Preparation method of active channel layer of organic electrochemical transistor and organic electrochemical transistor
By spin-coating and annealing a polymer and small molecule mixed solution, combined with solid electrolytes and specific materials, the stability and switching speed issues of OECT were solved, and the fabrication of high-performance organic electrochemical transistors was realized, which are suitable for high-frequency circuits and ECG signal detection.
Patent Information
- Application Number
- CN202510816280.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-18
- Publication Date
- 2025-11-07
AI Technical Summary
Existing organic electrochemical transistors (OECTs) suffer from expansion and performance degradation due to ion movement during device switching, resulting in slow switching speeds, narrow applicable temperature ranges, and easy leakage of liquid electrolytes, which limits their application in high-speed signal processing and various environments.
An active channel layer was prepared by spin-coating a polymer and small molecule mixed solution. Combined with annealing, an organic electrochemical transistor was constructed using a solid electrolyte and specific materials, including a Parylene-C layer and a doping system. The carrier migration path and interfacial contact were optimized.
It improves the stability and switching speed of OECT, increases the transconductance, and the device retains 90% of the initial on-state current after 10,000 cycles. It is suitable for high-frequency circuits and ECG signal detection. The inverter has clear logic switching and high gain.
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Figure CN120916619A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of organic electrochemical transistors, and particularly relates to a preparation method of an active channel layer of an organic electrochemical transistor and the organic electrochemical transistor. BACKGROUND
[0002] OECT (organic electrochemical transistor) controls the electrochemical doping of the channel material by regulating the ion migration through the gate voltage, thereby realizing the regulation of the channel current. The OECT has the characteristics of simple preparation process, low working voltage and solution workability, and has wide application prospects in the fields of printed electronics, biological and chemical signal sensing and neuron simulation.
[0003] However, the stability of the OECT is poor, and the ions in the electrolyte need to be injected and removed from the channel layer during the opening and closing of the device. However, this frequent ion movement is likely to cause the channel layer to swell, resulting in a significant performance degradation of the device after a plurality of opening and closing cycles. The defects in ion transport are also a key factor restricting the performance improvement of the OECT. Due to the relatively slow ion movement speed, the switching speed of the OECT is slow and the carrier mobility is low, which makes it difficult to play an effective role in the high-speed signal processing field and high-frequency circuit where the signal processing speed and working frequency are extremely high.
[0004] In addition, the diffusion coefficient of the ions is greatly affected by the temperature, which makes the suitable working temperature range of the OECT relatively narrow. Under normal circumstances, the OECT can only maintain good performance within a specific temperature range. Once the temperature is too high or too low, the on-off ratio and transconductance of the device will decrease sharply, greatly limiting its application in different environmental temperatures. Finally, the conventional structure of the OECT needs to reserve a large space for the liquid electrolyte, and the electrolyte solution is prone to leakage and volatilization during use, further reducing its service life and safety. SUMMARY
[0005] This part aims to summarize some aspects of the embodiments of the present application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this part and the abstract and title of the specification of the present application to avoid obscuring the purpose of this part, the abstract and the title of the specification, and such simplifications or omissions cannot be used to limit the scope of the present application.
[0006] In view of the above and / or problems existing in the prior art, the present application is proposed.
[0007] Therefore, the purpose of the present application is to overcome the deficiencies in the prior art and provide a preparation method of an active channel layer of an organic electrochemical transistor.
[0008] To solve the above technical problems, the present application provides the following technical solutions:
[0009] The polymer and the small molecule are dissolved in an organic solvent to obtain a mixed solution;
[0010] The mixed solution is spin-coated on a substrate and annealed to obtain an active channel layer;
[0011] The polymer includes one of PFT-100, P3HT, PEDOT:PSS, and PTHS; the small molecule includes one of C8-BTBT, NPB, BPEA, Dif-TES-ADT, and C10-BTBT; and the organic solvent includes one or more of chloroform, chlorobenzene, and toluene.
[0012] The concentration of the polymer in the mixed solution is 1-10 mg / mL, the concentration of the small molecule is 1-10 mg / mL, and the mass ratio of the polymer to the small molecule is 1-10:1-10.
