Colloid atomic layer deposition method for wurtzite Zn-based nanosheet non-polar surface

Abstract

The invention provides a colloidal atomic layer deposition method for a wurtzite Zn-based nanosheet non-polar surface, and belongs to the technical field of chemical engineering. The zinc oleate ligand exchanges the original oleylamine ligand, the zinc oleate is deposited on a non-polar surface to form a Zn < 2 + >-rich polar surface, and then anion deposition is performed, so that epitaxial growth of a homogeneous or heterogeneous material in the thickness direction of the oil-soluble Zn-based nanosheet is realized, and the thickness of the Zn-based nanosheet is increased or a core-shell structure is constructed. The optical property of the Zn-based nanosheet is regulated and controlled by increasing the thickness and constructing the core-shell structure. According to the method, the problem that epitaxial growth in the thickness direction is difficult to realize on the non-polar surface of the nanosheet in the traditional colloid atomic layer deposition is solved.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, specifically to a colloidal atomic layer deposition method for the nonpolar surface of fibrous zinc ore Zn-based nanosheets. Background Technology

[0002] Due to the quantum confinement effect in the thickness direction, the epitaxial growth of homogeneous or heterogeneous materials in the thickness direction of two-dimensional semiconductor nanosheets can achieve thickness growth or the construction of core-shell structures, thereby controlling the optical properties of the nanosheets and potentially leading to the development of novel optoelectronic devices. Zn-based nanosheets are a type of low-toxicity two-dimensional semiconductor material whose absorption / fluorescence range can theoretically cover the ultraviolet to visible light region, possessing extremely strong application potential. However, in practice, only wurtzite Zn-based nanosheets with a thickness of 8 atomic layers can be obtained so far. This is because the crystal planes of wurtzite Zn-based nanosheets in the thickness direction are nonpolar (i.e., the surface contains equal amounts of cations and anions, exhibiting electrical neutrality), requiring the overcoming of a high potential barrier for epitaxial growth in the thickness direction. This fixed thickness severely limits the control of its optical properties.

[0003] Due to the low thermal stability of Zn-based nanosheets, overcoming the epitaxial growth kinetic barrier at high temperatures can lead to their dissolution. Therefore, colloidal atomic layer deposition (ALD) at room temperature holds promise for achieving thickness-direction epitaxial growth of wurtzite Zn-based nanosheets. This method leverages the polarity of the nanosheet's thickness-direction crystal planes (i.e., the surface contains only cations, not anions). It utilizes the strong charge interaction between surface cations and free anions in solution to deposit anions. At this point, the nanosheet surface becomes a polar plane containing only anions, which then bind to the free cations in solution, achieving monolayer colloidal atomic layer deposition. Repeating these steps allows for the continuous epitaxial growth of various materials on the nanosheet surface. However, due to the non-polar nature of the thickness-direction crystal planes of Zn-based nanosheets, it is difficult to achieve thickness-direction epitaxial growth of Zn-based nanosheets using traditional colloidal atomic layer deposition strategies. Summary of the Invention

[0004] In view of the technical problems existing in the background art, this application provides a colloidal atomic layer deposition method for non-polar surfaces of fibrous zircon Zn-based nanosheets, aiming to solve the problem that existing colloidal atomic layer deposition technology can only be used for epitaxial growth on polar crystal surfaces.

[0005] This application provides a colloidal atomic layer deposition method for the nonpolar surface of fibrous wurtzite Zn-based nanosheets, comprising the following steps: S1. Cation deposition is performed on Zn-based nanosheets to obtain cation-deposited nanosheets; S2. Anion deposition is performed on the cationicly deposited nanosheets to obtain nanosheets with increased nonpolar surface thickness; The cation deposition and the anion deposition are performed alternately and cyclically, with the number of cation depositions being greater than or equal to 1 and the number of anion depositions being greater than or equal to 1. The cation deposition includes the following steps: S11. Add zinc acetate and oleic acid to chloroform and allow them to react completely to obtain a zinc oleate solution; S12. Mix the nanosheets to be deposited with chloroform to obtain mixed solution 1; S13. Add the zinc oleate solution to the mixed solution 1 and stir thoroughly to obtain mixed solution 2; S14. Add anhydrous ethanol to the mixed solution 2 and perform a first centrifugal separation to obtain cation-deposited nanosheets; The anion deposition includes the following steps: S21. The cation-deposited nanosheets are dispersed in chloroform to obtain mixed solution 3; S22. [The following appears to be a list of elements:] Containing S 2- or Se 2- The compound and oleylamine were added to chloroform and stirred until homogeneous to obtain a mixed solution 4; S23. Add the mixed solution 3 to the mixed solution 4 and stir until homogeneous to obtain mixed solution 5; S24. Add anhydrous ethanol to the mixed solution 5 and perform a second centrifugation to obtain nanosheets with increased nonpolar surface thickness.

