discloses a rare earth complex/graphene oxide fluorescent material and a preparation method and application thereof, wherein the preparation method comprises the following steps: the method comprises the following steps: reacting a compound 1 With compound 2)

1. A rare earth complex/graphene oxide fluorescent material is characterized in that: the rare earth complex/graphene oxide fluorescent material has the following structural formula:

m is a rare earth element, R1 and R2 are independently selected from C_2～6Alkenyl, phenyl, optionally substituted phenyl.

2. The rare earth complex/graphene oxide fluorescent material according to claim 1, wherein: the M comprises at least one of yttrium, europium, gadolinium, lanthanum, cerium, terbium and ytterbium, and preferably comprises europium.

3. A method for preparing the rare earth complex/graphene oxide fluorescent material according to claim 1 or 2, which is characterized in that: the method comprises the following steps:

reacting a compound 1With compound 2Reacting to obtain a long conjugated ligand;

mixing the long conjugated ligand with rare earth metal salt and amino-containing phenanthroline, and reacting to obtain a rare earth complex;

and mixing the rare earth complex with epoxy silane coupling agent modified graphene oxide, and reacting to obtain the rare earth complex/graphene oxide fluorescent material.

4. The method according to claim 3, wherein: the molar ratio of the compound 1 to the compound 2 is 1: 0.5 to 2, preferably 1: 0.9 to 1.2, more preferably about 1: 1.

5. the method according to claim 3, wherein: the reaction of the compound 1 and the compound 2 is carried out under the action of a catalyst; preferably, the catalyst is a basic catalyst; preferably, the alkaline catalyst comprises any one or more of sodium ethoxide, sodium hydroxide and potassium hydroxide; preferably, the amount of the catalyst is 5 to 30%, preferably 10 to 25% of the total mass of the compound 1 and the compound 2.

6. The method according to claim 3, wherein: the molar ratio of the long conjugated ligand to the rare earth metal salt to the amino-containing phenanthroline is 0.005-0.015: 0.05-0.15: 0.0006 to 0.016.

7. The method according to claim 3, wherein: the reaction temperature of the long conjugated ligand, the rare earth metal salt and the amino-containing phenanthroline is 50-100 ℃.

8. The method according to claim 3, wherein: the reaction temperature of the rare earth complex and the epoxy silane coupling agent modified graphene oxide is 10-50 ℃, and preferably 20-30 ℃.

9. The method according to claim 3, wherein: the preparation method of the epoxy silane coupling agent modified graphene oxide comprises the steps of mixing a suspension of graphene oxide with an epoxy silane coupling agent, and reacting to obtain epoxy silane coupling agent modified graphene oxide; preferably, the epoxysilane coupling agent comprises any one or more of gamma- (2, 3-glycidoxy) propyltrimethoxysilane, gamma- (2, 3-glycidoxy) propylmethyldimethoxysilane, gamma- (2, 3-glycidoxy) propylmethyldiethoxysilane, 5, 6-epoxyhexyltriethoxysilane, and 2- (3, 4-epoxycyclohexyl) ethyltriethoxysilane.

10. Use of the rare earth complex/graphene oxide fluorescent material according to claim 1 or 2 in biomarker or cell imaging.

Technical Field

The invention relates to the technical field of fluorescent materials, in particular to a rare earth complex/graphene oxide fluorescent material and a preparation method and application thereof.

Background

Graphene Oxide (GOs) has a special two-dimensional structure, and is widely used for modifying materials due to unique optical, electromagnetic and mechanical properties, and the like, and the surfaces of the graphene oxide are rich in oxygen-containing functional groups such as hydroxyl, carboxyl and epoxy groups. The aqueous solution of graphene oxide has weak fluorescence, but the application of the aqueous solution of graphene oxide in biomarkers and cell imaging is greatly limited due to the weak fluorescence.

The rare earth complex, such as europium complex, has certain luminescent property, and the emission peak is mainly from Eu³⁺Around 617nm⁵D₀—⁷F₂The characteristic emission of the fluorescent material is not changed along with the difference of ligands, the emission spectrum of the fluorescent material is almost a line spectrum, the half-peak width is only a few nanometers, the fluorescent material has saturated red light emission, and the theoretical upper limit of the luminous efficiency can reach 100 percent.