[0013] As a preferred scheme of the active channel layer, when the polymer is PFT-100 and the small molecule is C8-BTBT, the concentration of the polymer in the mixed solution is 5 mg / mL, the concentration of the small molecule is 2 mg / mL, and the mass ratio of the polymer to the small molecule is 5:2.
[0014] As a preferred scheme of the active channel layer, the annealing temperature is 20-140°C.
[0015] As a preferred scheme of the active channel layer, the annealing temperature is 120°C.
[0016] As a preferred scheme of the active channel layer, the annealing time is 15 min.
[0017] Another object of the present application is to overcome the deficiencies in the prior art and provide an active channel layer of an organic electrochemical transistor prepared by the preparation method.
[0018] Still another object of the present application is to overcome the deficiencies in the prior art and provide an organic electrochemical transistor.
[0019] To solve the above technical problems, the present application provides the following technical solutions: from bottom to top, sequentially including,
[0020] a substrate layer;
[0021] an electrode layer;
[0022] the active channel layer of claim 6.
[0023] Pry-C layer, material is Parylene-C;
[0024] Solid electrolyte layer;
[0025] Gate electrode;
[0026] The electrolyte layer is prepared from a PVDF matrix and an EMIM:TFSI ionic liquid;The gate electrode is prepared from a PI film substrate, Au and PEDOT:PSS;The substrate layer comprises one of a Si / SiO2 wafer, a glass sheet, a polyimide substrate and a parylene substrate;The electrode layer is prepared from one or more of Au, Ti, Ag, Mo and Al, and the electrode layer comprises one of a single layer and a stacked layer.
[0027] Another object of the present application is to provide an application of an organic electrochemical transistor in human ECG signal detection to overcome the deficiencies in the prior art.
[0028] Another object of the present application is to provide an application of an organic electrochemical transistor in constructing an inverter to overcome the deficiencies in the prior art.
[0029] Another object of the present application is to provide a preparation method of an organic electrochemical transistor to overcome the deficiencies in the prior art.
[0030] To solve the above technical problems, the present application provides the following technical solutions.
[0031] The silicon wafer is cut into small pieces, and then sequentially cleaned with acetone, ultrapure water and anhydrous ethanol, dried by nitrogen blowing, and pretreated with HMDS;
[0032] On the pretreated substrate, positive photoresist lithography is performed, and after development, the HMDS layer in the lithography pattern area is removed, Ti and Au are sequentially evaporated as source and drain electrodes, and the remaining photoresist and HMDS layer are removed, and the substrate is subjected to hydrophilic treatment;
[0033] The GOPS solution is spin-coated onto the hydrophilically treated substrate, annealed, and then evaporated with Parylene C powder to obtain a first Pry-C layer, annealed, spin-coated with Micro-90 solution as a release agent after hydrophilic treatment, and then evaporated with Parylene C powder to obtain a second Pry-C layer;
[0034] On the second Pry-C layer, after negative photoresist lithography, the two layers of Pry-C layer at the source and drain electrodes and the channel are removed to obtain a bottom-contact OECT substrate;
[0035] The preparation method of the active channel layer of the organic electrochemical transistor is used to prepare an active channel layer on the bottom-contact OECT substrate.
[0036] The PVDF is dissolved in acetone to obtain a polymer matrix solution, mixed with an ionic liquid EMIM:TSFI to obtain an electrolyte solution, and spin-coated on the active channel layer to obtain a solid-state electrolyte layer.
[0037] The PI film is cleaned, Au is evaporated, hydrophilic treatment and spin-coating PEDOT:PSS are performed, and after annealing, the gate electrode is cut and fixed to obtain an organic electrochemical transistor by adhering the gate electrode to the electrolyte layer.
[0038] The present application has the following beneficial effects:
[0039] (1) The present application successfully constructs a high-performance OECT by using the characteristics of high carrier mobility, high stability and excellent low-temperature environmental suitability of organic small molecules C8-BTBT, NPB and the like. The introduction of organic small molecule crystals significantly improves the performance of the device. The channel layer obtained by spin-coating a mixed solution based on PFT-100 and C8-BTBT and then annealing at 120°C is used to prepare an OECT. The OECT has a large maximum transconductance, and after 10,000 switching cycles, the on-state current can still maintain 90% of the initial value, showing excellent working stability.