[0006] In the technical solution of this application embodiment, zinc oleate is deposited on the nonpolar surface to form a Zn-rich layer by exchanging the original oleamine ligand with zinc oleate ligand. 2+ The polar surface of the Zn-based nanosheets is then subjected to anion deposition to achieve the epitaxial growth of homogeneous or heterogeneous materials along the thickness direction of the oil-soluble Zn-based nanosheets. This allows for the increase in the thickness of the Zn-based nanosheets and the construction of a core-shell structure, with cation and anion deposition being performed alternately and cyclically. The increase in thickness and the construction of the core-shell structure enable the modulation of the optical properties of the Zn-based nanosheets.

[0007] In some embodiments, in step S11, the molar ratio of zinc acetate to oleic acid is 4~10:3; the reaction temperature is 55~65℃; and the reaction time is 25~35min.

[0008] In this embodiment, specific amounts of zinc acetate and oleic acid are added to chloroform and reacted fully under specific conditions to generate zinc oleate, and ultimately no free oleic acid is present.

[0009] In some embodiments, in step S12, the concentration of the nanosheets to be deposited in the mixed solution 1 is 0.01~0.04 mol / L.

[0010] In this embodiment, the nanosheets to be deposited are dispersed in chloroform to facilitate the subsequent deposition process.

[0011] In some embodiments, in step S13, the molar ratio of the nanosheets to be deposited and zinc oleate in the mixed solution 3 is 1:5; and the stirring time is 30 min.

[0012] In this embodiment, a chloroform solution of nanosheets to be deposited and a chloroform solution of zinc oleate are mixed in a specific ratio. In the chloroform medium, the Zn in zinc oleate and the anions on the surface of the nanosheets to be deposited form bonds in a complexing form, so that zinc oleate is deposited on the surface of the nanosheets to be deposited.

[0013] In some embodiments, in step S14, the centrifugation speed is 7000 rpm and the centrifugation time is 3 min.

[0014] In this embodiment, an ethanol solution is added. The introduction of ethanol changes the polarity of the original solution, causing the oil-soluble nanosheets to precipitate at the bottom of the solution. Then, by centrifugation, the nanosheets of zinc oleate deposited at the bottom are obtained.

[0015] In some embodiments, in step S21, the concentration of the cation-deposited nanosheets in the mixed solution 3 is 0.01~0.04 mol / L.

[0016] In this embodiment, the cationic deposited nanosheets are dispersed in chloroform to facilitate subsequent deposition.

[0017] In some embodiments, in step S22, the one containing S 2- or Se 2- The molar ratio of the compound to oleylamine is 0.2~2:1.

[0018] In this embodiment, a specific ratio of S is used. 2- or Se 2- When compounds are mixed with oleylamine, if they contain S 2- or Se 2- The ratio of the compound and oleylamine is too high, and sufficient S is deposited on the surface of the nanosheets. 2- or Se 2- Subsequently, oleylamine molecules will be unable to complex with the nanosheet surface, leading to nanosheet aggregation; if it contains S... 2- or Se 2- The ratio of the compound to oleylamine was too small, and some zinc oleate on the surface of the nanosheets did not react with S. 2- or Se 2-In combination, this portion of zinc oleate will be replaced by oleylamine, resulting in incomplete single-atom deposition.

[0019] In some embodiments, in step S23, the mixed solution 5 contains cation-deposited nanosheets and nanosheets containing S. 2- or Se 2- The molar ratio of the compounds is 4:1.

[0020] In this embodiment, zinc oleate nanosheets are deposited on the surface. Since zinc oleate contains positively charged Zn, it can react with S-containing nanosheets. 2- or Se 2- The negatively charged atoms of the chalcogens in the compound combine to form further deposits.

