Inorganic nano product with 3D structure as well as printing method and application of inorganic nano product

Abstract

The invention provides a 3D structure inorganic nano product and a printing method and application thereof, and the printing method comprises the following steps: (1) mixing an inorganic nano crystal and a photosensitive crosslinking compound in a solvent to obtain a printing solution; wherein the surface of the inorganic nanocrystal is provided with a ligand containing a carbon-hydrogen bond; (2) laser 3D printing is adopted, and a 3D printing product is obtained; the photosensitive cross-linking compound is a nitrogen alkene photosensitive cross-linking agent and / or a carbene photosensitive cross-linking agent. According to the method, the submicron precision of semiconductor materials, metal materials and metal oxide materials and printing of any complex 3D structures are achieved through light-triggered ligand chemical covalent bonding, and the inherent morphology, electrical characteristics and optical characteristics of nanometer materials in the printed 3D structures are reserved.

Description

Technical Field

[0001] The invention belongs to the field of 3D printing of inorganic nanomaterials, and relates to a 3D printing method of inorganic nanomaterials based on ligand chemistry. Background Art

[0002] Additive manufacturing, also known as 3D printing, is a revolutionary technology that has been widely used. In addition to being used for rapid and personalized manufacturing of prototype workpieces and the production of artworks, 3D printing technology also has important applications in emerging fields such as flexible electronics, metamaterials, and bio-scaffolds. However, the materials for 3D printing are currently limited to polymers or metals, and cannot be used to print materials with important optical, electrical, and magnetic properties such as inorganic semiconductors or inorganic metal oxides. The reason is that the process of printing to form a 3D structure (especially a hollow structure) requires strong chemical bonds to form between the atoms or molecules of the material, thereby providing mechanical support for the 3D structure. For example, in processes such as photocuring or laser melting commonly used in 3D printing, strong metallic bonds or covalent bonds are easily formed between metal-metal or polymer molecules, while semiconductors or metal oxides are difficult to bond during the printing process. Therefore, the existing 3D printing technology is difficult to achieve 3D printing of semiconductors or metal oxides.

[0003] On the other hand, 3D micro-nano structures of semiconductors or metal oxides have important application prospects in chiral optics, optical antennas, electronic devices and sensors. The development of 3D printing methods for such materials is of great significance to the field of additive manufacturing and basic research. In previous reports, by using nano-sized semiconductors (quantum dots) as raw materials and selecting specific quantum dots and ligand combinations (required to contain both thiol and carboxyl groups), 3D printing of certain component quantum dot semiconductor materials can be achieved, and the printing accuracy can reach about 100 nanometers (3D nanoprinting of semiconductor quantumdots by photoexcitation-induced chemical bonding, Science, 2022, 377, 1112). However, this method relies on the strong two-photon absorption of quantum dots and requires a specific energy level distribution between quantum dots and ligands. Therefore, it can only be used for a few inorganic semiconductor materials, and cannot be applied to many other semiconductor materials. It is also difficult to use for printing semiconductor oxides or metals.

[0004] In summary, there is still a lack of universal 3D printing methods for inorganic semiconductors, metal oxides and other electrically / optically / magnetically active nanomaterials, and innovations in the principles, mechanisms and technologies of 3D printing of inorganic nanomaterials are needed. Summary of the invention

[0005] In order to solve the above problems, the purpose of the present invention is to provide a 3D structured inorganic nanoproduct and its printing method and application. The 3D structure obtained by the printing method retains the inherent electronic and optical properties of the original nanocrystal material, and has a high printing resolution, and is generally suitable for the printing of nanocrystals with a variety of different components (different nanocrystal materials) and different geometric structures.

[0006] In order to achieve the above object, the present invention provides a 3D printing method generally applicable to inorganic nanomaterials, which comprises the following steps:

[0007] (1) mixing inorganic nanocrystals and photosensitive cross-linking compounds in a solvent to obtain a printing solution; wherein the surface of the inorganic nanocrystals has a ligand containing a carbon-hydrogen bond;

[0008] (2) Using laser 3D printing to obtain 3D printed products;

[0009] The photosensitive cross-linking compound is a nitrene-based photosensitive cross-linking agent and / or a carbene-based photosensitive cross-linking agent.

[0010] According to a specific embodiment of the present invention, preferably, the surface of the inorganic nanocrystal has a ligand containing 4-18 carbon-hydrogen bonds.

[0011] According to a specific embodiment of the present invention, the above-mentioned printing method is applicable to various nanocrystals having (for example, coated with) original ligands containing carbon-hydrogen bonds on their surfaces. The nanocrystals refer to crystalline materials on the nanometer scale, or nanoparticles with a crystal structure, specifically single-phase or complex-phase polycrystals composed of nanometer-sized (for example, 1-1000nm) grains.

[0012] According to a specific embodiment of the present invention, preferably, the inorganic nanocrystals include one or a combination of two or more of metal nanocrystals, metal oxide nanocrystals, and semiconductor material nanocrystals.

[0013] According to a specific embodiment of the present invention, preferably, the inorganic nanocrystals include one or a combination of two or more of Group II-VI nanocrystals, Group III-V nanocrystals, Group IV-VI nanocrystals, Group IV nanocrystals, Group I-VI nanocrystals, Group I-III-VI nanocrystals, metal halide perovskite materials, core-shell structured semiconductor nanocrystals, metal nanocrystals, and metal oxide nanocrystals.

[0014] According to a specific embodiment of the present invention, preferably, the II-VI group nanocrystals include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, Cd x Zn 1-x Se, Cd x Zn1-x S, Hg x Cd 1-x S, Hg x Cd 1-x Se, Hg x Cd 1-x Te, Hg x Zn 1-x Te, one or a combination of two or more, where 0 <x<1。

[0015] According to a specific embodiment of the present invention, preferably, the III-V group nanocrystals include InP, InAs, InN, InSb, InAs 1-x Sb x , GaAs, GaN, GaP, GaSb, AlN, AlP, AlAs, or a combination of two or more thereof, wherein 0 <x<1。

[0016] According to a specific embodiment of the present invention, preferably, the IV-VI group nanocrystals include one or a combination of two or more of PbS, PbSe, and PbTe.

