Photoelectric materials based on ultrathin protein nanofilms and their preparation methods and applications

Abstract

The present invention discloses a photoelectric material based on an ultrathin protein nanofilm and a preparation method thereof. By breaking the disulfide bonds of the protein, the protein undergoes a phase transition and self-assembles at the solid-liquid interface to form an ultrathin protein nanofilm with a secondary structure mainly composed of α-helix. A metal coating is then prepared by magnetron ion sputtering or a chemical method to obtain the photoelectric material. The preparation method of the ultrathin protein nanofilm of the present invention is simple and has good stability, light transmittance, and good non-toxic biocompatibility. Moreover, since the surface of the ultrathin protein nanofilm has multiple functional groups such as free thiol, carboxyl, and amino groups, stable adhesion to the metal coating can be achieved. The photoelectric material of the present invention can be used to prepare secret information devices, Raman enhancement devices, smart window devices, printed devices, and tactile sensors. The metal layer can maintain stable performance in various harsh environments.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomaterials and optoelectronic materials, and specifically relates to a method for preparing a single-molecule protein ultrathin nanofilm, and using the single-molecule protein ultrathin nanofilm as an interlayer material to obtain a stable metal coating on various substrates, which is applied to secret information devices, Raman enhancement devices, smart window devices, printed devices, tactile sensors, etc. Background Art

[0002] By integrating multiple properties, the overall performance of materials can be improved, enabling the multifunctionalization of flexible polymer materials. For example, combining conductivity, optical properties, and mechanical toughness can create more efficient and flexible electronic and optical devices. At the same time, the development of multifunctional materials reduces the need to use different materials, reduces resource waste, and reduces the likelihood of waste generation. Such comprehensive materials can also promote the emergence of innovative applications and have a wide range of applications in areas such as electronic skin, medical implants, and biointelligence. They can achieve the mutual conversion of information signals such as light and electromagnetic signals, providing a potential pillar material for future information science reforms. Such materials are expected to improve people's quality of life and provide more comfortable, safer, and more convenient products and solutions.

[0003] It is crucial to broaden the application areas of flexible polymer materials and realize their multifunctionality. One important method is to "compound" two or more different materials. However, the interfacial adhesion between the two materials requires a strong interaction at their interface, which is often difficult to achieve for inert flexible polymer materials. Therefore, using simple and non-toxic methods to modify flexible polymer materials so that they form stable interfacial bonds with metal coatings is the key to achieving multifunctional and multi-morphological materials. For example, through chemical methods, substances such as dopamine and tannic acid can be attached to the surface of any material by simple dip coating, or the substrate can be modified by the physical method Plassma to help the metal layer be stably deposited on the substrate. However, since dopamine is expensive and takes a long time, and tannic acid has color and Plassma modification lasts for a short time, it may not be suitable for use in some scenarios. In industrial production, how to solve these limitations is extremely challenging.

[0004] CN112574578A discloses a protein / polysaccharide composite nanofilm and its application in preventing cracks in conductive coatings. The protein / polysaccharide composite nanofilm is a positively charged composite nanofilm obtained by crosslinking a nanofilm formed by phase transition protein and polysaccharide at the solid-liquid interface with a crosslinking agent. The composite nanofilm has good stability and optical transmittance. Moreover, because the composite nanofilm has positive charge and multiple groups, it can adsorb the conductive coating and reduce the microcracks formed in the conductive coating due to bending, thereby maintaining stable conductivity of the flexible device. When used as a substrate for making OLED devices, it can still maintain the stability of the light-emitting organic layer and the stability of the current density after bending. However, the composite nanofilm requires the addition of polysaccharides to increase the adhesion of the film, and a crosslinking agent is also required. Moreover, the secondary structure of the protein in the composite nanofilm is a β-sheet structure, which has poor stability to the metal layer and is easily torn by 3M tape. Summary of the Invention

[0005] In order to solve the problems of the prior art, the present invention provides a photoelectric material based on an ultra-thin protein nanofilm and a preparation method thereof. The ultra-thin protein nanofilm is a protein film with a secondary structure mainly characterized by α-helix formed by the unfolding and self-assembly of single-molecule proteins. It has stable adhesion and can play the role of stabilizing the metal layer on various substrates.