[0021] In some embodiments, in step S24, the centrifugation speed is 7000 rpm and the centrifugation time is 3 min.

[0022] In this embodiment, an ethanol solution is added. The introduction of ethanol changes the polarity of the original solution, causing the oil-soluble nanosheets to precipitate at the bottom of the solution. Then, through centrifugation, the surface of the precipitate at the bottom is further deposited with S. 2- or Se 2- Zn-based nanosheets with compound layers.

[0023] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0025] Figure 1 This is a schematic diagram of the deposition process of the colloidal atomic layer deposition method for the nonpolar surface of fibrous zircon Zn-based nanosheets in Example 1.

[0026] Figure 2 The image shows a transmission electron microscope image of the ZnSe / ZnS core-shell nanosheets prepared in Example 1.

[0027] Figure 3 The UV-Vis absorption spectra of ZnSe nanosheets and ZnSe / ZnS core-shell nanosheets in Examples 1-3 are shown.

[0028] Figure 4 The image shows a transmission electron microscope image of the ZnSe / ZnS core-shell nanosheets prepared in Comparative Example 1.

[0029] Figure 5 The image shows a transmission electron microscope image of the ZnSe / ZnS core-shell nanosheets prepared in Comparative Example 4.

[0030] Figure 6 The image shows the UV-Vis absorption spectrum of the ZnSe / ZnS core-shell nanosheets prepared in Comparative Example 2.

[0031] Figure 7 The image shows the UV-Vis absorption spectrum of the ZnSe / ZnS core-shell nanosheets prepared in Comparative Example 3. Detailed Implementation

[0032] The embodiments of the technical solution of this application are described in detail below. The following embodiments are only used to illustrate the technical solution of this application more clearly, and are therefore only examples, and should not be used to limit the scope of protection of this application.

[0033] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0034] To address the limitation of existing colloidal atomic layer deposition (ALD) techniques, which only enable epitaxial growth on the polar crystal surfaces of nanosheets, this application provides a colloidal ALD method for the non-polar surfaces of wurtzite Zn-based nanosheets. By exchanging the existing oleylamine ligand with zinc oleate ligands, zinc oleate is deposited on the non-polar surfaces of wurtzite Zn-based nanosheets to form Zn-rich deposits. 2+ The polar surface of the Zn-based nanosheets is then subjected to anion deposition to achieve the epitaxial growth of homogeneous or heterogeneous materials along the thickness direction of the oil-soluble Zn-based nanosheets. This allows for the increase in the thickness of the Zn-based nanosheets or the construction of core-shell structures, and the cation and anion deposition processes can be alternated cyclically. The increase in thickness and the construction of core-shell structures enable the modulation of the optical properties of the Zn-based nanosheets. Electronally neutral zinc oleate is deposited on the non-polar surface of the wurtzite Zn-based nanosheets because, although zinc oleate is generally electronegative, the zinc ions in zinc oleate can still complex with the anions in the lattice on the nanosheet surface through complexation, thereby replacing the original oleylamine ligands and depositing on the nanosheet surface. At the same time, due to the interaction between oleic acid and Zn in zinc oleate... 2+ The bonding ability of zinc oleate is much lower than that of the crystal lattice. Therefore, when nanosheets deposited with zinc oleate encounter free S...2- or Se 2- At this time, the oleic acid in the zinc oleate molecules on the surface is more easily converted by S. 2- or Se 2- This method replaces the traditional colloidal atomic layer deposition technique, forming a more stable ZnS or ZnSe monolayer on the nanosheet surface. It solves the problem of achieving epitaxial growth in the thickness direction on the non-polar surface of nanosheets in conventional methods.

