Organic-inorganic heterojunction material, preparation method therefor, and application thereof

Abstract

Disclosed are an organic-inorganic heterojunction material, a preparation method therefor, and an application thereof. The organic-inorganic heterojunction material comprises 2D TMDs disposed on a substrate, and a boronic ester polymer layer formed on a surface of the 2D TMDs, wherein a structural formula of a boronic ester polymer in the borate polymer layer is shown in (I). The present invention enables tuning of a thickness of a borate polymer layer by means of varying a monomer concentration, so as to consequently tune an optoelectronic property of a boronic ester polymer-TMD heterojunction. Field-effect transistors prepared by using the boronic ester polymer-TMD heterojunction as a channel material have a plurality of current levels, and fabricated optoelectronic devices exhibit improved photoresponse dynamics, effectively inhibiting persistent photoconductivity effects of TMD optoelectronic devices, and thereby allowing for optoelectronic devices to have long-term environmental stability.

Description

An organic-inorganic heterojunction material, its preparation method and application

[0001] Cross-references to related applications

[0002] This application claims priority to and is based on Chinese Patent Application No. 2024118241650, filed on December 12, 2024, with the invention entitled "An Organic-Inorganic Heterojunction Material and Its Preparation Method and Application", the contents of which are incorporated herein by reference. Technical Field

[0003] This invention belongs to the field of two-dimensional material optoelectronic device technology, specifically relating to an organic-inorganic heterojunction material, its preparation method, and its application. Background Technology

[0004] Since the initial isolation of graphene in 2004, the exploration of novel two-dimensional materials at the nanoscale has attracted widespread research interest, particularly two-dimensional transition metal dichalcogenides (TMDs), such as MoS2 and WSe2, which have garnered significant attention due to their unique electronic and optical properties, including tunable optical band gaps, direct-to-indirect band gap transitions, and strong spin-orbit coupling. Organic / inorganic heterojunctions exhibit unique properties, synergistically combining the advantages of both organic and inorganic materials, and even generating novel characteristics. Two-dimensional organic-TMD heterojunctions, with their broad tunability, show great promise for customized functionalization and applications.

[0005] Methods for constructing two-dimensional organic-TMD heterostructures mainly fall into two categories: one is to physically stack TMDs and organic materials using microtransfer techniques; the other is to form them by depositing or synthesizing organic layer materials on pre-prepared two-dimensional materials. Two-dimensional materials are generally more chemically and thermally stable. However, to date, constructing stable and controllable polymer layers on the surface of atomically-sized TMDs using chemical methods remains a significant challenge.

[0006] The transition from multilayer to single-layer MoS2 involves a change from an indirect bandgap to a direct bandgap and possesses excellent semiconductor properties, making it extremely promising for applications in optoelectronics. However, a major drawback of MoS2 and related heterostructures in optoelectronic applications is its persistent photoconductivity (PPC) effect. This means that while photoexcitation enhances the conductivity of the device, it cannot be completely shut off even in darkness for a long period after photoexcitation ceases. Therefore, suppressing the PPC effect is crucial for exploring the fundamental properties of MoS2 and developing various technological applications. Furthermore, controlling the current levels of MoS2 through heterostructure construction is also important for realizing applications such as neuron-like devices. Through these studies, researchers can better understand and utilize the properties of these materials, providing new possibilities for the future development of electronic and optoelectronic technologies. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems in the prior art of preparing and controlling polymer-TMD heterostructures through stable and efficient methods, as well as the problems of suppressing PPC effect and controlling current levels, and to provide an organic-inorganic heterojunction material.

[0008] Another object of the present invention is to provide a method for preparing the above-mentioned organic-inorganic heterojunction material.

[0009] Another object of the present invention is to provide the application of the above-mentioned organic-inorganic heterojunction material.

[0010] The principle of this invention is as follows:

[0011] This invention is based on the strong interfacial bonding force of the catechol group, which interacts with Mo atoms at defects through coordination. First, a monomer containing a three-armed catechol group is introduced onto the surface of CVD-prepared TMDs. This monomer is anchored to the TMD surface. Subsequently, a monomer containing a three-armed phenylboronic acid group is introduced. Intermolecular coordination with BN occurs, and the three-armed catechol and phenylboronic acid monomers condense and polymerize on the TMD surface to form a borate ester polymer layer, thereby preparing a borate ester polymer-TMDs heterostructure.

[0012] The technical solution of the present invention is as follows:

[0013] An organic-inorganic heterojunction material includes a 2D TMDs on a substrate and a borate polymer layer formed on the surface of the 2D TMDs.

