Functionalized ionic liquid regulated organic mixed ionic-electronic conductor thin film, organic electrochemical transistor and preparation method thereof
Patent Information
- Application Number
- CN202611067854.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-17
- Publication Date
- 2026-10-13
AI Technical Summary
其中，普通咪唑类离子液体可通过离子交换和聚合物链重排改善PEDOT:PSS沟道的转移特性，但对于功能化离子液体的分子结构设计与OMIEC离子-电子耦合行为之间的关联机制研究有限，现有离子液体调控策略多集中于阴离子种类或非功能化离子液体，难以兼顾高跨导、低工作电压和快速响应
[0027]1.通过离子液体阳离子侧链功能化设计，引入羧基等极性功能基团，可增强离子液体与PEDOT:PSS体系之间的相互作用，从而改善沟道层的离子-电子协同调控能力。
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Abstract
Description
Technical Field
[0001] This invention belongs to the technical fields of organic bioelectronic devices, organic mixed ion-electron conductor materials, and organic electrochemical transistors, specifically relating to a functionalized ionic liquid-regulated organic mixed ion-electron conductor thin film, an organic electrochemical transistor, and their preparation methods. Background Technology
[0002] Organic electrochemical transistors (OECTs) can regulate channel conductivity by allowing ions to enter or exit organic semiconductor channels in an electrolyte environment. They feature low operating voltage, interface friendliness, intrinsic signal amplification, and solution processing capabilities, and have significant application potential in bioelectric signal amplification, wearable monitoring, ion sensing, and flexible electronics.
[0003] PEDOT:PSS (poly(3,4-ethylenedioxythiophene):polystyrene sulfonate) has become one of the most widely used OMIEC materials due to its excellent electrical conductivity, water-dispersible processing capability, and good ion transport characteristics. In recent years, to further improve the electrical, mechanical, and ion transport capabilities of PEDOT:PSS, existing technologies typically involve adding ethylene glycol, dimethyl sulfoxide, surfactants, ionic liquids, or other additives to improve the thin film state and device performance of PEDOT:PSS. Among these, common imidazole ionic liquids can improve the transfer characteristics of PEDOT:PSS channels through ion exchange and polymer chain rearrangement. However, research on the correlation mechanism between the molecular structure design of functionalized ionic liquids and the ion-electron coupling behavior of OMIEC is limited. Existing ionic liquid modulation strategies mostly focus on anion-specific or non-functionalized ionic liquids, making it difficult to simultaneously achieve high transconductance, low operating voltage, and fast response.
[0004] Therefore, it is necessary to develop a functionalized ionic liquid control strategy that can take into account ion transport regulation, electron transport optimization, and interface stability, so as to achieve synergistic improvement of the performance of organic hybrid ionic-electron conductor materials and further improve the overall performance of organic electrochemical transistors. Summary of the Invention
[0005] The purpose of this invention is to provide a functionalized ionic liquid-controlled organic hybrid ion-electron conductor material, an organic electrochemical transistor, and a method for fabricating the same. By introducing a functionalized ionic liquid with a specific structure, the ion-electron transport behavior within the OMIEC is synergistically controlled. This improves the transconductance, response speed, operational stability, and overall electrical performance of the device while maintaining material processability, providing a new material design strategy for the construction of high-performance organic electrochemical transistors.
[0006] The technical solution of this invention is as follows:
[0007] An organic hybrid ionic-electron conductor thin film regulated by a functionalized ionic liquid, the thin film comprising PEDOT:PSS and a functionalized ionic liquid, wherein the functionalized ionic liquid is an imidazole-based ionic liquid with polar functional groups such as carboxyl, hydroxyl, ester or amide groups in its cationic side chain, and the thin film serves as the channel layer of an organic electrochemical transistor.
[0008] The PEDOT:PSS is a water-dispersible PEDOT:PSS, and the organic mixed ion-electron conductor film also includes a crosslinking agent, which is 3-glycidoxypropyltrimethoxysilane (GOPS), divinyl sulfone, or a combination thereof.