[0017] According to a specific embodiment of the present invention, preferably, the core-shell structure semiconductor nanocrystals include CdSe / ZnS, CdSe / CdS, CdTe / CdSe, PbS / CdS, ZnSe / CdS, ZnSe / CdSe, CuInS 2 / CuInS 2 、CuInS 2 / ZnS, HgSe / CdS, HgSe / CdSe, HgSe / CdSe / CdS, Cd 1-x Zn x S / ZnS or a combination of two or more, wherein 0 <x<1。

[0018] According to a specific embodiment of the present invention, preferably, the shape of the core-shell structure semiconductor nanocrystals includes one or a combination of two or more of spherical, rod-shaped, linear, sheet-shaped, and four-claw shapes.

[0019] According to a specific embodiment of the present invention, preferably, the metal nanocrystals include one or a combination of two or more of Au nanocrystals, Ag nanocrystals, and Pt nanocrystals.

[0020] According to a specific embodiment of the present invention, preferably, the metal oxide nanocrystals include TiO 2 、In 2 O 3 、CeO 2 、ZrO 2 , ZnO or a combination of two or more.

[0021] According to a specific embodiment of the present invention, preferably, the size of the inorganic nanocrystals is 1-1000nm, for example 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1000nm, or it can be a range with two of the above values ​​as endpoints.

[0022] According to a specific embodiment of the present invention, preferably, the photosensitive cross-linking compound is an azide compound or a diaziridine compound, such as a photosensitive cross-linking compound based on nitrene or carbene. After the generated nitrene or carbene intermediate forms a covalent chemical bond with the ligand of the nanocrystal, on the one hand, it reduces the colloidal stability of the nanocrystal in the solvent to produce deposition, and on the other hand, it provides mechanical support for the micro-nano 3D structure obtained by deposition.

[0023] According to a specific embodiment of the present invention, preferably, the azide compound has a structure shown in Formula I:

[0024]

[0025] In Formula I, X is independently selected from F or alkyl, at least one X is F, more preferably, all X are F; R is selected from hydrocarbon group and its derivatives, aryl group and its derivatives or ester group and its derivatives, n≥2, and R is more preferably C 1-8 Hydrocarbon and its derivatives or C 6-12 Aryl and its derivatives, C 1-8 The hydrocarbon group and its derivatives may be, for example, methyl, ethyl, isopropyl, n-butyl, n-pentyl, n-hexyl, cyclohexyl, n-octyl, etc. 6-12 The aryl group may be, for example, phenyl, biphenyl, naphthyl, etc.; n is more preferably 2, 3, 4, 5 or 6; more preferably, R contains one or a combination of two or more heteroatoms selected from O, N, P, and halogen atoms.

[0026] According to a specific embodiment of the present invention, preferably, the diaziridine compound has a structure shown in Formula II:

[0027]

[0028] In formula II, X' is a group that makes the carbene intermediate obtained by removing nitrogen from the compound containing the diaziridine group stable and capable of achieving insertion reaction, and can be selected from H, halogen, hydrocarbon group and its derivatives, ether group and its derivatives, such as Br, H, -CH 2CH 3 , -CCl 3 , -OCH 2 CH 3 etc.; R' is a hydrocarbon group and its derivatives, more preferably, R' contains one or a combination of two or more functional groups such as an ester group, an amide bond, an aromatic group, an ether, etc., and m≥2. The diaziridine compound can form a carbene intermediate after the diaziridine group removes nitrogen, and then non-selectively realizes a ligand insertion reaction for cross-linking.

[0029] According to a specific embodiment of the present invention, preferably, the photosensitive cross-linking compound is one or a combination of two or more of 1,5-bis(4-azido-2,3,5,6-tetrafluorophenyl)-1,4-pentadien-3-one, bis(4-azido-2,3,5,6-tetrafluorobenzoyl)ethylene glycol ester, N,N-dimethyl-N,N-trimethylenebis(4-azido-2,3,5,6-tetrafluorobenzamide)ammonium iodide, and 3,3'-((perfluorobutane-1,4-diyl)bis(4,1-phenylene))bis(3-(trifluoromethyl)-3H-diazirine)).

[0030] The structure of the above 1,5-bis(4-azido-2,3,5,6-tetrafluorophenyl)-1,4-pentadien-3-one (M460) is:

[0031]

[0032] The structure of bis(4-azido-2,3,5,6-tetrafluorobenzoyl)ethylene glycol ester (M496) is:

[0033]

[0034] The structure of N,N-dimethyl-N,N-trimethylenebis(4-azido-2,3,5,6-tetrafluorobenzamido)ammonium iodide (DBTAI) is:

[0035]

[0036] The structure of 3,3'-((perfluorobutane-1,4-diyl)bis(4,1-phenylene))bis(3-(trifluoromethyl)-3H-bis(ethyleneimine) (M570) is:

[0037]

[0038] According to a specific embodiment of the present invention, preferably, the absorption wavelength range of the photosensitive cross-linking compound is consistent with the laser wavelength of 3D printing, and the process is that the photosensitive cross-linking molecule produces single-photon absorption or two-photon absorption under laser irradiation, and the azide functional group in the cross-linking molecule decomposes to produce an unstable intermediate group-singlet nitrene. The electron-deficient monovalent nitrogen active intermediate will undergo a carbon-hydrogen insertion reaction with the ligand molecule on the surface of the nanocrystal in the solution, and finally the nanocrystal is cross-linked and deposited in the structure, such as Figure 2 shown.

[0039] According to a specific embodiment of the present invention, preferably, the surface ligands of the inorganic nanocrystals have C 3 -C 24 as the main chain, the main chain more preferably contains a carbon-hydrogen bond; under the irradiation of a focused laser beam, the photosensitive molecules can react with the ligands on the surface of the nanocrystals, so that the nanocrystals at the focus point lose their colloidal stability, so that the subsequent elution process can elute the nanocrystal solution in the laser untreated area without affecting the laser-treated deposition area, so that the nanocrystals cannot be dissolved by the eluent (or form a stable solution in the eluent) and remain on the substrate to form a 3D printed structure.

[0040] According to a specific embodiment of the present invention, preferably, the C 3 -C 24 The carbon chain contains one or more structures of carboxyl, amine, phosphine, phosphoric acid, quaternary ammonium salt, sulfonate, and thiol. The crystal surface ligands of the present invention are, for example, oleic acid, oleylamine, hexadecyltrimethylammonium bromide (CTAB), mercaptopropionic acid (MPA), and the like.

