CN106883854A

CN106883854A - Rare earth based quantum dot composite nano fiber element and its preparation method and application

Info

Publication number: CN106883854A
Application number: CN201710090850.9A
Authority: CN
Inventors: 张召; 李新平; 薛白亮; 李可成; 韩卿
Original assignee: Shaanxi University of Science and Technology
Current assignee: Shaanxi University of Science and Technology
Priority date: 2017-02-20
Filing date: 2017-02-20
Publication date: 2017-06-23
Anticipated expiration: 2037-02-20
Also published as: CN106883854B

Abstract

In mass ratio it is first (1~3) by rare earth based quantum dot and nano-cellulose the present invention relates to rare earth based quantum dot composite nano fiber element and its preparation method and application：(25~75) are dissolved in solvent, add catalyst, and reaction obtains rare earth based quantum dot composite nano fiber element；Wherein, rare earth based quantum dot includes carboxyl modified rare earth based quantum dot or amido modified rare earth base carbon nitrogen quantum dot, and nano-cellulose includes hydroxyl nano-cellulose or carboxyl nano-cellulose；Ester bond is carried out using carboxyl modified rare earth based quantum dot and hydroxyl nano-cellulose to be combined, or amido link is carried out using amido modified rare earth base carbon nitrogen quantum dot and carboxyl nano-cellulose being combined.Obtained rare earth based quantum dot composite nano fiber element can be used in preparing visible near-infrared double mode anti-fake material, and disguised and extensive identity is good.In addition prepared fluorescence nano paper is to Fe³⁺, Hg²⁺There is fine identity with TNT.

Description

Rare earth based quantum dot composite nano fiber element and its preparation method and application

【Technical field】

The invention belongs to field of compound material, and in particular to rare earth based quantum dot composite nano fiber element and preparation method thereof And application.

【Background technology】

With expanding economy, manufacturing and marketing fake illegal activity very disruptive stabilization of the social economy with market.In order to pre- Anti- and strike illegal activity, various anti-fake materials are developed.However, it is false proof with false making technology actually trial of strength in helically Ascendant trend, in the urgent need to opening high-performance anti-fake material.

Anti-fake material mainly includes：Dyeing, temperature induced color changing and fluorescence etc..Fluorescence falsification preventing material depends on fluorescent material Reversible luminescence generated by light, be the permanent anti-fake material of a class.The wavelength of transmitted light of fluorescence falsification preventing material is in the range of 380-780nm Can bore hole identification so as to meet Popular anti-frand identification.Near infrared range not can recognize that needs are advanced in 800-2500nm bore holes Detecting instrument so that have compared with highly concealed type.In view of visible ray anti-fake material in the market, its luminous bore hole is visible (wavelength is 380-780nm) there is extensive identity to ignore the disguise of anti-fake material；In contrast, near-infrared (800- 2500nm) anti-fake material can only meet disguise.With the development of anti-counterfeiting technology, the performance to fluorescence falsification preventing material is proposed more preferably It is required that, extensive identity and preferably disguise are such as met simultaneously.Additionally, anti-fake material is in actual application, also need to examine Consider the physical properties such as dissolubility (water solubility), processability, the film forming of material.

Hg²⁺It is heavy metal pollution ion, Fe³⁺It is present in life entity, trinitrotoluene (TNT) is dangerous explosive, opens Send out portable, easy-operating high sensitivity fluorescent optical sensor detects Hg²⁺, Fe³⁺And TNT has in fields such as environment, life and safety Significance.

【The content of the invention】

It is an object of the invention to overcome problems of the prior art, there is provided a kind of rare earth based quantum dot composite Nano Cellulose and its preparation method and application, obtained rare earth based quantum dot composite nano fiber element can be used in false proof and fluorescence and pass Sensor field.

In order to achieve the above object, the present invention is adopted the following technical scheme that：

Comprise the following steps：In mass ratio it is first (1~3) by rare earth based quantum dot and nano-cellulose：(25~75) It is dissolved in solvent, adds catalyst, reaction obtains rare earth based quantum dot composite nano fiber element；Wherein, rare earth based quantum dot Including carboxyl modified-rare earth based quantum dot or amido modified-rare earth base carbon nitrogen quantum dot, nano-cellulose includes hydroxyl-nanometer Cellulose or carboxyl-nano-cellulose；Ester bond is carried out using carboxyl modified-rare earth based quantum dot and hydroxyl-nano-cellulose to answer Close, or amido link is carried out using amido modified-rare earth base carbon nitrogen quantum dot and carboxyl-nano-cellulose and be combined.

Further, carboxyl modified-rare earth based quantum dot include carboxyl modified-rare earth base carbon quantum dot or carboxyl modified- Rare earth base carbon nitrogen quantum dot, its preparation process is specifically included：

It is in molar ratio 1 by rare-earth salts and citric acid:(5~15) mixing is dissolved in water, and reacting 4~8h at 150~200 DEG C obtains To carboxyl modified-rare earth base carbon quantum dot；

Or by rare-earth salts, citric acid and organic amine in molar ratio be 1:(27~81):(5~15) mixing is dissolved in water, 150~200 DEG C of 4~8h of reaction obtain carboxyl modified-rare earth base carbon nitrogen quantum dot.

Further, amido modified-rare earth base carbon nitrogen quantum dot is obtained by binary reaction or three elementary reactions are obtained, its system Standby step is specifically included：

It is in molar ratio 1 by rare-earth salts and organic amine:(27~81) mixing is dissolved in water, or by rare-earth salts, organic acid and Organic amine is in molar ratio 1:(5~15):(27~81) mixing is dissolved in water, and obtaining amino in 150~200 DEG C of 4~8h of reaction repaiies Decorations-rare earth base carbon nitrogen quantum dot.

Further, rare-earth salts is NdCl₃、YbCl₃Or ErCl₃；Organic acid is citric acid, acrylic acid, malonic acid or rich horse Acid；Organic amine is ethylenediamine, propane diamine or 1,3- diaminourea -2- propyl alcohol.

Further, the preparation process of hydroxyl-nano-cellulose includes：

Fibrous raw material is scattered in the H of mass fraction 60%₂SO₄In solution, 2~6 are stirred under 50~80 DEG C of water bath conditions Hour, obtain hydrating solution, the wherein dry weight and H of fibrous raw material₂SO₄The ratio of solution is (1~3) g：(40~120) mL；By water Solution solution sequentially passes through centrifugation and dialyses, and sediment and H are removed successively₂SO₄, obtain hydroxyl-nano-cellulose solution.

Further, the preparation process of carboxyl-nano-cellulose includes：

By 6~8h of stirring reaction in TEMPO-NaClO-NaBr oxidants addition fibrous raw material, wherein, fibrous raw material is used Mass fraction is 1% cork oar, NaClO use mass fraction for 12% NaClO solution, fibrous raw material, NaBr, TEMPO And the ratio between NaClO solution is (100~300) mL：(0.320~0.960) g：(25~75) mg：(6~18) g；Reaction Carboxyl-nano-cellulose is filtrated to get after end.

Further, solvent is the mixed solvent of ultra-pure water and dimethyl sulfoxide (DMSO), and rare earth based quantum dot, ultra-pure water and two The ratio of methyl sulfoxide is (1~3) mg：20mL：5mL.

Further, ester bond is combined, and is that 4~12h is reacted at 40~60 DEG C, and catalyst uses the mixed of DCC and DMAP Catalyst is closed, and the mass ratio of carboxyl modified-rare earth based quantum dot, DCC and DMAP is (1~3)：(1~3)：(0.6~1.8)；

Amido link is combined, and is that catalyst used the mixed catalyst of NHS and EDC in room temperature reaction 6~12 hours, And the mass ratio of amido modified-rare earth base carbon nitrogen quantum dot, NHS and EDC is (1~3)：(1~3)：(1.5~4.5).

One kind is using rare earth based quantum dot composite nano fiber element obtained in preparation method as described above.

Rare earth based quantum dot composite nano fiber element as described above is preparing the double mode anti-fake material of Visible-to-Near InfaRed and glimmering Application in optical sensor.

