Passivated polyelectrolyte composite dielectric film and organic transistor based on interface photocuring, and preparation method and application of passivated polyelectrolyte composite dielectric film and organic transistor

Abstract

The invention relates to a passivation type polyelectrolyte composite dielectric film based on interface photocuring, an organic transistor and a preparation method and application of the passivation type polyelectrolyte composite dielectric film and the organic transistor, and belongs to the technical field of dielectric materials and optoelectronic devices. The passivation type polyelectrolyte composite dielectric film is formed by mutually attaching the photocuring polymer passivation dielectric layer and the polyelectrolyte dielectric layer, has the characteristics of high capacitance and low electric leakage, and can be used for developing a low-power-consumption organic transistor, working under low voltage is achieved, and device performance such as carrier mobility and stability is remarkably improved. Compared with the prior art, the room-temperature interface photocuring passivation process is simple and convenient, low in cost and low in energy consumption, the prepared novel dielectric film can combine the double advantages of polyelectrolyte and photocuring polymer, and has potential in green manufacturing of high-performance and low-power organic transistors and flexible electronic devices thereof; and application and development in the fields of wearable equipment, sensors, flexible circuits, sensing, storing and computing integrated intelligent terminals or electrical equipment and the like are facilitated.

Description

Technical Field

[0001] The present invention belongs to the technical fields of dielectric materials and optoelectronic devices, and relates to a passivation-type polyelectrolyte composite dielectric film based on interfacial photocuring, an organic transistor, and a preparation method and use thereof. Background Art

[0002] In the rapid development process of modern optoelectronic technologies, dielectric films, as the core materials for electrical insulation, play an important role in various key fields such as transistors, sensors, detectors, memories, capacitors and other optoelectronic devices, electrical equipment, and energy storage and conversion. Organic polyelectrolyte dielectric materials have shown great potential in the preparation of low-cost flexible dielectric films and their low-power-consuming electronic devices due to their unique molecular structures, physical properties, and solution processability. However, there are some key problems to be solved urgently in the practical application of organic polyelectrolyte dielectric film materials.

[0003] From the perspective of stability, organic polyelectrolyte dielectric films are relatively sensitive to environmental humidity. In a humid environment, water molecules easily penetrate into the intermolecular chains and dissociate, resulting in a significant change in the dielectric constant of the material, seriously affecting the performance stability of the dielectric film and the corresponding devices. For example, in a high-humidity environment, the capacitance value of a capacitor based on an organic polyelectrolyte dielectric film will fluctuate greatly, unable to meet the actual requirements of high-precision electronic devices. Moreover, during the long-term use of organic polyelectrolyte dielectric films, the materials will be affected by factors such as heat and ultraviolet radiation, resulting in the degradation of molecular chains and the gradual decline of dielectric properties.

[0004] In terms of interfacial compatibility, when an organic polyelectrolyte dielectric film is compounded with other functional film materials, due to the large differences in surface energy and chemical properties between the two, it is difficult to form a good interfacial bond. This will not only generate a large number of defects at the interface, such as micropores and cracks, but also cause the charge transfer at the interface to be blocked and leakage, increasing the dielectric loss. These interfacial defects will also reduce the mechanical strength of the composite film, making it prone to delamination during practical applications, seriously limiting its service life and application scope.

[0005] As an effective means of material surface and interface treatment, the passivation strategy has unique advantages in improving material structure and properties. Applying the interface passivation strategy to the preparation of organic polyelectrolyte composite dielectric films is expected to solve the above problems. Through appropriate passivation treatment, a stable passivation dielectric layer film can be formed on the surface and interface of the organic polyelectrolyte dielectric layer, effectively isolating the interference of external environmental factors and enhancing the stability of the overall dielectric composite film material. At the same time, the passivation process can improve the interface properties between the dielectric layer and other functional films, enhance the interface bonding force, and reduce interface defects, thereby improving the overall dielectric properties and reliability of the composite dielectric film. However, traditional passivation strategies often rely on thermal annealing processes or vacuum deposition techniques to achieve the interface passivation dielectric layer of organic polyelectrolyte films, facing limitations such as high energy consumption, long time consumption, and complex processes. In contrast, the preparation of the passivation dielectric layer by room-temperature photocuring crosslinking technology has advantages such as simple process flow, fast time, and low energy consumption. However, currently, using room-temperature photocuring technology as a new passivation strategy for interface passivation of polyelectrolyte dielectric layers and constructing stable flexible composite dielectric films to achieve high-performance and low-power organic transistors is still extremely challenging. For example, in terms of materials, the chemical properties (such as polarity and surface energy) of photocuring materials need to be compatible with the organic semiconductor materials of the channel layer. Otherwise, charge traps or defect states are easily formed at the interface, resulting in a decrease in carrier mobility and affecting transistor performance. In terms of processes, factors such as light intensity, time, and precursor solution concentration also affect the quality and uniformity of the photocured film.