[0041] According to a specific embodiment of the present invention, preferably, in step (1), the mass ratio of the inorganic nanocrystals to the photosensitive cross-linking compound is 1000:1-1:10, more preferably 60:(0.1-10), such as 60:(0.1-10), such as 60:0.1, 60:0.5, 60:1, 60:2, 60:3, 60:5, 60:6, 60:8, 60:9, 60:10, etc.; by controlling the mass ratio of the nanocrystals to the photosensitive cross-linking compound within the above range, a better nanocrystal printing effect can be obtained. If the ratio of the nanocrystals to the photosensitive cross-linking compound is too high, the photosensitive cross-linking compound may not be able to completely realize the cross-linking deposition of the nanomaterial and affect the tightness of the particle linking. If the ratio of the nanocrystals to the photosensitive cross-linking compound is too low, the proportion of the effective inorganic components in the printed structure may be reduced, thereby reducing the purity of the inorganic nanomaterial in the printing.

[0042] According to a specific embodiment of the present invention, preferably, in step (1), the concentration of the inorganic nanocrystals in the printing solution is 1-600 mg / mL, preferably 100-600 mg / ml.

[0043] The selection of the printing solution solvent of the present invention can be conventionally selected based on the properties of the nanocrystal surface ligands and the photosensitive cross-linking compound; according to a specific embodiment of the present invention, preferably, when the nanocrystals contain longer carbon chain (such as hydrocarbon) ligands, they can form a stable colloidal solution in a non-polar solvent, and the selected photosensitive cross-linking compound should be soluble in the selected non-polar solvent. The concentration of nanocrystals in the printing solution can be 1-600 mg / mL, for example 2 mg / mL, 30 mg / mL, 60 mg / mL, 120 mg / mL, 200 mg / mL, 300 mg / mL, 600 mg / mL, etc. In order to facilitate the control of the compactness of the structure during printing, the concentration of nanocrystals is preferably 100-600 mg / mL; when printing nanomaterials with polar (ionic) ligands, the solvent for preparing the printing solution is preferably a polar solvent, and the concentration of nanocrystals in the printing solution can be 50-300 mg / mL, for example 50 mg / mL, 100 mg / mL, 150 mg / mL, 200 mg / mL, 250 mg / mL, 300 mg / mL, etc.

[0044] According to a specific embodiment of the present invention, preferably, the dielectric constant of the above-mentioned non-polar solvent is generally less than 10, and the polarity is less than 4.5, for example, it can be selected from one or a combination of more than two of toluene, benzene, chloroform, xylene, carbon tetrachloride, and butyl acetate; the dielectric constant of the above-mentioned polar solvent is generally greater than 10 (even greater than 30), for example, it can be selected from one or a combination of more than two of N,N-dimethylformamide, N-methylformamide, formamide, dimethyl sulfoxide, acetonitrile, acetone, and water.

[0045] According to a specific embodiment of the present invention, preferably, in step (2), after printing is completed, the base plate is immersed in a removal solvent to remove the uncrosslinked nanocrystals and unreacted crosslinking agent, thereby retaining the printed structure.

[0046] According to a specific embodiment of the present invention, preferably, the solvent used to prepare the printing solution is the same as the solvent used in the elution process.

[0047] According to a specific embodiment of the present invention, preferably, in step (2), the laser is a pulsed laser with a wavelength of 400-1600nm, a power of 1-100mW under two-photon absorption, a power of 1-50μW under single-photon absorption, a direct writing speed of 0.1-50μm / s, a frequency of 1-1000MHz (preferably 10-1000MHz), and a pulse width of 1-5000fs; specifically, the laser power can be 2mW, 4mW, 6mW, 10mW, 50mW, etc., and the scanning speed can be 1μm / s, 2μm / s, 4μm / s, 6μm / s, 8μm / s, 10μm / s, etc. The laser intensity combined with the laser scanning speed, the laser scanning frequency, the laser pulse width, etc. can comprehensively achieve a specific energy accumulation, thereby achieving a specific photon energy to achieve a fixed-point deposition printing at a specific position.

[0048] The curves of single-photon ultraviolet absorption and two-photon absorption of chemically bonded cross-linked molecules M460 and M496 as a function of power are shown in Figure 2. Figure 3 As shown. For the chemically bonded cross-linked molecule M460, the molecules that respond to the two bands of 390nm and 265nm are selected for comparison and it is found that the selected 780nm femtosecond laser can only be combined with the chemically bonded cross-linked molecule M460 that responds to the 390nm band to achieve the effect of 3D printing; therefore, the 3D printing method of the present invention is based on the absorption of light by the photosensitive compound, and the two-photon absorption mechanism becomes the reasonable mechanism support for the 3D printing of the M460 molecule in the solution, Figure 4 As shown, by changing the power of the incident laser, the two-photon absorption response of the chemically bonded cross-linked molecule M460 responding to 390nm at different powers can be observed; the optical response range of M460 forms two-photon absorption with a specific laser wavelength.

[0049] The present invention also provides a 3D structured inorganic nano-product, which is printed by the above-mentioned 3D printing method.

[0050] According to a specific embodiment of the present invention, preferably, the structural resolution of the 3D structured inorganic nano-product is 150-1000 nm, more preferably 150 nm.

[0051] According to a specific embodiment of the present invention, the above 3D printing method generally applicable to inorganic nanomaterials is as follows: Figure 1 As shown, the specific steps include:

[0052] (1) Preparation of nanocrystal raw material solution (printing solution) for 3D printing: pre-synthesized nanocrystals and photosensitive molecules based on nitrene or carbene are dissolved in a solvent at a certain ratio and concentration. The nanocrystals may be metals, semiconductors, or metal oxides, and their sizes are generally 1-1000 nanometers. The nanocrystals have ligands containing hydrocarbon chains (with 3-24 carbon atoms) on their surfaces. The photosensitive molecules are photosensitive cross-linking molecules based on nitrene or carbene.

[0053] (2) Laser 3D printing in raw material solution: Place the raw material solution in a solution tank (transparent to the laser wavelength and non-reactive with the raw material solvent, such as polydimethoxysilane, PDMS), and cover the solution tank with a substrate such as glass, silicon wafer, or organic substrate. Turn on the nanosecond or femtosecond laser beam and focus it from bottom to top onto the upper surface of the solution (the lower surface of the glass or other substrate), allowing the laser to perform 3D direct writing according to a preset program. The ligands on the surface of the nanocrystals in the laser focus micro-area undergo a photochemical reaction with the photosensitive molecules and lose their colloidal stability. During the printing process, nanocrystals are deposited in the area where the direct writing passes to form a 3D structure.

[0054] (3) Solvent elution: After printing, the substrate with the 3D structure is separated from the solution, and a pure solvent (similar in composition or polarity to the raw material solution) is used to soak and elute the substrate to obtain the 3D structure of the inorganic nanomaterial.

