Folding inner gate organic electrochemical transistor and preparation method thereof

Abstract

The invention relates to a folded inner gate organic electrochemical transistor and a preparation method thereof, and belongs to the field of novel flexible electronics. The transistor includes a bottom electrode, a folded organic semiconductor layer, a folded ion reservoir layer, a folded gate layer, and a top electrode. By regulating and controlling the adhesion between the semiconductor layer and the substrate and the mechanical property of the semiconductor layer, the organic semiconductor can bear deformation caused by folding, the integrity of the organic semiconductor is ensured, and stable ion-electron coupling performance can still be kept in a folding state. According to the transistor, a folding structure is introduced into an organic material, so that the electrochemical performance, the flexibility and the stability of a device are remarkably improved. The inner grid design can effectively control the ion doping efficiency, improve the current response speed and construct a fast-response organic electrochemical transistor; the invention has the advantages of simple structure, low manufacturing cost and large-scale application, and is particularly suitable for application in the fields of flexible electronic devices, wearable equipment, organic electronic circuits and the like.

Description

Technical Field

[0001] The invention belongs to the field of organic semiconductor materials and flexible electronic technology, and specifically relates to a folded inner-gate organic electrochemical transistor and a preparation method thereof. Background Art

[0002] With the rapid development of flexible electronic technology, emerging applications such as wearable devices, medical sensors and bendable displays have put forward higher demands on flexible and stretchable electronic devices. Organic electrochemical transistors have become an important research object in the field of flexible electronics due to their unique ion-electron coupling mechanism, low operating voltage and biocompatibility. However, limited by their ion doping mechanism, the switching response of organic electrochemical transistors has become an obstacle to their application in high-precision biosensing, organic electronic circuits, etc.

[0003] The improvement of the existing OECT switch response usually relies on new material design, semiconductor doping regulation and other methods. The rate of ion injection can be significantly improved by modifying the ethylene glycol side chain of traditional thin-film transistor materials and doping semiconductors with hydrophilic materials. However, this modification method requires precise control of the molecular structure and morphology of the semiconductor layer to optimize the ion doping efficiency and current response speed. This process complexity not only increases the manufacturing cost, but also limits the practical application of OECT in large-scale production.

[0004] To solve this problem, the performance of transistors can also be improved through innovative structural design. Recently, researchers designed the structure of the inner gate, which can effectively reduce the movement path of doped ions in semiconductors and greatly improve the response characteristics. However, the reported process is very complicated and requires sophisticated reactive ion etching, high-precision regulation, etc. How to simplify the inner gate preparation process and avoid dependence on high-precision equipment is still an important challenge in current research.

[0005] Therefore, it is necessary to develop a folded inner gate organic electrochemical transistor and a preparation method thereof to solve the above problems. Summary of the invention

[0006] The purpose of the present invention is to design a folded inner gate organic electrochemical transistor and a preparation method thereof in order to solve the above problems.

[0007] The present invention achieves the above-mentioned purpose through the following technical solutions: A folded inner gate organic electrochemical transistor, comprising: The folding structure is formed into a U shape, the opening of the folding structure is arranged horizontally, and the folding structure includes a folded semiconductor layer, a folded ion storage pool layer, and a gate electrode layer connected in sequence from the outside to the inside; bottom electrode; The top electrode; the folded structure is disposed between the bottom electrode and the top electrode, and the folded semiconductor layer of the folded structure is connected to the bottom electrode and the top electrode respectively; substrate; the bottom electrode is disposed on the substrate.

[0008] A method for preparing a folded inner gate organic electrochemical transistor comprises the following steps: S1, preparing a hydrophobic layer on a substrate; S2, sequentially spin-coating a PEDOT:PSS semiconductor solution and a chitosan solution on the hydrophobic layer to form a folded semiconductor layer and a folded ion reservoir layer, respectively; S3, spin coating a gate electrode solution on the folded ion reservoir layer to form a gate electrode layer; S4, patterning the functional layer prepared in steps S2-S3 by laser cutting; S5, using a PDMS stamp to lift the functional layer formed in step S4, partially fold it in half, and then use the PDMS stamp to dry-transfer it to the substrate on which the bottom electrode has been evaporated; S6. Use a mask to align and evaporate the top electrode to complete the preparation.