[0006] Therefore, it is necessary to develop and implement a passivation-type polyelectrolyte composite dielectric film system based on interface photocuring. By combining the dual advantages of the polyelectrolyte dielectric layer and the photocuring polymer passivation dielectric layer, it is of great significance for designing and optimizing high-performance low-voltage organic transistors, and is also expected to promote the application development of such new dielectric materials and devices in fields such as sensing, flexible circuits, wearable devices, intelligent terminals, and electrical equipment. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a passivation-type polyelectrolyte composite dielectric film based on interface photocuring, its organic transistor, preparation method, and uses. By preparing the passivation-type polyelectrolyte composite dielectric film and applying it to an organic transistor, its electrical properties and stability can be improved, the preparation process can be simplified, and the production cost can be reduced. In addition, by using the passivation-type polyelectrolyte composite dielectric film material as the dielectric layer of the organic transistor, the working voltage of the organic transistor can be reduced, energy consumption can be reduced, and energy loss can be reduced.

[0008] To achieve the above object, in the first aspect of the present invention, a passivation-type polyelectrolyte composite dielectric film with interface photocuring is provided, which includes a photocuring polymer passivation dielectric layer and a polyelectrolyte dielectric layer that are mutually adhered.

[0009] Among them, the photocurable polymer passivation dielectric layer material is a photocurable cross-linked polymer dielectric material c-DPHA, and the structural formula of the DPHA monomer of the c-DPHA material is

[0010] The polyelectrolyte dielectric layer material is any one of acrylic polyelectrolytes or their derivatives, acrylamide polyelectrolytes or their derivatives, polyelectrolyte composite dielectric materials formed by blending polyacrylic acid and polyethylene glycol, and polyelectrolyte composite dielectric materials formed by blending polyacrylic acid and polyvinyl alcohol.

[0011] Furthermore, the photocurable polymer passivation dielectric layer and the polyelectrolyte dielectric layer are mutually adhered to form any one of a composite bilayer structure, a composite sandwich structure, or a multi-layer composite structure with alternating layers of the two.

[0012] The second aspect of the present invention provides a method for preparing an interfacially photocured passivated polyelectrolyte composite dielectric film, and this method includes:

[0013] Dissolve the polyelectrolyte material in a first solvent, and after stirring at room temperature, obtain a precursor solution of the polyelectrolyte dielectric material; among them, the stirring time at room temperature is 3 to 24 hours;

[0014] Dissolve the DPHA monomer and the photoinitiator in a second solvent, and after stirring at room temperature, obtain a precursor solution of the photocurable polymer passivation dielectric layer material c-DPHA;

[0015] After forming a film from the precursor solution of the polyelectrolyte dielectric material by a solution processing method, anneal it at 50 to 200 °C for at least 30 minutes to obtain a polyelectrolyte dielectric layer;

[0016] Form a film from the precursor solution of the photocurable polymer passivation dielectric layer material c-DPHA on one surface of the polyelectrolyte dielectric layer by solution processing and through photocuring cross-linking, and then the interfacially photocured passivated polyelectrolyte composite dielectric film is obtained.

[0017] Among them, the polyelectrolyte dielectric layer and the photocurable polymer passivation dielectric layer are mutually adhered to form any one of a composite bilayer structure, a composite sandwich structure, or a multi-layer composite structure with alternating layers of the two.

[0018] Furthermore, the first solvent is any one of water, methanol, ethanol, or isopropanol; the concentration of the polyelectrolyte in the precursor solution of the polyelectrolyte dielectric material is 3 to 60 mg / mL. The mass fraction of the DPHA monomer in the precursor solution of the photocurable polymer passivation dielectric layer material c-DPHA is 0.1 to 20 wt.%, and the mass fraction of the photoinitiator is 0.01 to 2 wt.%; the second solvent is any one or several of methanol, ethanol, or isopropanol.

[0019] Preferably, the first solvent is any one of methanol, ethanol or isopropanol, and the concentration of the polyelectrolyte in the precursor solution of the polyelectrolyte dielectric material is 5-55 mg / mL. The mass fraction of the DPHA monomer in the precursor solution of the photocurable polymer passivation dielectric layer material c-DPHA is 0.2-15 wt.%, and the mass fraction of the photoinitiator Irgacure 184 is 0.02-1.5 wt.%. The second solvent is any one of methanol, ethanol or isopropanol.