[0055] In view of the limitations of the prior art, the present invention proposes a 3D printing method that is generally applicable to inorganic nanomaterials, and a 3D micro-nano structure of inorganic nanomaterials manufactured by this method. The method uses inorganic nanocrystals as raw materials, and the material components can be widely collected from semiconductor materials, metals and metal oxides; a certain amount of cross-linking agent molecules based on nitrene or carbene are added to the nanocrystal solution, and a pulsed laser is used to induce the cross-linking agent molecules in the solution to undergo a single-photon or two-photon reaction. The cross-linking agent molecules undergo a CH insertion reaction with the ligands on the surface of the nanocrystals to cross-link the nanocrystals. The cross-linked nanocrystals lose their colloidal stability and precipitate from the solution to form a 3D structure. At the same time, the covalent bonds formed by cross-linking can provide mechanical support for the 3D structure. The 3D structured inorganic nano product is obtained by direct writing in the solution through a pulsed laser and eluting the substrate with a solvent. Compared with the prior art, the nanocrystal 3D printing method based on ligand chemistry of the present invention has at least the following advantages and outstanding technical effects:

[0056] (1) The printed structure resolution (minimum printed line width) of the obtained product can reach about 150 nanometers, and the structure is stable;

[0057] (2) This method relies on the chemical reaction and deposition of inorganic nanomaterials at the focus of high-energy lasers and does not rely on any template;

[0058] (3) With the help of cross-linking covalent bonding, it is suitable for printing nanocrystals with different components (different nanocrystal materials) and different geometric structures;

[0059] (4) This method maintains the inherent fluorescence properties or dielectric constant of nanocrystals such as semiconductor quantum dots before printing; combining the versatility of materials with high-resolution structural features, it can create small-scale multi-material 3D heterostructures and exhibit new functions related to their arbitrarily designed 3D structures, thus achieving method innovation and concept expansion of additive manufacturing of functional inorganic nanomaterials;

[0060] (5) Furthermore, low laser power will allow high-throughput, rapid parallel nanofabrication. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 It is a schematic diagram of a printing device for 3D printing inorganic nanomaterials.

[0062] Figure 2 This is a schematic diagram of the chemical mechanism of achieving 3D printing structure by inducing cross-linking molecules to cross-link adjacent nanocrystals through the mechanism of two-photon absorption.

[0063] Figure 3 These are the ultraviolet absorption spectra of two photosensitive cross-linking compounds with different absorption capabilities.

[0064] Figure 4 This is the result of the change in transmittance of M460 molecules with different laser intensities.

[0065] Figure 5 SEM image of the printed circuit board using red quantum dot material.

[0066] Figure 6 A is a schematic diagram of the molecular mechanism of printing; B is the infrared spectrum analysis before and after printing; C and D are XPS spectrum analyses of the printed structure and photosensitive cross-linked compounds and nanomaterials.

[0067] Figure 7 The printed structure diagrams of different nanomaterials (composition, structure): A. CdSe / ZnS red quantum dots; B. InP nanocrystals; C. CdSe / ZnS green quantum dots; D. In 2 O 3 Nanocrystals; E.CdSe / ZnS green quantum dots; F.CdSe nanocrystals; G.TiO 2 Nanocrystals, H,I.CsPbBr 3 Nanocrystals (SEM and fluorescence images); J. CdSe / CdTe four-claw core-shell structure nanocrystals. Scale bars: 10 μm (A, B, G), 5 μm (E, J), 1 μm (C, I), 2 μm (D, F).

[0068] Figure 8 These are the SEM and EDS analysis results of Ag and Au nanoparticles printed into 2D flower patterns and 3D spiral structures.

[0069] Fig. 9 Middle A is a high-resolution printed line pattern; Fig. 9 Center B shows printed line arrays at different ratios of red quantum dot nanocrystals to cross-linker.

[0070] Fig.10 The dome structure printed with RGB three-color quantum dots (AC) and the analysis of the PL fluorescence spectrum changes before and after printing (D), and the fluorescence photograph of the heterogeneous array pattern printed with RGB three-color quantum dots (E).

[0071] Fig.11 It is the refractive index data diagram of titanium dioxide nanocrystal film under three different processing conditions.

[0072] Fig.12 Au NRs(CTAB) and Au NRs(PEG-SH) were used to perform SEM and EDS analysis of the printed structure respectively.

[0073] Fig.13 This is a SEM photo of the structure after printing using a 325nm ultraviolet laser and single-photon absorption of a photosensitive cross-linking compound. DETAILED DESCRIPTION

[0074] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0075] If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the field or the product instructions are used. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0076] Preparation Example 1

[0077] This preparation example provides a chemically bonded photosensitive cross-linking compound M460, the synthesis method of which is as follows (refer to the literature SX Cai, F. John, Evaluation of bis (perfluorophenyl azides) as cross-linkers for a soluble polyimide. J. Mater. Chem. 6, 1249-1252 (1996).):

[0078] (1) Synthesis of 4-azido-2,3,5,6-tetrafluorobenzaldehyde: 889 mg of 2,3,4,5,6-pentafluorobenzaldehyde and 300 mg of NaN 3 Mix in 3 mL HO 2 O and 8mL acetone, heated to 70°C and refluxed for 12 hours, during which the reaction solution gradually turned black; the black solution was collected in a 50mL single-necked flask and subjected to reduced pressure distillation to remove acetone from the product to obtain a crude product; 50mL of water was added to the crude product, and then extracted with ether (3×50mL), 100mL of saline solution was added to the organic phase to remove the residual aqueous phase, and then dried by adding sodium sulfate for 2 hours, concentrated and dried by rotary evaporation, and purified by silica gel column chromatography (petroleum ether: ethyl acetate gradient, for final product separation is 20:1), and spin-dried to obtain a product powder of 4-azido-2,3,5,6-tetrafluorobenzaldehyde;

[0079] (2) 500 mg of 4-azido-2,3,5,6-tetrafluorobenzaldehyde and 58 mg of acetone were mixed in 3 mL of methanol, and then added to 0.2 mL of 20% NaOH solution. The mixture was stirred at room temperature for 1 hour, and then 2 mL of methanol and 3 mL of water were added and the separated yellow solid was collected; the yellow solid was dried and dissolved in 10 mL of acetone and 500 μL of tetrahydrofuran, and the solution was added dropwise to 100 mL of water, stirred for 2 hours, and the final yellow powder was obtained after centrifugation, filtration, and reduced pressure distillation, i.e., the photosensitive cross-linking compound 1,5-bis(4-azido-2,3,5,6-tetrafluorophenyl)-1,4-pentadien-3-one (M460).

