Organic electronic device and preparation process thereof
By using meniscus-induced coating and thiol group-modified materials, the problem of metal-semiconductor interface damage during the manufacturing process of organic single-crystal OFETs was solved, improving the device performance and realizing organic electronic devices with high mobility and low subthreshold swing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-29
- Publication Date
- 2026-04-07
AI Technical Summary
Existing organic single-crystal field-effect transistors (OFETs) are prone to damage at the metal-semiconductor interface during manufacturing, resulting in weak gate electrostatic tuning performance, low transconductance, and high subthreshold slope, which limits their potential in high-gain applications.
Small molecule semiconductor thin film layers are formed on the dielectric layer, source and drain using a meniscus-induced coating method. The outer surfaces of the source and drain are modified with a polyfluorine-containing thiol group-modified material to form a smooth metal-organic semiconductor contact interface.
It achieves high mobility, low subthreshold swing, and high gain organic electronic device performance, conforms to the Schottky-Mott principle, and is suitable for fast turn-on at low gate voltage.
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Figure CN121815932A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of organic electronic devices, and particularly relates to an organic electronic device and a preparation process thereof. BACKGROUND
[0002] Organic field-effect transistors (OFETs) are one of the organic electronic devices, and are considered as a large-area, low-cost technology with great potential to drive the development of flexible and wearable electronics due to their flexibility and soluble processing characteristics. In recent decades, researchers have been committed to improving the gain of OFETs by designing high-mobility molecules and reducing interface / channel defects, etc. For example, the liquid-liquid interface-induced coating technology improves the crystal quality of small-molecule organic semiconductors. However, even single-crystal OFETs still have the problem of weak gate static tuning performance, which is manifested as small transconductance and large subthreshold slope, which fundamentally limits their potential in high-gain applications. This is because even though organic single crystals have extremely low defect density, during the manufacturing process, these fragile materials are often difficult to withstand the harsh conditions of the manufacturing process while maintaining their intrinsic properties, resulting in an undesirable gate static efficiency of SC-OFETs. Traditional organic electronic manufacturing processes usually use thermal evaporation metallization methods to deposit the top electrode. This metallization process usually involves high-energy metal atoms, cluster bombardment and strong local heating of the organic single crystal contact area. These aggressive processes can cause metal atoms or clusters to penetrate the organic semiconductor, introducing unnecessary structural perturbations and defects at the metal-semiconductor contact interface. This can generate a large number of mid-gap states at the metal-semiconductor contact interface, resulting in an undesirable Schottky junction. Therefore, there is a serious inconsistency between the basic electronic properties of the original organic single crystal and the actual SC-OFET performance.
[0003] The information disclosed in this Background section is only for the purpose of increasing the understanding of the general background of the application and should not be taken as an acknowledgement or any form of suggestion that this information forms prior art that is already known in this field. SUMMARY
[0004] The purpose of the present application is to provide an organic electronic device and a preparation process thereof, which can obtain a flat metal-organic semiconductor contact interface and improve the performance of the organic electronic device.
[0005] In order to achieve the above-mentioned purpose, the technical solutions of a specific embodiment of the present application are as follows:
[0006] A preparation process of an organic electronic device, comprising the following steps:
[0007] providing a substrate, forming a dielectric layer on the surface of the substrate;
[0008] forming a source electrode and a drain electrode on the dielectric layer;
[0009] The outer surfaces of the source and drain are modified using a polyfluorinated modifying material containing a thiol group;
[0010] A small-molecule semiconductor thin film layer is formed on the dielectric layer, the source and the drain by using a meniscus-induced coating method, and an organic electronic device is obtained after drying.
[0011] In one or more embodiments of the present application, the substrate is a single-polished silicon wafer having a silicon oxide layer, and the dielectric layer is formed on the silicon oxide layer.
[0012] In one or more embodiments of the present application, the step of providing a substrate specifically comprises:
[0013] After the substrate is soaked in concentrated sulfuric acid, it is cleaned.
