Quaternary ammonium salt organic semiconductor material, preparation method therefor, and use thereof

Abstract

Provided are a quaternary ammonium salt organic semiconductor material, a preparation method therefor, and use thereof, and the structural formula thereof is (I), wherein R is 2,5,8,11-tetraoxatridecyl, a benzophenone group, or 4-boronophenyl. The organic semiconductor material can achieve long-term and stable regulation of the semiconductor performance of a two-dimensional material, and has an electronic effect of n-type doping on single-layer MoS2, and the electrical performance of the single-layer MoS2 after being treated therewith is significantly improved. Specifically, the current density of a single-layer MoS2 field effect transistor device treated with the organic semiconductor material is increased by nearly 200 times compared with that before treatment; that is, the organic semiconductor material can be well applied to two-dimensional material field effect transistors.

Description

A quaternary ammonium salt organic semiconductor 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. 202510371210X, filed on March 27, 2025 with the China National Intellectual Property Administration, entitled "A Quaternary Ammonium Salt Organic Semiconductor 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 materials technology, specifically relating to a quaternary ammonium salt organic semiconductor material, its preparation method, and its application. Background Technology

[0004] Since the successful isolation of monolayer graphene from graphite in 2004, atomically thin two-dimensional (2D) materials, such as black phosphorus (BP), MXene, and transition metal dichalcogenides (TMDs), have attracted widespread attention due to their unique electronic, optical, magnetic, and mechanical properties. When these 2D materials are hybridized with organic substances (including small molecules and polymers), more complex heterostructures can be constructed, providing various possibilities for improving the inherent properties of 2D materials and even creating new properties. Modifying the optoelectronic properties of atomically thin TMDs through physical or chemical methods can not only optimize their inherent photoelectric properties but also inspire new characteristics. Therefore, research on "modifying" atomically thin TMDs at the atomic or molecular level has received considerable attention.

[0005] Atomic modification primarily employs elemental substitution doping strategies, which can damage the surface and introduce defects, affecting charge transport efficiency. Molecular modification includes methods such as thermal evaporation, spin coating, solution casting, and immersion, mainly relying on physical adsorption to immobilize small molecules or polymers on the surface of TMDs. The photoelectronic properties of TMDs are then modulated by charge transfer between the organic small molecule or polymer donor or acceptor and the TMD material. However, since no specific interfacial interaction is formed between the molecules or polymers and the TMDs, environmental changes can easily cause molecules to desorb from the TMD surface, thus affecting the stability of the material and device.

[0006] How to achieve long-term stable control of the electronic properties of TMDs through strong interfacial interactions without destroying the crystal structure of TMDs or sacrificing their inherent properties is an extremely challenging problem. Summary of the Invention

[0007] The purpose of this invention is to overcome the defects of the prior art and provide a quaternary ammonium salt organic semiconductor material.

[0008] Another object of the present invention is to provide a method for preparing the above-mentioned quaternary ammonium salt organic semiconductor material.

[0009] Another object of the present invention is to provide applications of the above-mentioned quaternary ammonium salt organic semiconductor materials.

[0010] The technical solution of the present invention is as follows:

[0011] A quaternary ammonium salt organic semiconductor material, characterized in that: its structural formula is as follows Wherein, R is 2,5,8,11-tetraoxatridecyl, benzophenone, or 4-boronic acid benzene.

[0012] Its structural formula is selected from one of the following:

[0013] The preparation method of the above-mentioned quaternary ammonium salt organic semiconductor material includes: under a nitrogen atmosphere, reacting 13-bromo-2,5,8,11-tetraoxatridecane\4-(bromomethyl)benzophenone\4-(bromomethyl)phenylboronic acid with 2,7-bis(2-(dimethylamino)ethyl)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone as raw materials and dichloromethane or N,N-dimethylformamide as solvent, and then recrystallizing after the reaction to obtain the quaternary ammonium salt organic semiconductor material.

[0014] In a preferred embodiment of the present invention, the molar ratio of 2,7-bis(2-(dimethylamino)ethyl)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone to 13-bromo2,5,8,11-tetraoxatridecane\4-(bromomethyl)benzophenone\4-(bromomethyl)phenylboronic acid is 1:2.5-3.