[0040] (2) A double-p-type inverter is constructed using a doped system OECT, and the maximum gain of 16.72 can be reached when V dd is -0.6V, the inverter has clear logic "0" and logic "1", can be repeatedly switched, and has good stability;
[0041] (3) The electrocardiogram signal is tested using a doped system OECT, and the P wave, QRS group wave, T wave and U wave of the measured electrocardiogram signal are clear, the peak-to-peak amplitude of the electrocardiogram signal is basically consistent in 15s of continuous monitoring, and has high fidelity. BRIEF DESCRIPTION OF DRAWINGS
[0042] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor. Among them:
[0043] Figure 1 The active channel layer structure diagram (a) and the movement mode of holes in the channel layer (b) prepared for Example 1 of the present application.
[0044] Figure 2 The topographic map of the channel layer prepared for Example 1 and Comparative Examples 1-3 of the present application is tested by AFM.
[0045] Figure 3 Flow chart for preparing the bottom-contact OECT substrate for steps (1)-(4) in Example 3 of the present application.
[0046] Figure 4 Flow chart for preparing the organic electrochemical transistor for steps (5)-(7) in Example 3 of the present application.
[0047] Figure 5 Structure diagram (a) and working mechanism diagram (b) of the organic electrochemical transistor prepared in Example 3 of the present application.
[0048] Figure 6 On-state current I of the OECT prepared in Examples 3-4 and Comparative Example 4 of the present application on Comparison diagram (a), maximum transconductance value g m Comparison diagram (b), threshold voltage V th Comparison diagram (c).
[0049] Figure 7 On-state current of the OECT prepared in Examples 3 and Comparative Example 4 of the present application after 10000 cycles.
[0050] Figure 8 Circuit (a) for electrocardio signal test of the OECT prepared in Examples 3 and Comparative Example 4 of the present application and test result diagrams (b)-(d).
[0051] Figure 9 Circuit diagram (a) for constructing an inverter based on the OECT prepared in Examples 3 and Comparative Example 4 of the present application and voltage transfer characteristic curve (b) and gain curve diagram (c) of the inverter.
[0052] Figure 10 Switching characteristic curve (a) and cycle stability curve (b) of the inverter constructed based on the OECT prepared in Examples 3 and Comparative Example 4 of the present application. DETAILED DESCRIPTION
[0053] In order to make the above objectives, features and advantages of the present application more apparent and comprehensible, the specific embodiments of the present application will be described in detail below with reference to the description examples.
[0054] In the following description, a lot of specific details are set forth in order to provide a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of the present application, therefore the present application is not limited by the specific examples disclosed below.
[0055] Second, the term "one embodiment" or "an embodiment" as may be used herein means a specific implementation, or example, that can include features that are, but are not required to be, included in at least one implementation of the present disclosure. This use of "in one embodiment" or "an embodiment" is simply used to provide a conception of features included in at least one embodiment and can be used interchangeably with the term "in some embodiments" or "one embodiment, or some embodiments, or one or some embodiments" where such features are, can be or are not included in the'some embodiments' or one or more embodiments.
[0056] PFT-100 (poly[(5-fluoro-2,1,3-benzothiadiazole-4,7-diyl)(4,4-hexacosyl-4H- cyclopenta[2,1-b:3,4-b']dithiophene-2,6-diyl)(6-fluoro-2,1,3-benzothiadiazole-4,7- diyl)(4,4-hexacosyl-4H-cyclopenta[2,1-b:3,4-b']dithiophene-2,6-diyl)]) used in the present disclosure, P3HT (poly-3-hexylthiophene), PEDOT:PSS (poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate), PTHS (polythiophene sulfonate) were purchased from 1-Material and purity ≥ 99%.
[0057] C8-BTBT (2,7-dioctyl[1]benzothieno[3,2-b]benzothiophene), NPB (N,N-diphenyl-N,N- bis(naphthalen-1-yl-4,4-biphenyldiamine), BPEA (9,10-bis(phenylethynyl)anthracene), dif-TES-ADT (2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene), C10-BTBT (2,7-didecyl[1]benzothieno[3,2-b][1]benzothiophene) used in the present disclosure were purchased from Luminescence Technology Corp and purity ≥ 99%.
