Mixed functional molecular film with high stability and preparation method and application thereof

Abstract

The invention belongs to the technical field of molecular electronics, and particularly relates to a mixed functional molecular film with high stability and a preparation method and application thereof. The mixed functional molecular film comprises a gold substrate, and a self-assembled molecular film and a reinforcing body which are positioned on the surface of the gold substrate, the self-assembled molecular film sequentially comprises an anchoring layer, a functional layer and a bridging layer from bottom to top. Compared with Rh2-ABP, the mixed functional molecular film prepared by the invention has the advantages that the non-breakdown probability can be increased from 10% to 89%, the maximum breakdown voltage can be increased from 2.4 V to 3.5 V, and the electrical stability of the molecular film is remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of molecular electronics, and more specifically relates to a mixed functional molecular film with high stability and a preparation method and application thereof. Background Art

[0002] As an emerging field of molecular electronics, hybrid molecular electronics provides researchers with a platform that allows them to explore unlimited space. Although homogeneous molecules for molecular devices have been intensively studied, the impact of the hybrid assembly of different molecules on various aspects of molecular devices has just attracted attention. The advantages of hybrid molecular electronics, especially its potential to increase the overall diversity and complexity of devices, are still a treasure to be tapped.

[0003] In some schemes, there are certain problems with the electrical stability (breakdown probability, breakdown voltage) of functional molecular membranes containing bimetallic coordination units during use. Therefore, how to obtain a molecular membrane with better electrical stability has become a difficult problem that technicians in this field urgently need to overcome. Summary of the invention

[0004] The purpose of the present invention is to provide a mixed functional molecular membrane with high stability and a preparation method and application thereof, so as to solve the problems existing in the above-mentioned prior art.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention is to provide a hybrid functional molecular film with high stability, wherein the hybrid functional molecular film comprises a gold substrate and a self-assembled molecular film located on the surface of the gold substrate, and a reinforcing body vertically inserted into the self-assembled molecular film;

[0007] The self-assembled molecular film comprises an anchoring layer, a functional layer and a bridging layer from bottom to top;

[0008] The anchoring layer includes 4-mercaptoethylpyridine and / or mercaptopyridine; the functional layer includes a bimetallic complex and a photosensitive molecule; the bridging layer includes a bimetallic complex and a Lewis base bridging ligand; and the reinforcing body is n-alkanethiol.

[0009] In the present invention, the layer-by-layer self-assembled molecular film layer grows on the gold substrate by forming covalent gold-sulfur bonds with the gold substrate by means of the anchoring groups in the anchoring layer.

[0010] Furthermore, the bimetallic complex includes at least one of rhodium trifluoroacetate dimer ([Rh2(O2CCF3)4]), rhodium acetate dimer, trimethyl rhodium acetate dimer and chromium acetate.

[0011] Furthermore, the photosensitive molecule includes at least one of 9,10-di(4-pyridyl)anthracene, 1,6-di(pyridin-4-yl)pyrene and tetrapyridylporphyrin.

[0012] Furthermore, the Lewis base bridging ligand includes at least one of pyrazine, 1,2-bis(4-pyridyl)ethane and 1,2-bis(4-pyridyl)ethylene.

[0013] Furthermore, the n-alkanethiol includes at least one of 18-thiol, 14-thiol and 10-thiol.

[0014] The second technical solution of the present invention is to provide a method for preparing the above-mentioned mixed functional molecular film with high stability, the steps comprising:

[0015] The gold substrate is immersed in the anchoring layer ethanol solution to obtain a first molecular film;

[0016] Soaking the first molecular film in a bimetallic complex ethanol solution and a photosensitive molecule ethanol solution in sequence to obtain a second molecular film;

[0017] The second molecular film is immersed in a bimetallic complex ethanol solution and a Lewis base bridging ligand ether solution in sequence to obtain a functional molecular film;

[0018] The functional molecular membrane is immersed in an ethanol solution of n-alkanethiol to obtain the mixed functional molecular membrane with high stability.

[0019] Furthermore, the anchoring layer ethanol solution is 4-mercaptoethylpyridine ethanol solution and / or mercaptopyridine ethanol solution, and the concentration is 0.2 mM.

[0020] Furthermore, the concentration of the bimetallic complex ethanol solution is 0.2 mM, wherein the bimetallic complex includes at least one of rhodium trifluoroacetate dimer, rhodium acetate dimer, trimethyl rhodium acetate dimer and chromium acetate.