Compared with prior art, the present invention has following beneficial technique effect：

It is combined by using rare earth based quantum dot and nano-cellulose in the inventive method, rare earth based quantum dot first has Measured efficient visible ray lights；On the other hand, rare earth based quantum dot is used as the near of " antenna group " sensitization rare earth ion Infraluminescence, the near-infrared luminous performance (such as big Stocks displacements, narrow line-spectra and fluorescence lifetime long) of its uniqueness Do not influenceed by environment, pH, pressure and temperature etc., especially suitable high-performance anti-fake material；Rare earth based quantum dot surface is easy to modification (amino, carboxyl or acyl chlorides etc.) so that rare earth based quantum dot is compound with the chemical bond of nano-cellulose to be possibly realized；While this hair The bright nano-cellulose using low absorptivity, biocompatibility, water solubility, good film-forming property is anti-by condensation as polymer matrix Supported rare earth based quantum dot is answered, both are compound by chemical bond, preparation has the double mode Fluorescent falsification-preventing fiber element of Visible-to-Near InfaRed Ln³⁺- CQDs-ONFC, as energy donor and rare earth as energy acceptor, the introducing of nano-cellulose enhances both to quantum dot Between energy transfer efficiency.

Further, rare earth based quantum dot is combined with oxidized cellulose nanofibers with chemical bonds such as amido links, surely Qualitative height.

Further, the present invention prepares rare earth based quantum dot using one kettle way, and product is easily-synthesized and separates, structure middle rare earth , with quantum dot with carboxyl double coordination, with good thermodynamics and kinetics stability, quantum dot synthesis is simple, former material for ion Material wide material sources, cheap, hypotoxicity and fluorescence radiation efficiency high.

The present invention prepare rare earth based quantum dot composite nano fiber element, can be dispersed in water, stability and into Film is good；Anti-counterfeiting performance is excellent, can be used in making anti-fake material, meets its extensive identifiability, disguise and physical property Requirement.

The present invention can be applied in prepared by the double mode false proof fluorescent material of Visible-to-Near InfaRed, such as obtain stable luminescence, glimmering Luminous intensity is strong and quantum efficiency water base fluorescent ink and fluorescence nano paper high.Tests prove that, the obtained fluorescence of the present invention is received It is water white transparency under rice paper natural conditions, under the conditions of 365nm ultra violet lamps, sends the visible visible ray of bore hole and near-infrared (invisible) characteristic luminescence, improves the disguise of anti-fake material while identification beneficial to Popular anti-frand；Therefore, rare earth base unit weight Point composite nano fiber element and the double mode false proof fluorescent material of Visible-to-Near InfaRed for preparing can meet extensive identity, hidden Property and good physical behavior, have huge applications to be worth in the false proof matter product such as marketable securities, banknote, certificate and packaging.In gold Category ion Fe³⁺, Hg²⁺And under the stimulation of explosive TNT, fluorescence nano paper visible ray is luminous substantially to be weakened, such that it is able to as paper The fluorescent optical sensor (sensor) of matter, detect metal ion and explosive, have the advantages that it is easy to operate, portable, easy to maintain, with Detection metal cations Fe³⁺, Hg²⁺And explosive TNT etc..

【Brief description of the drawings】

Fig. 1 is the preparation principle figure of carboxyl of the present invention or amido modified rare earth based quantum dot.

Fig. 2 is the separating-purifying schematic diagram of rare earth based quantum dot of the present invention.

Fig. 3 (a) is dicarboxyl modification-rare earth base carbon quantum dot structural representation of the present invention；Fig. 3 (b) is binary amino Modification-rare earth base carbon nitrogen quantum dot structural representation；Fig. 3 (c) is ternary carboxyl modified-rare earth base carbon nitrogen quantum dot structural representation Figure.

Fig. 4 is the schematic diagram of rare earth based quantum dot composite nano fiber element of the present invention.

Fig. 5 is emission spectrum of the rare earth based quantum dot of carboxyl modified of the present invention under the conditions of difference excites light irradiation.

Fig. 6 is rare earth based quantum dot of the present invention based on esterification in visible ray and near infrared region maximum emission peak institute Corresponding excitation spectrum.

Fig. 7 is VISIBLE LIGHT EMISSION of fluorescence nano paper of the present invention based on esterification under the conditions of difference excites light irradiation Spectrum.

Fig. 8 is near infrared emission of fluorescence nano paper of the present invention based on esterification under the conditions of difference excites light irradiation Spectrum.

Fig. 9 is fluorescence nano paper of the present invention based on esterification right in visible ray and near infrared region maximum emission peak institute The excitation spectrum answered.

Figure 10 is rare earth based quantum dot of the invention, pure nanometer paper, the infrared spectrogram of the fluorescence nano paper of acid amides reaction.

Figure 11 (a) is the transmission electron microscope of rare earth base carbon nitrogen quantum dot amido modified when scale size of the present invention is 50nm Figure；Figure 11 (b) is the transmission electron microscope picture of the fluorescent ink of acid amides reaction when scale size of the present invention is 10nm.

Figure 12 is the X-ray powder diffraction collection of the fluorescence nano paper of rare earth base unit weight of the invention and acid amides reaction.

Figure 13 is the fluorescent ink uv-visible absorption spectra of rare earth base unit weight of the invention and acid amides reaction.

Figure 14 (a) is that the fluorescence nano paper x-ray photoelectron spectroscopy figure that rare earth base unit weight of the invention and acid amides react is complete Spectrum；14 (b) is X-ray photoelectron of the sub fluorescence nano paper reacted with acid amides of rare earth base unit weight of the invention about Rare Earth Y b 4d Energy spectrum diagram；14 (c) is x-ray photoelectron spectroscopy figure of rare earth base unit weight of the invention about C 1s；14 (d) is of the invention X-ray photoelectron spectroscopy figure of the fluorescence nano paper of acid amides reaction about C 1s；14 (e) is that rare earth base unit weight of the invention has Close the x-ray photoelectron spectroscopy figure of N1s；14 (f) is the X-ray of the fluorescence nano paper about N 1s of acid amides reaction of the invention Photoelectron spectroscopy figure；

Figure 15 is the amido modified rare earth base carbon nitrogen quantum dot aqueous solution of the present invention under the conditions of difference excites light irradiation Visible color emission spectrum.

Figure 16 is that the rare earth base carbon nitrogen quantum dot aqueous solution of amino of the present invention is near red under the conditions of difference excites light irradiation Outer optical emission spectroscopy and excitation spectrum.

Figure 17 is visible color emission spectrum of the fluorescent ink of acid amides reaction of the present invention under the conditions of difference excites light irradiation And excitation spectrum.

Figure 18 is rare earth based quantum dot of the present invention CIE chromaticity diagram under different shooting conditions.

Figure 19 is fluorescent ink of the present invention CIE chromaticity diagram under different shooting conditions.

Figure 20 is fluorescence nano paper of the present invention CIE chromaticity diagram under different shooting conditions.

Figure 21 is near infrared spectroscopy of the fluorescent ink of acid amides reaction of the present invention under the conditions of difference excites light irradiation And excitation spectrum.

Figure 22 (a) is plane of structure scanning electron microscopic picture of the fluorescent paper of the present invention when scale size is 500nm；Figure 22 (b) is Plane of structure scanning electron microscopic picture of the fluorescent paper of the present invention when scale size is 1 μm；Figure 22 (c) is section fluorescent paper of the present invention in mark Profile scanning electron microscopic picture when chi size is 1 μm.

Figure 23 is the fluorescence spectrum of the amido modified rare earth base carbon nitrogen quantum dot aqueous solution.

Figure 24 is near infrared emission light of the fluorescence nano paper of acid amides reaction of the present invention under the conditions of difference excites light irradiation Spectrum and excitation spectrum.

Figure 25 is the visible ray of fluorescent paper of the present invention and the excitation spectrum of near infrared light.

Figure 26 is the visible fluorescence life curve of the amido modified rare earth base carbon nitrogen quantum dot aqueous solution of the present invention.

Figure 27 is the near infrared light life curve of the amido modified rare earth base carbon nitrogen quantum dot aqueous solution of the present invention.

Figure 28 is the visible ray life curve of fluorescent ink of the present invention and fluorescence nano paper.

Figure 29 is the near infrared light life curve of fluorescent ink of the present invention and fluorescence nano paper.

Figure 30 is the energy transmission and luminescence mechanism of rare earth based quantum dot of the present invention, fluorescent ink and fluorescence nano paper.

Figure 31 is the light transmittance curve figure of fluorescence nano of the present invention.

Figure 32 is the false proof model of anti-counterfeiting ink and false proof nanometer paper.

Figure 33 is the fluorescence pattern that fluorescence nano paper of the present invention detects different metal ions.

Figure 34 is the fluorescent quenching figure that fluorescence nano paper of the present invention detects different metal ions.

【Specific embodiment】

The present invention is described in further details below in conjunction with the accompanying drawings.

