Compound for improving transconductance value of organic electrochemical transistor and device manufacturing method

Abstract

The invention relates to a compound for improving the transconductance value of an organic electrochemical transistor and a device manufacturing method, which are characterized in that three polymer molecules with different conformation locks are synthesized, and the polymer molecules are opg2T-O, opg2T-S and opg2T-Se which are provided with 4, 4 '-position ethylene glycol side chains and contain furan, thiophene or selenophen interpolymers; obtaining conformation lock strength and molecular planarity of three polymer molecules; respectively dissolving the three polymer molecules to obtain respective diluted solutions; respectively coating the three diluted solutions on a substrate with an electrode, and annealing to form a thin film; respectively dispensing electrolyte solutions on the three films, and testing respective electrical properties; according to the method provided by the invention, the problem of low transconductance value of the organic electrochemical transistor (OECT) can be fundamentally solved from the molecular level; the finally obtained normalized transconductance value of the device is 415S cm <-1 >, which is the highest value reported at present.

Description

Technical Field

[0001] The invention belongs to the technical field of organic electrochemical transistors, in particular to an effective method for improving the transconductance value of an organic electrochemical transistor. Background Art

[0002] At present, organic electrochemical transistors (OECTs) have gradually become an ideal choice for building bioelectronics. Their unique ion-electron coupling properties give OECTs the advantages of ultra-low voltage (<1V) and good biocompatibility ((a) Liu G.C. et al. Advanced Materials 2023, 35, 2300242. (b) Huang W. et al. Nature 2023, 613, 496–502). However, low ionization performance has hindered its development in electrophysiological signal monitoring. Transconductance (g m ) is a key parameter for evaluating the ionization performance of OECT, which determines the signal amplification capability. m The value is proportional to the carrier mobility (μ) and volume capacitance (C * The active layer, as the core component of OECT, plays a key role in the performance of OECT because the coupling of ions and electrons (i.e., μC * The product of g will affect the conductivity of the active layer, and thus affect the output characteristics of OECT. Therefore, optimizing the ionization performance of the active layer material is crucial to improving g m It is crucial to explore the value and promote the development of OECTs in the field of bioelectronics.

[0003] In 2012, Professor Huang H. collaborated with Professor Facchetti A. and Professor Marks T. to develop a new strategy based on intramolecular SO non-covalent interactions, called "non-covalent conformational locks (NoCLs)" (J.Am.Chem.Soc.2012,134,10966–10973). NoCLs have been proven to be an effective method for developing high-performance organic semiconductor materials (Gu XB et al.Angew.Chem.Int.Ed.2024,e202418926). In 2021 and 2023, Professor McCulloch I. and Professor Nielsen CB introduced intramolecular S…O interactions in the OECT active layer through a regional chemical synthesis strategy. Experimental results show that the S…O interaction can significantly reduce the conformational disorder of the molecule, and the newly designed pgBTTT and inDTP-T polymers exhibit long-range order, giving them higher μC * , respectively 502F cm -1 V -1 s -1 and 267Fcm-1 V -1 s -1 According to the search, there is still a lack of research on the impact of NoCLs on molecular structure and OECT device performance. There is also a lack of reports on the impact of NoCLs type and strength on ionic and electronic conduction properties. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a material synthesis and device manufacturing method for improving the transconductance value of an organic electrochemical transistor, which can optimize the intramolecular non-covalent interaction and improve the transconductance value of the OECT.

[0005] The present invention solves the technical problem by adopting the following technical solutions:

[0006] A compound for improving the transconductance of an organic electrochemical transistor, wherein the compound is a furan, thiophene or selenophene copolymer with a 4,4′-position ethylene glycol side chain, and has the following structural formula:

[0007] Wherein, X is O, S or Se.

[0008] Furthermore, the compounds were used at an effective concentration of 3-10 mg / mL.

[0009] A method for preparing a compound that improves the transconductance of an organic electrochemical transistor comprises the following steps:

[0010] S1. A bithiophene monomer containing a 4,4′-position ethylene glycol side chain is reacted with a furan, thiophene or selenophene monomer in a dimethylformamide solvent at 120° C. for 24 hours to obtain a reaction product;

[0011] S2. The reaction product mixture is collected by filtration, purified, washed, and then vacuum-dried to obtain a compound.

[0012] A method for improving the transconductance of an organic electrochemical transistor comprises coating a solution containing the furan, thiophene or selenophene copolymer compound with a 4,4'-position ethylene glycol side chain on an electrode substrate, and annealing the solution to form a film.

[0013] Moreover, the solvent of the solution is chloroform and dichlorobenzene; and the concentration of the solution is 3-10 mg / mL.

[0014] Moreover, the film thickness formed after solution annealing is 30-45 nm.

[0015] Moreover, the material selected for the electrode is a combination of gold, chromium and gold; the thickness of the electrode is 25-35nm.