[0021] Furthermore, the concentration of the photosensitive molecule ethanol solution is 0.2 mM, wherein the photosensitive molecule includes at least one of 9,10-di(4-pyridyl)anthracene, 1,6-di(pyridin-4-yl)pyrene and tetrapyridylporphyrin.

[0022] Furthermore, the concentration of the Lewis base bridging ligand ether solution is 0.1 mM, wherein the Lewis base bridging ligand includes at least one of oxazine, 1,2-bis(4-pyridyl)ethane and 1,2-bis(4-pyridyl)ethylene.

[0023] Furthermore, the concentration of the n-alkanethiol ethanol solution is 0.2-20 mM, wherein the n-alkanethiol includes at least one of 18-thiol, 14-thiol and 10-thiol.

[0024] Furthermore, the gold substrate is immersed in the 4-mercaptoethylpyridine ethanol solution for 30 minutes to 3 hours.

[0025] Furthermore, the first molecular film is immersed in the bimetallic complex ethanol solution at a temperature of -15°C for a time of 30 minutes to 3 hours.

[0026] Furthermore, the first molecular film is immersed in the photosensitive molecular ethanol solution for 5 min to 30 min.

[0027] Furthermore, the second molecular film is immersed in the bimetallic complex ethanol solution at a temperature of -15°C for a time of 1 min to 10 min.

[0028] Furthermore, the second molecular film is immersed in the Lewis base bridging ligand ether solution for 1 min to 10 min.

[0029] Furthermore, the functional molecular membrane is immersed in the n-alkanethiol ethanol solution for 2 minutes to 12 hours.

[0030] Furthermore, the method further includes the steps of flushing with ethanol and purging with nitrogen for drying before changing the soaking solution each time.

[0031] Furthermore, the steps of preparing the gold substrate include:

[0032] S1. Prepare mica gold by vacuum evaporation method: Place the mica sheet on the base of the vacuum evaporation instrument, which is located directly above the tungsten boat tray used to place the pure gold wire. -5 -7×10 -6 Rapidly evaporating gold with a thickness of 120nm-180nm onto a mica sheet at a speed of 1.0Å-3.0Å under a Torr vacuum to obtain the mica gold;

[0033] S2. Prepare a gold substrate using the mica gold: wash the cover glass with piranha solution, water and ethanol in turn, and dry it in N2, stick the dried cover glass on the gold film surface of the mica gold with EPO-TEK 353ND glue (A and B glues are mixed at a ratio of 10:1), cure it at 150°C for 2h, and then peel off the cover glass from the mica substrate to obtain a gold film with extremely high flatness (super flat gold), which is the gold substrate.

[0034] The third technical solution of the present invention is to provide an application of the above-mentioned mixed functional molecular film with high stability in molecular electronic devices.

[0035] Furthermore, the molecular electronic devices include molecular switch devices, molecular rectifier devices and molecular wire devices.

[0036] The hybrid functional molecular film provided by the present invention can enhance the electrical stability when applied to molecular electronic devices.

[0037] The fourth technical solution of the present invention is to provide an application of the above-mentioned mixed functional molecular film with high stability in molecular photoelectric detection.

[0038] Technical solution 5 of the present invention: A method for improving the electrical stability of a functional molecular film is provided, the steps comprising:

[0039] The functional molecular film is immersed in an ethanol solution of n-alkanethiol to obtain a functional molecular film with high electrical stability.

[0040] Furthermore, the functional molecular membrane is immersed in the n-alkanethiol ethanol solution for 2 minutes to 12 hours.

[0041] Furthermore, the concentration of the n-alkanethiol ethanol solution is 0.2-20 mM.

[0042] Furthermore, the n-alkanethiol in the n-alkanethiol ethanol solution includes at least one of 18-thiol, 14-thiol and 10-thiol.

[0043] Furthermore, the preparation steps of the functional molecular film include:

[0044] The gold substrate is immersed in the anchoring layer ethanol solution to obtain a first molecular film;

[0045] Soaking the first molecular film in a bimetallic complex ethanol solution and a photosensitive molecule ethanol solution in sequence to obtain a second molecular film;

[0046] The second molecular membrane is sequentially immersed in a bimetallic complex ethanol solution and a Lewis base bridging ligand ether solution to obtain the functional molecular membrane.

[0047] Optionally, the anchoring layer ethanol solution is 4-mercaptoethylpyridine ethanol solution and / or mercaptopyridine ethanol solution, and the concentration is 0.2 mM.