[0009] The cation of the functionalized ionic liquid is one of 1-carboxyl-3-alkylimidazolium, 1-hydroxyalkyl-3-alkylimidazolium, 1-esterylalkyl-3-alkylimidazolium, or 1-amidoalkyl-3-alkylimidazolium.
[0010] The anion of the functionalized ionic liquid is one of the following: trifluoromethanesulfonate (OTF), bis(trifluoromethanesulfonyl)imide, tricyanomethane, tetrafluoroborate, hexafluorophosphate, chloride, and bromide.
[0011] Furthermore, the functionalized ionic liquid is preferably an imidazole-based ionic liquid such as 1-carboxyethyl-3-methylimidazolium trifluoromethane sulfonate (C2COOHMIM OTF), 1-hydroxyethyl-3-methylimidazolium trifluoromethane sulfonate (C2OHMIM OTF), or 1-ethyl-3-methylimidazolium trifluoromethane sulfonate (EMIM OTF).
[0012] Further, 0.02-0.20 mmol of functionalized ionic liquid, preferably 0.0450-0.1088 mmol, and more preferably 0.0675-0.0975 mmol, is added to each 1 mL of PEDOT:PSS aqueous dispersion. In a preferred embodiment, 0.0863 mmol of C2COOHMIM OTF is added to each 1 mL of PEDOT:PSS aqueous dispersion.
[0013] The present invention also provides an organic electrochemical transistor, comprising a substrate, a source electrode, a drain electrode, a channel layer, an electrolyte layer, and a gate electrode, wherein the channel layer is an organic mixed ion-electron conductor thin film regulated by the above-mentioned functionalized ion liquid.
[0014] The substrate is one of Si / SiO2 substrate, glass substrate, quartz substrate, polyethylene terephthalate substrate, polyimide substrate or Parylene C substrate.
[0015] The source and drain are respectively one or a combination of Au, Cr / Au, Ti / Au, Pt, Ag, ITO, FTO, PEDOT:PSS, graphene, carbon nanotube film or metal nanowire.
[0016] The electrolyte layer is one of phosphate buffer, NaCl aqueous solution, hydrogel electrolyte, polymer gel electrolyte or ion gel.
[0017] The gate electrode is one of Ag / AgCl, Au, Pt, Ag, or PEDOT:PSS.
[0018] The organic electrochemical transistor can be any of the following: planar structure, vertical structure, flexible structure, or array structure.
[0019] The present invention also provides a method for preparing the above-mentioned organic electrochemical transistor, comprising the following steps:
[0020] Step 1: Dissolve the functionalized ionic liquid in deionized water to obtain a functionalized ionic liquid solution;
[0021] Step 2: Mix the functionalized ionic liquid solution with PEDOT:PSS aqueous dispersion, add crosslinking agent and stir to obtain functionalized ionic liquid-doped PEDOT:PSS precursor solution;
[0022] Step 3: Deposit the precursor solution on the substrate with pre-fabricated source and drain electrodes; the substrate is treated with ultraviolet ozone, plasma treatment or solvent cleaning before deposition, and the precursor solution is stirred for 5-60 min before deposition.
[0023] Step 4: Anneal the deposited film to form an organic mixed ion-electron conductor channel layer. This channel layer is a functionalized ion liquid-controlled organic mixed ion-electron conductor film. The deposition method is one of spin coating, drop coating, blade coating, spray coating, inkjet printing, screen printing, roll coating, or embossing. The annealing temperature is 80-180℃, and the annealing time is 5-60 min.
[0024] Step 5: Introduce an electrolyte layer and a gate electrode onto the channel layer to obtain an organic electrochemical transistor.
[0025] The organic electrochemical transistor prepared under a drain voltage of -0.5 V maintains depletion-type transfer characteristics; preferably, when doped with 0.0863 mmol of 1-carboxyethyl-3-methylimidazolium trifluoromethanesulfonate, the maximum transconductance is not less than 6 mS and the response time is not more than 1 ms.