The preparation of the first step, rare earth based quantum dot

1. binary reaction prepares carboxyl modified-rare earth base carbon quantum dot

By 1mmol rare-earth salts (NdCl₃、YbCl₃Or ErCl₃) with citric acid with mol ratio be 1:(5~15) are dissolved in 10mL Water, 150~200 DEG C of 4~8h of reaction in 25mL water heating kettles.Yellow solution is obtained after cooling, it is further saturating using 3500Da Analysis separating-purifying 12h, obtain carboxyl modified-rare earth base carbon quantum dot, as shown in Figure 1, Figure 2 with Fig. 3 (a) Suo Shi.

2. binary reaction prepares amido modified-rare earth base carbon nitrogen quantum dot

By 1mmol rare-earth salts (NdCl₃、YbCl₃Or ErCl₃) and organic amine (ethylenediamine, propane diamine, 1,3- diaminourea -2- Propyl alcohol) with mol ratio be 1:(27~81) are dissolved in 10mL water, 150~200 DEG C of 4~8h of reaction in 25mL water heating kettles.After cooling Yellow solution is obtained, further using 3500Da dialysis separating-purifying 12h, the amido modified-rare earth of class graphene-structured is obtained Base carbon nitrogen quantum dot, shown in such as Fig. 3 (b).

3. three elementary reactions prepare carboxyl modified-rare earth base carbon nitrogen quantum dot

By 1mmol rare-earth salts (NdCl₃、YbCl₃Or ErCl₃), citric acid and organic amine (ethylenediamine, propane diamine or 1,3- bis- Amino -2- propyl alcohol) with mol ratio be 1:(27~81):(5~15) are dissolved in 10mL water, in 25mL water heating kettles 150~200 DEG C it is anti- Answer 4~8h.Yellow solution is obtained after cooling, further using 3500Da dialysis separating-purifying 12h, carboxyl modified-rare earth is obtained Base carbon nitrogen quantum dot, shown in such as Fig. 3 (c).

4. three elementary reactions prepare amido modified-rare earth base carbon nitrogen quantum dot

By 1mmol rare-earth salts (NdCl₃、YbCl₃Or ErCl₃), organic acid (citric acid, acrylic acid, malonic acid or fumaric acid) With organic amine (ethylenediamine, propane diamine or 1,3- diaminourea -2- propyl alcohol) with mol ratio be 1:(5~15):(27~81) are dissolved in 10mL water, 150~200 DEG C of 4~8h of reaction in 25mL water heating kettles.Yellow solution is obtained after cooling, 3500Da is further used Dialysis separating-purifying 12h, obtains amido modified-rare earth base carbon nitrogen quantum dot.

Wherein, the structural formula of organic acid and organic amine is as follows：

The preparation of second step, nano-cellulose

1. the preparation of hydroxyl-nano-cellulose

With cork oar as fibrous raw material, in H₂SO₄Hydrolysis obtains hydroxyl-nano-cellulose under the conditions of (mass fraction 60%). The fibrous raw material for taking 1~3g of dry weight is scattered in the H of 40~120mL₂SO₄In solution, 2~6 are stirred under 50~80 DEG C of water bath conditions Hour.Subsequent hydrating solution obtains hydroxyl-nano-cellulose and H by being centrifuged off sediment₂SO₄Solution, further with The dialysis of 3500Da bag filters removes H₂SO₄, final hydroxyl-nano-cellulose solution preserves under the conditions of 5 DEG C.Cellulosic molecule Structural formula is as follows：

2. the preparation of carboxyl-nano-cellulose

With cork oar as fibrous raw material, 2,2,6,6- tetramethyl piperidine oxygen radicals (TEMPO)-sodium hypochlorite (NaClO) carboxyl-nano-cellulose is prepared under the effect of-sodium bromide (NaBr) oxidant.Take the fiber that mass fraction is 1% 100~300mL of raw material is 1~3g of fibrous raw material dry weight, the NaBr of 0.320~0.960g, the TEMPO of 25~75mg and 6~18g Mass fraction is 12% NaClO solution mixing, and magnetic agitation is reacted 6~8h, NaOH (0.5mol/L) is added in course of reaction Make system pH close to 10, then 7 are always with HCl solution (0.5mol/L) regulation pH value of reaction system.Eventually through filtering Obtain carboxyl-nano-cellulose and preserved under the conditions of 5 DEG C.

3rd step, rare earth based quantum dot composite nano fiber element, as shown in Figure 4

1. ester bond is combined

Take above-mentioned carboxyl modified -1~3mg of rare earth based quantum dot and be dissolved in 20mL with above-mentioned hydroxyl-nano-cellulose solution Ultra-pure water/5mL dimethyl sulfoxide (DMSO) mixed solvents, in hydroxyl-nano-cellulose solution hydroxyl-nano-cellulose quality be 25~ 75mg, mixes in the dicyclohexyl carbodiimide (DCC) of 1~3mg with the DMAP (DMAP) of 0.6~1.8mg Under catalysts conditions, 40~60 DEG C of 4~12h of reaction.Reaction terminates, 3500Da bag filters dialysis separating-purifying 12h, ultrapure washing Wash.

2. amido link is combined

Above-mentioned amido modified-rare earth base carbon 1~3mg of nitrogen quantum dot and carboxyl -25~75mg of nano-cellulose is taken to be dissolved in 20mL ultra-pure waters/5mL dimethyl sulfoxide (DMSO) mixed solvents, pH is 5, the N-hydroxy-succinamide (NHS) of 1~3mg and 1.5~ Under the conditions of 1- (3- dimethylamino-propyls) -3- ethyl-carbodiimide hydrochlorides (EDC) mixed catalyst of 4.5mg, room temperature reaction 6 ~12 hours.Reaction terminates, 3500Da bag filters dialysis separating-purifying 12h, milli-Q water.

4th step, the preparation of fluorescence nano paper

By rare earth based quantum dot composite nano fiber element and ultra-pure water configuration feature fluorescent ink；Or by rare earth base Quantum dot composite nano fiber element solution decompression suction filtration, pours into polytetrafluoroethylene (PTFE) vessel, and 50~60 DEG C overnight dry moisture, obtain To transparent fluorescent nanometer paper.Wherein, the obtained nanometer paper thickness of 25mg nano-celluloses correspondence is in 0.03mm or so, fluorescence nano Paper can be applied in fluorescent optical sensor, used as metal-ion fluorescent probe in detecting Fe³⁺, Hg²⁺Ion and trinitrotoluene.

Obtained fluorescent ink and fluorescence nano paper, used as the double mode anti-fake material of Visible-to-Near InfaRed, its anti-counterfeiting characteristic exists It is that fluorescence radiation, luminescent lifetime are change that nanosecond and glow color depend on excitation wavelength in visible ray；It is near-infrared luminous For phosphorescence is luminous, luminescent lifetime be change that Microsecond grade and emission wavelength do not rely on excitation wavelength.

Requirement for fluorescence falsification preventing material to extensive identifiability, disguise and physical property, the present invention is using organic Sour (citric acid, acrylic acid, malonic acid, fumaric acid), organic amine (ethylenediamine, propane diamine, 1,3- diaminourea -2- propyl alcohol), rare earth Salt (NdCl₃、YbCl₃、ErCl₃) one kettle way prepares rare earth based quantum dot.Obtained by adjusting organic acid and organic amine mol ratio To carboxyl or amido modified visible ray (glow color is adjustable), emission spectrum (visible spectrum and near infrared spectrum) and fluorescence longevity On the one hand the luminous rare earth based quantum dot of life (nanosecond and Microsecond grade) triplex mode, resulting quantum dot itself has good Visible ray it is luminous, while as " organic antenna " sensitization rare earth ion (Nd³⁺、Yb³⁺、Er³⁺) it is near-infrared luminous；By original Material fiber is through sour water solution, oxidation means, the nanofiber that isolated nano-scale is uniform, hydroxyl or carboxyl are contained in surface of dialysing Element；Rare earth based quantum dot is compound in nano-cellulose as fluorescent material, its composite pathway is with the stabilization such as ester bond or amido link Property chemical bond linkage higher, rare earth based quantum dot-nano-cellulose composite is obtained, can be used for making visible ray (hair Light color is adjustable), emission spectrum (visible spectrum and near infrared spectrum) and fluorescence lifetime (nanosecond and Microsecond grade) triplex mode Fluorescence falsification preventing material, such as disperse functional nano cellulose in aqueous, and volatilization or direct suction filtration are obtained under the conditions of 60 DEG C To fluorescence nano paper, the physical properties such as dispersiveness, stability and the film forming of anti-fake material are solved.

Possible application field of the present invention：The false proof nanometer paper product such as marketable securities, banknote, certificate and packaging.