[0048] Optionally, the concentration of the bimetallic complex ethanol solution is 0.2 mM, wherein the bimetallic complex includes at least one of rhodium trifluoroacetate dimer, rhodium acetate dimer, trimethyl rhodium acetate dimer and chromium acetate.

[0049] Optionally, the concentration of the photosensitive molecule ethanol solution is 0.2 mM, wherein the photosensitive molecule includes at least one of 9,10-di(4-pyridyl)anthracene, 1,6-di(pyridin-4-yl)pyrene and tetrapyridylporphyrin.

[0050] Optionally, the concentration of the Lewis base bridging ligand ether solution is 0.1 mM, wherein the Lewis base bridging ligand includes at least one of oxazine, 1,2-bis(4-pyridyl)ethane and 1,2-bis(4-pyridyl)ethylene.

[0051] Optionally, the gold substrate is immersed in the anchoring layer ethanol solution for 30 minutes to 3 hours.

[0052] Optionally, the first molecular film is immersed in the bimetallic complex ethanol solution at a temperature of -15°C for a time of 30 min-3 h.

[0053] Optionally, the first molecular film is immersed in the photosensitive molecular ethanol solution for 5 min-30 min.

[0054] Optionally, the second molecular film is immersed in the bimetallic complex ethanol solution at a temperature of -15°C for a time of 1 min to 10 min.

[0055] Optionally, the second molecular film is immersed in the Lewis base bridging ligand ether solution for 1 min-10 min.

[0056] Optionally, the method further includes the steps of flushing with ethanol and drying with nitrogen purge before each replacement of the immersion solution.

[0057] The present invention discloses the following technical effects:

[0058] The present invention introduces n-alkanethiol into the functional molecular film to obtain a mixed functional molecular film with excellent electrical stability. Compared with the functional molecular film, the probability of not being broken down can be increased from 10% to 89%, and the maximum breakdown voltage can be increased from 2.4V to 3.5V.

[0059] The method for improving the electrical stability of the functional molecular film of the present invention is universal on various functional molecular films, and can enhance the electrical stability of molecular switch devices, molecular rectifier devices, and molecular wire devices.

[0060] Compared with the molecular film formed by pure functional molecules, the hybrid functional molecular film of the present invention shows better electrical performance. The introduction of n-alkanethiol does not affect the functionality of the functional molecular film, and it is universal for a variety of different functional molecules. Specifically, the self-assembled film of n-alkanethiol was widely studied in the early stage of molecular electronics because n-alkanethiol is easy to obtain and easy to adsorb to form dense SAMs (functional molecular films). Therefore, when making mixed SAMs, n-alkanethiol is selected as another component of the mixed SAMs. The switching phenomenon of the assembled double rhodium functional molecules comes from the single molecule effect rather than the cluster, and the surface potential test shows that the potential difference between the mixed SAMs and the pure functional molecule SAMs is very small, which can explain that the gold / molecule work function formed has not changed, which is the reason why the function of the functional molecule is not affected. After the insertion of n-alkanethiol, a denser mixed SAMs is obtained, and the intrinsic conductivity of n-alkanethiol and the conductivity of the functional molecules are several orders of magnitude different, so that the conductivity displayed by the mixed SAMs will not be affected.

[0061] The method of the present invention has significant guiding significance for the research of hybrid SAMs in the field. When the functional molecules are difficult to form a dense molecular film due to their own steric hindrance, another molecule with small steric hindrance and easy to combine with the substrate to form a dense molecular film is added to make up for the defects caused by the non-density of the pure functional molecular film, which extends the research of hybrid molecular electronics and is of great significance for meeting the needs of future high-performance electronic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0063] Figure 1 Schematic diagram of the structure and mechanism of Rh2-ABP.

[0064] Figure 2 This is a schematic diagram of the process flow of inserting 18-thiol into Rh2-ABP in step S4 of Example 1.

[0065] Figure 3 The differential voltammograms of 18-thiol molecular film, Layer 1 oligomer (rhodium trifluoroacetate dimer + 9,10-di(4-pyridyl)anthracene), Layer 2 oligomer (rhodium trifluoroacetate dimer + pyrazine), Rh2-ABP and Rh2-ABP / 18-thiol, wherein (A) is the differential voltammogram of Layer 1 oligomer, (B) is the differential voltammogram of Layer 2 oligomer, (C) is the differential voltammogram of 18-thiol molecular film, and (D) is the differential voltammogram of Rh2-ABP and Rh2-ABP / 18-thiol.

