Biphenyl vinyl derivative molecular single crystal and vertical field effect transistor device based on biphenyl vinyl derivative molecular single crystal

Abstract

The invention discloses a synthesis method of a biphenyl vinyl derivative BPVAn and application of the biphenyl vinyl derivative BPVAn in a high-performance vertical field effect transistor (VFET). In particular, the present invention describes in detail how to accurately control the mobility of carriers through a gate pulse voltage in a VFET using a biphenyl vinyl derivative single crystal, thereby significantly reducing the power consumption of the VFET. In the manufacturing process of the VFET, a BPVAn single crystal is firstly transferred to a single layer of graphene, and the graphene layer is located on a silicon dioxide layer formed on a silicon wafer. Then, a cesium fluoride (CsF) layer, a calcium (Ca) layer and a silver (Ag) layer are sequentially deposited on the BPVAn, and the silver layer serves as a drain electrode; the core innovation of the VFET design lies in the regulation and control mechanism of the grid pulse voltage, and the mechanism not only optimizes the carrier mobility, realizes quick switching through quick response to the pulse grid voltage, but also improves the overall equipment performance through reducing the energy consumption. The implementation of the technology shows the potential of BPVAn in improving the performance of the organic field effect transistor, especially the application value of BPVAn in the aspect of realizing low-energy-consumption high-speed electronic equipment.

Description

Technical Field

[0001] The present invention relates to the technical fields of organic lasers and semiconductor devices. Specifically, a stilbenyl derivative molecule is designed and synthesized. Its crystal has good optical and electrical properties, and can realize a vertical field-effect transistor (Vertical Field-Effect Transistor, VFET) that is driven by a gate pulse voltage and adjusts the carrier mobility, and is applicable to high-mobility light-emitting field-effect transistors and high-speed electronic devices. Background Art

[0002] In the applications of high-speed electronic devices and organic lasers, the carrier mobility and the response speed of the device are key performance indicators. Traditional field-effect transistors (FETs) usually adopt a planar structure, with a relatively long carrier transport path, which limits the switching speed and overall performance of the device, and also faces large power consumption and thermal management problems in high-frequency applications. With the development of organic semiconductor technology, organic materials have become an ideal choice for manufacturing high-performance electronic and optoelectronic devices due to their adjustable optical and electrical properties. In particular, stilbenyl derivative molecules (such as BPVAn) show great potential in the fields of organic lasers and organic light-emitting field-effect transistors (OLEFETs) due to their excellent optoelectronic properties. These molecules not only exhibit excellent photoluminescence performance, but also their crystalline morphology can achieve high mobility in electronic devices. However, applying these organic materials to traditional field-effect transistors still faces challenges, mainly due to the limitations of the device structure and material interfaces, and the high mobility of the materials cannot be fully utilized. Therefore, developing a new type of vertical field-effect transistor (VFET) that can not only drive the device through a gate pulse voltage, but also effectively adjust the carrier mobility, improve the device performance and expand its application range, and achieve a fast response of the device to the pulsed gate voltage to achieve a fast switching effect. Based on this need, the present invention proposes a design of a vertical field-effect transistor that combines the excellent optoelectronic properties of stilbenyl derivative molecules, aiming to solve these limitations in the prior art and promote the development of organic semiconductor devices towards higher performance. Summary of the Invention

[0003] The present invention relates to the technical fields of organic electroluminescence and field-effect transistors. Specifically, it is the synthesis of a stilbenyl derivative molecule BPVAn and its application in a vertical field-effect transistor (VFET). The purpose of the present invention is to achieve an organic photolaser with a low threshold and a high-mobility organic light-emitting field-effect transistor (OLEFET). The development of organic solid-state lasers provides new possibilities for simple preparation, low cost, and wide application range. However, the coexistence of high carrier mobility and excellent luminescence performance in organic single crystals has always been a challenge.

[0004] To solve the above problems, the present invention discloses a method for synthesizing a stilbenyl derivative molecule, and designs a novel VFET based on this molecule. The specific steps include:

[0005] S1. Oxidize a silicon wafer with a size of 1 cm 2 and a thickness of 2 mm to form a 300-nm-thick silicon dioxide (SiO2) layer, and then transfer and place a single-layer graphene above the silicon dioxide layer, where silicon serves as the gate and graphene serves as the source.