[0035] This application provides a colloidal atomic layer deposition method for the nonpolar surface of fibrous wurtzite Zn-based nanosheets, comprising the following steps: S1. Cation deposition is performed on Zn-based nanosheets to obtain cation-deposited nanosheets; S2. Anion deposition is performed on the cationicly deposited nanosheets to obtain nanosheets with increased nonpolar surface thickness; The cation deposition and the anion deposition are performed alternately and cyclically, with the number of cation depositions being greater than or equal to 1 and the number of anion depositions being greater than or equal to 1. The cation deposition includes the following steps: S11. Add zinc acetate and oleic acid to chloroform and allow them to react completely to obtain a zinc oleate solution; S12. Mix the nanosheets to be deposited with chloroform to obtain mixed solution 1; S13. Add the zinc oleate solution to the mixed solution 1 and stir thoroughly to obtain mixed solution 2; S14. Add anhydrous ethanol to the mixed solution 2 and perform a first centrifugal separation to obtain cation-deposited nanosheets; The anion deposition includes the following steps: S21. The cation-deposited nanosheets are dispersed in chloroform to obtain mixed solution 3; S22. [The following appears to be a list of elements:] Containing S 2- or Se 2- The compound and oleylamine were added to chloroform and stirred until homogeneous to obtain a mixed solution 4; S23. Add the mixed solution 3 to the mixed solution 4 and stir until homogeneous to obtain mixed solution 5; S24. Add anhydrous ethanol to the mixed solution 5 and perform a second centrifugation to obtain nanosheets with increased nonpolar surface thickness.

[0036] In the technical solution of this application embodiment, zinc oleate is deposited on the nonpolar surface to form a Zn-rich layer by exchanging the original oleamine ligand with zinc oleate ligand. 2+The polar surface of the Zn-based nanosheets is then subjected to anion deposition to achieve the epitaxial growth of homogeneous or heterogeneous materials along the thickness direction of the oil-soluble Zn-based nanosheets. This allows for the increase in the thickness of the Zn-based nanosheets or the construction of core-shell structures, and the deposition of cations and anions can be carried out alternately. The increase in thickness and the construction of core-shell structures enable the modulation of the optical properties of the Zn-based nanosheets.

[0037] Furthermore, in some embodiments, in step S11, the molar ratio of zinc acetate to oleic acid is 4~10:3; the reaction temperature is 55~65℃; and the reaction time is 25~35min.

[0038] In the technical solution of this application embodiment, a specific amount of zinc acetate and oleic acid are added to chloroform and reacted fully under specific conditions to generate zinc oleate, and ultimately no free oleic acid exists.

[0039] Furthermore, in some embodiments, in step S12, the concentration of the nanosheets to be deposited in the mixed solution 1 is 0.01~0.04 mol / L.

[0040] In the technical solution of this application embodiment, the nanosheets to be deposited are dispersed in chloroform to facilitate the subsequent deposition process.

[0041] Furthermore, in some embodiments, in step S13, the molar ratio of the nanosheets to be deposited and zinc oleate in the mixed solution 3 is 1:5; and the stirring time is 30 min.

[0042] In the technical solution of this application embodiment, a chloroform solution of nanosheets to be deposited and a chloroform solution of zinc oleate are mixed in a specific ratio. In the chloroform medium, the Zn in zinc oleate and the anions on the surface of the nanosheets to be deposited form bonds in a complexing form, so that zinc oleate is deposited on the surface of the nanosheets to be deposited.

[0043] Furthermore, in some embodiments, in step S14, the centrifugation speed is 7000 rpm and the centrifugation time is 3 min.

[0044] In the technical solution of this application embodiment, an ethanol solution is added, the mixed solution is placed in a centrifuge, and then the supernatant is poured out by centrifugation to obtain the bottom precipitate, which is the nanosheet of zinc oleate.

[0045] Furthermore, in some embodiments, in step S21, the concentration of the cation-deposited nanosheets in the mixed solution 3 is 0.01~0.04 mol / L.

[0046] In the technical solution of this application embodiment, the nanosheets deposited by cations are dispersed in chloroform to facilitate subsequent deposition.

[0047] Furthermore, in some embodiments, in step S22, the one containing S 2- or Se 2- The molar ratio of the compound to oleylamine is 0.2~2:1.

[0048] In the technical solution of this application embodiment, a specific proportion of S is used. 2- or Se 2- When compounds are mixed with oleylamine, if they contain S 2- or Se 2- The ratio of the compound and oleylamine is too high, and sufficient S is deposited on the surface of the nanosheets. 2- or Se 2- Subsequently, oleylamine molecules will be unable to complex with the nanosheet surface, leading to nanosheet aggregation; if S is present... 2- or Se 2- If the ratio of the compound to oleylamine is too small, then excess oleylamine will replace the deposited zinc oleate, at which point S 2- or Se 2- The lack of bonding sites prevents S from being deposited on the surface of the nanosheets. 2- or Se 2- .