[0080] The NMR data of M460 are as follows:

[0081] 1 H NMR (400 MHz, CDCl 3 ): δ7.68(s,2H), δ7.30(s,2H).

[0082] Preparation Example 2

[0083] This preparation example provides a chemically bonded cross-linking agent compound M496, and its synthesis method is as follows (reference literature M. Sundhoro, J. Park, B. Wu, M. Yan, Synthesis of polyphosphazenes by a fast perfluoroaryl azide-mediated staudinger reaction. Macromolecules 51, 4532–4540 (2018). and JF Keana, SX Cai, New reagents for photoaffinity labeling: synthesis and photolysis of functionalized perfluorophenyl azides. J. Org. Chem. 55, 3640–3647 (1990).):

[0084] (1) Weigh 0.30 g of sodium azide and 0.97 g of methyl pentafluorobenzoate, inject 8 mL of acetone and 10 mL of ultrapure water, mix the solid powder and the liquid and start stirring, and heat and reflux for 8 h; then cool the reaction system to room temperature, add 10 mL of ultrapure water, take out the reaction solution into a separatory funnel, extract it with 10 mL of ether, repeat the extraction operation 3 times, dry the excess extract with magnesium sulfate, remove the ether solvent by vacuum distillation, and obtain about 0.9 g of colorless solid 4-azido-2,3,5,6-tetrafluorobenzoic acid methyl ester;

[0085] (2) Prepare and measure 0.8 mL of 20% sodium hydroxide aqueous solution, add 10 mL of methanol and 1 mL of ultrapure water, mix well, weigh 0.59 g of the above-synthesized 4-azido-2,3,5,6-tetrafluorobenzoic acid methyl ester, stir the reaction system in an ice-water bath, and slowly add concentrated hydrochloric acid, and use pH test paper to monitor the change of pH value at any time; when the pH of the reaction solution is less than 1, stop adding acid, extract with 10 mL of chloroform, repeat the extraction 3 times, dry with magnesium sulfate after the extraction, and then use rotary evaporation to remove the solvent methanol and extract chloroform introduced in the reaction, and finally obtain about 0.5 g of colorless solid product 4-azido-2,3,5,6-tetrafluorobenzoic acid;

[0086] 10 mL of anhydrous dichloromethane was added to all the reaction product solids, 66 mg of ethylene glycol and 26 mg of 4-dimethylaminopyridine were introduced, the reaction system was mixed, and the reaction was continued for 30 minutes under stirring. Subsequently, 454 mg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride was added to the reaction system, and the reaction was continued to be stirred at room temperature overnight; 10 mL of ultrapure water was added and continued to be stirred for 30 minutes. After the reaction was completed, it was extracted with 10 mL of dichloromethane for 3 times, and the organic layer in the extraction system was continued to be washed with 50 mL of ultrapure water and 50 mL of saturated brine, and the organic solution was separated and dried with magnesium sulfate to remove water. Finally, a chromatographic column was used for molecular purification (using n-hexane and ethyl acetate as mobile phase solvents, volume ratio 3:2), and the solvent was removed by rotary evaporation to finally obtain about 350 mg of white solid powder bis(4-azido-2,3,5,6-tetrafluorobenzoyl)ethylene glycol ester (M496).

[0087] M496 1 H. 13 F NMR spectrum information is as follows: 1 H NMR (400 MHz, CDCl 3 ):δ4.68(s,4H); 19 FNMR (377MHz, CDCl 3 ): δ-150.81 to -150.70, (m, 4F), -138.27 to -138.18 (m, 4F).

[0088] Preparation Example 3

[0089] This preparation example provides a chemically bonded crosslinker compound DBTAI, and its synthesis method is as follows (reference document SHKhong et al., General photo-patterning of polyelectrolyte thin films via efficient ionic bis(fluorinated phenyl azide)photo-crosslinkers and their post-deposition modification. Adv. Funct. Mater. 17, 2490–2499 (2007).):

[0090] (1) Mix 0.29 mL of N,N-bis(3-aminopropyl)methylamine, 0.55 mL of triethylamine and 40 mL of chloroform in a 100 mL flask. Add the above mixture dropwise into a mixed solution of 40 mL of chloroform and 0.54 mL of pentafluorobenzoyl chloride. After all the additions are complete, the reaction stops. Filter to remove the white precipitate, wash it three times with 25 mL of saturated sodium chloride solution, and rinse it with anhydrous MgSO4 Drying to obtain N-methyl-N,N-di(pentafluorobenzamide)propylamine liquid;

[0091] (2) Dissolve 777 mg of the above-mentioned N-methyl-N,N-di(pentafluorobenzamide)propylamine liquid in 3.2 mL of acetone, and dissolve 192 mg of sodium azide in a mixed solution of 1.5 mL of water and 3 mL of acetone. Add the acetone solution of N-methyl-N,N-di(pentafluorobenzamide)propylamine to the sodium azide solution, reflux for 8 hours, filter to remove the precipitate, wash the filtrate with a saturated sodium chloride solution, and add MgSO 4 After drying, the solvent was evaporated to obtain yellow solid N-methyl-N,N-di(4-azido-2,3,5,6-tetrapentafluorobenzamido)propylamine;

[0092] (3) 505 mg of yellow powder of N-methyl-N,N-di(4-azido-2,3,5,6-tetrapentafluorobenzamido)propylamine was dissolved in 10 mL of chloroform, and 5 mL of iodomethane was added. The mixture was stirred overnight and recrystallized to obtain DBTAI.

[0093] DBTAI 1 H. 13 F NMR spectrum information is as follows: 1 H-NMR (400MHz, MeOD): δ = 3.42 (t, 2H), 3.28 (m, 2H), 3.03 (s, 3H), 2.01 (m, 2H); 19 F-NMR (377MHz, MeOD): δ = -143.5 (m, 4F), -152.2 (m, 4F).

[0094] Preparation Example 4

[0095] This preparation example provides a chemically bonded crosslinker M570, the synthesis of which refers to a literature method (Simhadri, C. et al., Flexible polyfluorinated bis-diazirines as molecular adhesives. Chemical Science 2021, 12, 4147–4153).

[0096] M570 1 H, 19 F NMR information is as follows: 1 H NMR (400 MHz, CDCl 3 ): δ7.60(d,4H), 7.31(d,4H); 19 F NMR (377 MHz, CDCl 3): δ-150.61(m,4F),-138.06(m,4F).