[0014] In one or more embodiments of the present application, the step of forming a dielectric layer on the surface of the substrate specifically comprises:
[0015] The substrate is placed in an ultraviolet ozone machine to improve the wettability of the surface of the substrate, and then a dielectric material coating solution is spin-coated on the surface of the substrate to form a dielectric layer.
[0016] In one or more embodiments of the present application, the dielectric material is any one of polyvinyl cinnamate and poly(4-vinylphenol).
[0017] In one or more embodiments of the present application, the step of forming a source and a drain on the dielectric layer specifically comprises:
[0018] A metal is plated on the dielectric layer by a vacuum thermal evaporation plating device to form a source and a drain.
[0019] In one or more embodiments of the present application, the step of modifying the outer surfaces of the source and the drain using a polyfluorinated modifying material containing a thiol group comprises:
[0020] The source and the drain are immersed in a solution of a polyfluorinated modifying material containing a thiol group, taken out, cleaned, and dried.
[0021] In one or more embodiments of the present application, the step of forming a small-molecule semiconductor thin film layer on the dielectric layer, the source and the drain by using a meniscus-induced coating method comprises:
[0022] A small-molecule semiconductor coating solution is coated on the dielectric layer, the source and the drain by using a meniscus-induced coating method to form a small-molecule semiconductor thin film layer.
[0023] In one or more embodiments of the present application, the small-molecule semiconductor coating solution is a toluene solution of a small-molecule semiconductor material blended with polystyrene.
[0024] The organic electronic device is prepared by the preparation process of the organic electronic device.
[0025] Compared with the prior art, the preparation process of the organic electronic device can make the metal and the organic semiconductor contact and fit together through the Van der Waals force, obtain a flat metal-organic semiconductor contact interface, improve the performance of the organic electronic device, make the sub-threshold swing close to the theoretical limit of 59.2 mV / dec (in a temperature of 300 K environment), and enable the transistor to be quickly turned on under a low gate voltage. BRIEF DESCRIPTION OF DRAWINGS
[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative labor.
[0027] Figure 1 The flow chart of the preparation process of the organic electronic device in an embodiment of the present application;
[0028] Figure 2 The schematic diagram of the steps of the preparation process of the organic electronic device in an embodiment of the present application;
[0029] Figure 3 The projection electron microscope image of the interface between the metal and the semiconductor in the organic field effect transistor prepared in Embodiment 1 of the present application;
[0030] Figure 4 The element distribution diagram of the cross-section scanning transmission electron microscope in the organic field effect transistor in Embodiment 1 of the present application;
[0031] Figure 5 The saturation curve diagram of the organic electronic device in Embodiment 1 of the present application at different temperatures;
[0032] Figure 6 The transfer curve relationship extraction diagram of the organic electronic device in Embodiment 1 of the present application at different temperatures;
[0033] Figure 7 The Schottky barrier and gate voltage relationship diagram of the organic electronic device in Embodiment 1 of the present application;
[0034] Figure 8This is a graph showing the relationship between the surface electrostatic potential of the semiconductor material and the gate voltage in Embodiment 1 of the present invention;
[0035] Figure 9 This is a graph showing the relationship between the subthreshold swing of the organic electronic device at different temperatures in Embodiment 1 of the present invention;
[0036] Figure 10 This is a saturation region diagram of the organic electronic device in Embodiment 1 of the present invention;
[0037] Figure 11 The images shown are cross-sectional transmission electron microscope images of silver and semiconductor in Comparative Example 1 of the present invention.
[0038] Figure 12 This is a graph showing the relationship between the surface electrostatic potential and the gate voltage of the organic electronic device in Comparative Example 1 of the present invention;
[0039] Figure 13 This is a graph showing the relationship between the Schottky barrier and the gate voltage of the organic electronic device in Comparative Example 1 of the present invention.