[0006] To achieve the above-mentioned purpose, the present invention provides a method for preparing an ultrathin protein nanofilm-based optoelectronic material, comprising the following steps:

[0007] Step 1: After adjusting the pH value of a 1-50 mmol / L reducing agent solution to 4.5-5.5 with NaOH, uniformly mix it with a 0.1-2 mg / mL protein solution in a volume ratio of 1:1 to obtain a mixed solution; dripping a layer of the mixed solution on the surface of a hydrophobic material and maintaining a moist environment, then turning a substrate upside down on the dripped droplets to fully contact the substrate surface with the droplets, reacting at room temperature for 20-60 minutes, forming a layer of colorless, transparent, single-molecule protein ultrathin nanofilm at the solid-liquid interface between the substrate and the droplets, absorbing excess solution on the substrate surface with filter paper, and then naturally drying in air to obtain an ultrathin protein nanofilm-modified substrate with a thickness of 3-15 nm.

[0008] Step 2: Depositing a layer of inorganic conductive material or conductive OLED material on the surface of the ultra-thin protein nanofilm modified substrate by ion sputtering or evaporation to obtain a photoelectric material; or immersing the ultra-thin protein nanofilm modified substrate in a 1-50 mmol / L ammonium tetrachloropalladate aqueous solution, placing it in the dark for 5-30 minutes, and then immersing it in a metal electroless deposition solution to deposit a metal conductive coating on the surface of the substrate to obtain a photoelectric material; or immersing the ultra-thin protein nanofilm modified substrate in a 0.5-20 mg / mL metal dispersion, placing it in the dark for 5-30 minutes. The substrate is placed in a shaker and shaken for 30 to 120 minutes to allow the metal conductive coating to be adsorbed on the surface of the substrate to obtain a photoelectric material; or the substrate modified with an ultra-thin protein nanofilm is immersed in an aqueous solution containing 1 to 20 mg / mL ferric chloride and 0.05 to 5 mg / mL conductive polymer monomer, and allowed to stand for 30 to 60 minutes to allow the conductive polymer to be adsorbed on the surface of the substrate to obtain a photoelectric material; or the perovskite precursor solution is spin-coated on the surface of the ultra-thin protein nanofilm modified substrate, and annealing is performed after spin coating to form a photoelectric material with a surface modified perovskite crystal film.

[0009] In the above step 1, the protein is, but is not limited to, any one or more of: lysozyme, lactalbumin, insulin, β-lactoglobulin, bovine serum albumin, human serum albumin, α-lactalbumin, fibrinogen, β-amyloid protein, transferrin, collagen, pepsin, keratin, myoglobin, hemoglobin, lactoferrin, albumin, albumin, thyrolactoglobulin, prion protein, Aβ peptide, α-synuclein, α-amylase, pepsin, horseradish peroxidase, ribonuclease A, cytochrome c, cystatin C, DNA polymerase, casein, huntingtin, immunoglobulin light chain, fibrinogen, keratin, soy protein isolate, pea protein isolate, zein, gliadin, gluten, oat protein, potato protein, hemp seed protein, walnut protein, etc.

[0010] In the above step 1, the reducing agent is, but is not limited to, any one or more of cysteine, tris(2-carboxyethyl)phosphine hydrochloride, reduced glutathione, 2-mercaptoethanol, dithiothreitol, dimercaptosuccinic acid, sodium sulfite, β-mercaptoethanol, hydrogen peroxide, ozone, sodium ferrate, trivalent cobalt salt, chlorate, potassium permanganate, persulfate, potassium dichromate, concentrated sulfuric acid, hydrochloric acid, nitric acid, hydrobromic acid, hydroiodic acid, perchloric acid, fluorine gas, chlorine gas, sodium bismuthate, periodic acid, lead dichloride, guanidine hydrochloride, urea, trifluoroethanol, hexafluoroisopropanol, trifluoroacetic acid, malonamide, thiourea, selenourea, tellurium urea, arginine ketoacid, arginine ester, arginine amide, citrulline ketoacid, citrulline ester, citrulline amide, ornithine ketoacid, ornithine ester, ornithine amide, xanthine, hypoxanthine, trioxypurine, theophylline, theobromine, caffeine, etc.

[0011] The reducing agent solution and protein solution are prepared by using 4-hydroxyethylpiperazineethanesulfonic acid buffer solution or ultrapure water as solvent.

[0012] In the above step 1, the hydrophobic material is but not limited to: any one of polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, polyethylene, polyacrylonitrile, polyacrylic acid or its derivatives, polypropylene, silicone rubber, nano-coating materials with hydrophobic function, etc.