[0020] More preferably, the first solvent is methanol or isopropanol, and the concentration of the polyelectrolyte in the precursor solution of the polyelectrolyte dielectric material is 10-50 mg / mL. The mass fraction of the DPHA monomer in the precursor solution of the photocurable polymer passivation dielectric layer material c-DPHA is 0.5-10 wt.%, and the mass fraction of the photoinitiator Irgacure 184 is 0.05-1 wt.%. The second solvent is methanol or ethanol.

[0021] In the third aspect of the present invention, an organic transistor is provided, which includes a substrate, a gate and a semiconductor layer stacked in sequence, and a source electrode and a drain electrode formed on the surface of the semiconductor layer. A conductive channel with a micro-nano scale spacing is formed between the source electrode and the drain electrode.

[0022] The transistor further includes a passivation-type polyelectrolyte composite dielectric thin film cured by light at the interface between the gate and the semiconductor layer. The passivation-type polyelectrolyte composite dielectric thin film cured by light at the interface is the passivation-type polyelectrolyte composite dielectric thin film cured by light at the interface provided in the first aspect or the second aspect of the present invention.

[0023] In the fourth aspect of the present invention, a method for preparing an organic transistor is provided, which includes the following steps:

[0024] First, obtain an organic transistor substrate and form a gate on the surface of the substrate;

[0025] Secondly, on the surface of the substrate and the gate, form a passivation-type polyelectrolyte composite dielectric thin film cured by light at the interface through solution spin coating and photocuring. The passivation-type polyelectrolyte composite dielectric thin film cured by light at the interface is the passivation-type polyelectrolyte composite dielectric thin film cured by light at the interface provided in the first aspect or the second aspect of the present invention;

[0026] Thirdly, on the surface of the passivation-type polyelectrolyte composite dielectric thin film cured by light at the interface, process an organic semiconductor material into a semiconductor layer by any one of vacuum deposition, spin coating, blade coating, drop coating or inkjet printing;

[0027] Finally, on the surface of the semiconductor layer, source and drain electrodes are formed by any one of magnetron sputtering, vacuum thermal evaporation, atomic layer deposition, inkjet printing, or drop coating. A conductive channel with a micro-nano scale spacing is formed between the source and drain electrodes, thus obtaining the organic transistor.

[0028] Further, when forming the passivation-type polyelectrolyte composite dielectric film by interfacial photocuring, the time of the photocuring effect is 2 to 30 minutes, and the environment of the photocuring effect is room temperature atmospheric environment;

[0029] The material of the substrate is any one or several of polyethylene terephthalate, polyethylene naphthalate, polyimide, polydimethylsiloxane, polycarbonate, polyvinyl alcohol, glass, silicon dioxide / silicon, or sapphire;

[0030] The material of the gate electrode is any one or several of gold, silver, aluminum, copper, chromium, platinum, titanium, nickel, indium tin oxide, fluorine-doped tin oxide, zinc aluminum oxide, carbon nanotubes, graphene, or conductive polymers;

[0031] The material of the semiconductor layer is any one of organic conjugated polymer materials, organic small molecule semiconductor materials, or composites of organic conjugated polymers and organic small molecules. For example: poly(3-hexylthiophene), indacenodithiophene-benzothiadiazole copolymer, polythiophene derivatives, polyfluorene derivatives, poly(phenylene vinylene) derivatives, pentacene, 7,7,8,8-tetracyanoquinodimethane, or copper phthalocyanine, etc.;

[0032] The material of the source and drain electrodes is any one or several of gold, silver, aluminum, copper, chromium, platinum, titanium, nickel, indium tin oxide, fluorine-doped tin oxide, zinc aluminum oxide, carbon nanotubes, graphene, or conductive polymers.

[0033] Preferably, the material of the substrate is any one or several of polyethylene terephthalate, polyethylene naphthalate, polyimide, polydimethylsiloxane, polycarbonate, polyvinyl alcohol, and the material of the gate electrode is any one of gold, silver, aluminum, copper, or nickel;

[0034] The material of the semiconductor layer is an organic conjugated polymer material, and the organic conjugated polymer material includes poly(3-hexylthiophene), indacenodithiophene-benzothiadiazole copolymer, polythiophene derivatives, polyfluorene derivatives, poly(phenylene vinylene) derivatives, etc.;

[0035] The material of the source and drain electrodes is any one of gold, silver, aluminum, copper, or nickel.

[0036] The fifth aspect of the present invention provides the application of the above-mentioned passivated polyelectrolyte composite dielectric film based on interfacial photocuring in the preparation of optoelectronic devices such as organic transistors, sensors, detectors, memories, capacitors, etc., or in the preparation of electrical equipment.

[0037] The sixth aspect of the present invention provides the application of the above-mentioned interfacial photocured passivated polyelectrolyte composite dielectric film or organic transistor in the fields of optoelectronic devices, sensing chips, flexible circuits, wearable devices, integrated sensing and computing intelligent terminals, or electrical equipment.