[0066] Figure 4 are the contact angles of 18-thiol molecular film, Rh2-ABP, and Rh2-ABP / 18-thiol, wherein (A) is the contact angle of 18-thiol molecular film, (B) is the contact angle of Rh2-ABP, and (C) is the contact angle of Rh2-ABP / 18-thiol.

[0067] Figure 5 Surface potentials of 18-thiol molecular film, Rh2-ABP, and Rh2-ABP / 18-thiol, where (A) is the surface potential of 8-thiol molecular film, (B) is the surface potential of Rh2-ABP, and (C) is the surface potential of Rh2-ABP / 18-thiol.

[0068] Figure 6 The IV properties of Rh2-ABP / 18-thiol, where (a) is without UV irradiation and (b) is under UV irradiation.

[0069] Figure 7 The non-breakdown probability and the maximum breakdown voltage of the molecular films obtained in Example 1 and Example 2, wherein (A) is the non-breakdown probability and (B) is the maximum breakdown voltage.

[0070] Figure 8 The non-breakdown probability and the maximum breakdown voltage of the molecular films obtained in Example 1 and Example 3, wherein (A) is the non-breakdown probability and (B) is the maximum breakdown voltage.

[0071] Fig. 9 The IV curves and electrical stabilities of Rh2-ZL and Rh2-ZL / 18-thiol, where (A) is the IV curve of Rh2-ZL, (B) is the IV curve of Rh2-ZL / 18-thiol, and (C) is the electrical stability.

[0072] Fig.10 The IV curves and electrical stabilities of Rh2-DX and Rh2-DX / 18-thiol, where (A) is the IV curve of Rh2-DX, (B) is the IV curve of Rh2-DX / 18-thiol, and (C) is the electrical stability. DETAILED DESCRIPTION

[0073] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0074] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0075] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0076] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0077] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0078] Unless otherwise specified, the "room temperature" and "normal temperature" referred to in the specific embodiments of the present invention refer to 20-30°C.

[0079] The raw materials and reagents used in the specific embodiments of the present invention are all commercially available products.

[0080] The steps for preparing the gold substrate used in the specific embodiment of the present invention include:

[0081] S1. Prepare mica gold by vacuum evaporation method: Place the mica sheet on the base of the vacuum evaporation instrument, which is located directly above the tray of the pure gold wire tungsten boat. -5 -7×10 -6 Rapidly evaporating gold with a thickness of 120nm-180nm onto a mica sheet at a speed of 1.0-3.0Å under a vacuum degree of Torr to obtain the mica gold;

[0082] S2. Prepare a gold substrate using the mica gold: wash the cover glass with piranha solution, water and ethanol in turn, and dry it in N2, stick the dried cover glass on the gold film surface of the mica gold with EPO-TEK 353ND glue (A and B glues are mixed at a ratio of 10:1), cure it at 150°C for 2h, and then peel off the cover glass from the mica substrate to obtain a gold film with extremely high flatness (super flat gold), which is the gold substrate.

[0083] Example 1

[0084] The steps for preparing the mixed functional molecular membrane with high stability include:

[0085] S1, immersing the prepared gold substrate (ultra-flat gold) in 0.2 mM 4-mercaptoethylpyridine ethanol solution at room temperature for 1 hour, washing with ethanol and drying by nitrogen purge, to obtain an anchoring group molecular film (first molecular film);

[0086] S2, soaking the anchoring group molecular film in 0.2 mM trifluoroacetate rhodium dimer ethanol solution at -15°C for 1 hour, rinsing with ethanol and drying by nitrogen purge, then soaking in 0.2 mM 9,10-di(4-pyridyl)anthracene ethanol solution at room temperature for 10 minutes, rinsing with ethanol and drying by nitrogen purge, to obtain the anchoring group-Layer1 molecular film (second molecular film);

[0087] S3, soak the anchor group-Layer1 molecular film in 0.2 mM trifluoroacetate rhodium dimer ethanol solution at -15 ° C for 2 minutes, rinse with ethanol and dry with nitrogen purge, then soak it in 0.1 mM pyrazine ether solution at room temperature for 2 minutes, rinse with ethanol and dry with nitrogen purge to obtain the anchor group-Layer1-Layer2 molecular film, that is, the functional molecular film, such as Figure 1 Shown is a photoswitch molecular film (Rh2-ABP);

[0088] S4, the anchoring group-Layer1-Layer2 molecular membrane was immersed in 2 mM 18-thiol ethanol solution at room temperature for 1 hour, rinsed with ethanol and dried by nitrogen purge to obtain a mixed functional molecular membrane with high stability, which was recorded as Rh2-ABP / 18-thiol. The process flow is as follows: Figure 2 shown.