[0058] Example 1
[0059] The present embodiment provides a method for preparing an active channel layer, in particular:
[0060] The polymer PFT-100 and the small molecule C8-BTBT were dissolved in chloroform to obtain a mixed solution, wherein the concentration of PFT-100 in the mixed solution was 5 mg / mL, and the concentration of C8-BTBT in the mixed solution was 2 mg / mL, at this time, the mass ratio of PFT-100 to C8-BTBT in the mixed solution was 5:2.
[0061] The mixed solution was spin-coated on a substrate and annealed at 120°C for 15 min to obtain an active channel layer.
[0062] The structure of the active channel layer of Example 1 is shown in Figure 1 (a), wherein the movement mode of holes in the channel layer is shown in Figure 1 (b).
[0063] Example 2
[0064] The difference between this example and Example 1 is that the mass ratio of PFT-100 to C8-BTBT in the mixed solution is adjusted to 5:1 and 5:3, respectively, and the rest of the preparation process is the same as that of Example 1, to obtain the active channel layer of this example.
[0065] Comparative Example 1
[0066] The difference between this comparative example and Example 1 is that the mass ratio of PFT-100 to C8-BTBT in the mixed solution is adjusted to 5:0, and the rest of the preparation process is the same as that of Example 1, to obtain the pure PFT-100 channel layer of this comparative example.
[0067] Comparative Example 2
[0068] The difference between this comparative example and Example 1 is that no annealing treatment is performed, and the rest of the preparation process is the same as that of Example 1, to obtain the active channel layer of this comparative example.
[0069] Comparative Example 3
[0070] The difference between this comparative example and Comparative Example 1 is that no annealing treatment is performed, and the rest of the preparation process is the same as that of Comparative Example 1, to obtain the pure PFT-100 channel layer of this comparative example.
[0071] The channel layer prepared in Example 1 and Comparative Examples 1-3 is tested for morphology by atomic force microscopy, and the results are shown in FIG. 1. Figure 2 (a) is a pure PFT-100 channel layer without annealing, (b) is an active channel layer without annealing, (c) is a pure PFT-100 channel layer after annealing, and (d) is an active channel layer after annealing.
[0072] As can be seen from FIG. 1, Figure 2 in the case of no annealing, the surface of the pure PFT-100 channel layer is relatively smooth. After adding C8-BTBT, the surface roughness increases, and a large number of fine grains are distributed in the channel layer. After annealing at 120°C, the residual solution in both samples is evaporated by heating, a large number of pores are formed on the surface, and the surface roughness is greatly improved. During the annealing process, the initially dispersed microcrystals in the active channel layer containing C8-BTBT are directionally rearranged to form a more optimal crystal quality and a more uniform grain distribution.
[0073] It can be seen that the annealing process improves the device performance through a double mechanism: on the one hand, the porous structure formed by solvent evaporation effectively increases the interface contact area between the solid-state electrolyte and the channel layer, which is beneficial to the injection and extraction of ions in the channel layer; on the other hand, the recrystallization of C8-BTBT microcrystals optimizes the charge carrier migration path, significantly improving the charge transport efficiency.
[0074] Example 3
[0075] The present embodiment provides a preparation method of an organic electrochemical transistor (OECT), in particular:
[0076] (1) A silicon wafer (Si / SiO2) is cut into small pieces, which are sequentially cleaned by ultrasonic cleaning with acetone, ultrapure water and anhydrous ethanol, and then dried by nitrogen blowing, and then placed into a hexamethyldisilazane (HMDS) pretreatment oven, and HMDS gas is injected to obtain a pretreated substrate;
[0077] (2) On the pretreated substrate, a positive photoresist (ARP-5350) is spin-coated, and after spin-coating, soft baking and photoexposure, development is performed in a developer (AR 300-26) diluted with ultrapure water, followed by cleaning with ultrapure water and drying with nitrogen blowing; finally, a source-drain electrode is evaporated to obtain a substrate containing a source-drain electrode, the remaining photoresist in the area is removed with acetone, and the substrate is placed into an ultraviolet ozone treatment machine to obtain a hydrophilic treated substrate;