For the deficiency that solution fluorescence sensor is present, the present invention is easy to operate, portable, easy to maintain using having the advantages that Paper substrate fluorescent optical sensor detection metal cations Fe³⁺, Hg²⁺And explosive TNT, have in life, environment and security fields important Meaning.

Embodiment 1

1. three elementary reactions prepare carboxyl modified-rare earth base carbon quantum dot

By rare-earth salts NdCl₃, citric acid and ethylenediamine with mol ratio be 1:27:5 are dissolved in 10mL water, in 25mL water heating kettles 150 DEG C of reaction 4h.Yellow solution is obtained after cooling, further using 3500Da dialyse separating-purifying 12h, obtain carboxyl modified- Rare earth base carbon nitrogen quantum dot.

2. the preparation of hydroxyl-nano-cellulose

With cork oar as fibrous raw material, in H₂SO₄(60%) hydrolysis obtains hydroxyl-nano-cellulose under the conditions of.Take fiber former Material 1g is scattered in the H of 40mL₂SO₄In solution, stirred 2 hours under 50 DEG C of water bath conditions.Subsequent hydrating solution is by being centrifuged off Sediment obtains hydroxyl-nano-cellulose and H₂SO₄Solution, H is removed further with the dialysis of 3500Da bag filters₂SO₄, finally Hydroxyl-nano-cellulose solution is preserved under the conditions of 5 DEG C.

3. ester bond is combined

Take above-mentioned carboxyl modified-rare earth base carbon nitrogen quantum dot 1mg ultrapure with hydroxyl-nano-cellulose 25mg is dissolved in 20mL Water/5mL dimethyl sulfoxide (DMSO) mixed solvents, in the dicyclohexyl carbodiimide (DCC) and the 4- dimethylamino pyrroles of 0.6mg of 1mg Under the conditions of pyridine (DMAP) mixed catalyst, 40 DEG C of reaction 6h.Reaction terminates, 3500Da bag filters dialysis separating-purifying 12h, ultrapure Water washing, obtains rare earth based quantum dot composite nano fiber element.

4. the preparation of fluorescence nano paper

The rare earth based quantum dot composite nano fiber element aqueous solution of above-mentioned esterification, pours into polytetrafluoroethylene (PTFE) vessel, 50 DEG C overnight dry moisture, obtain transparent nano paper.

Embodiment 2

1. three elementary reactions prepare carboxyl modified-rare earth base carbon nitrogen quantum dot

By rare-earth salts YbCl₃, citric acid and propane diamine with mol ratio be 1:81:15 are dissolved in 10mL water, in 25mL water heating kettles In 200 DEG C reaction 8h.Yellow solution is obtained after cooling, further using 3500Da dialysis separating-purifying 12h, carboxyl is obtained and is repaiied Decorations-rare earth base carbon nitrogen quantum dot.

2. the preparation of hydroxyl-nano-cellulose

With cork oar as fibrous raw material, in H₂SO₄(60%) hydrolysis obtains hydroxyl-nano-cellulose under the conditions of.Take fiber former Material 3g is scattered in the H of 120mL₂SO₄In solution, stirred 6 hours under 80 DEG C of water bath conditions.Subsequent hydrating solution is removed by centrifugation Sediment is gone to obtain hydroxyl-nano-cellulose and H₂SO₄Solution, H is removed further with the dialysis of 3500Da bag filters₂SO₄, most Whole hydroxyl-nano-cellulose solution is preserved under the conditions of 5 DEG C.

3. ester bond is combined

Take above-mentioned carboxyl modified-rare earth base carbon nitrogen quantum dot 3mg ultrapure with hydroxyl-nano-cellulose 75mg is dissolved in 20mL Water/5mL dimethyl sulfoxide (DMSO) mixed solvents, in the dicyclohexyl carbodiimide (DCC) and the 4- dimethylamino pyrroles of 1.8mg of 3mg Under the conditions of pyridine (DMAP) mixed catalyst, 60 DEG C of reaction 12h.Reaction terminates, 3500Da bag filters dialysis separating-purifying 12h, surpasses Pure water, obtains rare earth based quantum dot composite nano fiber element.

4. the preparation of fluorescence nano paper

Embodiment 3

By rare-earth salts ErCl₃, citric acid and 1,3- diaminourea -2- propyl alcohol with mol ratio be 1:50:10 are dissolved in 10mL water, 175 DEG C of reaction 6h in 25mL water heating kettles.Yellow solution is obtained after cooling, further using 3500Da dialysis separating-purifying 12h, is obtained To carboxyl modified-rare earth base carbon nitrogen quantum dot.

2. the preparation of hydroxyl-nano-cellulose

With cork oar as fibrous raw material, in H₂SO₄(60%) hydrolysis obtains hydroxyl-nano-cellulose under the conditions of.Take fiber former Material 2g is scattered in the H of 80mL₂SO₄In solution, stirred 4 hours under 65 DEG C of water bath conditions.Subsequent hydrating solution is by being centrifuged off Sediment obtains hydroxyl-nano-cellulose and H₂SO₄Solution, H is removed further with the dialysis of 3500Da bag filters₂SO₄, finally Hydroxyl-nano-cellulose solution is preserved under the conditions of 5 DEG C.

3. ester bond is combined

Take above-mentioned carboxyl modified-rare earth base carbon nitrogen quantum dot 2mg ultrapure with hydroxyl-nano-cellulose 50mg is dissolved in 20mL Water/5mL dimethyl sulfoxide (DMSO) mixed solvents, in the dicyclohexyl carbodiimide (DCC) and the 4- dimethylamino pyrroles of 1.2mg of 2mg Under the conditions of pyridine (DMAP) mixed catalyst, 50 DEG C of reaction 8h.Reaction terminates, 3500Da bag filters dialysis separating-purifying 12h, ultrapure Water washing, obtains rare earth based quantum dot composite nano fiber element.

4. the preparation of fluorescence nano paper

Embodiment 4

1. three elementary reactions prepare amido modified-rare earth base carbon nitrogen quantum dot

By rare-earth salts NdCl₃, citric acid and ethylenediamine with mol ratio be 1:5:27 are dissolved in 10mL water, in 25mL water heating kettles 150 DEG C of reaction 4h.Yellow solution is obtained after cooling, further using 3500Da dialysis separating-purifying 12h, carboxyl is obtained and is repaiied Decorations-rare earth base carbon nitrogen quantum dot.

2. the preparation of carboxyl-nano-cellulose

With cork oar as fibrous raw material, 2,2,6,6- tetramethyl piperidine oxygen radicals (TEMPO)-sodium hypochlorite (NaClO) carboxyl-nano-cellulose is prepared under the effect of-sodium bromide (NaBr) oxidant.Take the fibrous raw material of 100mL (1%), TEMPO the and 6g mass fractions of NaBr, 25mg of 0.320g are 12% NaClO solution mixing, magnetic agitation reaction 6h, adds NaOH (0.5mol/L) to make system pH close to 10, HCl (0.5mol/L) regulation reaction systems pH in course of reaction Be worth is 7.Eventually through be filtrated to get carboxyl-nano-cellulose and under the conditions of 5 DEG C preserve.

3. amido link is combined

Take above-mentioned amido modified-rare earth base carbon nitrogen quantum dot 1mg ultrapure with carboxyl-nano-cellulose 25mg is dissolved in 20mL Water/5mL dimethyl sulfoxide (DMSO) mixed solvents, pH is 5, in the N-hydroxy-succinamide (NHS) and 1- (the 3- diformazans of 1.5mg of 1mg Aminopropyl) under the conditions of -3- ethyl-carbodiimide hydrochlorides (EDC) mixed catalyst, room temperature reaction 12 hours.Reaction terminates, 3500Da bag filters dialysis separating-purifying 12h, milli-Q water.

4. the preparation of fluorescence nano paper

The rare earth based quantum dot composite nano fiber element aqueous solution that above-mentioned acid amides reaction is obtained, pours into polytetrafluoroethylene (PTFE) vessel In, 50 DEG C overnight dry moisture, obtain transparent nano paper.

Embodiment 5

By rare-earth salts YbCl₃, glycine and ethylenediamine with mol ratio be 1:15:81 are dissolved in 10mL water, in 25mL water heating kettles In 200 DEG C reaction 8h.Yellow solution is obtained after cooling, further using 3500Da dialysis separating-purifying 12h, carboxyl is obtained and is repaiied Decorations-rare earth base carbon nitrogen quantum dot.