[0006] S2. Transfer a 4,4'-bis((E)-2-(anthracen-2-yl)vinyl)-1,1'-biphenyl (BPVAn) crystal above the single-layer graphene. Sequentially deposit a 5-nm-thick cesium fluoride (CsF) layer, a 10-nm-thick calcium (Ca) layer, and a 20-nm-thick silver (Ag) layer above the BPVAn crystal, where the silver layer serves as the drain.

[0007] The present invention also discloses a method for synthesizing a stilbenyl derivative molecule, and designs a novel VFET based on this molecule. The specific steps include:

[0008] S1. Oxidize a silicon wafer with a size of 1 cm 2 and a thickness of 2 mm to form a 300-nm-thick silicon dioxide (SiO2) layer, and then transfer and place a single-layer graphene above the silicon dioxide layer, where silicon serves as the gate and graphene serves as the source.

[0009] S2. Transfer a 4,4'-bis((E)-2-(anthracen-2-yl)vinyl)-1,1'-biphenyl (BPVAn) crystal above the single-layer graphene. Sequentially deposit a 5-nm-thick cesium fluoride (CsF) layer, a 10-nm-thick calcium (Ca) layer, and a 20-nm-thick silver (Ag) layer above the BPVAn crystal, where the silver layer serves as the drain.

[0010] The VFET of the present invention realizes the optimization of carrier mobility through the regulation of the gate pulse voltage, has a fast response to the pulsed gate voltage to achieve the effect of fast switching, and reduces power consumption and improves device performance. In addition, the electroluminescence characteristics of the BPVAn crystal and its application potential in lasers and OLEFETs are also important parts of the present invention. The detailed description and other technical advantages of the present invention will be elaborated in the subsequent specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 Schematic diagram of the synthesis route of the stilbenyl derivative molecule in Example 1 of the present invention;

[0012] Figure 2 Schematic diagram of the two-dimensional single-crystal growth of the stilbenyl derivative molecule in Example 2 of the present invention;

[0013] Figure 3-1 Bright-field microscope photograph of the two-dimensional single crystal of the biphenylylvinyl derivative molecule in Example 3 of the present invention;

[0014] Figure 3-2 Fluorescence-field microscope photograph of the two-dimensional single crystal of the biphenylylvinyl derivative molecule in Example 3 of the present invention;

[0015] Figure 3-3 Absorption and emission spectra of the biphenylylvinyl derivative molecule in Example 3 of the present invention, including the absorption peak and emission peak wavelength data of the dilute solution in tetrahydrofuran and the solid single crystal, and the optical properties of the crystal in different states are shown through the spectral curves;

[0016] Figure 4 Test result diagram of the laser behavior of the biphenylylvinyl derivative molecule under femtosecond laser in Example 4 of the present invention

[0017] Figure 4-1 Diagram of the change of the luminescence photograph and luminescence spectrum above the crystal threshold as the pump energy increases for the biphenylylvinyl derivative molecule in Example 4 of the present invention;

[0018] Figure 4-2 S-type nonlinear relationship curve of the luminescence intensity of the biphenylylvinyl derivative molecule crystal varying with the pump energy in Example 4 of the present invention, illustrating the stimulated emission characteristics and laser threshold of the crystal;

[0019] Figure 5 Schematic diagram of the structure and top-down actual morphology of the vertical field-effect transistor (VFET) device of the biphenylylvinyl derivative molecule crystal in Example 5 of the present invention.

[0020] Figure 5-1 Three-dimensional schematic diagram of the vertical field-effect transistor device of the biphenylylvinyl derivative molecule crystal in Example 5 of the present invention.

[0021] Figure 5-2 Actual photograph of the vertical field-effect transistor device of the biphenylylvinyl derivative molecule crystal under the microscope in Example 5 of the present invention.

[0022] Figure 6 Test result diagram of the electrical performance of the vertical field-effect transistor of the biphenylylvinyl derivative molecule crystal in Example 6 of the present invention.

[0023] Figure 6-1 Transfer curve diagram of the vertical field-effect transistor device of the biphenylylvinyl derivative molecule crystal at different gate voltages in Example 6 of the present invention, with the abscissa being the gate voltage (V) and the ordinate being the drain current (A).