[0013] In the above step 1, the substrate is a flexible substrate or a non-flexible substrate. The non-flexible substrate is, but not limited to, any one of silicon, glass, quartz, mica, porcelain, etc. The flexible substrate is, but not limited to, any one of polyamide, polyacetal, polymethylpentene, polyvinyl chloride (PVC), polyurethane, polyoxyxylene, polyoxyxylene sulfide, polyether ketone, polyarylate, polysulfone, polyetherimide, polystyrene, acrylonitrile-butadiene-styrene copolymer, polyoxyxylene resin, polydimethylsiloxane (PDMS), polymethyl methacrylate, polyethylene, polyethylene terephthalate (PET), polypropylene (BOPP), polycarbonate (PC), photosensitive polyimide (PI), cellulose film, polytetrafluoroethylene film (PTFE), polyvinylidene fluoride film, nylon film, etc.

[0014] In the above step 2, the inorganic conductive material is but not limited to: any one of gold, platinum, silver, copper, indium tin oxide (ITO), zinc oxide (ZnO), titanium dioxide (TiO2) doped with aluminum, titanium nitride (TiN), sodium tungstate (NaWO3), lead iodide (CsPbI3), etc.

[0015] In the above step 2, the conductive OLED material is but not limited to: poly(p-phenylene vinylene) (PPV), poly(9,9-dioctylfluorene) (PFO), poly(3,4-ethylenedioxythiophene) (PEDOT) doped polystyrenesulfonic acid (PSS), polyfluorene (PF) derivative triphenylamine derivative (TPD), tris(8-hydroxyquinoline)aluminum (Alq3), anthracene, polycarbazole (PCz), gallium arsenide (GaAs), gallium nitride (GaN), gallium phosphide (GaP), zinc sulfide (ZnS), indium gallium nitride (InGaN), aluminum gallium nitride (AlGaN), aluminum gallium arsenide (AlGaAs), etc.

[0016] In the above step 2, the metal in the electroless metal deposition solution is but not limited to: any one of copper, silver, nickel, gold, etc. The electroless metal deposition solution of copper, silver, nickel, gold is the same as the electroless metal deposition solution disclosed in the prior art.

[0017] In the above step 2, the metal dispersion is, but is not limited to, a dispersion solution of any one of silver nanowires, ITO powder, MXene, carbon black, carbon nanotubes, graphene, carbon fiber, quantum dots, etc. in water or an organic solvent.

[0018] In the above step 2, the conductive polymer is, but not limited to, any one of polyaniline, polypyrrole, polyacetylene, polyphenylene sulfide, polyphenylene, polyphenylene ethylene, polydiyne, polymer liquid crystal, etc.

[0019] In the above step 2, the perovskite precursor is but not limited to: cesium lead bromide (CsPbBr3), cesium tin iodide (CsSnI3), cesium silver bismuth halide (Cs2AgBiBr6), cesium zinc tin halide (Cs2ZnSnI6), diphenylmethane ammonium lead halide ((Ph2CH2NH3)PbX3), fulvenemethylammonium lead halide (C6H5CH2NH3PbX3), etc.

[0020] During the preparation process of the above step 2, when the substrate is a flexible substrate, the substrate modified with the ultra-thin protein nanofilm is further stretched to prepare a photoelectric material.

[0021] The flexible optoelectronic material based on the ultrathin protein nanofilm of the present invention can be used to prepare any of the following: secret information devices, Raman enhancement devices, smart window devices, printed devices, and tactile sensors. The substrate of the optoelectronic material used to prepare the secret information devices or smart window devices is a flexible substrate, while the substrate of the optoelectronic material used to prepare the Raman enhancement devices, printed devices, and tactile sensors is a flexible or non-flexible substrate.

[0022] The beneficial effects of the present invention are as follows:

[0023] 1. The secondary structure of the ultrathin protein nanomembrane of the present invention is mainly α-helix. The unfolded protein forms new disulfide bonds at specific sites through sulfhydryl groups. Single molecules undergo exquisite self-assembly at the solid-liquid interface to form an ultrathin protein nanomembrane. The preparation method is simple and does not require the addition of substances such as polysaccharides and cross-linking agents. The conditions are mild, efficient, safe, and can be prepared on a large area. It is non-selective for the shape of the substrate, has strong adhesion, excellent optical transparency, and good chemical stability and mechanical stability.

[0024] 2. The thickness of the ultra-thin protein nanofilm of the present invention can be controlled according to the concentration of the protein, the concentration of the reducing agent, the pH value and the reaction time. As the film thickness increases, the adhesion weakens.