[0016] Furthermore, the method comprises a substrate, an electrode and an electrolyte. The electrode substrate is coated with a solution containing the furan, thiophene or selenophene copolymer compound with 4,4'-position ethylene glycol side chains as claimed in claim 1, and annealed after coating to form a film.

[0017] Furthermore, the electrolyte may optionally be EMIM: TFSI, KTFSI, NaCl, KCl.

[0018] The advantages and positive effects of the present invention are:

[0019] 1. The method of the present invention can fundamentally solve the problem of low transconductance of organic electrochemical transistors (OECTs) at the molecular level, and the device normalized transconductance obtained is 415 S cm –1 , which is the highest value reported so far.

[0020] 2. Compared with other reported strategies, the method for improving the transconductance of OECTs described in this invention systematically studies the effects of different intramolecular non-covalent interactions on molecular planarity and device ionization at the molecular level for the first time. It also concludes that stronger intramolecular non-covalent interactions are more conducive to improving device transconductance, providing a universal method for improving device transconductance in this field. This method solves the problem of low transconductance of OECTs at the fundamental level of molecular materials, and the resulting device has a normalized transconductance value of 415 S cm –1 , which is the highest value reported so far.

[0021] 3. This paper synthesized a series of polymers containing furan, thiophene, and selenophene copolymers with ethylene glycol side chains at the 4,4′ position: opg2T-O, opg2T-S, and opg2T-Se. Theoretical calculations show that the Se…O non-covalent interaction within the opg2T-Se molecule is stronger than the S…O interaction within the opg2T-S and opg2T-O molecules, and that the molecular structure of opg2T-Se has better planarity and rigidity. Experimental results show that the material has a maximum normalized transconductance of 415S cm -1 . BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The diagrams show the synthesis methods and molecular structures of three polymers with different conformational locks in the present invention.

[0023] Figure 2 Schematic diagram of the OECT device structure in the present invention.

[0024] Figure 3 This is the transfer curve performance diagram of OECT in the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below through specific examples. The following examples are only illustrative and not restrictive, and the scope of protection of the present invention cannot be limited thereto.

[0026] The present invention provides three compounds for improving the transconductance value of organic electrochemical transistors. The compounds are copolymers containing furan, thiophene and selenophene with 4,4'-position ethylene glycol side chains, and the structural formula is as follows.

[0027]

[0028] During use, a solution of one of the three compounds is coated on the electrode substrate. The coating solution is made of chloroform or dichlorobenzene at a concentration of 3-10 mg / mL.

[0029] The synthesis method of the three compounds of the present invention, opg2T-O, opg2T-S, or opg2T-Se, is as follows: Figure 1 As shown, the steps are as follows:

[0030] S1, a bithiophene monomer containing a 4,4′-ethylene glycol side chain was reacted with furan, thiophene, and selenophene monomers in dimethylformamide (DMF) solvent at 120°C for 24 hours; the catalyst was Pd2(dba)3, and a (o-tolyl)3P ligand was added to improve the catalytic activity.

[0031] S2. The reaction mixture was poured into methanol, collected by filtration, and purified by Soxhlet extraction with methanol (16 hours), acetone (16 hours), hexane (16 hours), tetrahydrofuran (16 hours), and chloroform (16 hours). The polymer was partially eluted in chloroform.

[0032] S3. Remove excess solvent under reduced pressure, then dissolve again in chloroform, precipitate into methanol and dry in vacuum.

[0033] Three polymer molecules with different conformational locks, opg2T-O, opg2T-S, and opg2T-Se, were synthesized using the Stille method.

[0034] The interaction energy (E) of S…O and Se…O in three polymer molecules was obtained by theoretical calculation. (2) ), the size of the conformational lock strength descriptor (S), and the molecular planarity;

[0035] E of S…O in the molecules opg2T-O and opg2T-S (2) are -0.53 and -1.61 kcal / mol, respectively. The E of Se…O in the molecule opg2T-Se is (2)is -2.62 kcal / mol; the S of the molecules opg2T-O, opg2T-S, and opg2T-Se are 0.13, 0.3, and 0.82, respectively;

[0036] The present invention also provides a method for improving the transconductance of an OECT based on an intramolecular non-covalent conformational lock, comprising the following steps:

[0037] 1) Synthesize three polymer molecules with different conformational locks;

[0038] 2) Obtain the conformational lock strength and molecular planarity of the three polymer molecules;

[0039] 3) dissolving the polymer material obtained in step 1) to obtain a diluted solution;

[0040] 4) coating the diluted solution in step 3) on a substrate with an electrode and annealing to form a thin film;

[0041] 5) Electrolyte solution is drop-coated on the thin film obtained in step 4) and the electrical properties are tested.

[0042] A further improvement of the present invention is that the greater the strength of the conformational lock in step 2), the better the molecular planarity.