[0078] (3) 3-glycidoxypropyltrimethoxysilane (GOPS) is mixed with anhydrous ethanol to obtain a coupling agent solution, which is spin-coated onto the hydrophilic treated substrate, and after annealing, Parylene C powder is evaporated to obtain a first Pry-C layer, which is placed into an ultraviolet ozone treatment machine, and then Micro-90 solution is spin-coated as a separator, and then Parylene C powder is evaporated to obtain a second Pry-C layer;
[0079] (4) On the second Pry-C layer, a negative photoresist (SU-82010) is spin-coated, and after spin-coating, soft baking and photoexposure, the negative photoresist is cured by post-baking and developed in a developer PGMEA (propylene glycol methyl ether acetate), and then cleaned with anhydrous ethanol; finally, O plasma treatment is performed to remove the two layers of Parylene at the electrode and channel, thereby obtaining a bottom-contact OECT substrate;
[0080] (5) The active channel layer is prepared on the bottom-contact OECT substrate according to the preparation method of Example 1;
[0081] (6) Polyvinylidene fluoride (PVDF) is mixed with acetone at 60°C to obtain a polymer matrix solution, which is mixed with an ionic liquid EMIM:TSFI (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide salt) to obtain an electrolyte solution, which is spin-coated on the active channel layer to obtain a solid electrolyte layer;
[0082] (7) Polyimide (PI) film was soaked in acetone, cleaned with ethanol, dried by nitrogen blowing, evaporated with Au electrode, treated by ultraviolet ozone treatment machine, spin-coated with PEDOT:PSS (poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)), annealed, cut into a thin strip, fixed on a glass slide as a gate electrode by using copper tape, attached to the electrolyte layer, and an organic electrochemical transistor (OECT) of the example was obtained.
[0083] Figure 3 Flow chart for preparing the bottom-contact OECT substrate of steps (1)-(4) in Example 3.
[0084] Figure 4 Flow chart for preparing the organic electrochemical transistor of steps (5)-(7) in Example 3.
[0085] The structure of the organic electrochemical transistor prepared in Example 3 is shown in Figure 5 (a), and the working mechanism is shown in Figure 5 (b).
[0086] Example 4
[0087] The difference between the example and Example 3 is that the preparation method of Example 1 in step (5) is adjusted to the preparation method of Example 2, and the rest of the preparation processes are the same as those of Example 3, and an OECT of the example is obtained.
[0088] Comparative Example 4
[0089] The difference between the example and Example 3 is that the preparation method of Example 1 in step (5) is adjusted to the preparation method of Example 2, and the rest of the preparation processes are the same as those of Example 3, and an OECT of the example is obtained.
[0090] Under a fixed gate voltage V G =-0.7 V, the on-state current I on of the OECTs with different doping ratios of Examples 3-4 and Comparative Example 4 was counted, as shown in Figure 6 (a).
[0091] As can be seen from Figure 6 (a), when the mass ratio of PFT-100 to C8-BTBT is 5:2, the on-state current I on is the largest, reaching 333.29±20.38 μA. The performance of the OECTs with mixing ratios of 5:1 and 5:3 is similar, and is better than that of the OECT with pure PFT-100.
[0092] The maximum transconductance value (g m ) of the OECTs prepared in Examples 3-4 and Comparative Example 4 with different doping ratios was further counted, as shown in Figure 6 (b).
[0093] From Figure 6 (b) can be seen that, also PFT-100 and C8-BTBT mass ratio of 5:2, g m max, up to 1.62±0.05mS, g m min (1.07±0.15mS). The performance of the device with a mixing ratio of 5:1 and 5:3 is similar, and is better than that of pure PFT-100 device.
[0094] The threshold voltage (V th ) of the OECTs with different doping ratios was determined by the transfer curve, and the results are shown in Figure 6 (c). It can be seen that with the increase of C8-BTBT content, the threshold voltage does not change significantly, only a small decrease, basically maintained at about-0.3V.
[0095] The on-state current of the OECTs prepared in Example 3 and Comparative Example 4 after 10000 cycles was tested, and the results are shown in Figure 7 (a) is the OECT prepared by pure PFT-100; (b) is the OECT prepared by PFT-100 and C8-BTBT with a mass ratio of 5:2.
[0096] Comparing Figure 7 (a) and (b) can be seen that, after 1000 cycles, the on-state current of the OECT doped with C8-BTBT can still maintain 90% of the initial value, with excellent working stability.