At present, the metal complex becomes a new choice for graphene functionalization and graphene-inorganic mixture preparation. The metal complex/graphene luminescent material is mainly a physical doping method and a chemical reaction method, and the physical doping method is mainly characterized in that weak interaction forces such as intermolecular force and hydrogen bond are combined together, so that the compatibility is poor, phase separation is easy to occur, the use of the material is influenced, and the like.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides the rare earth complex/graphene oxide fluorescent material which can effectively enhance the fluorescence property of graphene oxide and avoid the phase separation of the graphene oxide and the rare earth complex.

The invention also provides a preparation method and application of the rare earth complex/graphene oxide fluorescent material.

Specifically, the invention adopts the following technical scheme:

the first aspect of the invention provides a rare earth complex/graphene oxide fluorescent material, which has the following structural formula:

m is a rare earth element, R1 and R2 are independently selected from C_2～6Alkenyl, phenyl, optionally substituted phenyl.

The rare earth complex/graphene oxide fluorescent material according to the first aspect of the invention has at least the following beneficial effects:

according to the invention, a multi-layer rare earth complex is formed on a graphene oxide sheet layer, and a ligand of the rare earth complex contains a long conjugated chain segment, so that the rare earth complex has good conjugation property and coplanarity, and small steric hindrance, and can lower the energy required by the excited state of the rare earth complex, thereby greatly increasing the number of excited state molecules and further improving the fluorescence property of the graphene oxide; meanwhile, the rare earth complex and the graphene oxide are connected through a chemical bond instead of simple doping, so that the phase separation phenomenon of the graphene oxide and the rare earth complex is effectively avoided.

In some embodiments of the invention, M comprises at least one of yttrium, europium, gadolinium, lanthanum, cerium, terbium, ytterbium, preferably europium.

In some embodiments of the present invention, the rare earth complex/graphene oxide fluorescent material has the following structural formula:

the second aspect of the invention provides a preparation method of the rare earth complex/graphene oxide fluorescent material, which comprises the following steps:

reacting a compound 1With compound 2Reacting to obtain a long conjugated ligand;

mixing the long conjugated ligand with rare earth metal salt and amino-containing phenanthroline, and reacting to obtain a rare earth complex;

and mixing the rare earth complex with epoxy silane coupling agent modified graphene oxide, and reacting to obtain the rare earth complex/graphene oxide fluorescent material.

In some embodiments of the invention, the molar ratio of compound 1 to compound 2 is 1: 0.5 to 2, preferably 1: 0.9 to 1.2, more preferably about 1: 1.

in some embodiments of the present invention, the reaction of compound 1 and compound 2 is performed under the action of a catalyst, wherein the catalyst is a basic catalyst, and the catalyst comprises any one or more of sodium methoxide, sodium ethoxide, sodium hydroxide and potassium hydroxide. The dosage of the catalyst is 5-30%, preferably 10-25% of the total mass of the compound 1 and the compound 2.

In some embodiments of the invention, the reaction of compound 1 and compound 2 is carried out in a protective atmosphere, for example, a nitrogen, argon atmosphere. The reaction temperature is 50-100 ℃; preferably, a solvent is also present in the reaction system of the compound 1 and the compound 2, and the reaction temperature is not higher than the boiling point of the solvent. The solvent includes tetrahydrofuran, N-dimethylformamide DMF, ethanol, propanol, and the like. The reaction time is 5-30 h, preferably 10-30 h, and more preferably 15-25 h.

In some embodiments of the invention, the molar ratio of the long conjugated ligand to the rare earth metal salt and the amino-containing phenanthroline is 0.005-0.015: 0.05-0.15: 0.0006 to 0.016. Preferably, in practice, the amino-containing phenanthroline is first prepared as a solution and then mixed with a mixture of the long conjugated ligand and the rare earth metal salt. The concentration of the amino-containing phenanthroline solution is 0.02-0.08 mol/L, and preferably about 0.05 mol/L. The ratio of the long conjugated ligand to the rare earth metal salt to the amino-containing phenanthroline solution is 0.005-0.015 mol: 0.05-0.15 mol: 30 to 200mL, preferably about 0.010 mol: 0.010 mol: 100 mL.