[0015] More preferably, the amount of dichloromethane or N,N-dimethylformamide used is 15-25 times the total weight of 2,7-bis(2-(dimethylamino)ethyl)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone and 13-bromo2,5,8,11-tetraoxatridecane\4-(bromomethyl)benzophenone\4-(bromomethyl)phenylboronic acid.

[0016] In a preferred embodiment of the present invention, the reaction temperature is 35-80°C and the time is 10-12 hours.

[0017] The above-mentioned quaternary ammonium salt organic semiconductor materials are used in the fabrication of field-effect transistors based on two-dimensional materials.

[0018] A field-effect transistor based on two-dimensional materials, which has the aforementioned quaternary ammonium salt organic semiconductor material.

[0019] The beneficial effects of this invention are:

[0020] 1. The present invention contains a large-volume planar aromatic ring structure of naphthalimide in its molecular structure, which can form a strong interaction with the surface of two-dimensional materials.

[0021] 2. The molecular structure of the present invention contains quaternary ammonium organic cations, which can enhance the electrostatic interaction with the surface of two-dimensional materials.

[0022] 3. The specific R groups in the molecular structure of this invention can not only regulate the solubility of the molecule in organic solvents, but also adjust its interaction with the surface of two-dimensional materials by influencing the molecular configuration, energy level distribution, and dipole moment, thereby enhancing or weakening the adsorption performance of the molecule on the surface of two-dimensional materials.

[0023] 4. This invention can achieve long-term and stable control of the semiconductor properties of two-dimensional materials; it has an n-type doping electronic effect on monolayer MoS2, and the electrical properties of monolayer MoS2 after treatment are significantly improved; specifically, the current density of monolayer MoS2 field-effect transistor devices treated with this invention is nearly 200 times higher than that before treatment, that is, this invention can be well applied to field-effect transistors of two-dimensional materials.

[0024] 5. The preparation process of the present invention is simple and low in cost, and meets the requirements for large-scale preparation. Attached Figure Description

[0025] Figure 1 is the 1H NMR spectrum of the quaternary ammonium salt organic semiconductor material I prepared in Example 1 of the present invention;

[0026] Figure 2 is the 1H NMR spectrum of the quaternary ammonium salt organic semiconductor material II prepared in Example 2 of the present invention;

[0027] Figure 3 is the 1H NMR spectrum of the quaternary ammonium salt organic semiconductor material III prepared in Example 3 of the present invention;

[0028] Figure 4 shows the output characteristic curves of the monolayer MoS2 field-effect transistor device before and after treatment with the quaternary ammonium salt organic semiconductor materials prepared in Examples 1, 2 and 3 of Example 4 of the present invention;

[0029] Figure 5 shows the transfer characteristic curves of the quaternary ammonium salt organic semiconductor materials prepared in Examples 1, 2 and 3 of Example 4 of the present invention before and after treating the monolayer MoS2 field-effect transistor device. Detailed Implementation

[0030] The technical solution of the present invention will be further explained and described below with reference to specific embodiments and accompanying drawings.

[0031] Example 1

[0032] Preparation of Quaternary Ammonium Salt Organic Semiconductor Material I

[0033] The reaction route in this embodiment is as follows:

[0034] Specifically, the reaction involves: under a nitrogen atmosphere, weighing and adding 2,7-bis(2-(dimethylamino)ethyl)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone (200 mg, 10.0 mmol) and 13-bromo2,5,8,11-tetraoxatridecane (967.1 mg, 3.0 mmol) into a Schlenk reaction flask, then injecting 15 mL of N,N-dimethylformamide to form the reaction system; heating the reaction system to 80°C and reacting for 10 h; after the reaction is complete, filtering to obtain the crude product; recrystallizing the crude product from N,N-dimethylformamide to obtain a green solid, namely the quaternary ammonium salt organic semiconductor material I. The 1H NMR spectrum of the quaternary ammonium salt organic semiconductor material I obtained in this embodiment is shown in Figure 1, specifically: 1 HNMR (500MHz, d6-DMSO) δ8.73 (s, 4H), 4.54-4.38 (m, 4H), 3.97-3.09 (m, 50H), 2.93 (d, J = 16.1Hz, 2H), 2.53 (t, J = 5.4Hz, 2H).