[0040] Figure 14 This is a graph showing the transfer curves of different source-drain voltages of the organic electronic device in Comparative Example 1 of the present invention;
[0041] Figure 15 This is a saturation region transfer curve of the organic electronic device in Comparative Example 1 of the present invention. Detailed Implementation
[0042] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.
[0043] The fabrication process of the organic electronic device of the present invention can be used to fabricate a variety of organic electronic devices. In order to better introduce the fabrication process of the organic electronic device of the present invention, the fabrication process will be described below using the fabrication of organic field-effect transistors as an example.
[0044] like Figure 1 and 2 As shown, the fabrication process of the organic electronic device in one embodiment of the present invention includes the following steps:
[0045] S1. Provide a substrate and form a dielectric layer on the surface of the substrate.
[0046] The substrate is a single-layer polished silicon wafer with a silicon oxide layer, and the dielectric layer is formed on the silicon oxide layer.
[0047] Specifically, the substrate is an N-type single-layer polished silicon oxide wafer. Furthermore, the thickness of the silicon oxide can be 300nm-500nm, and the thickness of the substrate is approximately 500μm-700μm.
[0048] In one specific embodiment, the step of providing the substrate may include: immersing the substrate in concentrated sulfuric acid to remove adhering organic matter from the surface of the silicon oxide wafer, and rinsing the surface with deionized water. The immersion time can be selected according to actual needs, for example, 2-4 hours.
[0049] Specifically, the cleaning process involves removing the substrate after it has been soaked in concentrated sulfuric acid and then sequentially immersing it in analytical grade solvents such as deionized water, acetone, and isopropanol, while simultaneously subjecting it to ultrasonic treatment. This effectively removes the concentrated sulfuric acid from the substrate surface.
[0050] In one specific embodiment, the steps of forming a dielectric layer on the surface of the substrate include: placing the substrate in an ultraviolet ozone generator to improve the wettability of the substrate surface, and then spin-coating a dielectric material coating liquid onto the substrate surface to form a dielectric layer.
[0051] Specifically, after the cleaned substrate is removed from the isoamyl alcohol solvent, the isopropanol solvent can be removed with nitrogen gas before placing it in an ultraviolet ozone generator.
[0052] Specifically, the dielectric material coating solution can be a solution containing dielectric material, for example, the dielectric material can be dissolved in a solvent to form the dielectric material coating solution; or a commercially available dielectric material coating solution can be purchased. Specifically, the dielectric material can be at least one of polyvinyl cinnamate and poly(4-vinylphenol). The solvent in the dielectric material coating solution can be at least one of anisole, chlorobenzene, and propylene glycol methyl ether acetate.
[0053] Specifically, after spin-coating the dielectric material coating liquid onto the substrate surface, the solvent in the dielectric material can be removed by heating first, and then it can be placed in a UV curing machine for curing treatment, and then heated to cure again to improve the thermal stability of the insulation layer.
[0054] S2. Form the source and drain on the dielectric layer.
[0055] Specifically, the steps for forming the source and drain electrodes on the dielectric layer include: depositing metal onto the dielectric layer using a vacuum thermal evaporation coating device to form the source and drain electrodes. The metal can be an element such as gold, silver, or copper, or an alloy thereof.
[0056] Furthermore, a metal mask containing source and drain patterns can be brought into contact with a dielectric layer, and then the metal can be thermally evaporated to form the source and drain on the dielectric layer.
[0057] S3. Modify the outer surfaces of the source and drain electrodes using a polyfluorine-modified material containing thiol groups.
[0058] Specifically, the steps for modifying the outer surfaces of the source and drain electrodes using a polyfluorinated modification material containing thiol groups include: immersing the source and drain electrodes in a solution of the polyfluorinated modification material containing thiol groups, removing them, cleaning them, and drying them. That is, the device (substrate, dielectric layer, and source and drain electrodes) obtained in step S2 can be placed together in a solution containing perfluorothiol benzene, ensuring that at least the exposed surfaces of the source and drain electrodes are immersed in the solution containing perfluorothiol benzene. This forms a modification layer on the outer surfaces of the source and drain electrodes.