2. the preparation of carboxyl-nano-cellulose

With cork oar as fibrous raw material, 2,2,6,6- tetramethyl piperidine oxygen radicals (TEMPO)-sodium hypochlorite (NaClO) carboxyl-nano-cellulose is prepared under the effect of-sodium bromide (NaBr) oxidant.Take the fibrous raw material of 300mL (1%), TEMPO the and 18g mass fractions of NaBr, 75mg of 0.960g are 12% NaClO mixing, and magnetic agitation reacts 7h, NaOH (0.5mol/L) is added in course of reaction makes system pH close to 10, HCl (0.5mol/L) regulation pH value of reaction system It is 7.Eventually through be filtrated to get carboxyl-nano-cellulose and under the conditions of 5 DEG C preserve.

3. amido link is combined

Take above-mentioned amido modified-rare earth base carbon nitrogen quantum dot 3mg ultrapure with carboxyl-nano-cellulose 75mg is dissolved in 20mL Water/5mL dimethyl sulfoxide (DMSO) mixed solvents, pH is 5, in the N-hydroxy-succinamide (NHS) and 1- (the 3- diformazans of 4.5mg of 3mg Aminopropyl) under the conditions of -3- ethyl-carbodiimide hydrochlorides (EDC) mixed catalyst, room temperature reaction 8 hours.Reaction terminates, 3500Da bag filters dialysis separating-purifying 12h, milli-Q water.

4. the preparation of fluorescence nano paper

Embodiment 6

By rare-earth salts ErCl₃, fumaric acid and ethylenediamine with mol ratio be 1:10:50 are dissolved in 10mL water, in 25mL water heating kettles In 175 DEG C reaction 6h.Yellow solution is obtained after cooling, further using 3500Da dialysis separating-purifying 12h, carboxyl is obtained and is repaiied Decorations-rare earth base carbon nitrogen quantum dot.

2. the preparation of carboxyl-nano-cellulose

With cork oar as fibrous raw material, 2,2,6,6- tetramethyl piperidine oxygen radicals (TEMPO)-sodium hypochlorite (NaClO) carboxyl-nano-cellulose is prepared under the effect of-sodium bromide (NaBr) oxidant.Take the fibrous raw material of 200mL (1%), TEMPO the and 12g mass fractions of NaBr, 50mg of 0.640g are 12% NaClO mixing, and magnetic agitation reacts 8h, NaOH (0.5mol/L) is added in course of reaction makes system pH close to 10, HCl (0.5mol/L) regulation pH value of reaction system It is 7.Eventually through be filtrated to get carboxyl-nano-cellulose and under the conditions of 5 DEG C preserve.

3. amido link is combined

Take above-mentioned amido modified-rare earth base carbon nitrogen quantum dot 2mg ultrapure with carboxyl-nano-cellulose 50mg is dissolved in 20mL Water/5mL dimethyl sulfoxide (DMSO) mixed solvents, pH is 5, in the N-hydroxy-succinamide (NHS) and 1- (the 3- diformazan ammonia of 3mg of 2mg Base propyl group) under the conditions of -3- ethyl-carbodiimide hydrochlorides (EDC) mixed catalyst, room temperature reaction 6 hours.Reaction terminates, 3500Da bag filters dialysis separating-purifying 12h, milli-Q water.

4. the preparation of fluorescence nano paper

Embodiment 7

By 1mmol rare-earth salts NdCl₃With citric acid with mol ratio be 1:15 are dissolved in 10mL water, 160 in 25mL water heating kettles DEG C reaction 7.5h.Yellow solution is obtained after cooling, further using 3500Da dialyse separating-purifying 12h, obtain carboxyl modified- Rare earth base carbon quantum dot.

2. the preparation of hydroxyl-nano-cellulose

With cork oar as fibrous raw material, in H₂SO₄Hydrolysis obtains hydroxyl-nano-cellulose under the conditions of (mass fraction 60%). The fibrous raw material for taking dry weight 1.5g is scattered in the H of 60mL₂SO₄In solution, stirred 4 hours under 60 DEG C of water bath conditions.Then hydrolysis Solution obtains hydroxyl-nano-cellulose and H by being centrifuged off sediment₂SO₄Solution, it is saturating further with 3500Da bag filters Analysis removes H₂SO₄, final hydroxyl-nano-cellulose solution preserves under the conditions of 5 DEG C.

3. ester bond is combined

Take above-mentioned carboxyl modified-rare earth base carbon quantum dot 1.5mg and be dissolved in 20mL with above-mentioned hydroxyl-nano-cellulose solution Ultra-pure water/5mL dimethyl sulfoxide (DMSO) mixed solvents, hydroxyl-nano-cellulose quality is 40mg in hydroxyl-nano-cellulose solution, Under the conditions of the dicyclohexyl carbodiimide (DCC) of 1.5mg and the DMAP mixed catalysts of 1.0mg, 40 DEG C of reaction 6h.Reaction Terminate, 3500Da bag filters dialysis separating-purifying 12h, milli-Q water.

4. the preparation of fluorescence nano paper

The rare earth based quantum dot composite nano fiber element aqueous solution that above-mentioned esterification is obtained, pours into polytetrafluoroethylene (PTFE) vessel In, 50 DEG C overnight dry moisture, obtain transparent nano paper.

Embodiment 8

By 1mmol rare-earth salts ErCl₃With citric acid with mol ratio be 1:5 are dissolved in 10mL water, 165 DEG C in 25mL water heating kettles Reaction 7h.Yellow solution is obtained after cooling, further using 3500Da dialysis separating-purifying 12h, carboxyl modified-rare earth is obtained Base carbon quantum dot.

2. the preparation of hydroxyl-nano-cellulose

With cork oar as fibrous raw material, in H₂SO₄Hydrolysis obtains hydroxyl-nano-cellulose under the conditions of (mass fraction 60%). The fibrous raw material for taking dry weight 1.2g is scattered in the H of 45mL₂SO₄In solution, stirred 4.5 hours under 55 DEG C of water bath conditions.Subsequent water Solution solution obtains hydroxyl-nano-cellulose and H by being centrifuged off sediment₂SO₄Solution, further with 3500Da bag filters Dialysis removes H₂SO₄, final hydroxyl-nano-cellulose solution preserves under the conditions of 5 DEG C.

3. ester bond is combined

Take above-mentioned carboxyl modified-rare earth base carbon quantum dot 1.2mg and be dissolved in 20mL with above-mentioned hydroxyl-nano-cellulose solution Ultra-pure water/5mL dimethyl sulfoxide (DMSO) mixed solvents, hydroxyl-nano-cellulose quality is 30mg in hydroxyl-nano-cellulose solution, Under the conditions of the dicyclohexyl carbodiimide (DCC) of 1.2mg and the DMAP mixed catalysts of 0.8mg, 45 DEG C of reaction 5h.Reaction Terminate, 3500Da bag filters dialysis separating-purifying 12h, milli-Q water.

4. the preparation of fluorescence nano paper

Embodiment 9

1. binary reaction prepares amido modified-rare earth base carbon nitrogen quantum dot

By 1mmol rare-earth salts YbCl₃With propane diamine with mol ratio be 1:27 are dissolved in 10mL water, 170 in 25mL water heating kettles DEG C reaction 7h.Yellow solution is obtained after cooling, further using 3500Da dialysis separating-purifying 12h, class graphene-structured is obtained Amido modified-rare earth base carbon nitrogen quantum dot.

2. the preparation of carboxyl-nano-cellulose

With cork oar as fibrous raw material, 2,2,6,6- tetramethyl piperidine oxygen radicals (TEMPO)-sodium hypochlorite (NaClO) carboxyl-nano-cellulose is prepared under the effect of-sodium bromide (NaBr) oxidant.Take the fiber that mass fraction is 1% TEMPO the and 10g mass fractions of NaBr, 40mg of raw material 150mL, 0.480g are 12% NaClO solution mixing, magnetic agitation Reaction 6h, adds NaOH (0.5mol/L) to make system pH close to 10, then adjusted with HCl solution (0.5mol/L) in course of reaction Section pH value of reaction system is 7.Eventually through be filtrated to get carboxyl-nano-cellulose and under the conditions of 5 DEG C preserve.

3. amido link is combined

Take above-mentioned amido modified-rare earth base carbon nitrogen quantum dot 1.5mg ultrapure with carboxyl-nano-cellulose 40mg is dissolved in 20mL Water/5mL dimethyl sulfoxide (DMSO) mixed solvents, pH is 5, in the N-hydroxy-succinamide (NHS) and 1- (the 3- diformazans of 2mg of 1.5mg Aminopropyl) under the conditions of -3- ethyl-carbodiimide hydrochlorides (EDC) mixed catalyst, room temperature reaction 12 hours.Reaction terminates, 3500Da bag filters dialysis separating-purifying 12h, milli-Q water.