[0089] Figure 1 The schematic diagram and mechanism diagram of Rh2-ABP. As can be seen from the figure, on the gold substrate surface, from bottom to top, there are anchoring groups 4-mercaptoethylpyridine, Layer 1 is [Rh2(O2CCF3)4] and 9,10-di(4-pyridyl)anthracene, and Layer 2 is [Rh2(O2CCF3)4] and pyrazine.

[0090] Figure 2This is a schematic diagram of the process flow of inserting 18-thiol in step S4 of Example 1.

[0091] The structure of the molecular membrane of Example 1 was characterized by differential voltammetry using Chenhua electrochemical workstation CH1760E. The results are as follows: Figure 3 shown.

[0092] Figure 3 The differential voltammograms of 18-thiol molecular film, Layer 1 oligomer (rhodium trifluoroacetate dimer + 9,10-di(4-pyridyl)anthracene), Layer 2 oligomer (rhodium trifluoroacetate dimer + pyrazine), Rh2-ABP and Rh2-ABP / 18-thiol, wherein (A) is the differential voltammogram of Layer 1 oligomer, (B) is the differential voltammogram of Layer 2 oligomer, (C) is the differential voltammogram of 18-thiol molecular film, and (D) is the differential voltammogram of Rh2-ABP and Rh2-ABP / 18-thiol. As can be seen from the figure, the peak positions of Rh2-ABP and Rh2-ABP / 18-thiol are between Layer 1 oligomers and Layer 2 oligomers, and no obvious peak position was found in the 18-thiol molecular film, which proves that the mixed molecular film (Rh2-ABP / 18-thiol) was successfully grown on the surface of the gold substrate and Rh2-ABP was still successfully anchored on the surface of the gold substrate.

[0093] The contact angles of 18-thiol molecular film, Rh2-ABP, and Rh2-ABP / 18-thiol were tested using the Dataphysics Instruments GmbH fully automatic contact angle contact instrument OAC100. The results are as follows: Figure 4 shown.

[0094] Figure 4 are the contact angles of 18-thiol molecular film, Rh2-ABP, and Rh2-ABP / 18-thiol, wherein (A) is the contact angle of 18-thiol molecular film, (B) is the contact angle of Rh2-ABP, and (C) is the contact angle of Rh2-ABP / 18-thiol. As can be seen from the figure, the contact angle of Rh2-ABP is 37°, and the contact angle of Rh2-ABP / 18-thiol is 46°. This is due to the terminal group pyrazine. At the same time, the 18-thiol molecular film is hydrophobic, which further shows that Rh2-ABP in Rh2-ABP / 18-thiol is still successfully anchored, because the contact angle of the mixed molecular film is still hydrophilic, indicating that there are still a large number of Rh2-ABP molecules with pyrazine as the end in the mixed molecular film. 18-thiol has little effect on the contact angle due to its shorter length than the functional molecules, which also shows that the Rh2-ABP molecules have not been replaced by 18-thiol on a large scale in the exchange competition.

[0095] The surface potential of 18-thiol molecular film, Rh2-ABP, and Rh2-ABP / 18-thiol was measured using a Bruker Multimode 8 atomic force microscope. The results are shown in Figure 5 shown.

[0096] Figure 5 The surface potentials of 18-thiol molecular film, Rh2-ABP, and Rh2-ABP / 18-thiol, where (A) is the surface potential of 8-thiol molecular film, (B) is the surface potential of Rh2-ABP, and (C) is the surface potential of Rh2-ABP / 18-thiol. As can be seen from the figure, the surface potentials of Rh2-ABP and Rh2-ABP / 18-thiol are similar, which indicates that the insertion of 18-thiol does not have a significant impact on the surface work function, which can prove that Rh2-ABP / 18-thiol can maintain the characteristics of Rh2-ABP and does not change significantly due to the insertion of 18-thiol.

[0097] The IV properties of Rh2-ABP / 18-thiol were tested using STM-BJ4.0 from X-TECH. Figure 6 shown.