[0026] Compared with the prior art, the advantages of the present invention are as follows:
[0027] 1. By functionalizing the ionic liquid cationic side chain, introducing polar functional groups such as carboxyl groups can enhance the interaction between the ionic liquid and the PEDOT:PSS system, thereby improving the ion-electron synergistic regulation capability of the channel layer.
[0028] 2. When C2COOHMIM OTF-doped PEDOT:PSS is used as the channel layer, the device maintains typical depletion-type transfer characteristics and exhibits higher transconductance.
[0029] 3. The functionalized ionic liquid doping strategy described above can significantly shorten the device response time. In a preferred embodiment, the response time of the 0.0863 mmol C2COOHMIM OTF-doped device is approximately 0.43 ms, which is superior to the undoped PEDOT:PSS control device.
[0030] 4. The preparation method is mainly based on aqueous phase mixing, solution deposition and low temperature annealing processes. The preparation process is simple and suitable for the preparation of planar devices, flexible devices and arrayed devices. Attached Figure Description
[0031] Figure 1 This is a schematic diagram of the functionalized ionic liquid-doped PEDOT:PSS channel material, organic electrochemical transistor structure and fabrication process described in this invention; in the figure: 0-substrate, 1-source and drain, 2-functionalized ionic liquid-doped PEDOT:PSS channel layer, 3-electrolyte layer, 4-gate electrode.
[0032] Figure 2 These are the transfer curves and corresponding transconductance curves of PEDOT:PSS organic electrochemical transistors doped with different ionic liquids in Examples 2-4. Detailed Implementation
[0033] The present invention will be further described below with reference to specific embodiments. It should be understood that the described embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Unless otherwise stated, the PEDOT:PSS used in each embodiment is a Clevios PH1000 aqueous dispersion, the crosslinking agent is 3-glycidoxypropyltrimethoxysilane (GOPS), the source / drain electrodes are metal Au electrodes, the electrolyte is PBS buffer, and the gate electrode is Ag / AgCl. The device structure is as follows... Figure 1 As shown, a top-gate bottom contact structure is adopted. From bottom to top, the layers are: substrate 0 with SiO2 insulating layer, gold source and drain 1, functionalized ionic liquid doped PEDOT:PSS channel layer 2, PBS buffer as device working medium (electrolyte layer 3), and Ag / AgCl as Faraday gate electrode 4 on top.
[0034] All embodiments employ the same basic device fabrication process, differing only in the configuration of the organic semiconductor, which will be described in detail in the embodiments. The fabrication process includes the following steps:
[0035] Step 1: Clean the substrate using detergent, acetone solution, deionized water and isopropanol solution, and then dry it with nitrogen gas.
[0036] Step 2: Deposit Au electrodes on the substrate surface by vapor deposition, and then perform ultraviolet ozone (UVO) treatment for 15 min;
[0037] Step 3: Spin-coat the pre-prepared organic semiconductor solution onto the substrate treated in Step 2;
[0038] Step 4: After spin coating, anneal at 140℃ to thermally crosslink the semiconductor; obtain an organic mixed ion-electron conductor film with a thickness of 50-200 nm, which serves as the channel layer.
[0039] Step 5: After the organic electrochemical transistors of the functionalized ion-doped PEDOT:PSS were fabricated, the device performance was tested using PBS solution as the electrolyte and AgCl as the gate electrode.
[0040] Example 1: Undoped PEDOT:PSS control device.
[0041] 1 mL of PEDOT:PSS aqueous dispersion was mixed with 1.5 mL of deionized water, and 5 μL of GOPS was added. The mixture was stirred at room temperature for 15 min to obtain an undoped PEDOT:PSS solution. This precursor solution was deposited on a substrate with pre-fabricated source and drain electrodes using a two-step spin-coating process: 500 rpm pre-spinning for 10 s and 3000 rpm main spinning for 55 s. The resulting film was then annealed at 140 °C for 20 min to form an undoped PEDOT:PSS channel layer. Transfer curves and response rates were measured using PBS buffer and an Ag / AgCl gate electrode.