4. the preparation of fluorescence nano paper

Embodiment 10

By 1mmol rare-earth salts YbCl₃With 1,3- diaminourea -2- propyl alcohol with mol ratio be 1:40 are dissolved in 10mL water, in 25mL 185 DEG C of reaction 6.5h in water heating kettle.Yellow solution is obtained after cooling, further using 3500Da dialysis separating-purifying 12h, is obtained Amido modified-rare earth base carbon nitrogen the quantum dot of class graphene-structured.

2. the preparation of carboxyl-nano-cellulose

With cork oar as fibrous raw material, 2,2,6,6- tetramethyl piperidine oxygen radicals (TEMPO)-sodium hypochlorite (NaClO) carboxyl-nano-cellulose is prepared under the effect of-sodium bromide (NaBr) oxidant.Take the fiber that mass fraction is 1% TEMPO the and 9g mass fractions of NaBr, 60mg of raw material 220mL, 0.8g are 12% NaClO solution mixing, and magnetic agitation is anti- 7h is answered, adds NaOH (0.5mol/L) to make system pH close to 10 in course of reaction, then adjusted with HCl solution (0.5mol/L) PH value of reaction system is 7.Eventually through be filtrated to get carboxyl-nano-cellulose and under the conditions of 5 DEG C preserve.

3. amido link is combined

Take above-mentioned amido modified-rare earth base carbon nitrogen quantum dot 1.2mg ultrapure with carboxyl-nano-cellulose 65mg is dissolved in 20mL Water/5mL dimethyl sulfoxide (DMSO) mixed solvents, pH is 5, in the N-hydroxy-succinamide (NHS) and 1- (the 3- diformazans of 3mg of 1.2mg Aminopropyl) under the conditions of -3- ethyl-carbodiimide hydrochlorides (EDC) mixed catalyst, room temperature reaction 11 hours.Reaction terminates, 3500Da bag filters dialysis separating-purifying 12h, milli-Q water.

4. the preparation of fluorescence nano paper

Comparative example 1：Using inorganic rare earth salt EuCl₃·6H₂O replaces inorganic rare earth salt EuCl₃·6H₂O, obtains class graphite Amido modified-rare earth base carbon nitrogen the quantum dot of alkene structure, is obtained other reaction conditions and implements with carboxyl-nano-cellulose reaction Example 10 is identical.

Due to Gd³⁺First excited state energy level is higher than 32000cm^-1, the energy that quantum dot absorbs cannot effectively be transmitted to dilute Native ion Gd³⁺, gained rare earth base nanometer paper only have visible ray light.

Comparative example 2：DAP is substituted using alanine, other reaction conditions are same as in Example 10.

Because alanine is in 185 DEG C of hydrothermal reaction process, the one-dimensional linear polymer of formation rule (is gel in water Shape) cannot be carbonized to form rare earth base carbon nitrogen quantum dot, it is impossible to prepare fluorescence nano paper.

Comparative example 3：DAP hydrothermal temperature is adjusted to 100 DEG C by 185 DEG C, other reaction conditions and reality Apply example 10 identical.

Because DAP is in 100 DEG C of hydrothermal reaction process, it is impossible to which effectively carbonization forms rare earth base carbon nitrogen Quantum dot, it is impossible to prepare fluorescence nano paper.

As can be seen from Figure 5：Under the conditions of low concentration aqueous solution's dispersion, 360nm ultraviolet excitations, the rare earth base unit weight of carboxyl modified Son point can launch the visible ray of 440nm and 467nm and the near infrared light of 980nm.Wherein, it is seen that light it is luminous essentially from In the radiation transistion of quantum dot, while quantum dot passes to rare earth ion Yb as " antenna group " energy absorption³⁺, after sensitization Rare earth ion Yb³⁺By first excited state²F_5/2Lower state is returned to by radiation transistion²F_7/2Launch Yb³⁺Ion near-infrared feature Luminous (980nm).Additionally, visible region (left side) luminous collection of illustrative plates understands, as excitation wavelength is continuous from 300nm to 410nm Increase, it is seen that light luminous intensity first strengthens and weakens maximum excitation peak position afterwards and appear in 370nm.Rare earth based quantum dot is used as a class There is Red Shift Phenomena (438nm red shifts to 469nm) with the increase of excitation wavelength, demonstrate in nano material, its emission peak positions The presence of nano effect.

Fig. 6 finds out：Distinguish in visible ray and near infrared light region maximum emission peak in the rare earth based quantum dot of carboxyl modified It is 466nm and 980nm, due to visible ray and the difference near infrared emission center, different points of corresponding maximum excitation peak position Not in 370nm and 415nm.It is photochromic under the rare earth based quantum dot aqueous solution ultra violet lamp of carboxyl modified：In 0.1mg/ The rare earth based quantum dot aqueous solution of carboxyl modified is pale yellow transparent shape under ml concentration, but in 365nm ultra violet lamp conditions Under, there is clearly visible light to light.

As can be seen from Figure 7：Under the conditions of 360nm ultraviolet excitations, the fluorescence nano paper of esterification can launch 440nm With the visible ray and the near infrared light of 980nm of 467nm.Wherein, it is seen that light lights and mostlys come from the radiation transistion of quantum dot. Additionally, visible region (left side) luminous collection of illustrative plates understands, as excitation wavelength constantly increases from 330nm to 405nm, it is seen that light is sent out Luminous intensity first strengthens and weakens maximum excitation peak position afterwards and appear in 360nm.Used as a class nano material, it sends out rare earth based quantum dot Peak position is penetrated Red Shift Phenomena (440nm red shifts to 467nm) occur with the increase of excitation wavelength, demonstrate depositing for nano effect .

As can be seen from Figure 8：Under the conditions of 360nm ultraviolet excitations, in the fluorescence nano paper of esterification quantum dot as " my god Line group " energy absorption passes to rare earth ion Yb³⁺, the rare earth ion Yb after sensitization³⁺By first excited state²F_5/2By radiation Transition returns to lower state²F_7/2Launch Yb³⁺Ion near-infrared characteristic luminescence (980nm).Additionally, with excitation wavelength from 360nm Constantly increase to 385nm, near infrared luminous intensity weakens maximum excitation peak position and appears in 360nm.With the visible ray of quantum dot , as the change rare earth ion near-infrared characteristic luminescence of excitation wavelength is fixed on 980nm, there is no Red Shift Phenomena in luminous difference.

As can be seen from Figure 9：Due to the difference at visible ray and near infrared emission center in the fluorescence nano paper of carboxyl modified, institute is right The maximum excitation peak position answered is all in 370nm, but near-infrared excitation peak is wider.

As can be seen from Figure 10：With amido modified rare earth based quantum dot (3448cm^-1) compare (3400cm with pure nanometer paper^-1), The fluorescence nano paper absworption peak (3329cm of acid amides reaction^-1) distinguish blue shift 119cm^-1And 71cm^-1, this is due to acid amides reaction What the generation of amido link was caused.

As can be seen from Figure 11：The size of rare earth based quantum dot falls in 2-5nm, and can be very good to be distributed in nano-cellulose On.

As can be seen from Figure 12：The X-ray diffracting spectrum of rare earth based quantum dot contains three broad peaks, and this is due to rare earth base unit weight Mixed and disorderly unordered carbon atom causes in son point.

As can be seen from Figure 13：The absworption peak of rare earth based quantum dot has two, respectively 290nm and 350nm, wherein low energy π-π the * that the absworption peak 350nm at the place of putting is attributed to carbon quantum dot absorb.The fluorescent ink 261nm and 350nm of acid amides reaction, wherein Absworption peak is the n-π * of cellulose skeleton at 261nm, and absworption peak is the π-π * of carbon quantum dot at wherein 350nm.

As can be seen from Figure 14：Rare earth based quantum dot and the main appearance of fluorescence nano paper have O 1s, N 1s, C1s and Yb 4d, receive The restriction fluorescence nano paper middle rare earth Yb 4d of instrumental sensitivity fail to detect.Compared with rare earth based quantum dot, fluorescence nano paper It is larger that middle C 1s and N 1s go out peak shift.C 1s appearances can be attributed to alkyl carbon and C=O in quantum dot in rare earth based quantum dot Middle carbonyl carbon 1s absworption peaks, in addition pi-pi* can be attributed to C=C and C=N double bond 1s track absworption peaks in quantum dot primitive. C 1s appearances are mainly in nano-cellulose carbonyl carbon 1s absworption peaks in alkyl carbon and C=O in fluorescence nano paper, in addition pi-pi* C=C and C=N double bond 1s track absworption peaks in quantum dot primitive can be attributed to.Influenceed by acid amides reaction, rare earth base unit weight NH in point₂- absworption peak disappears.