[0049] Furthermore, in some embodiments, in step S23, the mixed solution 5 contains cation-deposited nanosheets and S... 2- or Se 2- The molar ratio of the compounds is 4:1.

[0050] In the technical solution of this application embodiment, zinc oleate nanosheets are deposited on the surface. Since zinc oleate contains positively charged Zn, it can react with S-containing nanosheets. 2- or Se 2- The negatively charged atoms of the chalcogens in the compound combine to form further deposits.

[0051] Furthermore, in some embodiments, in step S24, during the second centrifugal separation, the centrifugation speed is 7000 rpm and the centrifugation time is 3 min.

[0052] In the technical solution of this application embodiment, an ethanol solution is added. The introduction of ethanol changes the polarity of the original solution, causing the oil-soluble nanosheets to precipitate at the bottom of the solution. Then, through centrifugation, the surface of the precipitate at the bottom is further deposited with S. 2- or Se 2- Zn-based nanosheets with compound layers.

[0053] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0054] Example 1 This embodiment provides a colloidal atomic layer deposition method for the nonpolar surface of fibrous wurtzite Zn-based nanosheets, such as... Figure 1 As shown, the specific steps include the following: (1) Add 0.1 mmol of zinc acetate and 0.05 mmol of oleic acid to 1 mL of chloroform and heat in a water bath at 60 °C for 30 min to obtain zinc oleate solution.

[0055] (2) Add 1 mL of chloroform solution containing 0.02 mmol of ZnSe nanosheets to zinc oleate solution and stir thoroughly for 30 min; then add 2 mL of anhydrous ethanol and centrifuge at 7000 rpm for 3 min. The precipitate obtained is ZnSe nanosheets deposited with zinc oleate.

[0056] (3) Disperse the nanosheets into 3 mL of chloroform, then add 1 mL of chloroform solution containing 0.005 mmol Na2S and 0.01 mmol oleylamine, stir for 2 min, add 4 mL of anhydrous ethanol, and then centrifuge at 7000 rpm for 3 min. The precipitate obtained is ZnSe / ZnS core-shell nanosheets with a monomolecular ZnS layer grown on the surface.

[0057] Figure 2 Transmission electron microscope image of the ZnSe / ZnS core-shell nanosheets prepared in the embodiments of this paper.

[0058] Depend on Figure 2 It can be seen that the prepared ZnSe / ZnS core-shell nanosheets have good dispersibility and no obvious agglomeration phenomenon.

[0059] Examples 2-3 Examples 2 and 3 respectively provide a colloidal atomic layer deposition method for the nonpolar surface of fibrous wurtzite Zn-based nanosheets. Example 2 is to repeat the steps in Example 1, except that the ZnSe nanosheets in step (2) are replaced with ZnSe / ZnS core-shell nanosheets, and finally a core-shell nanosheet with two layers of ZnSe / ZnS is obtained. Example 3 is to repeat the steps in Example 2, except that the ZnSe / ZnS core-shell nanosheets in step (2) are replaced with a core-shell nanosheet with two layers of ZnSe / ZnS, and finally a core-shell nanosheet with three layers of ZnSe / ZnS is obtained.

[0060] The UV-Vis absorption spectra of ZnSe nanosheets and ZnSe / ZnS core-shell nanosheets from Examples 1-3 were measured, and the results are shown in [Figure number missing]. Figure 3 .

[0061] Depend on Figure 3 The results of ZnSe nanosheets and ZnSe / ZnS core-shell nanosheets in Examples 1-3 show that the absorption peak position red-shifted from 345 nm to 371 nm, 379 nm and 386 nm, respectively. The red-shift phenomenon of the absorption peak gradually became obvious, indicating that the first, second and third ZnS layer cyclic depositions were successfully completed in this example. The thickness of the nanosheets increased with the increase of the number of deposition layers.

[0062] Examples 4-5 and Comparative Examples 1-2 Examples 4-5 and Comparative Examples 1-2 respectively provide a colloidal atomic layer deposition method for the nonpolar surface of fibrous zircon Zn-based nanosheets. Compared with Example 1, the difference is that the amount of Na2S and oleylamine in step (3) is different, as shown in Table 1. Other steps are roughly the same as in Example 1, and will not be repeated here.