[0059] Among these effects, the modification enhances the work function of the metal, reduces the hole injection barrier between the metal and the semiconductor, and increases the turn-on current of the device.
[0060] Specifically, the preparation process of the solution of the polyfluorinated modified material containing thiol groups can be as follows: In a glass petri dish, the polyfluorinated modified material containing thiol groups is mixed with isopropanol (solvent) at a volume ratio of 5:1000 (this volume ratio can be adjusted according to actual needs). After ultrasonic treatment for 1 minute, a modifier is formed. The device is immersed in the modifier for 5 minutes, then removed, rinsed with isopropanol, and dried with nitrogen gas.
[0061] Specifically, the polyfluorinated modified material containing thiol groups can be either perfluorothiol benzene or monofluorothiol benzene.
[0062] S4. Small molecule semiconductor thin film layers are formed on the dielectric layer, source electrode and drain electrode using the meniscus-induced coating method, and organic electronic devices are obtained after drying.
[0063] Specifically, the steps of forming a small molecule semiconductor thin film layer on the dielectric layer, source electrode, and drain electrode using the meniscus-induced coating method include: coating a small molecule semiconductor coating liquid onto the dielectric layer, source electrode, and drain electrode using the meniscus-induced coating method to form a small molecule semiconductor thin film layer.
[0064] Specifically, the steps for coating small molecule semiconductor coating solution onto the dielectric layer, source, and drain using the meniscus-induced coating method can be as follows: Meniscus-induced coating is performed using a stepper motor and a doctor blade. The doctor blade is at a 30° acute angle to the dielectric layer (this angle can be adjusted as needed). Under heating conditions of 45°C (this temperature can be adjusted as needed), the small molecule semiconductor coating solution is injected into the gap between the doctor blade and the substrate using a pipette. Then, the stepper motor is controlled to drive the doctor blade at a speed of 500 μm / s (this speed can be adjusted as needed) to coat the solution, forming a small molecule semiconductor thin film layer (i.e., a semiconductor crystal thin film).
[0065] Specifically, the small molecule semiconductor coating solution is a toluene solution of a blend of small molecule semiconductor material and polystyrene. The preparation process of the small molecule semiconductor coating solution can be as follows: dissolve the small molecule semiconductor material and polystyrene in toluene solvent and stir for 2 hours until homogeneous.
[0066] Polystyrene can improve the film-forming properties of small molecule semiconductor materials. The mass ratio of polystyrene to small molecule semiconductor materials in the small molecule semiconductor coating solution can be (1-3):5 (the specific ratio can be adjusted according to actual needs).
[0067] Specifically, small molecule semiconductor materials can be C8-BTBT, C... 10 - Any of the BTBT types.
[0068] Specifically, in step S4, drying is performed to remove the solvent.
[0069] A specific embodiment of the present invention also provides an organic electronic device, which is prepared by the above-described organic electronic device fabrication process.
[0070] The organic electronic device of the present invention and its fabrication process will be described in detail below with reference to specific embodiments.
[0071] Example 1
[0072] (1) Select an N-type single-layer polished silicon oxide wafer (total thickness 500 μm, with silicon oxide thickness of 300 nm), cut it, and soak it in concentrated sulfuric acid for 2 hours. Then soak it in deionized water, acetone, and isopropanol analytical grade solvents in sequence, and sonicate for 15 minutes each for cleaning before use.
[0073] (2) Take out the cleaned silicon oxide wafer, remove the isopropanol solvent with nitrogen, place the wafer in a UV ozone generator to improve the wettability of the silicon oxide surface, and then spin coat the surface with a 30 mg / mL polyvinyl cinnamate anisole solution. The spin coating parameter is 3000 rpm. After spin coating, heat at 100°C for 5 minutes, cure in a 254 nm UV curing machine for 20 minutes, and heat at 100°C for half an hour to form a dielectric layer on the silicon oxide wafer.