[0097] The OECTs prepared in Example 3 and Comparative Example 4 were tested for electrocardiogram signal according to Figure 8 (a) electrocardiogram signal test circuit, and the results are shown in Figure 8 (b)-(d). Among them, (b) is the electrocardiogram signal test diagram of the OECT prepared by pure PFT-100, and (c) and (d) are the electrocardiogram signal test diagrams of the OECT prepared by PFT-100 and C8-BTBT with a mass ratio of 5:2.
[0098] From Figure 8 (c) can be seen that, using the OECT doped with C8-BTBT to test the electrocardiogram signal, the P wave, QRS group wave, T wave and U wave of the electrocardiogram signal are all clear. Compared with the electrocardiogram signal test diagram (b) of the OECT prepared by pure PFT-100, it can be seen from (d) that the peak-to-peak amplitude of the electrocardiogram signal is basically consistent in 15s continuous monitoring, and the signal-to-noise ratio of the electrocardiogram signal is 23.75dB, with high fidelity.
[0099] Reference Figure 9(a), the circuit diagram of the inverter constructed by the OECT prepared in Example 3 (A-OECT) and the OECT prepared in Comparative Example 4 (B-OECT), and the voltage transfer characteristic curve and the gain curve of the inverter were tested, and the results are shown in Figure 9 (b) and (c), respectively. Wherein, (b) is the voltage transfer characteristic curve, and (c) is the gain curve.
[0100] From Figure 9 (b) can be seen that when the applied V dd increases from -0.2 V to -0.6 V, the high-level output of the inverter is close to V dd , and the low-level output is close to the ground potential (0 V), indicating that the V dd of the inverter is defined as clear logic "1" and logic "0" between -0.2 V and -0.6 V.
[0101] The applied V dd increases from -0.2 V to -0.6 V, and the gain curve of the inverter is shown in Figure 9 (c). It can be found that as the V dd increases, the maximum gain of the inverter gradually rises, and when the V dd is -0.6 V, the maximum gain is 16.72, indicating that the circuit has high reliability.
[0102] The switching characteristic curve and the cycle stability curve of the inverter constructed by the OECT prepared in Example 3 (A-OECT) and the OECT prepared in Comparative Example 4 (B-OECT) were tested, and the results are shown in Figure 10 .
[0103] The switching characteristic curve of the inverter was tested, and the results are shown in Figure 10 (a). By applying a step-shaped V in , it can be found that when the V in is 0 V, the V out output by the inverter in each cycle can be stabilized at -0.6 V, and when the V in is converted to -0.6 V, the V out output in each cycle can also be stabilized at 0 V, indicating that the inverter can repeatedly switch between logic "0" and logic "1".
[0104] The time of applying 0 V and -0.6 V in each cycle was shortened and the test was continued, and the results are shown in Figure 10 (b). It can be seen that during the 100 cycles, the performance of the inverter did not change significantly.
[0105] The above test results show that the switching stability of the inverter is good.
[0106] Example 5
[0107] The embodiment provides a preparation method of an active channel layer, and particularly relates to the following steps:
[0108] The polymer P3HT and the small molecule C8-BTBT are dissolved in chloroform to obtain a mixed solution, wherein the concentration of the P3HT is 8 mg / mL, and the concentration of the C8-BTBT is 4 mg / mL, and at this time, the mass ratio of the P3HT to the C8-BTBT in the mixed solution is 8:4.
[0109] The mixed solution is spin-coated on a substrate at 2000 rpm for 30 s, and then annealed at 120 DEG C for 15 min to obtain the active channel layer.
[0110] Comparative Example 5
[0111] The comparative example is different from the embodiment 5 in that the mass ratio of the P3HT to the C8-BTBT in the mixed solution is adjusted to be 8:2 and 8:0 respectively, and the rest of the preparation processes are the same as those in the embodiment 5, so that the channel layer of the comparative example is obtained.
[0112] The channel layers prepared in the embodiment 5 and the comparative example 5 are used to prepare OECTs, and the corresponding on-state currents I on and transconductances g m of the OECTs are tested, and the results are shown in Table 1.
[0113] Table 1 Influence of the mass ratio of P3HT to C8-BTBT on the performance of prepared OECTs
[0114]
[0115] According to Table 1, when the mass ratio of the P3HT to the C8-BTBT is 8:4, the on-state current I on of the prepared OECT is the largest, reaches -804.46±78.34, and the power handling capability of the device is stronger, so that the device can be applied to high-load applications.