[0063] Table 1. Amounts of Na2S and oleylamine and positions of the first exciton absorption peak in Examples 4-5 and Comparative Examples 1-2 Experimental results showed that in Comparative Example 1, when the amount of oleylamine added was too small, the nanosheets agglomerated, such as... Figure 4 As shown, this is due to sufficient S deposited on the surface of the nanosheets. 2- or Se 2- Subsequently, too few oleylamine molecules cannot complex onto the surface of the nanosheets, leading to agglomeration of the nanosheets.

[0064] Examples 6-7 and Comparative Examples 3-4 Examples 6-7 and Comparative Examples 3-4 respectively provide a colloidal atomic layer deposition method for the nonpolar surface of fibrous wurtzite Zn-based nanosheets. Compared with Example 1, the difference is that the amounts of zinc acetate and oleic acid in step (1) are different, as shown in Table 2. The other steps are roughly the same as in Example 1, and will not be repeated here.

[0065] Table 2. Amounts of zinc acetate and oleic acid and positions of the first exciton absorption peak in Examples 6-7 and Comparative Examples 3-4. Experimental results show that in Comparative Example 4, the morphology of the nanosheets was completely destroyed, such as... Figure 5 As shown, this is because the hydroxyl groups in excessive oleic acid can disrupt the stability of the nanosheets.

[0066] The UV-Vis absorption spectra of ZnSe nanosheets, core-shell nanosheets prepared in Examples 4-7, and Comparative Examples 2-3 were measured respectively. The test results are shown in Tables 1 and 2. The specific test graphs of Comparative Examples 2 and 3 are shown in Tables 1 and 2 respectively. Figure 6 and Figure 7 As shown.

[0067] Similar to the test results in Examples 4-7 of Tables 1-2, after one ZnS layer deposition cycle, the first exciton absorption peak of the samples red-shifted to approximately 370-371 nm, indicating that a molar ratio of zinc acetate to oleic acid of 4-10:3 and a molar ratio of Na2S to oleylamine of 0.2-2:1 resulted in better deposition effects. Comparative Example 2 shows that after one ZnS layer deposition cycle, the position of the first exciton absorption peak of the product only red-shifted from 345 nm to 357 nm, indicating that a complete ZnS layer was not deposited. This is because excessive oleylamine replaced the deposited zinc oleate, at which point S... 2- The lack of bonding sites prevents S from being deposited on the surface of the nanosheets. 2- As can be seen from Comparative Example 3, the first exciton absorption peak of the ZnS deposition product after one cycle red-shifts from 345 nm to 360 nm. This is because when too little oleic acid is added, there is too little free zinc oleate in the solution, resulting in insufficient Zn deposition on the nanosheet surface. 2+ The amount of material is insufficient to complete a single-atom layer deposition.

[0068] In summary, this application provides a colloidal atomic layer deposition method for the nonpolar surface of wurtzite Zn-based nanosheets. By exchanging the original oleylamine ligand with zinc oleate ligands, zinc oleate is deposited on the nonpolar surface of wurtzite Zn-based nanosheets to form a Zn-rich layer. 2+ The polar surface of the zinc oleate is then subjected to anion deposition to achieve the epitaxial growth of homogeneous or heterogeneous materials along the thickness direction of oil-soluble Zn-based nanosheets. This allows for the increase in the thickness of Zn-based nanosheets and the construction of core-shell structures, with cation and anion deposition being carried out alternately. The increase in thickness and the construction of core-shell structures enable the modulation of the optical properties of Zn-based nanosheets. Although zinc oleate is generally electroneutrally neutral, zinc ions in zinc oleate can still complex with anions in the lattice on the surface of the nanosheets through complexation, thereby replacing the original oleylamine ligands and depositing on the nanosheet surface; simultaneously, due to the interaction between oleic acid and Zn in zinc oleate... 2+ The bonding ability of zinc oleate is much lower than that of the crystal lattice. Therefore, when nanosheets deposited with zinc oleate encounter free S... 2- or Se 2- The oleic acid in the zinc oleate molecules on the surface is more easily converted by S. 2- or Se 2-This method replaces the traditional colloidal atomic layer deposition technique, forming a more stable ZnS or ZnSe monolayer on the nanosheet surface. It solves the problem of achieving epitaxial growth in the thickness direction on the non-polar surface of nanosheets in conventional methods.