In some embodiments of the invention, the reaction temperature of the long conjugated ligand, the rare earth metal salt and the amino-containing phenanthroline is 50-100 ℃; preferably, a solvent is also present in the reaction system of the long conjugated ligand, the rare earth metal salt and the amino phenanthroline-containing reaction system, and the reaction temperature is not higher than the boiling point of the solvent. The solvent includes tetrahydrofuran, N-dimethylformamide DMF, ethanol, propanol, and the like. The reaction time is 0.5-3 h. After the reaction of the long conjugated ligand, the rare earth metal salt and the amino-containing phenanthroline is finished, separating and purifying the product to obtain the rare earth complex.

In some embodiments of the invention, the rare earth metal salt comprises any one or more of a nitrate, a sulfate, and a chloride salt of a rare earth metal.

In some embodiments of the invention, the amino-containing phenanthroline comprises at least one of 5-amino-1, 10-phenanthroline, 2-amino-1, 10-phenanthroline, 5, 6-diamino-1, 10-phenanthroline, and preferably 5-amino-1, 10-phenanthroline.

In some embodiments of the invention, the mass ratio of the rare earth complex to the epoxy silane coupling agent modified graphene oxide is 5-15: 10.

in some embodiments of the invention, the reaction temperature of the rare earth complex and the epoxy silane coupling agent modified graphene oxide is 10-50 ℃, preferably 20-30 ℃; the reaction time is 0.5-2 h.

In some embodiments of the present invention, the step of mixing and reacting the rare earth complex and the epoxy silane coupling agent modified graphene oxide is specifically to disperse the epoxy silane coupling agent modified graphene oxide in a solvent, then add a rare earth complex solution, stir for reaction, filter, and wash to obtain the rare earth complex/graphene oxide fluorescent material. The mass ratio of the graphene oxide to the solvent to the rare earth complex is 10: 100-500: 5-15, preferably about 10: 300: 10. the solvent includes tetrahydrofuran, N-dimethylformamide DMF, ethanol, propanol, and the like. It should be noted that, in the whole preparation process of the rare earth complex/graphene oxide fluorescent material, the solvents used in the steps may be the same or different.

In some embodiments of the present invention, the epoxy silane coupling agent modified graphene oxide is prepared by mixing a suspension of graphene oxide with an epoxy silane coupling agent, and reacting to obtain the epoxy silane coupling agent modified graphene oxide.

In some embodiments of the present invention, the reaction temperature of the graphene oxide and the epoxy silane coupling agent is 50-90 ℃, and the reaction time is 3-5 hours. The reaction of the graphene oxide with the epoxy silane coupling agent is performed in a protective atmosphere, for example, a nitrogen or argon atmosphere.

In some embodiments of the present invention, the mass ratio of the graphene oxide to the epoxy silane coupling agent is 1: 1 to 10, preferably about 1: 5.

in some embodiments of the present invention, in the suspension of graphene oxide, the mass concentration of graphene oxide is 0.5% to 5%, preferably 1% to 2%, and more preferably 1.2% to 1.5%. The suspension of graphene oxide adopts ethanol, propanol, butanol or water as a solvent.

In some embodiments of the invention, the epoxysilane coupling agent comprises any one or more of gamma- (2, 3-glycidoxy) propyltrimethoxysilane, gamma- (2, 3-glycidoxy) propylmethyldimethoxysilane, gamma- (2, 3-glycidoxy) propylmethyldiethoxysilane, 5, 6-epoxyhexyltriethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltriethoxysilane.

The third aspect of the invention is to provide an application of the rare earth complex/graphene oxide fluorescent material in biological labeling or cell imaging.

Compared with the prior art, the invention has the following beneficial effects:

according to the invention, an epoxy silane coupling agent is used for carrying out surface modification on graphene oxide, so that the surface of the graphene oxide has active epoxy groups; the long conjugated ligand and the amino-containing phenanthroline form a complex with rare earth metal, and the amino group in the complex is combined with the epoxy group on the surface of the graphene oxide through reaction, so that the graphene oxide and the rare earth complex are connected through a chemical bond, and the phase separation phenomenon of the graphene oxide and the europium complex in a doping method is effectively solved. Meanwhile, the ligand of the rare earth complex contains a flexible long conjugated chain segment, so that the rare earth complex has good conjugation and coplanarity and small steric hindrance, the energy required by the excited state of the rare earth complex is lower, the number of molecules in the excited state is greatly increased, and the fluorescence performance of the graphene oxide is improved.