[0097] Embodiment 1:

[0098] This embodiment provides a nanocrystal 3D printing method based on ligand chemistry

[0099] This embodiment uses red fluorescent quantum dot CdSe / ZnS nanocrystals (spherical, size 15nm) for laser 3D printing, and the process is as follows:

[0100] (1) Preparation of nanocrystal printing solution: nanocrystal CdSe / ZnS (600 mg / mL), a photosensitive cross-linking compound (50 mg / mL), and a toluene solvent are mixed to obtain a printing solution, and the printing solution is used to perform in-situ printing in a subsequent solution; wherein the surface of the nanocrystal CdSe / ZnS has an original ligand oleic acid, and the photosensitive cross-linking compound is a photosensitive cross-linking compound M460;

[0101] (2) Laser 3D printing in solution: Use a PDMS solution tank and a cover glass (base plate) to seal the printing solution, turn on the femtosecond laser beam and focus it from bottom to top on the upper surface of the solution (lower surface of the cover glass), and make the laser perform 3D direct writing in the solution on the cover glass according to the preset program (laser power 4mW, direct writing speed 3μm / s, wavelength 780nm, frequency 80MHz, pulse width 92fs). In the area where the direct writing passes, the nanocrystals undergo ligand photochemical reaction with the photosensitive cross-linking compound, lose colloidal stability, and form a deposited 3D structure;

[0102] (3) Solvent elution: Use clean toluene solvent for soaking and elution for 5-10 minutes to remove unreacted photosensitive cross-linking compounds and unreacted nanocrystals to obtain a 3D structure product of CdSe / ZnS nanocrystals.

[0103] The 3D structure product of CdSe / ZnS nanocrystals prepared in this embodiment is as follows: Figure 5 As shown in Figure 2, the surface chemical changes reflected by the new mechanism of the printing process are as follows Figure 6 As shown in A, it shows the photoinduced C–H insertion reaction process of the nanocrystal surface ligand cross-linked with the photosensitive cross-linking compound; Figure 6 Figures C and D show the C–N bond signal generated in the system after the insertion reaction (XPS spectrum analysis). Figure 6 B shows N 3 Evidence of azide signal change (FTIR spectrum).

[0104] Example 2-Example 10: Realizing 3D printing of various nanocrystalline materials such as oxides and perovskite nanomaterials

[0105] In Examples 2-10, nanocrystals with different material components, different core-shell structures, and different geometric shapes of core-shell structures were used for laser 3D printing. The specific nanocrystals used were red-luminescent CdSe / ZnS core-shell quantum dot nanoparticles (size 15 nm), green-luminescent CdSe / ZnS core-shell quantum dot nanoparticles (size 12 nm), InP nanocrystals (size 3 nm), CdSe / CdTe core-shell four-claw nanocrystals (size 35 nm), CdSe (size 4 nm), TiO 2 (size 25nm), CsPbBr 3 (size 7nm), the printing process is as follows:

[0106] (1) Preparation of nanocrystal printing solution: nanocrystals (600 mg / mL), a photosensitive cross-linking compound (50 mg / mL), and a toluene solvent are mixed to obtain a printing solution, and the printing solution is used for subsequent in-situ printing in a solution; wherein the surface of the nanocrystal has an original ligand oleic acid or oleylamine, and the photosensitive cross-linking compound is a photosensitive cross-linking compound M460;

[0107] (2) Laser 3D printing in solution: Use a PDMS solution tank and a cover glass (base plate) to seal the printing solution, turn on the femtosecond laser beam and focus it from bottom to top on the upper surface of the solution (lower surface of the cover glass), and make the laser perform 3D direct writing in the solution on the cover glass according to the preset program (laser power 4mW, direct writing speed 4μm / s, wavelength 780nm, frequency 80MHz, pulse width 92fs). In the area where the direct writing passes, the nanocrystals undergo ligand photochemical reaction with the photosensitive cross-linking compound, lose colloidal stability, and form a deposited 3D structure;

[0108] (3) Solvent elution: Use clean toluene solvent for soaking and elution for 5-10 minutes to remove unreacted photosensitive cross-linking compounds and unreacted nanocrystals to obtain a 3D structure product of nanocrystals.

[0109] The 3D printing structure of the inorganic nanomaterials prepared in Example 2-10 is as follows Figure 7 shown.

[0110] Example 11: Realizing 3D printing of metal nanomaterials

[0111] In this embodiment, metal nanocrystal Ag-MPA ligand (size 10nm) and Au-CTAB ligand (size 70nm) are used for laser 3D printing respectively, and the process is as follows:

[0112] (1) Preparation of nanocrystal printing solution: metal nanocrystal Ag-MPA ligand or Au-CTAB ligand (100 mg / mL), photosensitive cross-linking compound DBTAI (10 mg / mL), and solvent water are mixed to obtain a printing solution, and the printing solution is used for subsequent in-situ printing in the solution;

[0113] (2) Laser 3D printing in solution: Use a PDMS solution tank and a cover glass (base plate) to seal the printing solution, turn on a 515 nm femtosecond laser beam and focus it from bottom to top on the upper surface of the solution (lower surface of the cover glass), and make the laser perform 3D direct writing in the solution on the cover glass according to a preset program (laser power 0.2 mW, direct writing speed 1 μm / s, wavelength 515 nm, frequency 0.2 MHz, pulse width 400 fs). In the area where the direct writing passes, the nanocrystals undergo a ligand photochemical reaction with the photosensitive cross-linking compound, lose colloidal stability, and form a deposited 3D structure;

[0114] (3) Solvent elution: Use clean water solvent for soaking and elution for 5-10 minutes to remove unreacted photosensitive cross-linking compounds and unreacted nanocrystals to obtain a 3D structure product of metal Ag and Au nanocrystals.

[0115] The 3D printed structures of the inorganic nanomaterials Ag and Au prepared in this embodiment are as follows: Figure 8 As shown in A and B.