[0069] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A colloidal atomic layer deposition method for the nonpolar surface of fibrous wurtzite Zn-based nanosheets, characterized in that, Includes the following steps: S1. Cation deposition is performed on Zn-based nanosheets to obtain cation-deposited nanosheets; S2. Anion deposition is performed on the cationicly deposited nanosheets to obtain nanosheets with increased nonpolar surface thickness; The cation deposition and the anion deposition are performed alternately and cyclically, with the number of cation depositions being greater than or equal to 1 and the number of anion depositions being greater than or equal to 1. The cation deposition includes the following steps: S11. Add zinc acetate and oleic acid to chloroform and allow them to react completely to obtain a zinc oleate solution; S12. Mix the nanosheets to be deposited with chloroform to obtain mixed solution 1; S13. Add the zinc oleate solution to the mixed solution 1 and stir thoroughly to obtain mixed solution 2; S14. Add anhydrous ethanol to the mixed solution 2 and perform a first centrifugal separation to obtain cation-deposited nanosheets; The anion deposition includes the following steps: S21. The cation-deposited nanosheets are dispersed in chloroform to obtain mixed solution 3; S22. [The following appears to be a list of elements:] Containing S 2- or Se 2- The compound and oleylamine were added to chloroform and stirred until homogeneous to obtain a mixed solution 4; S23. Add the mixed solution 3 to the mixed solution 4 and stir until homogeneous to obtain mixed solution 5; S24. Add anhydrous ethanol to the mixed solution 5 and perform a second centrifugation to obtain nanosheets with increased nonpolar surface thickness.

2. The colloidal atomic layer deposition method for the nonpolar surface of fibrous wurtzite Zn-based nanosheets according to claim 1, characterized in that, In step S22, the one containing S 2- or Se 2- The molar ratio of the compound to oleylamine is 0.2~2:

1.

3. The colloidal atomic layer deposition method for the nonpolar surface of fibrous wurtzite Zn-based nanosheets according to claim 1, characterized in that, In step S11, the molar ratio of zinc acetate to oleic acid is 4~10:

3.

4. The colloidal atomic layer deposition method for the nonpolar surface of fibrous wurtzite Zn-based nanosheets according to claim 1, characterized in that, In step S11, the reaction temperature is 55~65℃ and the reaction time is 25~35min.

5. The colloidal atomic layer deposition method for the nonpolar surface of fibrous wurtzite Zn-based nanosheets according to claim 1, characterized in that, In step S12, the concentration of the nanosheets to be deposited in the mixed solution 1 is 0.01~0.04 mol / L.

6. The colloidal atomic layer deposition method for the nonpolar surface of fibrous wurtzite Zn-based nanosheets according to claim 1, characterized in that, In step S13, the molar ratio of the nanosheets to be deposited and zinc oleate in the mixed solution 3 is 1:5; the stirring time is 30 min.

7. The colloidal atomic layer deposition method for the nonpolar surface of fibrous wurtzite Zn-based nanosheets according to claim 1, characterized in that, In step S14, during the first centrifugal separation, the centrifugation speed is 7000 rpm and the centrifugation time is 3 min.

8. The colloidal atomic layer deposition method for the nonpolar surface of fibrous wurtzite Zn-based nanosheets according to claim 1, characterized in that, In step S21, the concentration of the cation-deposited nanosheets in the mixed solution 3 is 0.01~0.04 mol / L.

9. The colloidal atomic layer deposition method for the nonpolar surface of fibrous wurtzite Zn-based nanosheets according to claim 1, characterized in that, In step S23, in the mixed solution 5, the cation-deposited nanosheets and those containing S 2- or Se 2- The molar ratio of the compounds is 4:

1.

10. The colloidal atomic layer deposition method for the nonpolar surface of fibrous wurtzite Zn-based nanosheets according to claim 1, characterized in that, In step S24, during the second centrifugal separation, the centrifugation speed is 7000 rpm and the centrifugation time is 3 min.

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