In addition, the preparation method of the rare earth complex/graphene oxide fluorescent material has the advantages of mild conditions, simple reaction process and environmental protection.

Detailed Description

The technical solution of the present invention is further described below with reference to specific examples. The starting materials used in the following examples, unless otherwise specified, are available from conventional commercial sources; the processes used, unless otherwise specified, are conventional in the art.

Example 1

(1) Preparation of europium complexes

Carrying out reflux reaction on 5g of sodium ethoxide, 80mL of tetrahydrofuran, 11mL of acetophenone and 15g of cinnamic acid under the protection of nitrogen for 20h, extracting an organic substance by using diethyl ether after the reaction is finished, then carrying out rotary evaporation to remove the diethyl ether to obtain a viscous light yellow oily liquid, and separating by using a silica gel column to obtain the long conjugated ligand. Adding 0.0050mol of long conjugated ligand and 0.015mol of europium nitrate into 200mL of DMF, heating, stirring and dissolving, then dropwise adding 120mL of 5-amino-1, 10-phenanthroline solution, carrying out heating reflux reaction for 0.5h after dropwise adding is finished, and after the reaction is finished, separating and purifying the product to obtain the europium complex.

The yield is 80%, and the melting point is 278-280 ℃.

(2) Preparation of silane coupling agent modified graphene oxide

1g of graphene oxide is subjected to 700W ultrasonic treatment for 15min and then dispersed in 50g of absolute ethyl alcohol to obtain a graphene oxide suspension. And then under the condition of stirring, dropwise adding 1g of epoxy silane coupling agent gamma- (2, 3-glycidoxy) propyl methyl dimethoxy silane into the graphene oxide suspension, reacting for 4h at 60 ℃ in the atmosphere of nitrogen, filtering, and drying to obtain the silane coupling agent modified graphene oxide.

(3) Preparation of europium complex/graphene oxide fluorescent material

And (3) dispersing 10g of the silane coupling agent modified graphene oxide prepared in the step (2) in 100g of solvent ethanol after 700W ultrasonic treatment for 20min, then adding 5g of europium complex solution, continuously stirring, reacting for 1h, filtering, and washing to obtain a black solid, namely the europium complex/graphene oxide fluorescent material.

Infrared analysis was performed on a black solid, which was 910cm in its infrared spectrum^-1The epoxy group disappears, which indicates that the epoxy group of the silane coupling agent modified graphene oxide reacts with the amino group of the europium complex; 1680cm of C ═ O double bonds with amide in the infrared spectrum^-1Absorption of 1570-1510 cm^-1And 1310-1200 cm^-1And absorption peaks of C-N and N-H are generated, which indicates that carboxyl of the silane coupling agent modified graphene oxide reacts with amino of the europium complex.

Example 2

(1) Preparation of europium complexes

Carrying out reflux reaction on 5g of sodium ethoxide, 80mL of tetrahydrofuran, 11mL of acetophenone and 15g of cinnamic acid under the protection of nitrogen for 20h, extracting an organic substance by using diethyl ether after the reaction is finished, then carrying out rotary evaporation to remove the diethyl ether to obtain a viscous light yellow oily liquid, and separating by using a silica gel column to obtain the long conjugated ligand. Adding 0.0200mol of long conjugated ligand and 0.0050mol of europium nitrate into 200mL of tetrahydrofuran and 200mL of ethanol, heating, stirring and dissolving, then dropwise adding 30mL of 5-amino-1, 10-phenanthroline solution, heating, refluxing and reacting for 2h after dropwise adding is finished, and separating and purifying the product to obtain the europium complex.

The yield was 80%, and the melting point was 278-.