[0035] Example 2

[0036] Preparation of Quaternary Ammonium Salt Organic Semiconductor Material II:

[0037] The reaction route in this embodiment is as follows:

[0038] Specifically, the process involves: under a nitrogen atmosphere, weighing and adding 2,7-bis(2-(dimethylamino)ethyl)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone (200 mg, 10.0 mmol) and 4-(bromomethyl)benzophenone (967.1 mg, 3.0 mmol) into a Schlenk reaction flask, then injecting 15 mL of dichloromethane to form the reaction system; heating the reaction system to 35°C and reacting for 10 h; after the reaction is complete, filtering to obtain the crude product; recrystallizing the crude product from dichloromethane to obtain a yellow solid, namely the quaternary ammonium salt organic semiconductor material II. The 1H NMR spectrum of the quaternary ammonium salt organic semiconductor material II obtained in this embodiment is shown in Figure 2, specifically: 1H NMR (500MHz, d6-DMSO) δ8.74(d,J=14.4Hz,4H),7.86(s,8H),7.79(d,J=7.0Hz,4H),7.73(t,J=7. 4Hz,2H),7.60(t,J=7.7Hz,4H),4.88(s,4H),4.68-4.58(m,4H),3.86-3.55(m,4H),3.24(s,12H).

[0039] Example 3

[0040] Preparation of Quaternary Ammonium Salt Organic Semiconductor Material III:

[0041] The reaction route in this embodiment is as follows:

[0042] Specifically, the process involves: under a nitrogen atmosphere, weighing and adding 2,7-bis(2-(dimethylamino)ethyl)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone (200 mg, 10.0 mmol) and 4-(bromomethyl)phenylboronic acid (967.1 mg, 3.0 mmol) into a Schlenk reaction flask, then injecting 15 mL of dichloromethane to form the reaction system; heating the reaction system to 35°C and reacting for 10 h; after the reaction is complete, filtering to obtain the crude product; recrystallizing the crude product from dichloromethane to obtain a yellow solid, namely the quaternary ammonium salt organic semiconductor material III. The 1H NMR spectrum of the quaternary ammonium salt organic semiconductor material III obtained in this embodiment is shown in Figure 3, specifically: 1 H NMR(500MHz,d6-DMSO)δ8.74(s,4H),8.22(s,4H),7.92(d,J=7.9Hz,4H),7.61(d ,J=8.0Hz,4H),4.74(s,4H),4.68-4.54(m,4H),3.70-3.56(m,4H),3.18(s,12H).

[0043] Example 4

[0044] (1) Preparation of monolayer MoS2: Monolayer MoS2 was grown using a typical chemical vapor deposition (CVD) method. In a dual-temperature zone tube furnace, MoO3 and S powder were placed 2.5 cm (second region) and 26 cm upstream (first region) of the Si / SiO2 substrate, respectively. An argon flow rate of 100 cm⁻¹ was used. 3 min -1Under these conditions, the temperature of the Si / SiO2 substrate and the MoO3 placed in the second region was gradually increased to 800℃. Once the Si / SiO2 substrate reached the growth temperature, the S powder placed in the first region was heated to 200℃ to provide S vapor for the growth of a monolayer of MoS2. After reacting for 10 minutes, the furnace was allowed to cool naturally to room temperature. The sample was then sealed in argon gas for further use.

[0045] (2) Fabrication of Field-Effect Transistor (FET) Devices: A standard wet transfer process was used, with polymethyl methacrylate (PMMA) as the support layer, to transfer a monolayer of MoS2 grown on a Si / SiO2 substrate to a clean Si / SiO2 substrate. The specific steps were as follows: First, a layer of PMMA was spin-coated onto the Si / SiO2 substrate with 1L-MoS2 grown on it, and then annealed on a hot plate at 100°C for 3 min; then, the sample was placed in a 1M KOH solution and immersed at 90°C for 30 min to separate the PMMA film from the original substrate; next, after washing three times with deionized water, the PMMA / 1L-MoS2 composite film was transferred to the target substrate; finally, after drying on a hot plate at 60°C for 1 h, the sample was immersed in acetone for 1 h to remove the PMMA film; for electrode fabrication, AZ5214 photoresist was spin-coated onto the Si substrate and patterned, and a 60 nm thick layer of gold (Au) was deposited as the electrode by electron beam evaporation. Au electrodes were precisely aligned and attached to monolayer MoS2 using a microtransfer device via dry transfer. To achieve functional modification, the FET devices based on monolayer MoS2 were immersed in dimethyl sulfoxide (DMSO) solutions of quaternary ammonium salt organic semiconductor materials I, II, and III at a concentration of 10 mg / mL. After standing for 30 min in a light-protected environment, they were rinsed with DMSO and acetone in sequence, dried with nitrogen, and finally stored in a desiccator for later use.