[0042] Example 2: EMIM OTF-doped PEDOT:PSS device.
[0043] 0.0750 mmol EMIM OTF was dissolved in 1.5 mL of deionized water, 1 mL of PEDOT:PSS aqueous dispersion was added, followed by 5 μL of GOPS. The mixture was stirred at room temperature for 15 min to obtain the EMIM OTF-doped PEDOT:PSS precursor solution. The remaining device fabrication steps were the same as in Example 1. The transfer curve and transconductance of this device are shown below. Figure 2 As shown in the figure on the right, it exhibits a typical P-type depletion operating mode. Under the condition of a drain voltage of -0.5V, the on-state current reaches 4.76E-5mA, and the maximum transconductance is 6.50E-5mS.
[0044] Example 3: C2OHMIM OTF-doped PEDOT:PSS device
[0045] 0.0750 mmol C2OHMIM OTF was dissolved in 1.5 mL of deionized water, 1 mL of PEDOT:PSS aqueous dispersion was added, followed by 5 μL of GOPS. The mixture was stirred at room temperature for 15 min to obtain a C2OHMIM OTF-doped PEDOT:PSS precursor solution. The remaining device fabrication steps were the same as in Example 1. The transfer curve and transconductance of this device are shown below. Figure 2 As shown in the middle figure, it also exhibits a typical P-type depletion operating mode. Under the condition of a drain voltage of -0.5V, the on-state current reaches 8.21E-4mA, and the maximum transconductance is 9.98E-4mS.
[0046] Example 4: C2COOHMIM OTF-doped PEDOT:PSS device
[0047] 0.0750 mmol C2COOHMIM OTF was dissolved in 1.5 mL of deionized water, 1 mL of PEDOT:PSS aqueous dispersion was added, followed by 5 μL of GOPS. The mixture was stirred at room temperature for 15 min to obtain a C2COOHMIM OTF-doped PEDOT:PSS precursor solution. The remaining device fabrication steps were the same as in Example 1. The transfer curve and transconductance of this device are shown below. Figure 2 As shown in the left figure, it also exhibits a typical P-type depletion operating mode. Under the condition of a drain voltage of -0.5V, the on-state current reaches 1.02E-3mA, and the maximum transconductance is 1.04E-3mS.
[0048] The device performance of Examples 2-4 was evaluated by transfer curves and response speed, and the results are shown in the table below.
[0049] Example 2 EMIM OTF 0.065 9.200 Example 3 C2OHMIM OTF 0.998 1.903 Example 4 C2COOHMIM OTF 1.038 0.813
[0050] The results in the table show that, under the condition that the anion is OTF, imidazole ionic liquids with the introduction of hydroxyl or carboxyl functional groups can improve the device response speed. Among them, the C2COOHMIM OTF-doped device has higher transconductance and shorter response time, indicating that the carboxyl functionalization of ionic liquids has a better regulatory effect on the transfer characteristics and dynamic response of the PEDOT:PSS channel.
[0051] Example 5: C2COOHMIM OTF-doped PEDOT:PSS devices with different doping levels
[0052] 0.0450 mmol C2COOHMIM OTF was dissolved in 1.5 mL of deionized water, 1 mL of PEDOT:PSS aqueous dispersion was added, and then 5 μL of GOPS was added. The mixture was stirred at room temperature for 15 min to obtain the corresponding doped C2COOHMIM OTF-doped PEDOT:PSS precursor solution. The remaining device fabrication steps were the same as in Example 1.