[0038] The beneficial effects of the present invention are as follows:

[0039] (1) The present invention proposes an interfacial photocured passivated polyelectrolyte composite dielectric film and its preparation method. The passivation process of this novel composite dielectric film forms a dense protective film on the surface of the polyelectrolyte dielectric layer, effectively blocking the intrusion of water molecules. When water molecules come into contact with the film, the passivated film can effectively block the intrusion of water molecules, thereby improving the service life of the film in a humid environment. In addition, the interfacial photocured passivated polyelectrolyte composite dielectric film based on the passivation strategy can better maintain its physical and chemical properties in the face of external factors such as light and voltage changes, can inhibit the leakage phenomenon, improve the insulation performance of the polyelectrolyte dielectric material, and provides a beneficial way for the preparation of high-performance organic transistors.

[0040] (2) The interfacial photocured passivated polyelectrolyte composite dielectric film proposed by the present invention uses materials with rich sources and low costs, is easy to process in large areas and manufacture on a large scale, and has good compatibility with the room-temperature photocuring strategy and lithography technology in the semiconductor industry. It has unique advantages in constructing low-cost and high-performance flexible low-power organic transistors.

[0041] (3) The organic transistor proposed by the present invention uses the interfacial photocured passivated polyelectrolyte composite dielectric film as the dielectric layer and can work normally at a voltage as low as -2.5V. This interfacial photocured passivated polyelectrolyte composite dielectric film combines the dual advantages of the polyelectrolyte dielectric layer and the photocured polymer passivated dielectric layer, making the gate dielectric layer not only have high capacitance characteristics, but also effectively inhibit the leakage and hysteresis of organic transistors under low-voltage working conditions.

[0042] (4) After the interfacial photocured passivated polyelectrolyte composite dielectric film is introduced in the present invention, the carrier mobility and on / off current ratio of the organic transistor are both greatly improved, significantly improving the performance of the organic transistor. Compared with traditional organic transistors that require high voltages to operate, the organic transistors proposed by the present invention significantly reduce energy consumption and reduce unnecessary energy losses, providing strong support for the realization of green electronics development and helping to promote the development of electronic devices towards a more environmentally friendly and low-energy consumption direction.

[0043] Other advantages, objectives, and features of the present invention will, to some extent, be set forth in the subsequent description, and to some extent, will be obvious to those skilled in the art based on an examination of the following, or can be learned from the practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the following description. Description of the Drawings

[0044] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be described in detail preferably with reference to the accompanying drawings, where:

[0045] Figure 1 It is the atomic force microscope image of the passivated polyelectrolyte composite dielectric film with interfacial photocuring provided in Embodiment 1 of the present invention;

[0046] Figure 2 It is the comparison chart of the water resistance test of the polyelectrolyte dielectric layer and the photocured polymer passivation dielectric layer provided in Embodiment 1 of the present invention;

[0047] Figure 3 It is the capacitance-frequency dependence characteristic curve of the passivated polyelectrolyte composite dielectric film with interfacial photocuring provided in Embodiments 1 to 4 of the present invention;

[0048] Figure 4 It is the leakage current density-voltage dependence characteristic curve of the passivated polyelectrolyte composite dielectric film with interfacial photocuring provided in Embodiments 1 to 4 of the present invention;

[0049] Figure 5 It is the structural schematic diagram of the organic transistor based on the passivated polyelectrolyte composite dielectric film with interfacial photocuring provided in Embodiment 5 of the present invention;

[0050] Figure 6 It is the transfer characteristic curve of the organic transistor based on the passivated polyelectrolyte composite dielectric film with interfacial photocuring provided in Embodiments 5 to 8 of the present invention in an air environment;

[0051] Figure 7 It is the output characteristic curve of the organic transistor based on the passivated polyelectrolyte composite dielectric film material with interfacial photocuring provided in Embodiments 5 to 8 of the present invention in an air environment, where Figure 7 a, Figure 7 b, Figure 7 c, and Figure 7 d use the DPHA monomer contents of 0.5 wt.%, 1 wt.%, 2 wt.%, and 4 wt.% respectively for the photocured passivation dielectric layer.