[0024] Figure 6-2: Output curve of the P-type vertical field-effect transistor device of the biphenylethenyl derivative molecular crystal in Example 6 of the present invention. The abscissa is the source-drain voltage (V), and the ordinate is the drain current (A).

[0025] Figure 6-3 : Output curve of the N-type vertical field-effect transistor device of the biphenylethenyl derivative molecular crystal in Example 6 of the present invention. The abscissa is the source-drain voltage (V), and the ordinate is the drain current (A).

[0026] Figure 7 : Luminescence characteristic diagram of the vertical field-effect transistor device of the biphenylethenyl derivative molecular crystal in Example 6 of the present invention under different gate voltages and drain voltages.

[0027] Figure 7-1 : Luminescence intensity distribution diagram of the BPVAn transistor of the vertical field-effect transistor device of the biphenylethenyl derivative molecular crystal in Example 6 of the present invention under different source-drain voltages and different gate voltages.

[0028] Figure 7-2 : Luminescence spectrum diagram of the BPVAn transistor of the vertical field-effect transistor device of the biphenylethenyl derivative molecular crystal in Example 6 of the present invention when the source-drain voltage is -110V under different gate voltages. The abscissa is the wavelength (nm), and the ordinate is the luminescence intensity (a.u.).

[0029] Figure 7-3 : Luminescence spectrum diagram of the BPVAn transistor of the vertical field-effect transistor device of the biphenylethenyl derivative molecular crystal in Example 6 of the present invention when the source-drain voltage is -120V under different gate voltages. Detailed implementation manners

[0030] The following will combine the drawings and examples to detail the implementation manners of the present invention, so as to fully understand how the present invention uses technical means to solve technical problems and the implementation process of achieving technical effects and implement accordingly. It should be noted that as long as there is no conflict, the various features in the various embodiments of the present invention can be combined with each other, and the formed technical solutions are all within the protection scope of the present invention.

[0031] Example 1:

[0032] A synthesis method of a biphenylethenyl derivative molecule, designed and synthesized a biphenylethenyl derivative 4,4'-bis((E)-2-(anthracen-2-yl)vinyl)-1,1'-biphenyl, namely BPVAn. The specific steps include:

[0033] 1. Weigh 520 mg (2 mmol) of 2-bromoanthracene powder into a side-arm reactor. Use a double manifold to repeatedly evacuate and fill with Ar gas and a vacuum pump 3 - 4 times to remove water and oxygen in the side-arm reactor, then protect it with Ar. Then, use a syringe to add 10 mL of ultra-dry tetrahydrofuran and stir at 500 r / min for 5 min at -70 °C. Slowly add 0.5 mL (5.3 mmol) of butyllithium to the reaction using a syringe and stir for 1 h under the same conditions. Then, slowly add 0.5 mL (6.4 mmol) of ultra-dry N,N-dimethylformamide (DMF) to the reaction using a syringe and let it react overnight under the same conditions. Quench the reaction with deionized water, extract the reaction product with dichloromethane and water, collect the lower layer solution, remove water using anhydrous sodium sulfate, and then dry it using a rotary evaporator. Purify the obtained yellow powder product by silica gel column chromatography (CHCl 2 : petroleum ether = 1:3) to obtain 396 mg of anthracene-2-carbaldehyde (yield 95.6%) for later use.

[0034] 2. Weigh 227 mg (0.5 mmol) of 4,4'-bis(diethoxyphosphonomethyl)biphenyl powder and 80 mg (3.3 mmol) of NaH powder into a side-arm reactor. Use a double manifold to repeatedly evacuate and fill with Ar gas and a vacuum pump 3 - 4 times to remove water and oxygen in the side-arm reactor, then protect it with Ar. Then, use a syringe to add 10 mL of ultra-dry tetrahydrofuran and stir at 500 r / min for 1 h in an ice-water bath. Weigh 230 mg (1.1 mmol) of anthracene-2-carbaldehyde powder, dissolve it in 10 mL of ultra-dry tetrahydrofuran, and then add it to the reaction using a syringe and stir at 500 r / min overnight at room temperature. Quench the reaction with deionized water. Extract the obtained suspension with dichloromethane, collect the lower layer suspension, filter it under negative pressure, and then wash it repeatedly with deionized water, ethanol, and dichloromethane 3 - 4 times. After drying, obtain 250 mg of the final product BPVAn powder (yield 89%).