[0025] 3. The ultrathin protein nanofilm of the present invention has a thickness of approximately 3 to 15 nm and enhances adhesion by balancing the contributions of interfacial and internal adhesion. The ultrathin film effectively reduces defects during the self-assembly process, reduces the possibility of film breakage, and enhances interfacial activity.

[0026] 4. The present invention modifies the substrate with an ultrathin protein nanofilm, increasing the number of oxygen-containing functional groups on the substrate surface, including thiol groups, forming interactions such as gold-sulfur bonds, van der Waals forces, and hydrogen bonds, thereby improving the substrate's surface adhesion. Simultaneously, its ultrathin nature weakens the adhesion of the ultrathin film itself, enhancing interfacial adhesion and preventing the possibility of fracture. This ultrathin protein nanofilm effectively enhances the adhesion between the substrate surface and the conductive coating, maintaining the stability of the conductive coating and withstanding harsh environments such as tearing from 3M Tape, immersion in various solvents, and ultrasound.

[0027] 5. The ultrathin protein nanofilm prepared by this invention has strong adhesion. After modifying the substrate surface, metal layers of varying thicknesses can be deposited on the modified substrate surface through magnetron ion sputtering. The metal layers of varying thicknesses have different colors, enabling flexible metal printing of varying colors. Even after being bent and folded 1,000 times, it can still resist being torn by 3M Tape.

[0028] 6. The ultrathin protein nanofilm prepared by this invention has strong stability and can enhance the stability of metal layers on flexible substrates. When the substrate is in a stretched state, magnetron ion sputtering of the metal layer is performed. The resulting optoelectronic material can withstand multiple ultrasonic cleanings and is reusable. Furthermore, when stretched, hidden information can be revealed. After being bent and stretched 1,000 times, the enhanced Raman spectroscopy signal is still maintained, making it suitable for the preparation of hidden information devices or Raman enhancement devices.

[0029] 7. After the ultrathin protein nanofilm prepared by the present invention is attached to the surface of the substrate, the metal layer is magnetron ion sputtered when the substrate is in different stretching states. The metal coating is used to form wrinkles to produce optical diffraction, which can make the resulting photoelectric material change from a transparent state to an opaque state, realizing transparency control. After being stretched 1000 times, the transparency control function is still maintained, and it can be used to prepare smart window devices.

[0030] 8. After modifying the substrate surface with an ultrathin protein nanofilm, the present invention uses scale structures to design two types of flexible tactile sensors. These devices can be stretched, folded, and twisted. The point-type tactile sensor can control the rotation of a robotic arm, while the multilayer tactile sensor can identify different materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 These are transparency photos and optical images of the ultrathin protein nanofilm prepared in Example 1.

[0032] Figure 2 This is a thickness diagram of the ultrathin protein nanofilm prepared in Example 1.

[0033] Figure 3 This is a secondary structure diagram of the ultrathin protein nanomembrane prepared in Example 1.

[0034] Figure 4 These are microscope optical images of the gold layer deposited by ion sputtering on the surface of the ultrathin protein nanofilm modified PDMS in Example 1, after being soaked in various solvents and resisting tearing with 3M tape.

[0035] Figure 5 These are optical images of the gold layer deposited by ion sputtering on the surface of PDMS modified with protein nanofilms of different thicknesses obtained by standing at room temperature for different reaction times in Example 1, resisting tearing with 3M tape after a 180-degree peeling test using a tensile testing machine.

[0036] Figure 6 This is an optical picture of the secret information transmission of the optoelectronic material in Example 2.

[0037] Figure 7 These are optical photographs and SEM images of the optoelectronic material of Example 3 before and after the 3M tape is torn.

[0038] Figure 8 This is the effect of bending on the usability of the photovoltaic material of Example 3.

[0039] Figure 9 This is the effect of stretching on the usability of the photovoltaic material of Example 3.

[0040] Figure 10 is an optical picture of the photovoltaic material of Example 4 (transparent to opaque).

[0041] Figure 11 This is an optical picture of the photovoltaic material of Example 5 (opaque to transparent).

[0042] Figure 12 This is an optical picture of the optoelectronic material of Example 6.

[0043] Figure 13 3M tape is torn off before and after the capacitance response diagram of the photoelectric material of Example 7.

[0044] Figure 14 This is an optical diagram of the control robot arm of the optoelectronic material of Example 7.

[0045] Figure 15 This is an optical picture of the optoelectronic material of Example 7.

[0046] Figure 16 This is a diagram of the secondary structure of ultra-thin protein nanomembranes prepared from different proteins. DETAILED DESCRIPTION

[0047] The present invention will be further described in detail below with reference to the accompanying drawings and examples, but the protection scope of the present invention is not limited to these examples.