[0116] Example 12: Achieving high-resolution printing

[0117] This embodiment uses red light emitting quantum dot CdSe / ZnS nanocrystals (spherical; size 15nm) for laser 3D printing, and the process is as follows:

[0118] (1) Preparation of nanocrystal printing solution: nanocrystal CdSe / ZnS (600 mg / mL), a photosensitive cross-linking compound (50 mg / mL), and a toluene solvent are mixed to obtain a printing solution, and the printing solution is used to perform in-situ printing in a subsequent solution; wherein the surface of the nanocrystal CdSe / ZnS has an original ligand oleic acid, and the photosensitive cross-linking compound is a photosensitive cross-linking compound M460;

[0119] (2) Laser 3D printing in solution: Use a PDMS solution tank and a cover glass (base plate) to seal the printing solution, turn on the femtosecond laser beam and focus it from bottom to top on the upper surface of the solution (lower surface of the cover glass), and make the laser perform 3D direct writing in the solution on the glass slide according to the preset program (laser power 3mW, direct writing speed 4μm / s, wavelength 780nm, frequency 80MHz, pulse width 92fs). In the area where the direct writing passes, the nanocrystals undergo ligand photochemical reaction with the photosensitive cross-linking compound, lose colloidal stability, and form a deposited 3D structure;

[0120] (3) Solvent elution: Use clean toluene solvent for soaking and elution for 5-10 minutes to remove unreacted photosensitive cross-linking compounds and unreacted nanocrystals to obtain a 3D structure product of CdSe / ZnS nanocrystals.

[0121] The red quantum dot pattern prepared in this embodiment can obtain a high-resolution pattern of about 150nm, such as Fig. 9 As shown in A. The printed line arrays at different ratios of red quantum dot nanocrystals to crosslinking agent prepared in this embodiment are as follows Fig. 9 As shown in B, the percentage is the mass percentage of the photosensitive cross-linking compound in the nanocrystals.

[0122] Example 13: Achieving non-destructive printing of heterogeneous structures while maintaining PL performance

[0123] This embodiment uses red light, green light, and blue light emitting quantum dot CdSe / ZnS nanocrystals (spherical; size 8-15nm) for laser printing, and the process is as follows:

[0124] (1) Preparation of nanocrystal printing solution: red luminescent quantum dot CdSe / ZnS nanocrystals (600 mg / mL), a photosensitive cross-linking compound (50 mg / mL), and a toluene solvent are mixed to obtain a printing solution, and the printing solution is used to perform in-situ printing in a subsequent solution; wherein the surface of the nanocrystal has an original ligand oleic acid, and the photosensitive cross-linking compound is a photosensitive cross-linking compound M460;

[0125] (2) Laser 3D printing in solution: Use a PDMS solution tank and a cover glass (base plate) to seal the printing solution, turn on the femtosecond laser beam and focus it from bottom to top on the upper surface of the solution (lower surface of the cover glass), and make the laser perform 3D direct writing in the solution on the glass slide according to the preset program (laser power 4mW, direct writing speed 3μm / s, wavelength 780nm, frequency 80MHz, pulse width 92fs). In the area where the direct writing passes, the nanocrystals undergo ligand photochemical reaction with the photosensitive cross-linking compound, lose colloidal stability, and form a deposited 3D structure;

[0126] (3) Solvent elution: Use clean toluene solvent for immersion elution for 5-10 minutes to remove unreacted photosensitive cross-linking compounds and unreacted nanocrystals to obtain the first batch of arrays of nanocrystal 3D structures;

[0127] (4) Repeat the printing process from steps (1) to (3) twice, using green and blue luminescent quantum dot CdSe / ZnS nanocrystals for heterogeneous printing of parallel arrays.

[0128] Fig.10Shown are the dome structure printed with RGB three-color quantum dots prepared in this embodiment (AC) and the PL fluorescence spectrum change analysis before and after printing (D), and the fluorescence photograph of the heterogeneous array pattern printed with RGB three-color quantum dots (E).

[0129] Test Example 1: Printing of oxide nanomaterials with refractive index retention

[0130] In this test example, titanium dioxide nanocrystal thin film samples were first prepared under the following different conditions, and the refractive index of each film was measured:

[0131] 1. Pure TiO 2 Nanocrystal spin-coated film (100 mg / ml);

[0132] 2. TiO 2 (size 25nm) and photosensitive cross-linking compound M460 (mass ratio: 600:1) were mixed and spin-coated and the cross-linked film was exposed;

[0133] 3. Film after ligand stripping after crosslinking (NOBF 4 (0.1 M acetonitrile solution), soak for 1 min for ligand stripping).

[0134] The three groups of samples were all spin-coated at a speed of 1000 rpm and a spin-coating time of 30 s, and the refractive index of each film (thickness ˜100 nm) on a silicon wafer was measured on a Horiba UVISEL ellipsometer.

[0135] The refractive index results of the titanium dioxide nanocrystal films prepared under three different treatment conditions in this test example are as follows: Fig.11 shown.

[0136] Test Example 2: Investigating the effect of polymer on printing purity

[0137] Au NRs (CTAB) and Au NRs (PEG-SH) with a size of 70 nm were respectively used with a photosensitive cross-linking compound DBTAI (the mass ratio of nanocrystals to photosensitive cross-linking compound was 10:1) for solution 3D printing (the printing process refers to Example 11), and the obtained structure is shown in Fig.12 A (Au NRs (CTAB)) and B (Au NRs (PEG-SH)). The above gold nanorod materials are all Au nanorods stabilized by long-chain ligands on the surface. Fig.12 The purity of the inorganic part of the two structures.

[0138] Depend on Fig.12It can be seen that the proportion of Au in the obtained structural components is significantly reduced in the printing experiment using the gold rod with polymer ligand, while the cross-linking effect is not affected in the printing experiment using the original short-chain ligand CTAB. The dense structure can still be seen through SEM, and the Au component in the printed structure is very obvious, which shows that the participation of polymer in printing has a great influence on the purity of the printed structure.

[0139] Test Example 3: Comparison of printing effects of chemically bonded cross-linked molecules responding to different UV bands

[0140] The 3D printing method used in this test example is the same as the printing method in Example 1 (the mass ratio of nanocrystals to photosensitive cross-linking compounds is 12:1, the laser power is 4 mW, and the direct writing speed is 4 μm / s). The difference is that M496 molecules absorbing at around 265 nm are used as cross-linking molecules. The ultraviolet absorption spectrum is shown in FIG. Figure 3 As shown. From the printing process, changing the laser power and direct writing speed cannot make the solution print out 3D structures, and even 2D structures cannot be formed; but printing can be achieved under a 515nm light source. This test example shows that for a 780nm light source, only the cross-linked molecule M460 with absorption near the half wavelength can be printed in this system, and for a 515nm light source, only the cross-linked molecule M496 with absorption near the half wavelength can be printed, reflecting the chemical mechanism of two-photon absorption that M460 and M496 rely on in this 3D printing system.