(2) Preparation of silane coupling agent modified graphene oxide

1g of graphene oxide is subjected to 700W ultrasonic treatment for 10min and then dispersed in 80g of absolute ethyl alcohol to obtain a graphene oxide suspension. And then under the condition of stirring, dropwise adding 2g of epoxy silane coupling agent gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane and 3g of gamma- (2, 3-epoxypropoxy) propyl methyl dimethoxy silane into the graphene oxide suspension, carrying out reflux reaction at 90 ℃ for 3h under the atmosphere of nitrogen, filtering, and drying to obtain the silane coupling agent modified graphene oxide.

(3) Preparation of europium complex/graphene oxide fluorescent material

And (3) dispersing 10g of the silane coupling modified graphene oxide prepared in the step (2) in 200g of solvent ethanol after 700W ultrasonic treatment for 15min, then adding 5g of europium complex solution, continuously stirring, reacting for 0.5h, filtering, and washing to obtain a black solid, namely the europium complex/graphene oxide fluorescent material.

Infrared analysis was carried out on a black solid, the infrared spectrum of which was 910cm, the same as in example 1^-1The epoxy group disappears, which indicates that the epoxy group of the silane coupling agent modified graphene oxide reacts with the amino group of the europium complex; 1680cm of C ═ O double bonds where amides are present^-1Absorption of 1570-1510 cm^-1And 1310-1200 cm^-1And absorption peaks of C-N and N-H are generated, which indicates that carboxyl of the silane coupling agent modified graphene oxide reacts with amino of the europium complex.

Example 3

(1) Preparation of europium complexes

Carrying out reflux reaction on 5g of sodium ethoxide, 80mL of tetrahydrofuran, 11mL of acetophenone and 15g of cinnamic acid under the protection of nitrogen for 20h, extracting an organic substance by using diethyl ether after the reaction is finished, then carrying out rotary evaporation to remove the diethyl ether to obtain a viscous light yellow oily liquid, and separating by using a silica gel column to obtain the long conjugated ligand. Adding 0.0100mol of long conjugated ligand and 0.0100mol of europium nitrate into 200mL of ethanol and 100mL of propanol, heating, stirring, dissolving, then dropwise adding 100mL of 5-amino-1, 10-phenanthroline solution, heating, refluxing and reacting for 0.8h after dropwise adding is finished, and separating and purifying the product after the reaction is finished to obtain the europium complex.

The yield was 80%, and the melting point was 278-.

(2) Preparation of silane coupling agent modified graphene oxide

1g of graphene oxide is subjected to ultrasonic treatment for 25min by 700W, and then dispersed in 100g of absolute ethyl alcohol to obtain a graphene oxide suspension, 5g of epoxy silane coupling agent gamma- (2, 3-epoxypropoxy) propyl methyl diethoxysilane and 5g of 2- (3, 4-epoxycyclohexyl) ethyl triethoxysilane are dropwise added into the graphene oxide suspension under the stirring condition, and the mixture is subjected to reflux reaction for 3h at 80 ℃ in a nitrogen atmosphere, filtered and dried to obtain the silane coupling agent modified graphene oxide.

(3) Preparation of europium complex/graphene oxide fluorescent material

And (3) dispersing 10g of the silane coupling agent modified graphene oxide prepared in the step (2) in 500g of a solvent after 700W ultrasonic treatment for 30min, then adding 8g of europium complex solution, continuously stirring, reacting for 1h, filtering, and washing to obtain a black solid, namely the europium complex/graphene oxide fluorescent material.

Infrared analysis was carried out on a black solid, the infrared spectrum of which was 910cm, the same as in example 1^-1The epoxy group disappears, which indicates that the epoxy group of the silane coupling agent modified graphene oxide reacts with the amino group of the europium complex; 1680cm of C ═ O double bonds where amides are present^-1Absorption of 1570-1510 cm^-1And 1310-1200 cm^-1And absorption peaks of C-N and N-H are generated, which indicates that carboxyl of the silane coupling agent modified graphene oxide reacts with amino of the europium complex.

Example 4

(1) Preparation of europium complexes

Carrying out reflux reaction on 5g of sodium ethoxide, 80mL of tetrahydrofuran, 11mL of acetophenone and 15g of cinnamic acid under the protection of nitrogen for 20h, extracting an organic substance by using diethyl ether after the reaction is finished, then carrying out rotary evaporation to remove the diethyl ether to obtain a viscous light yellow oily liquid, and separating by using a silica gel column to obtain the long conjugated ligand. Adding 0.0150mol of long conjugated ligand and 0.0150mol of europium nitrate into 500mL of organic solvent DMF, heating, stirring and dissolving, then dropwise adding 50mL of 5-amino-1, 10-phenanthroline solution, carrying out heating reflux reaction for 1h after dropwise adding is finished, and separating and purifying the product after the reaction is finished to obtain the europium complex.