[0116] Embodiment 6
[0117] The embodiment provides a preparation method of an active channel layer, and particularly relates to the following steps:
[0118] The polymer P3HT and the small molecule NPB are dissolved in chloroform to obtain a mixed solution, wherein the concentration of the P3HT is 5 mg / mL, and the concentration of the NPB is 5 mg / mL, and at this time, the mass ratio of the P3HT to the NPB in the mixed solution is 5:5.
[0119] The mixed solution is spin-coated on a substrate at 2000 rpm for 30 s, and then annealed at 120 DEG C for 15 min to obtain the active channel layer.
[0120] Comparative Example 6
[0121] The difference between the present comparative example and Example 6 is that the mass ratio of P3HT to NPB in the mixed solution is adjusted to 5:0, and the rest of the preparation process is the same as that of Example 6, thereby obtaining the channel layer of the present comparative example.
[0122] The channel layers prepared in Example 6 and Comparative Example 6 are used to prepare OECTs, and the corresponding on-state currents I on and transconductances g m are tested, and the results are shown in Table 2.
[0123] Table 2 Influence of mass ratio of P3HT to NPB on performance of prepared OECTs
[0124]
[0125] According to Table 2, compared with no doping of small molecule NPB, when the mass ratio of P3HT to NPB is 5:5, the on-state current I on of the prepared OECT is larger.
[0126] Example 7
[0127] The present example provides a preparation method of an active channel layer, in particular:
[0128] The polymer P3HT and the small molecule BPEA are dissolved in chloroform to obtain a mixed solution, wherein the concentration of P3HT is 5 mg / mL, and the concentration of BPEA is 5 mg / mL, and at this time, the mass ratio of P3HT to BPEA in the mixed solution is 5:5.
[0129] The mixed solution is spin-coated on a substrate at 2000 rpm for 30 s, and annealed at 120°C for 15 min, thereby obtaining an active channel layer.
[0130] Comparative Example 7
[0131] The difference between the present comparative example and Example 7 is that the mass ratio of P3HT to BPEA in the mixed solution is adjusted to 5:0, and the rest of the preparation process is the same as that of Example 7, thereby obtaining the channel layer of the present comparative example.
[0132] Table 3 Influence of mass ratio of P3HT to BPEA on performance of prepared OECTs
[0133]
[0134] According to Table 3, compared with no doping of small molecule NPB, when the mass ratio of P3HT to NPB is 5:5, the on-state current I on of the prepared OECT is larger.
[0135] Comparative Example 8
[0136] The difference between the present comparative example and example 1 is that the annealing treatment temperature is adjusted to 20℃, 60℃, 80℃, 100℃ and 140℃ respectively, and the rest of the preparation process is the same as that of example 1, and the channel layer of the present comparative example is prepared.
[0137] Table 4: Effect of temperature on the performance of prepared OECT
[0138]
[0139] According to table 4, when the mass ratio of PFT-100 and C8-BTBT is 5:2, the annealing treatment temperature is 120℃, and the time is 15min, the corresponding OECT performance is the best.
[0140] In summary, the high carrier mobility, high stability and excellent low-temperature environmental suitability of organic small molecules C8-BTBT, NPB and the like are utilized to successfully construct a high-performance OECT. The organic small molecules effectively promote the hole transport in the channel layer, significantly improving the electrical performance of the channel layer, and the organic small molecule crystals are uniformly dispersed in the long-chain polymer matrix of PFT-100, P3HT and the like, forming an effective carrier transport channel and promoting the migration of carriers between the long-chain polymer molecules.
[0141] The introduction of organic small molecule crystals significantly improves the performance of the device. The channel layer obtained by spin-coating a mixed solution of PFT-100 and C8-BTBT and then annealing at 120℃ is used to prepare an OECT, and the maximum transconductance of the OECT reaches 1.56mS. After 10000 switching cycles, the on-state current can still maintain 90% of the initial value, showing excellent working stability.