[0098] Figure 6 Figure 2 is the IV property of Rh2-ABP / 18-thiol, where (a) is without UV irradiation, and (b) is under UV irradiation. It can be seen from the figure that under the stimulation of 365nm UV light, the Rh2-ABP / 18-thiol device shows a switching response.

[0099] Example 2

[0100] Compared with Example 1, the difference is that the time for soaking in the 2 mM 18-thiol ethanol solution in step S4 is 0 min, 2 min, 5 min, 10 min, 30 min or 120 min.

[0101] Among them, the 0min solution obtains the anchoring group-Layer1-Layer2 molecular membrane in step S3, also known as the functional molecular membrane, denoted as Rh2-ABP.

[0102] The molecular films prepared in Example 1 and Example 2 were tested for performance using a Bruker Multimode 8 atomic force microscope. The specific method is as follows: a bias voltage is applied between the conductive probe and the sample, and the breakdown voltage and breakdown probability of the sample under a bias voltage of 1 V are tested. Each time, a point is taken at a different position to ensure that the breakdown is not affected by the previous needle configuration voltage. The performance diagram is shown in FIG. Figure 7 shown.

[0103] Figure 7The non-breakdown probability and maximum breakdown voltage of the molecular film obtained in Example 1 and Example 2, where (A) is the non-breakdown probability and (B) is the maximum breakdown voltage. As can be seen from the figure, after inserting 18-thiol, the non-breakdown probability of Rh2-ABP / 18-thiol obtained with different immersion times relative to Rh2-ABP can be increased from 10% to 89% at most, and the maximum breakdown voltage can be increased from 2.4V to 3.5V at most.

[0104] Example 3

[0105] Compared with Example 1, the difference is that the concentration of the 18-thiol ethanol solution in step S4 is 0.2 mM and 20 mM.

[0106] Among them, the 0 mM solution obtained the anchoring group-Layer1-Layer2 molecular membrane in step S3, also known as the functional molecular membrane, denoted as Rh2-ABP.

[0107] The molecular films prepared in Example 1 and Example 3 were tested for performance using a Bruker Multimode 8 atomic force microscope. The specific method is as follows: a bias voltage is applied between the conductive probe and the sample, and the breakdown voltage and breakdown probability of the sample under a bias voltage of 1 V are tested. Each time, a point is taken at a different position to ensure that the breakdown is not affected by the previous needle configuration voltage. The performance diagram is shown in FIG. Figure 8 shown.

[0108] Figure 8 The non-breakdown probability and maximum breakdown voltage of the molecular films obtained in Example 1 and Example 3, where (A) is the non-breakdown probability and (B) is the maximum breakdown voltage. As can be seen from the figure, after inserting 18-thiol, the non-breakdown probability and maximum breakdown voltage of Rh2-ABP / 18-thiol obtained by soaking in different 18-thiol ethanol solution concentrations are improved relative to Rh2-ABP, and the Rh2-ABP / 18-thiol obtained at a 2mM soaking concentration achieves the best electrical stability effect.

[0109] Example 4

[0110] Compared with Example 1, the Lewis base bridging ligand used was 1,2-bis(4-pyridyl)ethane, and the specific growth sequence was as follows:

[0111] S1, soaking the prepared ultra-flat gold in a 0.2 mM 4-mercaptoethylpyridine ethanol solution of the anchoring group at room temperature for 1 hour, washing with ethanol and drying with nitrogen purge to obtain an anchoring group molecular film;

[0112] S2, soaking the anchoring group molecular membrane in 0.2 mM rhodium acetate dimer ethanol solution at -15°C for 1 hour, rinsing with ethanol and drying by nitrogen purge, then soaking in 0.1 mM pyrazine ether solution at room temperature for 10 minutes, rinsing with ethanol and drying by nitrogen purge;

[0113] S3, soaking the molecular film obtained in step S2 in 0.2 mM rhodium acetate dimer ethanol solution at -15°C for 2 min, rinsing with ethanol and drying by nitrogen purge, then soaking in 0.1 mM 1,2-bis(4-pyridyl)ethane ethanol solution at room temperature for 2 min, rinsing with ethanol and drying by nitrogen purge;

[0114] S4, soaking the molecular film obtained in step S3 in 0.2 mM rhodium trifluoroacetate dimer ethanol solution at -15°C for 2 min, rinsing with ethanol and drying by nitrogen purge, then soaking in 0.1 mM pyrazine ether solution at room temperature for 2 min, rinsing with ethanol and drying by nitrogen purge, repeating the above operation in step S4 twice to obtain a molecular rectifier molecular film (Rh2-ZL);

[0115] S4. The molecular rectifier molecular film is immersed in a 2 mM 18-thiol ethanol solution at room temperature for 1 hour, rinsed with ethanol and dried by nitrogen purge to obtain a mixed molecular film (Rh2-ZL / 18-thiol).