[0014] The structural formula of the borate polymer in the borate polymer layer is as follows:

[0015] In a preferred embodiment of the present invention, the 2D TMDs include molybdenum disulfide, molybdenum diselenide, tungsten disulfide, tungsten diselenide, hafnium disulfide, zirconium disulfide, rhenium disulfide, rhenium diselenide, platinum disulfide, platinum diselenide, molybdenum ditelluride, and tungsten ditelluride.

[0016] More preferably, the substrate material includes Si, sapphire, SiO2 / Si, Al2O3 / Si, HfO2 / Si, and ITO.

[0017] The above-mentioned method for preparing organic-inorganic heterojunction materials uses monomers containing three-armed catechol groups and monomers containing three-armed phenylboronic acid groups as precursors to form a borate polymer layer on the surface of 2D TMDs located on a substrate through solution self-assembly.

[0018] In a preferred embodiment of the present invention, the structural formula of the monomer containing the three-armed catechol group is as follows:

[0019] In a preferred embodiment of the present invention, the structural formula of the monomer containing the three-armed phenylboronic acid group is as follows:

[0020] The above-mentioned organic-inorganic heterojunction material is used in the fabrication of optoelectronic devices, wherein the optoelectronic device is a photodetector based on a field-effect transistor, and the organic-inorganic heterojunction material is used as its channel material.

[0021] An optoelectronic device, which is a photodetector based on a field-effect transistor, wherein the field-effect transistor has the aforementioned organic-inorganic heterojunction material as the channel material.

[0022] The above-mentioned organic-inorganic heterojunction materials are used in the fabrication of field-effect transistors.

[0023] A field-effect transistor, wherein the channel material is the aforementioned organic-inorganic heterojunction material.

[0024] The beneficial effects of this invention are:

[0025] 1. In the prior art, TMDs prepared by CVD have atomic-level surfaces, which are usually difficult to chemically modify. However, the present invention is based on the strong interfacial bonding force of the catechol group and its interaction with the transition metal atoms at the defects. First, molecules containing three-armed catechol groups are anchored on the TMDs, and then molecules containing three-armed phenylboronic acid groups are introduced and condensation polymerization occurs to form a borate polymer layer on the surface of the TMDs.

[0026] 2. This invention can control the thickness of the borate polymer layer by controlling the concentration of molecules containing catechol groups and molecules containing phenylboronic acid groups, and further prepare organic / inorganic heterojunctions with different organic layer thicknesses, ultimately achieving the control of photoelectric properties. It is applicable to various forms of electronic and optoelectronic device applications, including field-effect transistors (FETs), phototransistors, memory devices, etc.

[0027] 3. The borate polymer layer and TMDs layer prepared by this invention have rapid interlayer charge transfer, which enables the prepared optoelectronic device to have fast photoresponse dynamics and can effectively suppress the PPC effect.

[0028] 4. The thickness of the borate ester polymer layer obtained by the present invention is controllable, which enables the prepared optoelectronic device to exhibit multiple current levels;

[0029] 5. The borate polymer layer prepared by this invention is dense and flat, which enables the device to have long-term environmental stability. Attached Figure Description

[0030] Figure 1 shows the 1L-MoS2 and BP prepared in Example 1 of this invention. 3.8 -MoS2, BP 7.9 -MoS2, BP 12.6 -Atomic force microscopy image of MoS2 and corresponding height curve.

[0031] Figure 2 shows the BP obtained in Example 1 of the present invention. 3.8 High-resolution transmission electron microscopy image of the MoS2 cross section.

[0032] Figure 3 shows the 1L-MoS2 and BP prepared in Example 1 of this invention. 3.8 -MoS2, BP 7.9 -MoS2, BP 12.6 Raman spectrum of -MoS2.

[0033] Figure 4 shows the 1L-MoS2 and BP prepared in Example 1 of this invention. 3.8 -MoS2, BP 7.9 -MoS2, BP 12.6 Photoluminescence spectrum of -MoS2.

[0034] Figure 5 shows the 1L-MoS2 and BP prepared in Example 1 of this invention. 3.8 -MoS2, BP 7.9 -MoS2, BP 12.6 -Surface potential diagram and corresponding curve of MoS2.

[0035] Figure 6 shows the 1L-MoS2 and BP prepared in Example 2 of this invention. 3.8 -MoS2, BP7.9 -MoS2, BP 12.6 -A schematic diagram of the device structure and (b) a physical image of MoS2.

[0036] Figure 7 shows the 1L-MoS2 and BP prepared in Example 2 of this invention. 3.8 -MoS2, BP 7.9 -MoS2, BP 12.6 - Output characteristic curves (ab), transfer characteristic curves (c), and device stability of the MoS2 FET.