[0009] The advantages of the present invention are: 1. Simple folding process: The present invention proposes a very simple folding process that does not rely on high-precision equipment, reduces manufacturing complexity and cost, and is suitable for large-scale production and application.

[0010] 2. High electrochemical performance: The present invention effectively improves the ion doping efficiency and current response speed through the optimized design of the inner gate, enhances the electrochemical performance of the transistor, and is particularly suitable for fast-response organic electronic devices.

[0011] 3. Broad application prospects: This technology has a simple structure, low cost, and is feasible in large-scale manufacturing. It is particularly suitable for application in emerging fields such as flexible electronics, wearable devices, and organic electronic circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the structure of a folded inner gate organic electrochemical transistor; The reference numerals in the figure are: 1. substrate, 2. bottom electrode, 3. folded semiconductor layer, 4. gate electrode layer, 5. folded ion reservoir layer, 6. top electrode. DETAILED DESCRIPTION

[0013] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0014] like Figure 1 As shown, a folded inner gate organic electrochemical transistor comprises: Folding structure; the folding structure is formed into a U shape, the opening of the folding structure is arranged horizontally, and the folding structure includes a folded semiconductor layer 3, a folded ion storage pool layer 5, and a gate electrode layer 4 connected sequentially from the outside to the inside; Bottom electrode 2; The top electrode 6; the folded structure is disposed between the bottom electrode 2 and the top electrode 6, and the folded semiconductor layer 3 of the folded structure is connected to the bottom electrode 2 and the top electrode 6 respectively; Substrate 1; the bottom electrode is placed on the substrate 1.

[0015] The preparation material of the substrate is any one of SiO2, PI, and PDMS. When the preparation material of the substrate is any one of PI and PDMS, the thickness of the substrate ranges from 500nm to 500um. The preparation material of the folded semiconductor layer is PEDOT:PSS, and the thickness of the folded semiconductor layer is 50-200nm. The preparation material of the folded ion reserve pool layer is chitosan, and the thickness of the folded ion reserve pool layer is 500nm-2um. The preparation material of the gate electrode layer is any one of PEDOT:PSS, graphene, and PBFDO, and the thickness of the gate electrode layer is 50-200nm. The preparation materials of the bottom electrode and the top electrode are both gold, and the thickness of the bottom electrode and the top electrode are both 100nm.

[0016] A method for preparing a folded inner gate organic electrochemical transistor comprises the following steps: S1, preparing a hydrophobic layer on a substrate; S2, sequentially spin-coating a PEDOT:PSS semiconductor solution and a chitosan solution on the hydrophobic layer to form a folded semiconductor layer and a folded ion reservoir layer, respectively; S3, spin coating a gate electrode solution on the folded ion reservoir layer to form a gate electrode layer; S4, patterning the functional layer prepared in steps S2-S3 by laser cutting; S5, using a PDMS stamp to pull up the functional layer formed in step S4, partially fold it in half, and then use a PDMS stamp to dry-transfer it to the substrate with the bottom electrode deposited. The pulling height is 0.5-1 mm; S6. Use a mask to align and evaporate the top electrode to complete the preparation.

[0017] Example 1 (control group): 1. Prepare the bottom electrode by evaporating chromium and gold electrodes on a clean glass substrate; 2. No treatment is done on the cleaned glass substrate; 3. Spin-coat the PEDOT:PSS / GOPS / DBSA mixed solution, chitosan solution, and PEDOT:PSS / DMSO solution on the substrate in step 2, respectively, wherein the first film is annealed at 120 degrees for 5 minutes after spin coating; 4. Use a laser cutting machine to cut it into a rectangle of 1000*400um; 5. The film cannot be lifted using the PDMS stamp due to interfacial adhesion; 6. The device prepared using conventional process has an on-state current of 10-13 mA, a transconductance of 50-100 mS, and a response time of ~200-500 ms. The conventional process is a structure of bottom electrode, semiconductor layer, top electrode, electrolyte layer, and gate electrode.