[0053] Example 6: C2COOHMIM OTF-doped PEDOT:PSS devices with different doping levels
[0054] 0.0563 mmol C2COOHMIM OTF was dissolved in 1.5 mL of deionized water, 1 mL of PEDOT:PSS aqueous dispersion was added, and then 5 μL of GOPS was added. The mixture was stirred at room temperature for 15 min to obtain the corresponding doped C2COOHMIM OTF-doped PEDOT:PSS precursor solution. The remaining device fabrication steps were the same as in Example 1.
[0055] Example 7: C2COOHMIM OTF-doped PEDOT:PSS devices with different doping levels
[0056] 0.0675 mmol C2COOHMIM OTF was dissolved in 1.5 mL of deionized water, 1 mL of PEDOT:PSS aqueous dispersion was added, and then 5 μL of GOPS was added. The mixture was stirred at room temperature for 15 min to obtain the corresponding doped C2COOHMIM OTF-doped PEDOT:PSS precursor solution. The remaining device fabrication steps were the same as in Example 1.
[0057] Example 8: C2COOHMIM OTF-doped PEDOT:PSS devices with different doping levels
[0058] 0.0750 mmol C2COOHMIM OTF was dissolved in 1.5 mL of deionized water, 1 mL of PEDOT:PSS aqueous dispersion was added, and then 5 μL of GOPS was added. The mixture was stirred at room temperature for 15 min to obtain the corresponding doped C2COOHMIM OTF-doped PEDOT:PSS precursor solution. The remaining device fabrication steps were the same as in Example 1.
[0059] Example 9: C2COOHMIM OTF-doped PEDOT:PSS devices with different doping levels
[0060] 0.0863 mmol C2COOHMIM OTF was dissolved in 1.5 mL of deionized water, 1 mL of PEDOT:PSS aqueous dispersion was added, and then 5 μL of GOPS was added. The mixture was stirred at room temperature for 15 min to obtain the corresponding doped C2COOHMIM OTF-doped PEDOT:PSS precursor solution. The remaining device fabrication steps were the same as in Example 1.
[0061] Example 10: C2COOHMIM OTF-doped PEDOT:PSS devices with different doping levels
[0062] 0.0975 mmol C2COOHMIM OTF was dissolved in 1.5 mL of deionized water, 1 mL of PEDOT:PSS aqueous dispersion was added, followed by 5 μL of GOPS. The mixture was stirred at room temperature for 15 min to obtain the corresponding doped C2COOHMIM OTF-doped PEDOT:PSS precursor solution. The remaining device fabrication steps were the same as in Example 1.
[0063] Example 11: C2COOHMIM OTF-doped PEDOT:PSS devices with different doping levels
[0064] 0.1088 mmol C2COOHMIM OTF was dissolved in 1.5 mL of deionized water, 1 mL of PEDOT:PSS aqueous dispersion was added, followed by 5 μL of GOPS. The mixture was stirred at room temperature for 15 min to obtain the corresponding doped C2COOHMIM OTF-doped PEDOT:PSS precursor solution. The remaining device fabrication steps were the same as in Example 1.
[0065] The transfer curve test results of Examples 5-11 are shown in the table below.
[0066] Example 5 0.0450 3.950 Example 6 0.0563 5.768 Example 7 0.0675 6.800 Example 8 0.0750 3.680 Example 9 0.0863 6.850 Example 10 0.0975 6.770 Example 11 0.1088 7.465
[0067] The results in the table show that the doping amount of C2COOHMIM OTF significantly affects the transfer characteristics of the PEDOT:PSS channel. Within the range of 0.0675–0.1088 mmol, the devices exhibited high transconductance, indicating that carboxyl-functionalized ionic liquids have a wide effective control window.
[0068] Further response speed tests were conducted on the devices with the preferred doping levels, and the results are shown in the table below.
[0069] Undoped PEDOT:PSS Comparison Device 0 2.26 Preferred C2COOHMIM OTF doped devices 0.0863 0.43
[0070] The response speed test results show that when PEDOT:PSS is doped with 0.0863 mmol C2COOHMIM OTF as the channel layer, the device response time is reduced from approximately 2.26 ms in the undoped control device to approximately 0.43 ms, indicating that this functionalized ionic liquid doping strategy can effectively improve the dynamic response performance of OECT. Based on the transfer curve and response speed test results, 0.0863 mmol C2COOHMIM OTF can be considered the preferred doping amount for this invention.