[0074] (3) A metal mask containing source and drain patterns is brought into contact with a dielectric layer, and then the source and drain are formed on the dielectric layer by thermal evaporation of metal. The metal used for the source and drain is silver, with a work function of 4.67 eV.
[0075] (4) Perfluorothiol benzene and isopropanol were mixed in a glass petri dish at a volume ratio of 5:1000 and sonicated for 1 minute to form a modifier. The device prepared in (4) was immersed in the modifier for 5 minutes, then rinsed with isopropanol and dried with nitrogen. The work function of the modified silver electrode was 5.19 eV.
[0076] (5) First, prepare the C8-BTBT small molecule semiconductor coating solution: Dissolve C8-BTBT at a concentration of 10 mg / mL in toluene solvent, and dissolve polystyrene at a concentration of 2 mg / mL in toluene solution. Mix the two in a 1:1 volume ratio to obtain the coating solution, and stir with a small magnetic stirrer for 2 hours. Then, use a stepper motor and a doctor blade for meniscus-induced coating. The doctor blade is at a 30-degree acute angle with the dielectric layer. Under the heating condition of 45°C, inject 3 μL of solution into the gap between the doctor blade and the dielectric layer through a pipette. Then, control the stepper motor to drive the doctor blade to coat the solution at a speed of 500 μm / s to form a C8-BTBT semiconductor crystal thin film (small molecule semiconductor thin film layer).
[0077] (6) The device obtained in (5) was placed on a heating plate at 60°C and heated for 2 hours to remove the toluene solvent in the small molecule semiconductor thin film, thus obtaining an organic field-effect transistor.
[0078] like Figure 3 This is a metal-semiconductor interface observed by transmission electron microscopy in bright field mode. The interface is clear, and the metal has not penetrated or damaged the semiconductor layer.
[0079] like Figure 4 The image shows the metal-semiconductor interface observed by transmission electron microscopy in dark-field mode (left image). Elemental analysis (right image) shows that C and Ag have distinct layers, and the metal has not penetrated or damaged the semiconductor layer.
[0080] like Figures 5 to 7 As shown, Figure 5 The transfer curves obtained from tests at different temperatures are shown. Figure 6 After data processing, the relationship between the Schottky barrier and the gate voltage was obtained. Figure 7 The corresponding flat-band Schottky barrier was extracted. The metal-semiconductor Schottky barrier measured by temperature variation is consistent with the theoretically predicted barrier, which conforms to the Schottky-Mott rule.
[0081] like Figure 8 As shown, the slope of the surface potential change with the OFET gate voltage is close to 1V / V.
[0082] like Figure 9 As shown, the measured subthreshold swing is close to the theoretical limit of thermionic emission, ln10×K. B T / q, at room temperature (300K), this value is 59.2mV / dec.
[0083] like Figure 10 As shown in the figure (curve 1 in the figure is the transfer characteristic curve of the organic electronic device; curve 2 is the square root value of the current of the organic electronic device), the measured mobility of C8-BTBT is 10 cm⁻¹.2 V -1 s -1 .
[0084] Example 2
[0085] (1) Select an N-type single-layer polished silicon oxide wafer (total thickness 700 μm, with silicon oxide thickness of 500 nm), cut it, and soak it in concentrated sulfuric acid for 4 hours. Then soak it in analytical grade solvents of deionized water, acetone, and isopropanol in sequence, and sonicate it for 15 minutes each time for cleaning before use.