[0052] Reference numerals: 1 - substrate; 2 - gate; 3 - polyelectrolyte dielectric layer; 4 - photocurable polymer passivation dielectric layer; 5 - semiconductor layer; 6 - source electrode; 7 - drain electrode. Detailed implementation manners

[0053] The following uses specific specific examples to illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the drawings provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0054] Among them, the drawings are only for illustrative purposes, showing only schematic diagrams, not physical diagrams, and cannot be understood as a limitation to the present invention; in order to better illustrate the embodiments of the present invention, some components in the drawings will be omitted, enlarged or reduced, which do not represent the dimensions of actual products; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0055] In the drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicating the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only for illustrative purposes and cannot be understood as a limitation to the present invention. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0056] The photocurable polymer passivation dielectric layer material used in each embodiment of the present invention is c-DPHA, and the structural formula of the DPHA monomer used in this material is

[0057] For those conditions not specified in the embodiments of the present invention, they are all carried out according to the prior art. Unless otherwise specified, the raw materials and solvents in the embodiments of the present invention can be obtained through public channels, where:

[0058] The organic polyelectrolyte materials polyacrylic acid (PAA) and polyethylene glycol (PEG) can be purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.

[0059] The chlorobenzene solvent and methanol solvent can be purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.;

[0060] The polymer semiconductor material indacenodithiophene-benzothiadiazole copolymer (PIDT-BT) can be purchased from Shenzhen Ruixun Optoelectronic Materials Technology Co., Ltd.;

[0061] The pentaerythritol penta / hexacrylate monomer DPHA and photoinitiator Irgacure 184 can be purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.;

[0062] The plastic substrates, polyethylene terephthalate (PET) film, polyethylene naphthalate (PEN) film, and the PET film deposited with indium tin oxide (ITO) electrode and the PEN film deposited with ITO, can all be purchased from Shenzhen Huana Xiangcheng Technology Co., Ltd.

[0063] Example 1

[0064] This example provides a preparation method of an interface photo-cured passivation-type polyelectrolyte composite dielectric film, which is prepared by solution spin-coating and ultraviolet photo-curing means. The specific method is as follows:

[0065] (1) Dissolve PAA and PEG with a mass ratio of 6:4 in methanol to make the concentration of PAA in the precursor solution of the polyelectrolyte dielectric material 30 mg / mL, and stir at room temperature for 5 h to mix evenly to obtain the precursor solution of the polyelectrolyte dielectric material;

[0066] (2) Mix and dissolve the DPHA monomer and photoinitiator Irgacure 184 in methanol, and control the mass fractions of DPHA and Irgacure 184 in the methanol solution to be 2 wt.% and 0.2 wt.% respectively, and stir at room temperature for 4 h to obtain the precursor solution of the photo-cured polymer passivation dielectric layer material c-DPHA;

[0067] (3) In a glove box under a nitrogen atmosphere, spin-coat the precursor solution of the polyelectrolyte dielectric material prepared in step (1) onto the PET-ITO substrate (the rotation speed is 500 rpm, the spin-coating time is 30 s, and spin-coat 2 times during the spin-coating process), and perform annealing treatment on a heating table at 80 °C for 120 min to obtain the polyelectrolyte dielectric layer.

[0068] (4) Subsequently, spin-coat the precursor solution of the photo-cured polymer passivation dielectric layer material c-DPHA prepared in step (2) on the surface of the polyelectrolyte dielectric layer (the rotation speed is 3000 rpm and the spin-coating time is 30 s during the spin-coating process), and irradiate with ultraviolet light for 10 min to obtain the passivation-type polyelectrolyte composite dielectric film based on interface photo-curing.

[0069] Example 2

[0070] This embodiment provides a method for preparing a passivated polyelectrolyte composite dielectric film by interfacial photocuring. Compared with Embodiment 1, there are differences in step (2). Specifically, in this embodiment, "the mass fractions of DPHA and Irgacure 184 in the methanol solution are 2 wt.% and 0.2 wt.%, respectively" is changed to "the mass fractions of DPHA and Irgacure 184 in the methanol solution are 0.5 wt.% and 0.05 wt.%, respectively".

[0071] Embodiment 3

[0072] This embodiment provides a method for preparing a passivated polyelectrolyte composite dielectric film by interfacial photocuring. Compared with Embodiment 1, there are differences in step (2). Specifically, in this embodiment, "the mass fractions of DPHA and Irgacure 184 in the methanol solution are 2 wt.% and 0.2 wt.%, respectively" is changed to "the mass fractions of DPHA and Irgacure 184 in the methanol solution are 1 wt.% and 0.1 wt.%, respectively".

[0073] Embodiment 4

[0074] This embodiment provides a method for preparing a passivated polyelectrolyte composite dielectric film by interfacial photocuring. Compared with Embodiment 1, there are differences in step (2). Specifically, in this embodiment, "the mass fractions of DPHA and Irgacure 184 in the methanol solution are 2 wt.% and 0.2 wt.%, respectively" is changed to "the mass fractions of DPHA and Irgacure 184 in the methanol solution are 4 wt.% and 0.4 wt.%, respectively".