[0018] Embodiment 2: 1. Prepare the bottom electrode by evaporating chromium and gold electrodes on a clean glass substrate; 2. Place the cleaned glass substrate in a vacuum oven at 120 degrees Celsius for 2 hours and perform OTS treatment on the glass substrate; 3. Spin-coat the PEDOT:PSS / GOPS / DBSA mixed solution, chitosan solution, and PEDOT:PSS / DMSO solution on the substrate in step 2, respectively, wherein the first film is annealed at 120 degrees for 5 minutes after spin coating; 4. Use a laser cutting machine to cut it into a rectangle of 1000*400um; 5. The prepared film was stuck to the PDMS stamp and could not be lifted or folded.

[0019] Embodiment 3: 1. Prepare the bottom electrode by evaporating chromium and gold electrodes on a clean glass substrate; 2. Spin-coat a 2% by mass aqueous solution of Micro-90 cleaning agent on the cleaned glass substrate; 3. Spin-coat the PEDOT:PSS / GOPS / DBSA mixed solution, chitosan solution, and PEDOT:PSS / DMSO solution on the substrate in step 2, respectively, wherein the first film is annealed at 120 degrees for 5 minutes after spin coating; 4. Use a laser cutting machine to cut it into a rectangle of 1000*400um; 5. Use a PDMS stamp to pull the prepared film and fold it, and then transfer it to the bottom electrode substrate treated with oxygen plasma using a PDMS stamp; 6. Align the nickel salt template and then evaporate the gold top electrode; 7. The prepared inner-gate organic electrochemical transistor has an on-state current of 600-700uA, a transconductance of 20-30mS, and a response time of 20-40ms.

[0020] Embodiment 4: 1. Prepare the bottom electrode by evaporating chromium and gold electrodes on a clean glass substrate; 2. Spin-coat a 2% by mass aqueous solution of Micro-90 cleaning agent on the cleaned glass substrate; 3. Spin-coat the PEDOT:PSS / GOPS / DBSA / PVA mixed solution, chitosan solution, and PEDOT:PSS / DMSO solution on the substrate in step 2, respectively, wherein the first film is annealed at 120 degrees for 5 minutes after spin coating; 4. Use a laser cutting machine to cut it into a rectangle of 1000*400um; 5. Use a PDMS stamp to pull the prepared film and fold it, and then transfer it to the bottom electrode substrate treated with oxygen plasma using a PDMS stamp; 6. Align the nickel salt template and then evaporate the gold top electrode; 7. The prepared inner-gate organic electrochemical transistor has an on-state current of 1-5 mA, a transconductance of 40-60 mS, and a response time of 40-100 ms.

[0021] Embodiment 5: 1. Prepare the bottom electrode by evaporating chromium and gold electrodes on a clean glass substrate; 2. Spin-coat a 2% by mass aqueous solution of Micro-90 cleaning agent on the cleaned glass substrate; 3. Spin-coat the PEDOT:PSS / GOPS / DBSA / PEO mixed solution, chitosan solution, and PEDOT:PSS / DMSO solution on the substrate in step 2, respectively, wherein the first film is annealed at 120 degrees for 5 minutes after spin coating; 4. Use a laser cutting machine to cut it into a rectangle of 1000*400um; 5. Use a PDMS stamp to pull the prepared film and fold it, and then transfer it to the bottom electrode substrate treated with oxygen plasma using a PDMS stamp; 6. Align the nickel salt template and then evaporate the gold top electrode; 7. The prepared inner-gate organic electrochemical transistor has an on-state current of 3-8 mA, a transconductance of 50-120 mS, and a response time of 10-25 ms.

[0022] Embodiment 6: 1. Prepare the bottom electrode by evaporating chromium and gold electrodes on a clean glass substrate; 2. Spin-coat a 2% by mass aqueous solution of Micro-90 cleaning agent on the cleaned glass substrate; 3. Spin-coat the PEDOT:PSS / GOPS / DBSA / PEGDMA mixed solution, chitosan solution, and PEDOT:PSS / DMSO solution on the substrate in step 2, respectively, wherein the first film is annealed at 120 degrees for 5 minutes after spin coating; 4. Use a laser cutting machine to cut it into a rectangle of 1000*400um; 5. Use a PDMS stamp to pull the prepared film and fold it, and then transfer it to the bottom electrode substrate treated with oxygen plasma using a PDMS stamp; 6. Align the nickel salt template and then evaporate the gold top electrode; 7. The prepared inner-gate organic electrochemical transistor has an on-state current of 5-10 mA, a transconductance of 80-140 mS, and a response time of 0.8-5 ms.