[0048] Example 1

[0049] Step 1: Add 0.7165g tris(2-carboxyethyl)phosphonate to 50mL ultrapure water to prepare a 50mmol / L tris(2-carboxyethyl)phosphonate aqueous solution, and adjust its pH value to 5 with a 5mol / LNaOH aqueous solution; add 100mg bovine serum albumin to 50mL ultrapure water to prepare a 2mg / mL bovine serum albumin aqueous solution; then evenly mix the two solutions in a volume ratio of 1:1 to obtain a mixed solution; add a layer of the mixed solution to the surface of the polypropylene film and maintain a moist environment, then turn the PDMS substrate upside down on the droplets added to the surface of the polypropylene film to fully contact the surface of the PDMS substrate with the droplets, let it stand at room temperature for 40 minutes to form a layer of colorless, transparent, single-molecule protein ultrathin nanofilm at the solid-liquid interface between the PDMS substrate and the droplets, absorb the excess solution on the surface of the PDMS substrate with filter paper, and then dry it naturally in the air to obtain an ultrathin protein nanofilm modified PDMS. By Figure 1 It can be seen that the film formed on the PDMS surface is colorless and transparent, and its transmittance in the visible light band is close to 100%. Figure 2 It can be seen that the thickness of the film is 5.5 nm, which is very thin, close to a monolayer, and can effectively reduce the probability of the bioadhesive layer breaking in the middle. Figure 3 It can be seen that the secondary structure of the protein in the obtained ultrathin protein nanomembrane is α-helix, while the secondary structure of the protein in the traditional protein nanomembrane is β-sheet (preparation method see DOI:10.1002 / adma.202000128, the membrane thickness is about 50nm).

[0050] Step 2: Place the PDMS modified with the ultrathin protein nanofilm in step 1 in a magnetron ion sputtering instrument, perform magnetron ion sputtering for 90 seconds, and deposit a layer of Au on the surface of the ultrathin protein nanofilm in an unstretched state to obtain a photoelectric material composed of an Au layer, an ultrathin protein nanofilm, and PDMS.

[0051] The photoelectric materials obtained above were immersed in deionized water, pH = 1 HCl aqueous solution, pH = 11 NaOH aqueous solution, DMSO, ethanol, pepsin, trypsin, 1 mmol / L vitamin C aqueous solution, and 1% sodium dodecyl sulfate (SDS) aqueous solution for 1 hour, and then tested with 3M tape and atomic force microscopy (see Figure 4Then, the room temperature reaction time in step 1 was extended to 1.5 hours and 6 hours to prepare two different thicknesses of protein nanofilm-modified PDMS and deposit the Au layer. The optical images were taken with a camera using the hundred-grid knife test method (see Figure 5 ).Depend on Figure 4 and Figure 5 It can be seen that the Au layer on the optoelectronic material modified with ultra-thin protein nanofilm (mainly α-helixt structure) can resist the tearing of 3M tape and immersion in various solvents, while the thick protein nanofilm (mainly β-sheet structure) prepared by prolonging the reaction time cannot achieve this effect.

[0052] Example 2

[0053] Step 1 of this example is the same as step 1 of Example 1, and an ultrathin protein nanofilm-modified PDMS is prepared. In step 2 of this example, the ultrathin protein nanofilm-modified PDMS prepared in step 1 is placed in a magnetron ion sputtering apparatus, a five-pointed star template is placed on top of the unstretched PDMS, and magnetron ion sputtering is performed for 5 seconds to deposit a five-pointed star-shaped Au layer on the surface of the ultrathin protein nanofilm, thereby obtaining an optoelectronic material composed of the five-pointed star-shaped Au layer, the ultrathin protein nanofilm, and the PDMS.

[0054] Depend on Figure 6 As can be seen, in the unstretched state, the five-pointed star information is hidden because the PDMS and Au coatings have similar light reflectivity. However, after stretching, the hidden five-pointed star pattern appears. This is because the cracks form perpendicular to the stretching direction, and the Poisson effect enhances light scattering, revealing the hidden five-pointed star information, demonstrating its ability to conceal information. Furthermore, the five-pointed star-shaped Au layer sputtered onto the ultra-thin protein nanofilm-modified PDMS surface can withstand multiple tearing operations with 3M tape. Therefore, the optoelectronic material of this embodiment can be used to prepare secret information devices.