[0075] Embodiment 5

[0076] This embodiment provides an organic transistor based on a passivated polyelectrolyte composite dielectric film material by interfacial photocuring. As Figure 5 shown, the organic transistor includes a substrate 1, a gate 2, a passivated polyelectrolyte composite dielectric film by interfacial photocuring, and a semiconductor layer 5 from bottom to top. The source electrode 5 and the drain electrode 6 with channel patterns are respectively located on the surfaces at both ends of the semiconductor layer 5.

[0077] Among them, the passivated polyelectrolyte composite dielectric film by interfacial photocuring includes a polyelectrolyte dielectric layer 3 and a photocured polymer passivation dielectric layer 4 located on the surface of the polyelectrolyte dielectric layer 3.

[0078] Embodiment 6

[0079] This embodiment provides a method for preparing the organic transistor described in Embodiment 5. The preparation method includes the following steps:

[0080] (1) Use PET-ITO with a thickness of 125 μm as the substrate / gate;

[0081] (2) In a glove box with a nitrogen atmosphere, spin-coat the precursor solution of the polyelectrolyte dielectric material (prepared according to step (1) in Example 1) onto the substrate / gate obtained in step (1) (where the rotation speed during spin-coating is 500 rpm, the spin-coating time is 30 s, and the number of spin-coating times is 2). Subsequently, anneal for 120 min on a heating table at 80 °C to prepare the polyelectrolyte dielectric layer; then spin-coat the precursor solution of the photo-curable polymer passivation dielectric layer material c-DPHA (prepared according to step (2) in Example 1) onto the polyelectrolyte dielectric layer (where the rotation speed during spin-coating is 3000 rpm and the spin-coating time is 30 s), and then irradiate with ultraviolet light for 10 min to prepare the interfacial photo-cured passivated polyelectrolyte composite dielectric film;

[0082] (3) In a glove box with a nitrogen atmosphere, prepare a PIDT-BT chlorobenzene solution with a concentration of 5 mg / mL and spin-coat it onto the surface of the interfacial photo-cured passivated polyelectrolyte composite dielectric film prepared in step (2) (where the rotation speed during spin-coating is 2000 rpm and the spin-coating time is 30 s). After spin-coating, anneal for 20 min on a heating table at 80 °C to prepare the semiconductor layer;

[0083] (4) On the above semiconductor layer, through a mask and using a vacuum thermal evaporation process (the vacuum degree is about 2×10 - 4 Pa, and the evaporation rate is about ) to prepare 50-nm-thick gold as the source and drain electrodes. There is a channel with a width and length of 22.5 mm and 0.15 mm respectively between the prepared source and drain electrodes, and thus the organic transistor based on the interfacial photo-cured passivated polyelectrolyte composite dielectric film can be prepared.

[0084] Examples 7 - 19

[0085] Examples 7 - 19 all provide methods for preparing organic transistors based on interfacial photo-cured passivated polyelectrolyte composite dielectric film materials. There are some differences between the preparation methods provided in Examples 7 - 19 and the preparation method provided in Example 6, as shown in Table 1 below. Among them, the parts not described in Table 1 are the same as those in the preparation method described in Example 6.

[0086] Table 1

[0087]

[0088]

[0089] The preparation method provided in Comparative Example 1 in Table 1 is used to prepare an organic transistor based on an unpassivated polyelectrolyte dielectric film. Its structure from bottom to top includes a substrate, a gate, an unpassivated polyelectrolyte dielectric film, and a semiconductor layer. The source and drain with channel patterns are respectively located on the surfaces at both ends of the semiconductor layer. The difference between the preparation method described in Comparative Example 1 and the preparation method described in Example 6 is that only the polyelectrolyte dielectric layer is used as the dielectric film. That is, compared with the preparation method described in Example 6, only the polyelectrolyte dielectric layer is prepared in step (2), and the c-DPHA photocurable polymer passivation dielectric layer is not prepared.

[0090] The relevant performance tests were carried out on the dielectric film materials or organic transistors prepared in the above examples, as follows:

[0091] 1. Characterize the surface morphology of the passivated polyelectrolyte composite dielectric film by interfacial photocuring

[0092] The surface morphology of the passivated polyelectrolyte composite dielectric film by interfacial photocuring described in Example 1 was characterized by an atomic force microscope (Bruker Dimension ICON), and the test results are as Figure 1 shown. It can be seen that the surface of the passivated polyelectrolyte composite dielectric film by interfacial photocuring is dense and flat, and its root mean square roughness is small (about 1.44 nm), indicating that this type of passivated polyelectrolyte composite dielectric film material has good film quality and can meet the application requirements of related devices.