The yield was 80%, and the melting point was 278-.

(2) Preparation of silane coupling agent modified graphene oxide

1g of graphene oxide is subjected to ultrasonic treatment for 30min at 700W, and then dispersed in 80g of absolute ethanol to obtain a graphene oxide suspension, 5g of epoxy silane coupling agent epoxy triethoxysilane is dropwise added into the graphene oxide suspension under the stirring condition, reflux reaction is carried out for 5h at 50 ℃ in a nitrogen atmosphere, and the graphene oxide modified by the silane coupling agent is obtained after filtration and drying.

(3) Preparation of europium complex/graphene oxide fluorescent material

And (3) dispersing 10g of the modified graphene oxide prepared in the step (2) in 300g of solvent propanol after 700W ultrasonic treatment for 30min, then adding 10g of europium complex solution, continuously stirring, reacting for 2h, filtering, and washing to obtain a black solid, namely the europium complex/graphene oxide fluorescent material.

Infrared analysis was carried out on a black solid, the infrared spectrum of which was 910cm, the same as in example 1^-1The epoxy group disappears, which indicates that the epoxy group of the silane coupling agent modified graphene oxide reacts with the amino group of the europium complex; 1680cm of C ═ O double bonds where amides are present^-1Absorption of 1570-1510 cm^-1And 1310-1200 cm^-1And absorption peaks of C-N and N-H are generated, which indicates that carboxyl of the silane coupling agent modified graphene oxide reacts with amino of the europium complex.

Example 5

(1) Preparation of europium complexes

Carrying out reflux reaction on 5g of sodium ethoxide, 80mL of tetrahydrofuran, 11mL of acetophenone and 15g of cinnamic acid under the protection of nitrogen for 20h, extracting an organic substance by using diethyl ether after the reaction is finished, then carrying out rotary evaporation to remove the diethyl ether to obtain a viscous light yellow oily liquid, and separating by using a silica gel column to obtain the long conjugated ligand. Adding 0.0200mol of long conjugated ligand and 0.0150mol of europium nitrate into 300mL of organic solvent, heating, stirring and dissolving, then dropwise adding 200mL of 5-amino-1, 10-phenanthroline solution, carrying out heating reflux reaction for 3h after dropwise adding is finished, and after the reaction is finished, separating and purifying the product to obtain the europium complex.

The yield was 80%, and the melting point was 278-.

(2) Preparation of silane coupling agent modified graphene oxide

1g of graphene oxide is subjected to ultrasonic treatment for 20min by 700W, and then dispersed in 85g of absolute ethyl alcohol to obtain a graphene oxide suspension, then under the condition of stirring, 2g of gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane, 2g of 2- (3, 4-epoxycyclohexyl) ethyl triethoxy silane and 4g of gamma- (2, 3-epoxypropoxy) propyl methyl diethoxy silane are dropwise added into the graphene oxide suspension, and the mixture is subjected to reflux reaction for 4h at 80 ℃ in a nitrogen atmosphere, filtered and dried to obtain the silane coupling agent modified graphene oxide.

(3) Preparation of europium complex/graphene oxide fluorescent material

And (3) dispersing 10g of the modified graphene oxide prepared in the step (2) in 400g of a solvent after 700W ultrasonic treatment for 10min, then adding 6g of europium complex solution, continuously stirring, reacting for 1.5h, filtering, and washing to obtain a black solid, namely the europium complex/graphene oxide fluorescent material.

910cm in the IR spectrum of a black solid^-1The epoxy group disappears, which indicates that the epoxy group of the silane coupling agent modified graphene oxide reacts with the amino group of the europium complex; the absorption of amide C ═ O double bond 1680 is 1570-1510 cm^-1And 1310-1200 cm^-1Absorption peaks of C-N and N-H appear, which indicates that carboxyl of the modified graphene oxide reacts with amino of the europium complex.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.