[0055] Example 3

[0056] Step 1 of this example is the same as step 1 of Example 1, and an ultrathin protein nanofilm-modified PDMS is prepared. In step 2 of this example, the ultrathin protein nanofilm-modified PDMS prepared in step 1 is pre-stretched by 50% and then placed in a magnetron ion sputtering apparatus. Magnetron ion sputtering is performed for 90 seconds to deposit a layer of Au on the surface of the ultrathin protein nanofilm, thereby obtaining a composite optoelectronic material comprising an Au layer, an ultrathin protein nanofilm, and PDMS.

[0057] After the Au layer deposited by magnetron sputtering on the PDMS surface modified by ultrathin protein nanofilm and the Au layer deposited by direct magnetron ion sputtering on the PDMS surface were ultrasonicated in deionized water with a power of 150W, the Au layer deposited by magnetron sputtering on the PDMS surface modified by ultrathin protein nanofilm was more stable and the Au layer was basically intact. Figure 7 .

[0058] Rhodamine B is a strong fluorescent dye with a significant Raman scattering cross section. When Rhodamine B molecules are adsorbed on a metal surface with a nanostructure (such as gold or silver nanoparticles), its Raman signal will be significantly enhanced, which is the SERS effect. Due to its strong Raman signal, Rhodamine B is often used as a standard probe molecule in SERS research to calibrate and evaluate SERS. Rhodamine B was used to perform SERS testing on the optoelectronic material obtained in this example. The Raman spectrum showed that the Au layer deposited by magnetron sputtering on the PDMS surface modified with ultra-thin protein nanofilm has the effect of enhancing the Raman spectrum and can be reused many times. Figure 8 and Figure 9 The results show that after being stretched or bent 1000 times by ultrasound, the Raman characteristic spectrum of Rhodamine B still remains stable, which proves that the photoelectric material prepared in this example can be used to prepare Raman enhancement devices and can be reused many times.

[0059] Example 4

[0060] Step 1 of this embodiment is the same as step 1 of Example 1, and an ultrathin protein nanofilm-modified PDMS is prepared. In step 2 of this embodiment, the ultrathin protein nanofilm-modified PDMS in step 1 is placed in a magnetron ion sputtering instrument, and magnetron ion sputtering is performed for 90 seconds in an unstretched state to deposit a layer of Au on the surface of the ultrathin protein nanofilm, thereby obtaining a photoelectric material composed of an Au layer, an ultrathin protein nanofilm, and PDMS. At the same time, a comparative experiment was performed using an Au layer directly deposited by magnetron ion sputtering on the PDMS surface. The results showed that the unstretched photoelectric material exhibited opaque properties, while the stretched photoelectric material exhibited transparent properties. Figure 10 The optical photographs show that the optoelectronic material of this embodiment still has the ability to reversibly change its optical properties after being torn, and can withstand multiple tearings of the 3M tape. Therefore, the optoelectronic material prepared in this embodiment can be used to prepare smart window devices.

[0061] Example 5

[0062] Step 1 of this example is the same as Step 1 of Example 1, and an ultrathin protein nanofilm-modified PDMS is prepared. In Step 2 of this example, the ultrathin protein nanofilm-modified PDMS prepared in Step 1 is pre-stretched 50% and then placed in a magnetron ion sputtering instrument. Magnetron ion sputtering is performed for 90 seconds to deposit an Au layer on the surface of the ultrathin protein nanofilm, thereby obtaining an optoelectronic material comprising the Au layer, ultrathin protein nanofilm, and PDMS. The results showed that the optoelectronic material obtained by pre-stretching the PDMS by 50% and then magnetron ion sputtering the Au layer exhibited opaque properties, but the photoelectric material became transparent after stretching. Figure 11The optical photographs show that the optoelectronic material of this embodiment still has the ability to reversibly change its optical properties after being torn, and can withstand multiple tearings of the 3M tape. Therefore, the optoelectronic material prepared in this embodiment can be used to prepare smart window devices.

[0063] Example 6

[0064] Step 1 of this embodiment is the same as step 1 of embodiment 1, and an ultrathin protein nanofilm-modified PDMS is prepared. In step 2 of this embodiment, the unstretched PDMS modified with the ultrathin protein nanofilm in step 1 is placed in a magnetron ion sputtering instrument, and the ultrathin protein nanofilm-modified PDMS is covered with a five-pointed star template. The magnetron ion sputtering is performed for different times to obtain Au layers of different thicknesses. Figure 12 As can be seen from the optical images, the resulting optoelectronic material reflects light in different colors, and has the ability to be printed on flexible metals. Therefore, the optoelectronic material prepared in this example can be used to prepare printed devices.