[0093] 2. Conduct water resistance tests on the photocurable polymer passivation dielectric layer and the polyelectrolyte dielectric layer

[0094] The photocurable polymer passivation dielectric layer (c-DPHA) and the polyelectrolyte dielectric layer prepared in Example 1 were immersed in water for three minutes, and the comparison results before and after the test are as Figure 2 shown. It can be seen that the film material of the polyelectrolyte dielectric layer shows obvious surface damage under the action of water, and the continuity of the film surface morphology is destroyed. However, the photocurable polymer passivation dielectric layer (c-DPHA) material is not significantly affected by water. Therefore, it can be known that the c-DPHA passivation dielectric layer material has a tight cross-linking and good physical and chemical stability, making the photocurable polymer passivation dielectric layer have good water resistance and can reduce the adverse effects of ion migration and moisture exposure, and is used to realize stable optoelectronic devices such as organic transistors.

[0095] 3. Conduct capacitance and leakage current characteristics tests on the passivated polyelectrolyte composite dielectric film by interfacial photocuring

[0096] Using an LCR digital bridge (TH2827C), the capacitance-frequency dependence characteristics of the four different interface photo-cured passivated polyelectrolyte composite dielectric films provided in the above Examples 1-4 were tested, and the results are as Figure 3 shown. The capacitances of the passivated polyelectrolyte composite dielectric film materials prepared in Examples 1, 2, 3, and 4 at 0.1 Hz were 10.2, 28.2, 14.9, and 8.5 nF / cm 2 respectively. As the amount of DPHA monomer in the photo-cured polymer passivated dielectric layer material precursor solution increased, c-DPHA effectively filled and repaired the defects inside the film, reduced the number of free charges, and inhibited the disordered migration of charges, resulting in a gradual decrease in capacitance. Overall, however, the interface photo-cured passivated polyelectrolyte composite dielectric film maintained the high-capacitance characteristics of the polyelectrolyte system in the low-frequency region, thus ensuring the low-voltage operating ability of subsequent transistor devices.

[0097] Using an Agilent 4155C semiconductor parameter analyzer, the leakage current density-voltage dependence characteristics of the four different interface photo-cured passivated polyelectrolyte composite dielectric films provided in the above Examples 1-4 were tested, and the results are as Figure 4 shown. It can be seen that the leakage currents of the passivated polyelectrolyte composite dielectric films prepared in Examples 1, 2, 3, and 4 at -2.5 V were 4.8×10 -9 , 1.9×10 -8 , 1.1×10 -8 and 7.4×10 -10 A / cm 2 respectively. These results indicate that the c-DPHA photo-cured polymer passivated dielectric layer can effectively inhibit the leakage phenomenon, thus effectively improving the insulation performance of the polyelectrolyte dielectric material. The improvement of the insulation performance means that under the same working conditions, the gate dielectric layer can better maintain the stability of the electric field and reduce the electric field distortion caused by charge leakage, which is crucial for maintaining the stable operation of the device and reducing signal interference.

[0098] 4. Performance testing of organic transistors based on interface photo-cured passivated polyelectrolyte composite dielectric films

[0099] Using an Agilent 4155C semiconductor parameter analyzer, the electrical performance of different organic transistors prepared in Examples 6-9 was tested in an air environment, and the transfer characteristic curves of the devices are as Figure 6 shown. From Figure 6It can be seen that the organic transistor prepared in Example 6 of the present invention has good low-voltage operating ability and the optimal transistor characteristics among them. After introducing the passivation dielectric layer based on the c-DPHA material, the off-state current of the device is significantly reduced, resulting in an increase in the overall mobility and on / off current ratio of the device. At a low operating voltage of -2.5 V, the carrier mobility of the organic transistor reaches up to 1.17 cm 2 V - 1 s -1 , and the on / off current ratio is 3.31×10 3 . In contrast, the device of Comparative Example 1 is based on an unpassivated polyelectrolyte dielectric film (passivation - 0 wt.%), with relatively serious leakage and hysteresis phenomena, resulting in a smaller carrier mobility (only ~0.04 cm 2 V -1 s -1 ) and a lower on / off current ratio (~0.54×10 3 ) for its organic transistor. It can be seen that the design of the passivated polyelectrolyte composite dielectric film based on interfacial photocuring helps to improve the device performance of the organic transistor and shows good potential in subsequent applications.

[0100] In addition, the output characteristic curves of the different organic transistors prepared in Examples 6 - 9 were also tested and analyzed, as shown in Figure 7 a - 7d respectively (where Figure 7 a - Figure 7 d are the conditions of the photocured polymer passivation dielectric layers corresponding to Examples 7, 8, 6, and 9 respectively: passivation - 0.5 wt.%, passivation - 1 wt.%, passivation - 2 wt.%, and passivation - 4 wt.%). It can be seen that the c-DPHA photocured polymer passivation dielectric layer can effectively inhibit the problem of drift of the output characteristic curve of the organic transistor under the action of an electric field, improving the operating stability of the device in a voltage environment.