[0035] For example, in step S1 above, the molar ratio of each drug is 2-bromoanthracene: butyllithium: N,N-dimethylformamide = 2:5.3:5.4; in step S2, the molar ratio of each drug is 4,4'-bis(diethoxyphosphonomethyl)biphenyl: NaH: anthracene-2-carbaldehyde = 0.5:3.3:1.1.

[0036] In step S1, the eluent used in silica gel column chromatography is a mixed solution of dichloromethane and petroleum ether, and their volume ratio is 1:3.

[0037] A biphenylethenyl derivative molecule BPVAn, prepared according to the above synthesis method, has the structure:

[0038]

[0039] Example 2:

[0040] Take 0.5 mg of BPVAn powder and evenly apply it on a pre-washed ordinary glass coverslip. After placing it on a hot stage, add a spacer with a thickness of 0.34 mm, and then place a clean glass slide as the upper substrate directly above it. Heat it to 435 °C, stop heating after 5 min, and wait for the temperature to drop to room temperature before removing the upper substrate. Shining BPVAn crystals can be seen, and most of the single crystals are observed to grow perpendicular to the substrate surface under a microscope. Attach the upper substrate with BPVAn single crystals to a Si / SiO 2 wafer spin-coated with 20 nm thick PMMA, and the BPVAn crystals can be transferred and tiled onto the PMMA surface.

[0041] Example 3:

[0042] Observe the transferred BPAVn crystals under a fluorescence microscope. Under white light, it can be seen that the crystallization is good, the surface is flat, and the edges are smooth and sharp; from the fluorescence photo, it can be seen that the crystals have good optical waveguide and optical confinement effects, and the edges emit brighter green light. From the absorption and emission spectra, the absorption peak wavelengths of its dilute solution in tetrahydrofuran are located at 326 nm, 338 nm, 376 nm, and 395 nm, and the emission peak wavelengths are located at 430 nm and 447 nm; the absorption peaks of the solid single crystal are located at 424 nm and 460 nm, and the emission peaks are located at 502 nm and 536 nm.

[0043] Example 4:

[0044] Characterization of the laser behavior of the crystal: Place the transferred BPVAn crystals under a 400 nm femtosecond laser and observe and collect their laser behavior. The left figure shows the change in the emission spectrum of the crystal as the pump energy increases. It can be seen that its full width at half maximum decreases rapidly as the pump energy increases after reaching 10 μJ / cm 2 , showing obvious stimulated emission behavior. The inset is a photo of the crystal emission above the threshold. The right figure shows the change in the emission intensity as the pump energy increases, showing an obvious S-shaped nonlinear relationship. The laser threshold is 10.2 μJ / cm 2 .

[0045] Example 5:

[0046] Transfer and tile the BPVAn thin single crystal onto a Si / SiO2 substrate coated with a single layer of graphene, and then sequentially evaporate a 5 nm thick cesium fluoride, a 10 nm thick calcium, and a 20 nm thick silver electrode on the crystal after masking, and remove the mask to obtain an organic light-emitting field-effect transistor device.

[0047] For example, a mask plate is covered on a BPVAn crystal tiled on a Si / SiO2 substrate, and then it is placed in a vacuum metal evaporation machine to sequentially evaporate 5 nm thick cesium fluoride, 10 nm thick calcium, and 20 nm thick silver. After removing the sample, the mask plate is torn off to obtain a VOFET device with an Ag asymmetric electrode for the source and drain and a channel width of 280 nm (crystal thickness). The device is pasted on a copper plate with copper glue to ensure that the potential of the bottom layer Si is equal to that of the copper plate. The field effect of the device is tested using a Keithley 4200SCS semiconductor electrical test system as follows Figure 5 for testing.

[0048] Example 6:

[0049] Testing of the migration and output curves of the OLET device: The hole migration signals of the device are tested using source-drain voltages of -60 V, -90 V, and -120 V and a gate voltage range of 20 V to -100 V. The hole mobility at a source-drain voltage of -60 V is 5.24 cm 2 V -1 s -1 , and the output curve of the hole signal is shown in the middle figure. Subsequently, the electron migration signals of the device are tested using source-drain voltages of 60 V, 90 V, and 120 V and a gate voltage range of 0 to 200 V. The electron mobility measured at a source-drain voltage of 60 V is 0.16 cm 2 V -1 s -1 , and then the output curve of the electron signal is shown in the right figure. The experimental data prove that the BPVAn crystal can achieve double injection and high mobility of holes and electrons under symmetric electrodes.