[0141] Test Example 4: Printing effect of chemically bonded cross-linked molecules using single-photon absorption

[0142] This test example uses a low-energy (4μW) 325nm continuous laser as the light source, and triggers a photochemical bonding reaction through a single-photon absorption process: 5μL 600mg / mL of green-emitting CdSe / ZnS quantum dots are mixed with 0.5μL 50mg / mL of M460 molecules and toluene solvent. The green-emitting CdSe / ZnS quantum dots have the original ligand oleic acid; under the condition of 4μW laser, using a 50x magnification and a 0.4NA objective lens, the printing of II-VI quantum dots can be achieved at different scanning speeds (5μm / s, 10μm / s, 20μm / s), such as Fig.13 As shown in A and B. Therefore, this technology can be integrated with various existing laser printing systems to achieve 3D printing with adjustable accuracy and cost.

[0143] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0144] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A 3D printing method generally applicable to inorganic nanomaterials, comprising the following steps: (1) mixing inorganic nanocrystals and photosensitive cross-linking compounds in a solvent to obtain a printing solution; wherein the surface of the inorganic nanocrystals has a ligand containing a carbon-hydrogen bond; (2) Using laser 3D printing to obtain 3D printed products; The photosensitive cross-linking compound is a nitrene-based photosensitive cross-linking agent and / or a carbene-based photosensitive cross-linking agent.

2. The 3D printing method according to claim 1, wherein: The inorganic nanocrystals include one or a combination of two or more of metal nanocrystals, metal oxide nanocrystals, and semiconductor material nanocrystals; Preferably, the inorganic nanocrystals include one or a combination of two or more of II-VI group nanocrystals, III-V group nanocrystals, IV-VI group nanocrystals, IV group nanocrystals, I-VI group nanocrystals, I-III-VI group nanocrystals, metal halide perovskite materials, core-shell structure semiconductor nanocrystals, metal nanocrystals, and metal oxide nanocrystals; Preferably, the II-VI group nanocrystals include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, Cd x Zn 1-x Se, Cd x Zn 1-x S, Hg x Cd 1-x S, Hg x Cd 1-x Se, Hg x Cd 1-x Te, Hg x Zn 1-x Te, one or a combination of two or more, where 0 <x<1; Preferably, the III-V group nanocrystals include InP, InAs, InN, InSb, InAs 1-x Sb x , GaAs, GaN, GaP, GaSb, AlN, AlP, AlAs, or a combination of two or more thereof, wherein 0 <x<1; Preferably, the IV-VI group nanocrystals include one or a combination of two or more of PbS, PbSe, and PbTe; Preferably, the core-shell structure semiconductor nanocrystals include CdSe / ZnS, CdSe / CdS, CdTe / CdSe, PbS / CdS, ZnSe / CdS, ZnSe / CdSe, CuInS2 / CuInS2, CuInS2 / ZnS, HgSe / CdS, HgSe / CdSe, HgSe / CdSe / CdS, Cd 1-x Zn x S / ZnS or a combination of two or more thereof, wherein 0 <x<1; Preferably, the shape of the core-shell structure semiconductor nanocrystals includes one or a combination of two or more of spherical, rod-shaped, linear, sheet-shaped, and four-claw shapes; Preferably, the metal nanocrystals include one or a combination of two or more of Au nanocrystals, Ag nanocrystals, and Pt nanocrystals; Preferably, the metal oxide nanocrystals include one or a combination of two or more of TiO2, In2O3, CeO2, ZrO2, and ZnO; Preferably, the size of the inorganic nanocrystals is 1-1000 nm.

3. The 3D printing method according to claim 1, wherein: The photosensitive cross-linking compound is an azide compound or a diaziridine compound; Preferably, the azide compound has a structure shown in Formula I: In formula I, X is independently selected from F or alkyl, at least one X is F, R is selected from hydrocarbon group and its derivatives, aryl group and its derivatives or ester group and its derivatives, n≥2; R is preferably C 1-8 Hydrocarbon and its derivatives or C 6-12 Aryl and its derivatives, n is preferably 2, 3, 4, 5 or 6; preferably, R contains heteroatoms selected from O, N, P, halogen atoms or a combination of two or more thereof; The diaziridine compound has a structure shown in Formula II: In formula II, X' is selected from H, halogen, hydrocarbon group and its derivatives, ether group and its derivatives, R' is hydrocarbon group and its derivatives; preferably, R' contains one or more structures of ester group, amide bond, aromatic group and ether group; m≥2; Preferably, the photosensitive cross-linking compound is one or a combination of two or more of 1,5-bis(4-azido-2,3,5,6-tetrafluorophenyl)-1,4-pentadien-3-one, bis(4-azido-2,3,5,6-tetrafluorobenzoic acid) ethylene glycol ester, N,N-dimethyl-N,N-trimethylenebis(4-azido-2,3,5,6-tetrafluorobenzamide) ammonium iodide, and 3,3'-((perfluorobutane-1,4-diyl)bis(4,1-phenylene))bis(3-(trifluoromethyl)-3H-bisaziridine).

4. The 3D printing method according to claim 1 or 3, wherein: The absorption wavelength range of the photosensitive cross-linking compound meets the single-photon absorption or two-photon absorption range of the laser wavelength for 3D printing.

5. The 3D printing method according to claim 1, wherein: The surface ligands of the inorganic nanocrystals have C3-C 24 As the main chain, the main chain preferably contains a carbon-hydrogen bond; Preferably, the C3-C 24 The carbon chain contains one or more structures of carboxyl, amine, phosphine, phosphoric acid, quaternary ammonium salt, sulfonate, and thiol.

6. The 3D printing method according to claim 1, wherein: In step (1), the mass ratio of the inorganic nanocrystals to the photosensitive cross-linking compound is 1000:1-1:10, preferably 60:(0.1-10).

7. The 3D printing method according to claim 1, wherein: In step (1), the concentration of the inorganic nanocrystals in the printing solution is 1-600 mg / mL, preferably 100-600 mg / ml.

8. The 3D printing method according to claim 1, wherein: In step (2), the laser is a pulsed laser with a wavelength of 400-1600nm, a power of 1-100mW under two-photon absorption, a power of 1-50μW under single-photon absorption, a direct writing speed of 0.1-50μm / s, a frequency of 1-1000MHz, and a pulse width of 1-5000fs.

9. A 3D structured inorganic nano-product, which is printed by the 3D printing method according to any one of claims 1 to 8.

10. The 3D structured inorganic nano-product according to claim 9, wherein: The structural resolution of the 3D structured inorganic nano-product is 150-1000 nm, preferably 150 nm.

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