[0086] (2) Take out the cleaned silicon oxide wafer, remove the isopropanol solvent with nitrogen, place the wafer in a UV ozone generator to improve the wettability of the silicon oxide surface, and then spin coat the surface with a 30 mg / mL poly(4-vinylphenol) chlorobenzene solution. The spin coating parameter is 3000 rpm. After spin coating, heat at 100°C for 5 minutes, cure in a 254 nm UV curing machine for 20 minutes, and heat at 100°C for half an hour to form a dielectric layer on the silicon oxide wafer.
[0087] (3) A metal mask containing source and drain patterns is brought into contact with a dielectric layer, and then the source and drain are formed on the dielectric layer by thermal evaporation of metal. The metal used for the source and drain is silver, and the work function obtained by the test is 4.67 eV.
[0088] (4) Perfluorothiol benzene and isopropanol were mixed in a glass petri dish at a volume ratio of 5:1000, and the mixture was sonicated for 1 minute to form a modifier. The device prepared in (4) was immersed in the modifier for 5 minutes, then rinsed with isopropanol and dried with nitrogen. The work function of the modified gold electrode was 5.19 eV.
[0089] (5) First, prepare the C8-BTBT small molecule semiconductor coating solution: Dissolve C8-BTBT at a concentration of 10 mg / mL in toluene solvent, and dissolve polystyrene at a concentration of 2 mg / mL in toluene solution. Mix the two in a 1:1 volume ratio to obtain the coating solution, and stir with a small magnetic stirrer for 2 hours. Then, use a stepper motor and a doctor blade for meniscus-induced coating. The doctor blade is at a 30-degree acute angle with the dielectric layer. Under the heating condition of 45°C, inject 3 μL of solution into the gap between the doctor blade and the dielectric layer through a pipette. Then, control the stepper motor to drive the doctor blade to coat the solution at a speed of 500 μm / s to form a C8-BTBT semiconductor crystal thin film (small molecule semiconductor thin film layer).
[0090] (6) The device obtained in (5) was placed on a heating plate at 60°C and heated for 2 hours to remove the toluene solvent from the small molecule semiconductor thin film, thus obtaining an organic field-effect transistor. The performance of the organic field-effect transistor in this embodiment is similar to that of the organic field-effect transistor in Example 1.
[0091] Example 3
[0092] (1) Select an N-type single-layer polished silicon oxide wafer (total thickness 600 μm, with silicon oxide thickness of 400 nm), cut it, and soak it in concentrated sulfuric acid for 3 hours. Then soak it in deionized water, acetone, and isopropanol analytical grade solvents in sequence, and sonicate it for 15 minutes each time for cleaning before use.
[0093] (2) Take out the cleaned silicon oxide wafer, remove the isopropanol solvent with nitrogen, place the wafer in a UV ozone generator to improve the wettability of the silicon oxide surface, and then spin coat the surface with a 30 mg / mL polyvinyl cinnamate anisole solution. The spin coating parameter is 3000 rpm. After spin coating, heat at 100°C for 5 minutes, cure in a 254 nm UV curing machine for 20 minutes, and heat at 100°C for half an hour to form a dielectric layer on the silicon oxide wafer.
[0094] (3) A metal mask containing source and drain patterns is brought into contact with a dielectric layer, and then the source and drain are formed on the dielectric layer by thermal evaporation of metal. The metal used for the source and drain is silver, and the work function obtained by the test is 4.67 eV.
[0095] (4) Perfluorothiol benzene and isopropanol were mixed in a glass petri dish at a volume ratio of 5:1000, and the mixture was sonicated for 1 minute to form a modifier. The device prepared in (4) was immersed in the modifier for 5 minutes, then rinsed with isopropanol and dried with nitrogen. The work function of the modified silver electrode was 5.19 eV.