[0065] Example 7

[0066] Step 1 of this embodiment is the same as step 1 of embodiment 1, and an ultra-thin protein nanofilm-modified PDMS is prepared. In step 2 of this embodiment, the ultra-thin protein nanofilm-modified PDMS in step 1 is pre-stretched by 50% and then placed in a magnetron ion sputtering instrument. The template covers the ultra-thin protein nanofilm-modified PDMS, and magnetron ion sputtering is performed for 90 seconds to deposit a patterned Au layer on the surface of the ultra-thin protein nanofilm, thereby obtaining a photoelectric material composed of a patterned Au layer, an ultra-thin protein nanofilm, and PDMS. Figure 13 The capacitance response graph shows that compared with the Au layer deposited directly on the PDMS surface by magnetron ion sputtering, the PDMS modified with ultrathin protein nanofilm is more stable to the Au layer and maintains sensitive responsiveness when tested before and after the 3M tape is torn off. Figure 14 As can be seen from the optical picture, the optoelectronic material of this embodiment is integrated into the robot arm to control the robot arm. Figure 15 The photoelectric material of this embodiment is stretchable, bendable, foldable, and has good skin-friendliness. Therefore, the photoelectric material prepared in this embodiment can be used to prepare tactile sensors.

[0067] In step 1 of the above embodiment, the 2 mg / mL bovine serum albumin aqueous solution in Example 1 was replaced with an equal volume of 2 mg / mL lysozyme aqueous solution, 2 mg / mL insulin aqueous solution, or 2 mg / mL human serum albumin aqueous solution, and the reaction time at room temperature was shortened to 10 minutes. The other steps of this step were the same as those in Example 1 to obtain an ultrathin protein nanofilm. Figure 16 It can be seen that lysozyme ( Figure 16 a) Insulin Figure 16 b), human serum albumin ( Figure 16 c) The secondary structure of the proteins in the prepared ultrathin protein nanofilms is α-helix.

Claims

1. A method for preparing an ultrathin protein nanofilm-based optoelectronic material, characterized in that: The method comprises the following steps: Step 1: After adjusting the pH value of a 1-50 mmol / L reducing agent solution to 4.5-5.5 with NaOH, the solution is uniformly mixed with a 0.1-2 mg / mL protein solution at a volume ratio of 1:1 to obtain a mixed solution; a layer of the mixed solution is dropped onto the surface of a hydrophobic material and a moist environment is maintained; then a substrate is inverted on the added droplet to fully contact the substrate surface with the droplet, and the reaction is carried out at room temperature for 20-60 minutes to form a layer of colorless, transparent, single-molecule protein ultrathin nanofilm at the solid-liquid interface between the substrate and the droplet; excess solution on the substrate surface is absorbed with filter paper, and then the substrate is naturally dried in air to obtain an ultrathin protein nanofilm-modified substrate with a thickness of 3-15 nm; Step 2: Depositing a layer of inorganic conductive material or conductive OLED material on the surface of the substrate modified with the ultra-thin protein nanofilm by ion sputtering or evaporation to obtain a photoelectric material; Alternatively, the substrate modified with the ultrathin protein nanofilm is immersed in a 1-50 mmol / L aqueous solution of ammonium tetrachloropalladate, placed in the dark for 5-30 minutes, and then immersed in a metal electroless deposition solution to deposit a metal conductive coating on the surface of the substrate to obtain a photoelectric material; Alternatively, the substrate modified with the ultrathin protein nanofilm is immersed in a 0.5-20 mg / mL metal dispersion and shaken in a shaker for 30-120 minutes to allow the metal conductive coating to be adsorbed on the surface of the substrate to obtain a photoelectric material; Alternatively, the substrate modified with the ultrathin protein nanofilm is immersed in an aqueous solution containing 1-20 mg / mL ferric chloride and 0.05-5 mg / mL conductive polymer monomer, and allowed to stand for 30-60 minutes to allow the conductive polymer to be adsorbed on the surface of the substrate, thereby obtaining a photoelectric material; Alternatively, a perovskite precursor solution is spin-coated on the surface of a substrate modified with an ultrathin protein nanofilm, and then annealed to form a photoelectric material with a surface-modified perovskite crystal film; The protein is selected from any one or more of lysozyme, insulin, β-lactoglobulin, bovine serum albumin, human serum albumin, α-lactalbumin, fibrinogen, β-amyloid protein, transferrin, keratin, hemoglobin, lactoferrin, thyrolactoglobulin, Aβ peptide, α-amylase, pepsin, horseradish peroxidase, ribonuclease A, cystatin C, DNA polymerase, immunoglobulin light chain, fibrinogen, soy protein isolate, and pea protein isolate; The reducing agent is selected from any one or more of cysteine, tris(2-carboxyethyl)phosphine hydrochloride, reduced glutathione, 2-mercaptoethanol, dithiothreitol, dimercaptosuccinic acid, and β-mercaptoethanol.