[0142] A double-p-type inverter is constructed using the doped system OECT, and the maximum gain of the inverter reaches 16.72 when V dd The inverter has clear logic "0" and logic "1" and can be repeatedly switched with good stability. The electrocardiogram signal is tested using the OECT based on the doped system, and the P wave, QRS group wave, T wave and U wave of the measured electrocardiogram signal are clear, and the peak-to-peak amplitude of the electrocardiogram signal remains basically unchanged in 15s of continuous monitoring. The signal-to-noise ratio of the electrocardiogram signal is 23.75dB, which has high fidelity.
[0143] It should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.
Claims
1. A method of preparing an active channel layer of an organic electrochemical transistor, characterized in that: comprising, dissolving the polymer and the small molecule in an organic solvent to obtain a mixed solution; spin-coating the mixed solution on a substrate and performing annealing treatment to obtain an active channel layer; wherein the polymer comprises one of PFT-100, P3HT, PEDOT:PSS and PTHS; the small molecule comprises one of C8-BTBT, NPB, BPEA, Dif-TES-ADT and C10-BTBT; and the organic solvent comprises one or more of chloroform, chlorobenzene and toluene; the concentration of the polymer in the mixed solution is 1-10 mg / mL, the concentration of the small molecule is 1-10 mg / mL, and the mass ratio of the polymer to the small molecule is 1-10:1-10.
2. The method of claim 1, wherein: when the polymer is PFT-100 and the small molecule is C8-BTBT, the concentration of the polymer in the mixed solution is 5 mg / mL, the concentration of the small molecule is 2 mg / mL, and the mass ratio of the polymer to the small molecule is 5:
2.
3. The method for preparing the active channel layer as described in claim 1, characterized in that: the annealing treatment is performed at a temperature of 20-140 ℃.
4. The method of claim 3, wherein the active channel layer is formed by the steps of: the annealing treatment is performed at a temperature of 120 ℃. 5. The method of claim 3, wherein the active channel layer is formed by the steps of: the annealing treatment is performed for 15 min. 6. The active channel layer prepared by the preparation method in any one of claims 1-5.
7. An organic electrochemical transistor, characterized by: comprising, from bottom to top, a substrate layer; an electrode layer; the active channel layer of claim 6; a Pry-C layer, which is made of Parylene-C; a solid electrolyte layer; a gate electrode; wherein the electrolyte layer is prepared from PVDF matrix and EMIM:TFSI ionic liquid; the gate electrode is prepared from PI film substrate, Au and PEDOT:PSS; the substrate layer comprises one of Si / SiO2 wafer, glass wafer, polyimide substrate and parylene substrate; the electrode layer is prepared from one or more of Au, Ti, Ag, Mo and Al, and the electrode layer comprises one of single layer and stacked layer.
8. The application of the organic electrochemical transistor of claim 7 in human body electrocardiosignal detection.
9. The application of the organic electrochemical transistor of claim 7 in constructing an inverter.
10. A method of preparing an organic electrochemical transistor, characterized by: comprising, cutting a silicon wafer into small pieces, sequentially ultrasonic cleaning with acetone, ultrapure water and anhydrous ethanol, drying with nitrogen, and pretreating with HMDS; on the pretreated substrate, performing positive photoresist lithography, removing the HMDS layer in the photoresist pattern area after development, sequentially evaporating Ti and Au as source and drain electrodes, removing the remaining photoresist and HMDS layer, and performing hydrophilic treatment on the substrate; spin-coating GOPS solution on the hydrophilic treated substrate, evaporating Parylene C powder after annealing to obtain a first Pry-C layer, spin-coating Micro-90 solution as a spacer after hydrophilic treatment and annealing, and evaporating Parylene C powder to obtain a second Pry-C layer; on the second Pry-C layer, performing negative photoresist lithography, removing the two layers of Pry-C layer at the source and drain electrodes and the channel to obtain a bottom-contact OECT substrate; applying the preparation method of claim 1 to prepare an active channel layer on the bottom-contact OECT substrate; The PVDF is dissolved in acetone to obtain a polymer matrix solution, mixed with an ionic liquid EMIM:TSFI to obtain an electrolyte solution, and spin-coated on an active channel layer to obtain a solid-state electrolyte layer; After cleaning a PI film, evaporating Au, hydrophilic treatment and spin-coating PEDOT:PSS, cutting and fixing after annealing to obtain a gate electrode, and adhering the gate electrode to the electrolyte layer to obtain an organic electrochemical transistor.