[0096] (5) First configure C 10 -BTBT small molecule semiconductor coating solution: C 10 BTBT was dissolved in toluene at a concentration of 10 mg / mL, and polystyrene was dissolved in toluene at a concentration of 2 mg / mL. The two solutions were mixed at a 1:1 volume ratio to obtain a coating solution, which was then stirred with a small magnetic stirrer for 2 hours. Then, a meniscus-induced coating was performed using a stepper motor and a doctor blade. The doctor blade was positioned at a 30-degree acute angle to the dielectric layer. Under heating conditions at 45°C, 3 μL of the solution was injected into the gap between the doctor blade and the dielectric layer using a pipette. The stepper motor was then controlled to drive the doctor blade at a speed of 500 μm / s to coat the solution, forming C... 10 -BTBT semiconductor crystal thin film (small molecule semiconductor thin film layer).
[0097] (6) The device obtained in (5) was placed on a heating plate at 60°C and heated for 2 hours to remove the toluene solvent from the small molecule semiconductor thin film, thus obtaining an organic field-effect transistor. The performance of the organic field-effect transistor in this embodiment is similar to that of the organic field-effect transistor in Example 1.
[0098] Comparative Example 1
[0099] (1) Select an N-type single-layer polished silicon oxide wafer (total thickness 500 μm, with silicon oxide thickness of 300 nm), cut it, and soak it in concentrated sulfuric acid for 2 hours. Then soak it in deionized water, acetone, and isopropanol analytical grade solvents in sequence, and sonicate for 15 minutes each for cleaning before use.
[0100] (2) Take out the cleaned silicon oxide wafer, remove the isopropanol solvent with nitrogen, place the wafer in a UV ozone generator to improve the wettability of the silicon oxide surface, and then spin coat the surface with a 30 mg / mL polyvinyl cinnamate anisole solution. The spin coating parameter is 3000 rpm. After spin coating, heat at 100°C for 5 minutes, cure in a 254 nm UV curing machine for 20 minutes, and heat at 100°C for half an hour to form a dielectric layer on the silicon oxide wafer.
[0101] (3) Preparation of C8-BTBT small molecule semiconductor coating solution: C8-BTBT was dissolved in toluene solvent at a concentration of 10 mg / mL, and polystyrene in toluene solution at a concentration of 2 mg / mL was mixed with the two in a 1:1 volume ratio to obtain the coating solution, and stirred with a small magnetic stirrer for 2 hours. Then, the solution was coated by bending surface induction using a stepper motor and a doctor blade. The doctor blade was at a 30-degree acute angle to the dielectric layer. Under the heating condition of 45°C, 3 μL of solution was injected into the gap between the doctor blade and the dielectric layer through a pipette. Then, the stepper motor was controlled to drive the doctor blade to coat the solution at a speed of 500 μm / s to form a C8-BTBT semiconductor crystal thin film (small molecule semiconductor thin film layer).
[0102] (4) A metal mask containing source and drain patterns is brought into contact with a semiconductor layer, and then the source and drain are formed on the dielectric layer by thermal evaporation of metal.
[0103] (5) The device obtained in (4) was placed on a heating plate at 60°C and heated for 2 hours to remove the toluene solvent from the small molecule semiconductor film.
[0104] like Figure 11 The transmission electron microscope image shown indicates that the metal has penetrated into the semiconductor layer, causing damage to the C8-BTBT layer.
[0105] like Figure 12 As shown in the figure (curve 1 in the figure represents the relationship between the surface potential and gate voltage of the device in Comparative Example 1; curve 2 represents the relationship between the surface potential and gate voltage of the device in Example 1), the metal-semiconductor Schottky barrier measured by temperature variation is approximately 0.2 eV, which is significantly different from the theoretically predicted value of 0.5 eV and does not conform to the Schottky-Mott rule.
[0106] like Figure 13 As shown, the slope of the surface potential change with the OFET gate voltage is low, much lower than 1V / V.
[0107] like Figure 14 As shown, the measured subthreshold swing was 275 mV / dec, which is far worse than the theoretical limit of 59.2 mV / dec for thermionic emission.