[0071] The above description is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, without departing from the technical principle of the present invention, several improvements and modifications can be made to the type of functionalized ionic liquid, doping amount, channel deposition method, annealing conditions, substrate material, electrode material and electrolyte system. These improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A functionalized ionic liquid-controlled organic hybrid ionic-electron conductor thin film, characterized in that, It includes PEDOT:PSS and functionalized ionic liquids, wherein the functionalized ionic liquids are imidazole ionic liquids with polar functional groups on their cationic side chains, and the polar functional groups include at least one of carboxyl, hydroxyl, ester, and amide groups.
2. The functionalized ionic liquid-controlled organic hybrid ion-electron conductor thin film according to claim 1, characterized in that, The cation of the functionalized ionic liquid is one of 1-carboxyl-3-alkylimidazolium, 1-hydroxyalkyl-3-alkylimidazolium, 1-esterylalkyl-3-alkylimidazolium, or 1-amidoalkyl-3-alkylimidazolium.
3. The functionalized ionic liquid-controlled organic hybrid ion-electron conductor thin film according to claim 1, characterized in that, The functionalized ionic liquid is one of 1-carboxyethyl-3-methylimidazolium trifluoromethane sulfonate, 1-hydroxyethyl-3-methylimidazolium trifluoromethane sulfonate, or 1-ethyl-3-methylimidazolium trifluoromethane sulfonate.
4. The functionalized ionic liquid-controlled organic hybrid ion-electron conductor thin film according to claim 1, characterized in that, The PEDOT:PSS is a water-dispersible PEDOT:PSS, and the organic mixed ionic-electron conductor film further includes a crosslinking agent, which is 3-glycidoxypropyltrimethoxysilane, divinyl sulfone, or a combination thereof.
5. The functionalized ionic liquid-controlled organic hybrid ion-electron conductor thin film according to claim 4, characterized in that, Add 0.0450-0.1088 mmol of functionalized ionic liquid to each 1 mL of PEDOT:PSS aqueous dispersion.
6. The functionalized ionic liquid-controlled organic hybrid ion-electron conductor thin film according to claim 5, characterized in that, Add 0.0863 mmol of 1-carboxyethyl-3-methylimidazolium trifluoromethane sulfonate to each 1 mL of PEDOT:PSS aqueous dispersion.
7. An organic electrochemical transistor, comprising a substrate, a source electrode, a drain electrode, a channel layer, an electrolyte layer, and a gate electrode, characterized in that, The channel layer is a functionalized ionic liquid-controlled organic hybrid ionic-electron conductor thin film as described in any one of claims 1-6.
8. The method for fabricating an organic electrochemical transistor as described in claim 7, characterized in that, Includes the following steps: Step 1: Dissolve the functionalized ionic liquid in deionized water to obtain a functionalized ionic liquid solution; Step 2: Mix the functionalized ionic liquid solution with PEDOT:PSS aqueous dispersion, add crosslinking agent and stir to obtain functionalized ionic liquid-doped PEDOT:PSS precursor solution; Step 3: Deposit the precursor solution on the substrate with pre-fabricated source and drain electrodes; Step 4: Anneal the deposited film to form an organic mixed ion-electron conductor channel layer; Step 5: Introduce an electrolyte layer and a gate electrode onto the channel layer to obtain an organic electrochemical transistor.
9. The method for fabricating an organic electrochemical transistor according to claim 8, characterized in that, The deposition method is one of spin coating, drop coating, scraping coating, spraying, inkjet printing, screen printing, roll coating, or embossing.
10. The method for fabricating an organic electrochemical transistor according to claim 9, characterized in that, The annealing temperature is 80-180℃, and the annealing time is 5-60 min.