[0037] Figure 8 shows the 1L-MoS2 and BP prepared in Example 2 of this invention. 3.8 - Photoresponse curve of MoS2 FET.

[0038] Figure 9 shows the Raman spectrum of BP-WSe2 obtained in Example 3 of this invention.

[0039] Figure 10 shows the photoluminescence spectrum of BP-WSe2 obtained in Example 3 of the present invention. Detailed Implementation

[0040] The technical solution of the present invention will be further explained and described below with reference to specific embodiments and accompanying drawings.

[0041] Example 1: Preparation of BP-MoS2 heterojunction

[0042] (1) Prepare TC solution and TB solution with a concentration of 10 mmol / L respectively. The preparation of TC and TB refers to CN107082411A;

[0043] (2) A monolayer MoS2 (1L-MoS2) was prepared by chemical vapor deposition, and then the 1L-MoS2 was transferred to a clean SiO2 / Si substrate by PMMA wet transfer method to obtain MoS2 / SiO2 / Si.

[0044] (3) Add different amounts of TC solution (50, 100 and 200 μL) to 5 mL of anhydrous ethanol, mix well, add the MoS2 / SiO2 / Si prepared in step (2), and let stand for 30 min.

[0045] (4) Add TB solution (50, 100 and 200 μL) with the same volume as the TC solution added in step (3), let stand in the dark for 12 h to obtain BP-MoS2 / SiO2 / Si.

[0046] (5) Take out the BP-MoS2 / SiO2 / Si obtained in step (4), rinse it with anhydrous ethanol at least 3 times, and then blow it dry with nitrogen to obtain the BP-MoS2 heterojunction.

[0047] The thicknesses of the BP layer (borate ester polymer layer) in the BP-MoS2 heterojunction obtained by using different amounts of TC and TB (50, 100, 200 μL) were 3.8, 7.9, and 12.6 nm, respectively. Therefore, the obtained BP-MoS2 heterojunctions are denoted as BP. 3.8 -MoS2, BP 7.9 -MoS2 and BP 12.6 -MoS2. Figure 1 shows 1L-MoS2 and BP. 3.8 -MoS2, BP 7.9 -MoS2, BP 12.6 -Atomic force microscopy image of MoS2 and corresponding height curve. Figure 2 shows the BP. 3.8 The high-resolution transmission electron microscopy (TEM) image and elemental distribution of the 1L-MoS2 cross-section demonstrate that the heterojunction possesses a uniform layered structure. The Raman spectrum shown in Figure 3 illustrates that the intensity of the characteristic peak of the BP layer significantly increases with increasing BP layer thickness. The photoluminescence spectrum after Lorentz fitting shown in Figure 4 demonstrates that more electrons in 1L-MoS2 undergo recombination and reorganization with increasing BP layer thickness. The surface potential diagram shown in Figure 5 illustrates that the greater the surface potential difference and the higher the work function, the greater the BP layer thickness.

[0048] Example 2 Fabrication of BP-MoS2 FET

[0049] (1) S1805 photoresist was spin-coated on the surface of MoS2 / SiO2 / Si obtained in Example 1 at a speed of 4000 rpm for 60 s, and then photolithography was performed by heat treatment at 96°C for 3 min.

[0050] (2) After photolithography to form electrode channels, develop for 60s and rinse quickly with ultrapure water for 30s, then dry with nitrogen.

[0051] (3) Electron beam evaporation of 30nm Ag / 30nm Au was used as the electrode, and then acetone was soaked overnight to obtain MoS2 FET;

[0052] (4) Referring to steps (3) to (5) of Example 1, the MoS2 FET obtained in step (3) of this example is immersed in 5 mL of anhydrous ethanol, and different amounts (50, 100 and 200 μL) of TC and TB solutions are added successively to prepare BP. 3.8 -MoS2 FET, BP 7.9 -MoS2 FET, BP 12.6 -MoS2 FET.