[0023] It can be seen that by introducing a folded inner gate organic electrochemical transistor and its preparation method (i.e., the folded inner gate device prepared in Examples 2 to 6), compared with the organic electrochemical transistor device prepared by conventional spin coating (i.e., the device prepared by the conventional process described in Step 6 of Example 1), a significant improvement in electrochemical performance has been achieved, which is specifically manifested in a significant reduction in switching time and a change in transconductance. By optimizing the doping ratio, the damage to the active layer structure during the folding process was reduced, and several elastomers, PVA, PEO, and PEGDMA, were tried respectively. Among them, PEGDMA can well ensure the integrity of its film without reducing its conductivity, and greatly shorten the response time. Compared with other examples, the best inner gate electrochemical transistor performance (i.e., the inner gate organic electrochemical transistor device prepared in Examples 4 to 6) is achieved, which has a wide range of application prospects in the fields of flexible electronic sensors and organic electronic circuits.

[0024] The present invention has been described by the above embodiments, but it should be understood that the above embodiments are only for the purpose of example and description, and are not intended to limit the present invention to the scope of the described embodiments. In addition, it can be understood by those skilled in the art that the present invention is not limited to the above embodiments, and more variations and modifications can be made according to the teachings of the present invention, and these variations and modifications all fall within the scope of the protection claimed by the present invention. The protection scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A folded inner gate organic electrochemical transistor, characterized in that: include: Folding structure; The folding structure is formed into a U shape, the opening of the folding structure is arranged horizontally, and the folding structure includes a folding semiconductor layer, a folding ion storage pool layer, and a gate electrode layer connected in sequence from the outside to the inside; bottom electrode; Top electrode; The folded structure is placed between the bottom electrode and the top electrode, and the folded semiconductor layer of the folded structure is connected to the bottom electrode and the top electrode respectively; substrate; the bottom electrode is disposed on the substrate.

2. The folded inner gate organic electrochemical transistor according to claim 1, characterized in that: The preparation material of the substrate is any one of SiO2, PI, and PDMS. When the preparation material of the substrate is any one of PI and PDMS, the thickness range of the substrate is 500nm-500um.

3. The folded inner gate organic electrochemical transistor according to claim 1, characterized in that: The preparation material of the folded semiconductor layer is PEDOT:PSS, and the thickness of the folded semiconductor layer is 50-200nm.

4. The folded inner gate organic electrochemical transistor according to claim 1, characterized in that: The preparation material of the folded ion reserve pool layer is chitosan, and the thickness of the folded ion reserve pool layer is 500nm-2um.

5. The folded inner gate organic electrochemical transistor according to claim 1, characterized in that: The gate electrode layer is made of any one of PEDOT:PSS, graphene, and PBFDO, and the thickness of the gate electrode layer is 50-200 nm.

6. The folded inner gate organic electrochemical transistor according to claim 1, characterized in that: The bottom electrode and the top electrode are both made of gold, and the thickness of the bottom electrode and the top electrode is 100 nm.

7. A method for preparing a folded inner gate organic electrochemical transistor according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, preparing a hydrophobic layer on a substrate; S2, sequentially spin-coating a PEDOT:PSS semiconductor solution and a chitosan solution on the hydrophobic layer to form a folded semiconductor layer and a folded ion reservoir layer, respectively; S3, spin coating a gate electrode solution on the folded ion reservoir layer to form a gate electrode layer; S4, patterning the functional layer prepared in steps S2-S3 by laser cutting; S5, using a PDMS stamp to lift the functional layer formed in step S4, partially fold it in half, and then use the PDMS stamp to dry-transfer it to the substrate on which the bottom electrode has been evaporated; S6. Use a mask to align and evaporate the top electrode to complete the preparation.

8. The method for preparing a folded inner gate organic electrochemical transistor according to claim 7, characterized in that: The pulling height is 0.5-1mm.

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