2. The method for preparing an ultrathin protein nanofilm-based optoelectronic material according to claim 1, wherein: In step 1, the hydrophobic material is selected from any one of polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, polyethylene, polyacrylonitrile, polyacrylic acid or its derivatives, polypropylene, silicone rubber, and nano-coating materials containing hydrophobic function.

3. The method for preparing an ultrathin protein nanofilm-based optoelectronic material according to claim 1, wherein: In step 1, the substrate is a flexible substrate or a non-flexible substrate, the non-flexible substrate is selected from any one of silicon, glass, quartz, mica, and porcelain, and the flexible substrate is selected from any one of polyamide, polyacetal, polymethylpentene, polyvinyl chloride, polyurethane, polyoxyxylene, polyoxyxylene sulfide, polyether ketone, polyarylate, polysulfone, polyetherimide, polystyrene, acrylonitrile-butadiene-styrene copolymer, polyoxyxylene resin, polydimethylsiloxane, polymethyl methacrylate, polyethylene, polyethylene terephthalate, polypropylene, polycarbonate, photosensitive polyimide, cellulose film, polytetrafluoroethylene film, polyvinylidene fluoride film, and nylon film.

4. The method for preparing an ultrathin protein nanofilm-based optoelectronic material according to claim 3, wherein: In step 2, when the substrate is a flexible substrate, the substrate modified with the ultrathin protein nanofilm is stretched to prepare a photoelectric material.

5. The method for preparing an ultrathin protein nanofilm-based optoelectronic material according to claim 1, wherein: In step 2, the inorganic conductive material is selected from any one of gold, platinum, silver, copper, indium tin oxide, zinc oxide, titanium dioxide doped with aluminum, titanium nitride, sodium tungstate, and lead iodide.

6. The method for preparing an ultrathin protein nanofilm-based optoelectronic material according to claim 1, wherein: In step 2, the conductive OLED material is selected from any one of poly(p-phenylene vinylene), poly(9,9-dioctylfluorene), poly(3,4-ethylenedioxythiophene) doped polystyrene sulfonic acid, polyfluorene derivatives, triphenylamine derivatives, tris(8-hydroxyquinoline)aluminum, anthracene, polycarbazole, gallium arsenide, gallium nitride, gallium phosphide, zinc sulfide, indium gallium nitride, aluminum gallium nitride, and aluminum gallium arsenide.

7. The method for preparing an ultrathin protein nanofilm-based optoelectronic material according to claim 1, wherein: In step 2, the metal in the electroless metal deposition solution is any one of copper, silver, nickel and gold.

8. The method for preparing an ultrathin protein nanofilm-based optoelectronic material according to claim 1, wherein: In step 2, the metal dispersion is a dispersion solution of any one of silver nanowires, ITO powder, MXene, carbon black, carbon nanotubes, graphene, carbon fiber, and quantum dots in water or an organic solvent.

9. The method for preparing an ultrathin protein nanofilm-based optoelectronic material according to claim 1, wherein: In step 2, the conductive polymer is selected from any one of polyaniline, polypyrrole, polyacetylene, polyphenylene sulfide, polyphenylene, polyphenylene ethylene, polydiyne, and polymer liquid crystal.

10. The method for preparing an ultrathin protein nanofilm-based optoelectronic material according to claim 1, wherein: In step 2, the perovskite precursor is selected from any one of cesium lead bromide, cesium tin iodide, cesium silver bismuth halide, cesium zinc tin halide, diphenylmethane ammonium lead halide, and fulvenemethylammonium lead halide.

11. Photoelectric material based on ultrathin protein nanofilm prepared by the preparation method according to any one of claims 1 to 10.

12. Use of the optoelectronic material based on ultrathin protein nanofilm according to claim 11 in the preparation of any one of secret information devices, Raman enhancement devices, smart window devices, printed devices, and tactile sensors, wherein the substrate of the optoelectronic material used to prepare the secret information device or smart window device is a flexible substrate, and the substrate of the optoelectronic material used to prepare the Raman enhancement device, printed device, and tactile sensor is a flexible substrate or a non-flexible substrate.

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