[0116] Example 5

[0117] Compared with Example 4, the Lewis base bridging ligand used was 1,2-bis(4-pyridyl)ethylene, and the remaining steps were the same as Example 4. The molecular membranes obtained were molecular wire molecular membranes (Rh2-DX) and mixed molecular membranes (Rh2-DX / 18-thiol).

[0118] Fig. 9 The IV curves and electrical stabilities of Rh2-ZL and Rh2-ZL / 18-thiol, wherein (A) is the IV curve of Rh2-ZL, (B) is the IV curve of Rh2-ZL / 18-thiol, and (C) is the electrical stability; Fig.10 The IV curves and electrical stabilities of Rh2-DX and Rh2-DX / 18-thiol, where (A) is the IV curve of Rh2-DX, (B) is the IV curve of Rh2-DX / 18-thiol, and (C) is the electrical stability. Figure 9-10 It can be seen that, with the same molecular switch Rh2-ABP / 18-thiol, the functions of the molecular rectifier mixed molecular membrane (Rh2-ZL / 18-thiol) and the molecular wire mixed molecular membrane (Rh2-DX / 18-thiol) are not affected, and the electrical stability is improved compared with the pure functional molecular membrane.

[0119] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0120] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A hybrid functional molecular film with high stability, characterized in that: The hybrid functional molecular film comprises a gold substrate, a self-assembled molecular film located on the surface of the gold substrate, and a reinforcing body vertically inserted into the self-assembled molecular film; The self-assembled molecular film comprises an anchoring layer, a functional layer and a bridging layer from bottom to top; The anchoring layer includes 4-mercaptoethylpyridine and / or mercaptopyridine; the functional layer includes a bimetallic complex and a photosensitive molecule; the bridging layer includes a bimetallic complex and a Lewis base bridging ligand; the reinforcing body is n-alkanethiol; The bimetallic complex comprises at least one of rhodium trifluoroacetate dimer, rhodium acetate dimer, trimethyl rhodium acetate dimer and chromium acetate; The photosensitive molecule includes at least one of 9,10-di(4-pyridyl)anthracene, 1,6-di(pyridin-4-yl)pyrene and tetrapyridylporphyrin; The Lewis base bridging ligand includes at least one of pyrazine, 1,2-bis(4-pyridyl)ethane and 1,2-bis(4-pyridyl)ethylene; The n-alkanethiol includes at least one of 18-thiol, 14-thiol and 10-thiol.

2. A method for preparing a hybrid functional molecular film with high stability as claimed in claim 1, characterized in that the steps include: The gold substrate is immersed in the anchoring layer ethanol solution to obtain a first molecular film; Soaking the first molecular film in a bimetallic complex ethanol solution and a photosensitive molecule ethanol solution in sequence to obtain a second molecular film; The second molecular film is immersed in a bimetallic complex ethanol solution and a Lewis base bridging ligand ether solution in sequence to obtain a functional molecular film; The functional molecular membrane is immersed in an ethanol solution of n-alkanethiol to obtain the mixed functional molecular membrane with high stability.

3. The preparation method according to claim 2, characterized in that: The anchoring layer ethanol solution is 4-mercaptoethylpyridine ethanol solution and / or mercaptopyridine ethanol solution, with a concentration of 0.2 mM; and / or, The concentration of the bimetallic complex ethanol solution is 0.2 mM, wherein the bimetallic complex comprises at least one of rhodium trifluoroacetate dimer, rhodium acetate dimer, trimethyl rhodium acetate dimer and chromium acetate; and / or, The concentration of the photosensitive molecule ethanol solution is 0.2 mM, wherein the photosensitive molecule includes at least one of 9,10-di(4-pyridyl)anthracene, 1,6-di(pyridin-4-yl)pyrene and tetrapyridylporphyrin; and / or, The concentration of the Lewis base bridging ligand ether solution is 0.1 mM, wherein the Lewis base bridging ligand comprises at least one of oxazine, 1,2-bis(4-pyridyl)ethane and 1,2-bis(4-pyridyl)ethylene; and / or, The concentration of the n-alkanethiol ethanol solution is 0.2-20 mM, wherein the n-alkanethiol includes at least one of 18-thiol, 14-thiol and 10-thiol.