[0046] As shown in Figure 4, using the Keithley 4200 semiconductor parameter analysis system, under vacuum conditions, the gate (V) GS The voltage is 10V, and the source-drain voltage (V) SD The output characteristic curves of the FET devices were measured at a voltage of -2V to 2V. As can be seen from the figure, the output curves of the FET devices based on MoS2, MoS2-I, MoS2-II, and MoS2-III are all linear, indicating that the metal electrodes of these devices have good ohmic contact with the active layers (MoS2, MoS2-I, MoS2-II, and MoS2-III).

[0047] As shown in Figure 5, using the Keithley 4200 semiconductor parameter analysis system, under vacuum conditions, the source-drain voltage (V) DSWith a gate voltage of 1V and a range of -60V to 60V, the transfer characteristic curves of the FET device were measured. The figures show that quaternary ammonium salt organic semiconductor materials I, II, and III exhibit n-type doping electronic effects on monolayer MoS2. Compared to MoS2-based FET devices, the performance of FET devices based on MoS2-I, MoS2-II, and MoS2-III is significantly improved, with the MoS2-II FET device showing the largest increase in current density, nearly 200 times that of the MoS2-based device.

[0048] 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

[0049] This invention discloses a quaternary ammonium salt organic semiconductor material, its preparation method, and its application. Its structural formula is as follows: Wherein, R is 2,5,8,11-tetraoxatridecyl, benzophenone, or 4-benzene borate. This invention enables long-term and stable control of the semiconductor properties of two-dimensional materials; it exhibits an n-type doping electronic effect on monolayer MoS2, significantly improving the electrical properties of the treated monolayer MoS2; specifically, the current density of the monolayer MoS2 field-effect transistor device treated with this invention is nearly 200 times higher than that before treatment, meaning this invention can be well applied to field-effect transistors made of two-dimensional materials and has industrial applicability.

Claims

1. A quaternary ammonium salt organic semiconductor material, characterized in that: Its structural formula is Wherein, R is 2,5,8,11-tetraoxatridecyl, benzophenone, or 4-boronic acid phenyl.

2. The quaternary ammonium salt organic semiconductor material as described in claim 1, and its application in the fabrication of field-effect transistors based on two-dimensional materials.

3. The application as described in claim 1, characterized in that... The quaternary ammonium salt organic semiconductor material is attached to the surface of a monolayer MoS2 and has an n-type doped electronic effect.

4. The application as described in claim 3, characterized in that... The surface-modified MoS2 is used in FET devices.

5. The method for preparing a quaternary ammonium salt organic semiconductor material as described in claim 1, characterized in that: include: Under a nitrogen atmosphere, 13-bromo-2,5,8,11-tetraoxatridecane\4-(bromomethyl)benzophenone\4-(bromomethyl)phenylboronic acid and 2,7-bis(2-(dimethylamino)ethyl)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone were reacted with dichloromethane or N,N-dimethylformamide as solvent. After the reaction was completed, the quaternary ammonium salt organic semiconductor material was obtained by recrystallization.

6. The preparation method according to claim 5, characterized in that: The molar ratio of 2,7-bis(2-(dimethylamino)ethyl)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone to 13-bromo2,5,8,11-tetraoxatridecane\4-(bromomethyl)benzophenone\4-(bromomethyl)phenylboronic acid is 1:2.5-3.

7. The preparation method according to claim 6, characterized in that: The amount of dichloromethane or N,N-dimethylformamide used is 15-25 times the total weight of 2,7-bis(2-(dimethylamino)ethyl)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone and 13-bromo2,5,8,11-tetraoxatridecane\4-(bromomethyl)benzophenone\4-(bromomethyl)phenylboronic acid.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The reaction is carried out at a temperature of 35-80℃ for 10-12 hours.

9. A field-effect transistor based on two-dimensional materials, characterized in that: It has the quaternary ammonium salt organic semiconductor material as described in claim 1.

Images