As can be seen from Figure 15：In amido modified rare earth based quantum dot in visible region emission wavelength with excitation wavelength Increase and increase, excite peak position in 390nm corresponding to most strong emission peak.Increase to from 390nm in excitation wavelength simultaneously During 470nm increases, its luminous intensity is gradually lowered.

As can be seen from Figure 16：In the maximum excitation peak position of amido modified rare earth based quantum dot in 416nm.Its emission peak is Rare earth ion Yb³⁺Characteristic peak, be sensitization after rare earth ion Yb³⁺By first excited state²F_5/2Low energy is returned to by radiation transistion State²F_7/2Launch Yb³⁺Ion near-infrared characteristic luminescence (980nm).With the increase of excitation wavelength, near infrared luminous intensity exists Reduce.

As can be seen from Figure 17：Visible region emission wavelength is with the increasing of excitation wavelength in the fluorescent ink of acid amides reaction It is big and increase weak, peak position is excited in 370nm corresponding to most strong emission peak.Increase to 450nm from 370nm in excitation wavelength simultaneously During increase, its luminous intensity is gradually lowered.Its visible ray luminous intensity of the attention of value and amido modified rare earth base Quantum dot is compared, and has been weakened.And maximum excitation wavelength 370nm is shorter than the 390nm of amido modified rare earth based quantum dot.

As can be seen from Figure 18：Bright its glow color of visible chromaticity coordinates chart of amido modified rare earth based quantum dot according to Rely and change in the change of excitation wavelength, respectively by A → J.

As can be seen from Figure 19：Bright its glow color of visible chromaticity coordinates chart of the fluorescent ink of acid amides reaction is depended on The change of excitation wavelength and change, respectively by A ' → K '.

As can be seen from Figure 20：Fluorescence nano paper bright its glow color of visible chromaticity coordinates chart of acid amides reaction is depended on The change of excitation wavelength and change, respectively by A " → J ".

As can be seen from Figure 21：The fluorescent ink of acid amides reaction has stronger near-infrared characteristic luminescence, and maximum excitation wavelength is 400nm.It is noted that, its near infrared luminous intensity increases more obvious compared with amido modified rare earth based quantum dot. Its emission peak is rare earth ion Yb³⁺Characteristic peak, be sensitization after rare earth ion Yb³⁺By first excited state²F_5/2Jumped by radiating Move back to lower state²F_7/2Launch Yb³⁺Ion near-infrared characteristic luminescence (980nm).Understood with reference to Figure 12-13, carbon carbon quantum dot As energy donor and rare earth as energy acceptor, the introducing of nano-cellulose enhances energy transfer efficiency between the two.

As can be seen from Figure 22：The fluorescence nano paper of ESEM display acid amides reaction has preferable smoothness, nano-cellulose Pile up tight between nano-cellulose, without obvious space.

As can be seen from Figure 23：Fluorescence spectrum of the amido modified rare earth base carbon nitrogen quantum dot under the conditions of different excitation wavelengths. Knowable to from collection of illustrative plates, emitted luminescence intensity is most strong when excitation wavelength is 370nm, as excitation wavelength increases to 480nm from 370nm, Emitted luminescence intensity gradually weakens and to long wavelength's red shift.

As can be seen from Figure 24：The fluorescent ink of acid amides reaction has stronger near-infrared characteristic luminescence, and maximum excitation wavelength exists Near 400nm.Its near infrared luminous intensity increases more obvious compared with amido modified rare earth base carbon nitrogen quantum dot.

As can be seen from Figure 25：There is larger spectrum in the exciting light of visible ray and near infrared light for the fluorescence nano paper that acid amides reacts Figure is overlapped, and showing can be while be sensitized visible ray and near infrared light under the shooting condition of same excitation wavelength.

As can be seen from Figure 26：Amido modified rare earth base carbon nitrogen quantum dot fluorescence lifetime at visible ray 450nm is 13.33ns, its fluorescence lifetime is shorter, is a class fluorescence radiation.

As can be seen from Figure 27：Amido modified rare earth base carbon nitrogen quantum dot fluorescence lifetime near infrared light 980nm is 5.84 μ S, its fluorescence lifetime is more long to reach delicate level, is that a class phosphorescence lights.

As can be seen from Figure 28：The fluorescent ink and fluorescence nano paper of acid amides reaction fluorescence lifetime difference at visible ray 450nm It is 8.84ns and 8.83ns.This has obvious reduction compared with amido modified rare earth base carbon nitrogen quantum dot, demonstrate Figure 12 and The fluorescence intensity of Figure 14 weakens.

As can be seen from Figure 29：The fluorescent ink and fluorescence nano paper of acid amides reaction fluorescence lifetime difference at near-infrared 980nm It is 5.95 μ and 6.70 μ s.This has and is remarkably reinforced, it follows that nanometer compared with amido modified rare earth base carbon nitrogen quantum dot Cellulose is introduced into fluorescent quenching caused by the aggregation avoided in color development, while enhance carbon quantum dot to rare earth ion Energy transfer efficiency.

As can be seen from Figure 30：The spectrum under the conditions of 77K and life-span according to ultra-violet absorption spectrum and visible ray and near infrared light Result shows, it is seen that light is fluorescence radiation, near-infrared luminous for phosphorescence is luminous.Water white transparency, acid amides reaction rare earth base unit weight The compound nano-cellulose of son point, smearing on currency does not have any vestige, but has stronger under the ultra violet lamp of 365nm Visible ray occurs, and fluorescence falsification preventing well, and stronger visible ray, and bore hole is visible.Excite in the case where 365nm under cover simultaneously 980nm sightless near-infrared luminous (compared with highly concealed type).Can be with effective detection using near-infrared fluorescent spectrometer.

As can be seen from Figure 31：Simultaneously water white transparency, the nano-cellulose that the rare earth based quantum dot of acid amides reaction is compound passes through Filtration under diminished pressure substantially obtains water white transparency nanometer paper, pure nanometer and fluorescence nano paper background printed words " SUST " and " Shaanxi science and technology is big Learn " can be high-visible, show that pure nanometer and fluorescence nano have good light transmittance.And at 200-400nm fluorescence nano Paper has light absorbs, this be quantum dot primitive π-π absorb cause.

As can be seen from Figure 32：The double mode cheque paper of Visible-to-Near InfaRed and anti-counterfeiting ink are characterised by：First, anti-counterfeiting ink and Cheque paper glow color bore hole under the conditions of ultraviolet irradiation is visible, and glow color changes with the change of excitation wavelength； Second, visible and near infrared spectrum can be detected simultaneously by under the conditions of same excitation wavelength, and spectrum can be by CIE (1931) its chromaticity coordinate value is calculated；3rd, it is seen that the luminescent lifetime of region and near infrared region respectively falls in nanosecond and microsecond, Its concrete numerical value can be by exponential fitting I (t)=B₁exp(–t/τ₁)+B₂exp(–t/τ₂), wherein B1 and B2 is weighted value, τ₁ And τ₂It is fluorescence lifetime paper.

As can be seen from Figure 33：Metal ion detection test paper different metal ions Hg under the conditions of same concentrations²⁺, Pb²⁺, Zn²⁺, Cu²⁺, Ni²⁺, Mn²⁺, Mg²⁺, Fe³⁺, Ca²⁺, K⁺And Na⁺Fluorescence spectra.

As can be seen from Figure 34：Different metal ions are different to the fluorescent quenching degree of Test paper, and it is to Hg²⁺And Fe³⁺Ion There is good identity, especially Fe³⁺Ion.

It is water white transparency under obtained fluorescence nano paper natural conditions of the invention, tests prove that, shone in 365nm uviol lamps Under the conditions of penetrating, the visible ray of Glassless is sent, be conducive to Popular anti-frand to recognize.It is glimmering simultaneously under the conditions of 365nm ultraviolet irradiations The rare earth ion characteristic luminescence (980nm) that light nanometer paper is launched is not visible to the human eye, and need to just be recognized by any special measures, Improve the disguise of anti-fake material.Through experiment, metal ion detection test paper different metal under the conditions of same concentrations of the present invention IONS OF H g²⁺, Pb²⁺, Zn²⁺, Cu²⁺, Ni²⁺, Mn²⁺, Mg²⁺, Fe³⁺, Ca²⁺, K⁺And Na⁺Material object is quenched, wherein to Hg²⁺And Fe³⁺Tool There is preferably response.