[0053] Figure 6 shows a schematic diagram and physical image of the BP-MoS2 FET. Figure 7(ab) shows the output characteristic curve of the BP-MoS2 FET, illustrating that the FET still exhibits good ohmic contact characteristics even with the BP layer, and different current levels are observed with varying BP layer thickness. Figure 7(c) shows the transfer characteristic curve of the BP-MoS2 FET, indicating that the threshold voltage of the FET shifts towards the forward voltage as the BP thickness increases. Figure 7(d) shows the stability test of the BP-MoS2 FET, demonstrating that the BP-MoS2 FET still exhibits good electrical performance after being placed in air for 100 days, indicating its good environmental stability. Figure 8(a) shows the photoresponse curve of 1L-MoS2, illustrating that 1L-MoS2 exhibits typical rise and fall of photo-switching current, while also displaying the PPC effect. Figure 8(b) shows the BP... 3.8 The photoresponse curve of -MoS2 illustrates that, compared to 1L-MoS2, BP 3.8 The rise and fall rates of the MoS2 optical switching current are significantly improved, resulting in an enhanced photoresponse speed and effectively suppressing the PPC effect.

[0054] Example 3 Preparation of BP-WSe2

[0055] Step (1) is the same as in Example 1;

[0056] (2) The monolayer WSe2 prepared by chemical vapor deposition was transferred to a clean SiO2 / Si substrate by PMMA wet transfer method to obtain WSe2 / SiO2 / Si;

[0057] (3) Add 200 μL of TC solution to 5 mL of anhydrous ethanol, mix well, then add the WSe2 / SiO2 / Si prepared in step (2) and let stand for 30 min.

[0058] (4) Add 200 μL of TB solution, let stand in the dark for 12 h to obtain BP-WSe2 / SiO2 / Si;

[0059] (5) Take out the BP-WSe2 / SiO2 / Si obtained in step (4), rinse it three times with anhydrous ethanol, and dry it with nitrogen. The Raman spectrum shown in Figure 9 and the photoluminescence spectrum shown in Figure 10 show that the introduction of the BP layer leads to recombination and reorganization of electrons in 1L-WSe2, resulting in a decrease in electron concentration.

[0060] The above description is merely a preferred embodiment of the present invention, and therefore should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the patent and the contents of the specification should still fall within the scope of the present invention. Industrial applicability

[0061] This invention discloses an organic-inorganic heterojunction material, its preparation method, and its application, comprising a 2D TMDs on a substrate and a borate polymer layer formed on the surface of the 2D TMDs, wherein the borate polymer in the borate polymer layer has the following structural formula: This invention can regulate the thickness of the borate polymer layer by changing the concentration of the monomer, thereby regulating the photoelectric properties of the borate polymer-TMDs heterojunction. Field-effect transistors prepared with it as the channel material have multiple current levels, and the prepared optoelectronic devices have improved photoresponse dynamics, effectively suppressing the persistent photoconductivity effect of TMDs optoelectronic devices, making the optoelectronic devices have long-term environmental stability and industrial applicability.

Claims

1. An organic-inorganic heterojunction material, characterized in that: Includes a 2D TMDs on a substrate and a borate polymer layer formed on the surface of the 2D TMDs. The structural formula of the borate polymer in the borate polymer layer is as follows:

2. The organic-inorganic heterojunction material as described in claim 1, characterized in that: The 2D TMDs include molybdenum disulfide, molybdenum diselenide, tungsten disulfide, tungsten diselenide, hafnium disulfide, zirconium disulfide, rhenium disulfide, rhenium diselenide, platinum disulfide, platinum diselenide, molybdenum ditelluride, and tungsten ditelluride.

3. The organic-inorganic heterojunction material as described in claim 2, characterized in that: The substrate material includes Si, sapphire, SiO2 / Si, Al2O3 / Si, HfO2 / Si, and ITO.

4. The method for preparing the organic-inorganic heterojunction material according to any one of claims 1 to 3, characterized in that: Using monomers containing three-armed catechol groups and monomers containing three-armed phenylboronic acid groups as precursors, a borate polymer layer is formed on the surface of 2D TMDs located on a substrate via solution self-assembly.

5. The preparation method according to claim 4, characterized in that: The structural formula of the monomer containing the three-armed catechol group is as follows:

6. The preparation method according to claim 4, characterized in that: The structural formula of the monomer containing the three-armed phenylboronic acid group is as follows:

7. The use of the organic-inorganic heterojunction material according to any one of claims 1 to 3 in the fabrication of optoelectronic devices, characterized in that: The optoelectronic device is a photodetector based on a field-effect transistor, wherein the organic-inorganic heterojunction material serves as its channel material.

8. An optoelectronic device, characterized in that: It is a photodetector based on a field-effect transistor, wherein the field-effect transistor has an organic-inorganic heterojunction material as the channel material according to any one of claims 1 to 3.

9. Use of the organic-inorganic heterojunction material according to any one of claims 1 to 3 in the fabrication of field-effect transistors.

10. A field-effect transistor, characterized in that: The material of its channel is the organic-inorganic heterojunction material as described in any one of claims 1 to 3.

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