4. The preparation method according to claim 2, characterized in that: The gold substrate is immersed in the 4-mercaptoethylpyridine ethanol solution for 30 min-3 h; and / or, The first molecular film is immersed in the bimetallic complex ethanol solution at a temperature of -15°C for a time of 30 minutes to 3 hours; and / or, The first molecular film is immersed in the photosensitive molecular ethanol solution for 5 min to 30 min; and / or, The second molecular film is immersed in the bimetallic complex ethanol solution at a temperature of -15°C for a time of 1 min to 10 min; and / or, The second molecular film is immersed in the Lewis base bridging ligand ether solution for 1 min to 10 min; and / or, The functional molecular membrane is immersed in the n-alkanethiol ethanol solution for 2 minutes to 12 hours.

5. The preparation method according to claim 2, characterized in that: It also includes the steps of flushing with ethanol and drying with nitrogen purge before each replacement of the immersion solution.

6. The preparation method according to claim 2, characterized in that: The steps of preparing the gold substrate include: S1. Prepare mica gold by vacuum evaporation method: Place the mica sheet on the base of the vacuum evaporation instrument, which is located directly above the tungsten boat tray used to place the pure gold wire. -5 -7×10 -6 Rapidly evaporating gold with a thickness of 120nm-180nm onto a mica sheet at a speed of 1.0-3.0Å under a vacuum degree of Torr to obtain the mica gold; S2. Prepare a gold substrate using the mica gold: wash the cover glass with piranha solution, water and ethanol in sequence, and dry it in N2, adhere the dried cover glass to the gold film surface of the mica gold with EPO-TEK 353ND glue, cure it at 150° C. for 2 hours, and then peel the cover glass from the mica substrate to obtain a gold film with extremely high flatness, which is the gold substrate; Among them, glue A and glue B in EPO-TEK 353ND glue are mixed in a volume ratio of 10:

1.

7. Use of the highly stable hybrid functional molecular film according to claim 1 in molecular electronic devices.

8. Use of the highly stable mixed functional molecular film according to claim 1 in molecular photoelectric detection.

9. A method for improving the electrical stability of a functional molecular film, characterized in that the steps include: The functional molecular film is immersed in an ethanol solution of n-alkanethiol to obtain a functional molecular film with high electrical stability; The soaking time is 2min-12h; The concentration of the n-alkanethiol ethanol solution is 0.2-20 mM; The n-alkanethiol in the n-alkanethiol ethanol solution comprises at least one of 18-thiol, 14-thiol and 10-thiol; The preparation steps of the functional molecular film include: soaking the gold substrate in an anchoring layer ethanol solution to obtain a first molecular film; soaking the first molecular film in a bimetallic complex ethanol solution and a photosensitive molecule ethanol solution in sequence to obtain a second molecular film; soaking the second molecular film in a bimetallic complex ethanol solution and a Lewis base bridging ligand ether solution in sequence to obtain the functional molecular film; The anchoring layer ethanol solution is 4-mercaptoethylpyridine ethanol solution and / or mercaptopyridine ethanol solution, and the concentration is 0.2mM; the concentration of the bimetallic complex ethanol solution is 0.2mM, wherein the bimetallic complex includes at least one of trifluoroacetate rhodium dimer, acetate rhodium dimer, trimethylacetate rhodium dimer and chromium acetate; the concentration of the photosensitive molecule ethanol solution is 0.2mM, wherein the photosensitive molecule includes at least one of 9,10-di(4-pyridyl)anthracene, 1,6-di(pyridin-4-yl)pyrene and tetrapyridylporphyrin; the concentration of the Lewis base bridging ligand ether solution is 0.1mM, wherein the Lewis base bridging ligand includes at least one of oxazine, 1,2-bis(4-pyridyl)ethane and 1,2-bis(4-pyridyl)ethylene; The gold substrate is immersed in the anchoring layer ethanol solution for 30 minutes to 3 hours; the first molecular film is immersed in the bimetallic complex ethanol solution at a temperature of -15°C for 30 minutes to 3 hours; the first molecular film is immersed in the photosensitive molecule ethanol solution for 5 minutes to 30 minutes; the second molecular film is immersed in the bimetallic complex ethanol solution at a temperature of -15°C for 1 minute to 10 minutes; the second molecular film is immersed in the Lewis base bridging ligand ether solution for 1 minute to 10 minutes.

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