Claims

1. A method for manufacturing a vertical organic light-emitting field effect transistor (VOFET) based on a distyryl derivative 4,4'-bis((E)-2-(anthracen-2-yl)vinyl)-1,1'-biphenyl (i.e., BPVAn), the specific steps comprising: S1. In a piece of 1cm 2 , an oxidation treatment is performed on a 2mm thick silicon wafer to form a 300nm thick silicon dioxide (SiO2) layer, and then a single layer of graphene is transferred and placed on top of the silicon dioxide layer, with silicon serving as the gate and graphene as the source. S2. Transfer 4,4'-bis((E)-2-(anthracen-2-yl)vinyl)-1,1'-biphenyl (BPVAn) crystals onto the monolayer graphene. Deposit a 5nm thick cesium fluoride (CsF) layer, a 10nm thick calcium (Ca) layer, and a 20nm thick silver (Ag) layer on the BPVAn crystals in sequence, wherein the silver layer serves as a drain.

2. The method for synthesizing a distyryl derivative molecule according to claim 1, characterized in that: A distyryl derivative 4,4'-bis((E)-2-(anthracen-2-yl)vinyl)-1,1'-biphenyl, namely BPVAn, was designed and synthesized, and the specific steps included: S1. 2-bromoanthracene powder is loaded into a branch reactor tube, ultra-dry tetrahydrofuran is used as solvent, butyl lithium is added at -70°C, ultra-dry nitrogen-nitrogen dimethylformamide (DMF) is added dropwise after stirring for 1-2 hours, and a preliminary product is obtained after stirring overnight. Deionized water is added to quench the reaction, and anthracene 2-carboxaldehyde solid is obtained after extraction and purification by silica gel column chromatography; S2. Charge 4,4'-bis(diethoxyphosphonomethyl)biphenyl powder and dry NaH powder into the same branch tube reactor, use ultra-dry tetrahydrofuran as solvent, stir for 1 hour in an ice-water bath, then dissolve the anthracene 2-carboxaldehyde solid powder obtained in step S1 in ultra-dry tetrahydrofuran and add it to the reaction using a syringe, stir overnight at room temperature, add deionized water to quench the reaction, filter the resulting suspension under negative pressure, repeatedly wash the solid product with ethanol and dichloromethane, and obtain the final product, BPVAn powder, after drying.

3. The method for manufacturing a vertical field effect transistor (VFET) according to claim 1, characterized in that: The deposition of the cesium fluoride (CsF) layer, the calcium (Ca) layer and the silver (Ag) layer in step S2 needs to be performed under the condition of being free of water and oxygen.

4. The method for synthesizing a distyryl derivative molecule according to claim 2, characterized in that: The reaction must be carried out under anhydrous and oxygen-free conditions.

5. The vertical field effect transistor based on a distyryl derivative according to claim 1, characterized in that: The single-layer graphene is prepared by a chemical vapor deposition (CVD) method.

6. A vertical field effect transistor (VFET) based on a distyryl derivative, characterized in that: Prepared according to the preparation method according to claim 1.

7. The distyryl derivative molecule according to claim 2, characterized in that: The absorption peak wavelengths of its tetrahydrofuran dilute solution are located at 326nm, 338nm, 376nm and 395nm, the luminescence peak wavelengths are located at 430nm and 447nm, and the fluorescence quantum yield is 0.56; the absorption peaks of the solid single crystal are located at 424nm and 460nm, the luminescence peaks are located at 502nm and 536nm, and the fluorescence quantum yield is 0.

35.

8. The distyryl derivative single crystal according to claim 4, characterized in that: Under the excitation of a 400nm femtosecond laser, laser emission can be achieved at the edge of the crystal. The laser wavelength is 503nm and has a threshold of ≤10μJ / cm 2 .

9. The method for manufacturing a vertical field effect transistor (VFET) according to claim 1, wherein: The amplitude of the pulse voltage applied to the gate is 2V to 210V, the duty cycle is 1% to 50%, and the pulse width is 40ns to 10ms.

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