[0043] A further improvement of the present invention is that in step 3), the required solvent may optionally be chloroform, dichlorobenzene, or the like.

[0044] A further improvement of the present invention is that the electrode in step 4) can be gold or chromium / gold, the thickness of the electrode is 25-35 nanometers, and the substrate can be glass, silicon dioxide, etc.

[0045] A further improvement of the present invention is that in step 5), the electrolyte may optionally be EMIM: TFSI, KTFSI, NaCl, or KCl.

[0046] A further improvement of the present invention is that the coating technology referred to above can be spin-coating, solution shearing, etc.

[0047] The annealing conditions in the present invention can be performed according to existing technologies.

[0048] Example 1

[0049] An effective method for improving the transconductance of OECTs based on intramolecular non-covalent conformational locks includes the following steps:

[0050] S1. Three polymer molecules with different conformational locks, opg2T-O, opg2T-S, and opg2T-Se, were synthesized using the Stille method.

[0051] S2. The interaction energy (E (2) ), the size of the conformational lock strength descriptor (S), and the molecular planarity;

[0052] S3, dissolving the polymer molecules obtained in step S1 in chloroform to obtain a 5 mg / mL diluted solution;

[0053] S4, coating the solution in step S3 on a substrate with an electrode and annealing at 110° C. for 0.5 h to form a thin film;

[0054] S5. Drop-coat a 0.1 mol / L electrolyte solution on the thin film obtained in step S4, test the transfer curve of the device and calculate the transconductance value.

[0055] The solvent required in step S3 is preferably chloroform, optionally chlorobenzene, dichlorobenzene, etc.;

[0056] In step S4, the electrode is preferably Au or Cr / Au, and the substrate is optionally glass or silicon wafer; a film is formed by spin-coating at a rotation speed of 2000 rpm and annealed at 110° C. for 0.5 h, with a film thickness of 30-45 nm;

[0057] The electrolyte solution in step S5 is preferably a NaCl aqueous solution, optionally a KCl or KTFSI aqueous solution.

[0058] The coating technology referred to above may be spin-coating, solution shearing, etc.

[0059] Performance Testing

[0060] like Figure 2 As shown, this embodiment provides an effective method for improving the transconductance value of an organic electrochemical transistor to prepare an organic electrochemical transistor device. Figure 3 The transfer curve of OECT is perfectly displayed, and it can be seen that the operating voltage is very low and it can work normally at a voltage of less than 0.6V. The method in this invention can effectively improve the transconductance value of OECT, which can be obtained from Figure 3 Calculated in .

[0061] Although the embodiments of the present invention are disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments.

Claims

1. A compound for increasing the transconductance of an organic electrochemical transistor, characterized in that: The compound is a furan, thiophene or selenophene copolymer with a 4,4′-position ethylene glycol side chain, and the structural formula is as follows: Wherein, X is O, S or Se.

2. The compound for improving the transconductance of an organic electrochemical transistor according to claim 2, wherein: Compounds were used at an effective concentration of 3-10 mg / mL.

3. A method for preparing the compound for improving the transconductance of an organic electrochemical transistor according to claim 1 or 2, characterized in that: Here are the steps: S1. A bithiophene monomer containing a 4,4′-position ethylene glycol side chain is reacted with a furan, thiophene or selenophene monomer in a dimethylformamide solvent at 120° C. for 24 hours to obtain a reaction product; S2. The reaction product mixture is collected by filtration, purified, washed, and vacuum-dried to obtain a compound.

4. A method for increasing the transconductance of an organic electrochemical transistor, characterized by: A solution containing the furan, thiophene or selenophene copolymer compound with 4,4'-position ethylene glycol side chains as claimed in claim 1 is coated on the electrode substrate, and annealed after coating to form a film.

5. The method for increasing the transconductance of an organic electrochemical transistor according to claim 4, wherein: The solvent of the solution is chloroform and dichlorobenzene; the concentration of the solution is 3-10 mg / mL.

6. The method for increasing the transconductance of an organic electrochemical transistor according to claim 4, wherein: The film thickness formed after solution annealing is 30-45nm.

7. The method for increasing the transconductance of an organic electrochemical transistor according to claim 4, wherein: The material selected for the electrode is a combination of gold, chromium and gold; the thickness of the electrode is 25-35nm.

8. An organic electrochemical transistor device with a high organic electrochemical transistor transconductance value according to claim 1 or 2, characterized in that: The method comprises a substrate, an electrode and an electrolyte. The electrode substrate is coated with a solution containing the furan, thiophene or selenophene copolymer compound with 4,4'-position ethylene glycol side chains as claimed in claim 1, and annealed after coating to form a film.

9. The organic electrochemical transistor device according to claim 8, characterized in that: The electrolyte may optionally be EMIM: TFSI, KTFSI, NaCl, KCl.

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