[0108] like Figure 15 As shown in the figure (curve 1 is the transfer characteristic curve of the organic electronic device; curve 2 is the square root value of the current of the organic electronic device), the measured mobility of C8-BTBT is 1.77 cm⁻¹. 2 V -1 s -1 .
[0109] In summary, the beneficial effects of the organic electronic device and its fabrication process of the present invention are as follows:
[0110] 1. By inducing the growth of a complete organic semiconductor crystalline thin film through liquid surface coating on a metal, a flat contact interface is formed between the metal and the organic semiconductor, avoiding the penetration and damage of the organic semiconductor by the metal, and achieving the improvement of key parameters of organic electronic devices.
[0111] 2. Compared with the traditional method of thermally evaporating and depositing metal on semiconductor thin films, devices constructed using this method have higher effective carrier mobility, lower subthreshold swing, and higher intrinsic gain.
[0112] 3. This method is compatible with inkjet printing electrode technology. Electrodes are first prepared on the insulating layer and then semiconductor thin films are deposited. This process avoids the deep damage of the semiconductor layer by the metal ink. Compared with thermal evaporation deposition, inkjet printing has advantages such as low cost and large area.
[0113] 4. This method can obtain the Schottky barrier height of gold-semiconductor contacts that is consistent with the theoretical (Schottky-Mott principle) prediction, which is very important for the selection of materials in the band matching relationship during device design.
[0114] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.
[0115] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A fabrication process for an organic electronic device, characterized in that, Includes the following steps: Provide a substrate, and form a dielectric layer on the surface of the substrate; The source and drain electrodes are formed on the dielectric layer; The outer surfaces of the source and drain electrodes are modified using a polyfluorine-modified material containing thiol groups; Small molecule semiconductor thin film layers are formed on the dielectric layer, source electrode, and drain electrode using the meniscus-induced coating method, and organic electronic devices are obtained after drying.
2. The fabrication process of the organic electronic device according to claim 1, characterized in that, The substrate is a single-layer polished silicon wafer with a silicon oxide layer, and the dielectric layer is formed on the silicon oxide layer.
3. The fabrication process of the organic electronic device according to claim 1, characterized in that, The step of providing the substrate specifically includes: After soaking the substrate in concentrated sulfuric acid, it was thoroughly cleaned.
4. The fabrication process of the organic electronic device according to claim 1, characterized in that, The specific steps for forming a dielectric layer on the surface of the substrate include: The substrate is placed in an ultraviolet ozone generator to improve the wettability of the substrate surface, and then a dielectric material coating liquid is spin-coated onto the substrate surface to form a dielectric layer.
5. The fabrication process of the organic electronic device according to claim 4, characterized in that, The dielectric material is either polyvinyl cinnamate or poly(4-vinylphenol).
6. The fabrication process of the organic electronic device according to claim 1, characterized in that, The specific steps for forming the source and drain on the dielectric layer include: Using a vacuum thermal evaporation coating equipment, metal is deposited onto a dielectric layer to form the source and drain electrodes.
7. The fabrication process of the organic electronic device according to claim 1, characterized in that, The step of modifying the outer surfaces of the source and drain electrodes with a polyfluorine-modified material containing thiol groups includes: The source and drain electrodes were immersed in a solution of a polyfluorine-modified material containing thiol groups, then removed, cleaned, and dried.
8. The fabrication process of the organic electronic device according to claim 1, characterized in that, The step of forming a small molecule semiconductor thin film layer on the dielectric layer, source electrode, and drain electrode using the meniscus-induced coating method includes: A small molecule semiconductor coating liquid is coated onto the dielectric layer, source electrode, and drain electrode using a meniscus-induced coating method to form a small molecule semiconductor thin film layer.
9. The fabrication process of the organic electronic device according to claim 8, characterized in that, The small molecule semiconductor coating solution is a toluene solution of small molecule semiconductor material and polystyrene.
10. An organic electronic device, characterized in that, It is prepared by the fabrication process of the organic electronic device according to any one of claims 1 to 9.