Metal ion of the invention obtained and explosive (TNT) Test paper, tests prove that, in different metal ions and Its fluorescent quenching degree is different under the stimulation of TNT, and the test paper is to Fe³⁺, Hg²⁺There is fine identity with TNT.With conventional soln type Fluorescent optical sensor is compared, and the Test paper sensor is easy to preserve, carry and detect.

The present invention with organic acid and/or organic amine as carbon source, rare earth ion Ln³⁺(Ln³⁺=Nd³⁺,Yb³⁺Or Er³⁺) it is miscellaneous Change the Ln of metal ion³⁺Based quantum dot (Ln³⁺- CQDs) design；With bleached softwood wood wood pulp as fibrous raw material, in TEMPO- Under NaClO-NaBr oxidation systems, oxidized cellulose nanofibers (ONFC) are prepared；In dicyclohexyl carbodiimide (DCC) with Ln under DMAP (DMAP) catalyst action³⁺Based quantum dot and oxidized cellulose nanofibers (ONFC) Condensation reaction is carried out, the double mode Fluorescent falsification-preventing fiber element (Ln of Visible-to-Near InfaRed is obtained³⁺-CQDs-ONFC)；By energy donor (CQDs) fine setting of maximum light absorption intensity and position, strengthens triplet sensitized luminescence, and by steady-state fluorescence, transient state fluorescence longevity The means such as life and UV-visible spectrum, specify CQDs to Ln³⁺Energy delivery mechanism, be that the preparation of excellent anti-false fiber element is carried For theory support.With reference to Ln³⁺It is fugitive in the extensive identity of visible ray, the disguise of near-infrared, water and solid in-CQDs-ONFC The advantages of state easy film forming, it is obtained in that the double mode water base fluorescent ink of Visible-to-Near InfaRed and fluorescence nano paper of stable luminescence.

The rare earth based quantum dot Ln of multi-functional of the present invention³⁺The unique distinction of-CQDs is also resided in：

①Ln³⁺The preparation of-CQDs is that, by one kettle way hydro-thermal reaction, product is easily-synthesized and separates；Structure Rare Earth Ion Ln³⁺With quantum dot with carboxyl double coordination, with good thermodynamics and kinetics stability；

2. triplet sensitization hair can be strengthened by the fine setting of energy donor (CQDs) maximum light absorption intensity and position Light, realizes CQDs to rare earth ion Ln³⁺Effective transmission of energy；

3. quantum dot surface is easy to modify (amino, carboxyl or acyl chlorides etc.) so that Ln³⁺- CQDs with it is cellulose nano-fibrous Chemical bond compound be possibly realized；

4. unique double mode fluorescence.On the one hand, the rare earth ion Nd after false proof sensitization³⁺, Yb³⁺And Er³⁺(near-infrared is sent out Penetrate respectively in 1080nm, 980nm and 1560nm), (phosphorescence is luminous, Microsecond grade fluorescence lifetime and half-peak width for its characteristic luminescence Line-spectra) do not influenceed by temperature, pressure and pH etc., and be independent of with the change of excitation wavelength and change.On the other hand, quantum Point to light be visible ray, its light emitting region covers whole visible ray, fluorescence radiation, depends on the change of excitation wavelength and changes Become, luminescent lifetime is nanosecond.

Claims

1. rare earth based quantum dot composite nano fiber element preparation method, it is characterised in that comprise the following steps：First by rare earth Based quantum dot is (1~3) with nano-cellulose in mass ratio：(25~75) are dissolved in solvent, add catalyst, and reaction is obtained Rare earth based quantum dot composite nano fiber element；Wherein, rare earth based quantum dot includes that carboxyl modified-rare earth based quantum dot or amino are repaiied Decorations-rare earth base carbon nitrogen quantum dot, nano-cellulose includes hydroxyl-nano-cellulose or carboxyl-nano-cellulose；Repaiied using carboxyl Decorations-rare earth based quantum dot carries out ester bond and is combined with hydroxyl-nano-cellulose, or using amido modified-rare earth base carbon nitrogen quantity Point carries out amido link and is combined with carboxyl-nano-cellulose.

2. the preparation method of rare earth based quantum dot composite nano fiber according to claim 1 element, it is characterised in that carboxyl Modification-rare earth based quantum dot includes carboxyl modified-rare earth base carbon quantum dot or carboxyl modified-rare earth base carbon nitrogen quantum dot, its system Standby step is specifically included：

It is in molar ratio 1 by rare-earth salts and citric acid:(5~15) mixing is dissolved in water, and reacting 4~8h at 150~200 DEG C obtains carboxylic Base modification-rare earth base carbon quantum dot；

Or by rare-earth salts, citric acid and organic amine in molar ratio be 1:(27~81):(5~15) mixing is dissolved in water, 150~ 200 DEG C of 4~8h of reaction obtain carboxyl modified-rare earth base carbon nitrogen quantum dot.

3. the preparation method of rare earth based quantum dot composite nano fiber according to claim 1 element, it is characterised in that amino Modification-rare earth base carbon nitrogen quantum dot is obtained by binary reaction or three elementary reactions are obtained, and its preparation process is specifically included：

It is in molar ratio 1 by rare-earth salts and organic amine:(27~81) mixing is dissolved in water, or by rare-earth salts, organic acid and organic Amine is in molar ratio 1:(5~15):(27~81) mixing is dissolved in water, and reacting 4~8h at 150~200 DEG C obtains amido modified-dilute Soil matrix carbon nitrogen quantum dot.

4. the plain preparation method of rare earth based quantum dot composite nano fiber according to Claims 2 or 3, it is characterised in that Rare-earth salts is NdCl₃、YbCl₃Or ErCl₃；Organic acid is citric acid, acrylic acid, malonic acid or fumaric acid；Organic amine is second two Amine, propane diamine or 1,3- diaminourea -2- propyl alcohol.

5. the preparation method of rare earth based quantum dot composite nano fiber according to claim 1 element, it is characterised in that hydroxyl The preparation process of base-nano-cellulose includes：

Fibrous raw material is scattered in the H of mass fraction 60%₂SO₄In solution, 2~6 are stirred under 50~80 DEG C of water bath conditions small When, obtain hydrating solution, the wherein dry weight and H of fibrous raw material₂SO₄The ratio of solution is (1~3) g：(40~120) mL；Will hydrolysis Solution sequentially passes through centrifugation and dialyses, and sediment and H are removed successively₂SO₄, obtain hydroxyl-nano-cellulose solution.

6. the preparation method of rare earth based quantum dot composite nano fiber according to claim 1 element, it is characterised in that carboxylic The preparation process of base-nano-cellulose includes：

By 6~8h of stirring reaction in TEMPO-NaClO-NaBr oxidants addition fibrous raw material, wherein, fibrous raw material uses quality Fraction is 1% cork oar, NaClO use mass fraction for 12% NaClO solution, fibrous raw material, NaBr, TEMPO and Ratio between NaClO solution is (100~300) mL：(0.320~0.960) g：(25~75) mg：(6~18) g；Reaction knot Carboxyl-nano-cellulose is filtrated to get after beam.

7. the preparation method of rare earth based quantum dot composite nano fiber according to claim 1 element, it is characterised in that solvent It is the mixed solvent of ultra-pure water and dimethyl sulfoxide (DMSO), and the ratio of rare earth based quantum dot, ultra-pure water and dimethyl sulfoxide (DMSO) is (1~3) mg：20mL：5mL.

8. the preparation method of rare earth based quantum dot composite nano fiber according to claim 1 element, it is characterised in that ester bond It is compound, it is that 4~12h are reacted at 40~60 DEG C, catalyst uses the mixed catalyst of DCC and DMAP, and carboxyl modified-dilute The mass ratio of soil matrix quantum dot, DCC and DMAP is (1~3)：(1~3)：(0.6~1.8)；

Amido link is combined, and is that catalyst used the mixed catalyst of NHS and EDC, and ammonia in room temperature reaction 6~12 hours Base modification-rare earth base carbon nitrogen quantum dot, the mass ratio of NHS and EDC are (1~3)：(1~3)：(1.5~4.5).

9. a kind of using rare earth based quantum dot composite nano fiber element obtained in preparation method described in claim 1.

10. rare earth based quantum dot composite nano fiber element as claimed in claim 9 is preparing the double mode false proof material of Visible-to-Near InfaRed Application in material and fluorescent optical sensor.