[0101] Similarly, the performance of the passivated polyelectrolyte composite dielectric film based on interfacial photocuring and its organic transistor prepared in other examples was tested according to the above test method, and the results are similar to the device performance characteristics of the organic transistor prepared in Example 6 above, indicating that the organic transistor of the passivated polyelectrolyte composite dielectric film based on interfacial photocuring prepared according to the method provided by the present invention has low power consumption and good electrical properties. From these electrical performance test results, it can be seen that the passivated polyelectrolyte composite dielectric film based on interfacial photocuring proposed by the present invention has good dielectric properties in organic transistor devices and can exert the advantages of polyelectrolytes and photocured polymer passivation dielectric layers. By reasonably optimizing the photocured polymer passivation dielectric layer, the electrical properties of the device can be effectively adjusted and improved, enhancing the comprehensive stability, which is thus beneficial to the practical application of the device.

[0102] In summary, the present invention provides a passivated polyelectrolyte composite dielectric film based on an interfacial photocuring strategy. The dielectric layer is passivated by a photocured polymer and the polyelectrolyte dielectric layer are mainly compounded with each other. At the same time, applying the composite dielectric film to an organic transistor can effectively improve the electrical performance and stability of the device. The passivated polyelectrolyte composite dielectric film material with interfacial photocuring proposed by the present invention forms a high-quality, smooth and uniform film, which can effectively prevent the erosion of the film by air moisture. At the same time, the composite dielectric film can combine the dual advantages of the polyelectrolyte dielectric layer and the photocured polymer passivated dielectric layer, and has characteristics such as high capacitance and low leakage. The organic transistor based on the passivated polyelectrolyte composite dielectric film with interfacial photocuring has good working performance at low voltage, which helps to reduce energy consumption and promote the application development of green electronics. Compared with the traditional technology, the passivated polyelectrolyte composite dielectric film with interfacial photocuring proposed by the present invention has a simple processing process, and has the advantages of low energy consumption, simple structure and excellent performance, providing a useful idea for the research of future high-performance dielectric materials and the potential applications in the fields of optoelectronic devices, wearable devices, sensors, flexible circuits, integrated sensing and computing intelligent terminals or electrical equipment, etc.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the present technical solution, and they should all be covered within the scope of the claims of the present invention.

Claims

1. An interfacial photocured passivation polyelectrolyte composite dielectric film, characterized in that: It includes a photocurable polymer passivation dielectric layer and a polyelectrolyte dielectric layer bonded to each other; The photocurable polymer passivation dielectric layer material is a photocurable cross-linked polymer dielectric material c-DPHA, and the DPHA monomer structure of the c-DPHA material is The polyelectrolyte dielectric layer material is any one of acrylic acid polyelectrolytes or their derivatives, acrylamide polyelectrolytes or their derivatives, polyelectrolyte composite dielectric materials formed by blending polyacrylic acid and polyethylene glycol, and polyelectrolyte composite dielectric materials formed by blending polyacrylic acid and polyvinyl alcohol.

2. The interfacial photocured passivation polyelectrolyte composite dielectric film according to claim 1, characterized in that: The photocurable polymer passivation dielectric layer and the polyelectrolyte dielectric layer are laminated to each other to form any one of a composite double-layer structure, a composite sandwich structure or a multi-layer composite structure of the two alternating.

3. A method for preparing an interfacial photocured passivation polyelectrolyte composite dielectric film, characterized in that: The method includes: Dissolving a polyelectrolyte material in a first solvent, and stirring at room temperature to obtain a precursor solution of a polyelectrolyte dielectric material; Dissolving DPHA monomer and photoinitiator in a second solvent, and stirring at room temperature to obtain a precursor solution of photocurable polymer passivation dielectric layer material c-DPHA; After the precursor solution of the polyelectrolyte dielectric material is formed into a film by a solution processing method, annealing is performed at 50 to 200° C. for at least 30 minutes to obtain a polyelectrolyte dielectric layer; The precursor solution of the photocurable polymer passivation dielectric layer material c-DPHA is processed into a film on one surface of the polyelectrolyte dielectric layer through solution processing and subjected to photocuring and cross-linking to obtain the interfacial photocured passivation polyelectrolyte composite dielectric film.

4. The preparation method according to claim 3, characterized in that: The first solvent is any one of water, methanol, ethanol or isopropanol; the concentration of the polyelectrolyte in the precursor solution of the polyelectrolyte dielectric material is 3-60 mg / mL.

5. The preparation method according to claim 3, characterized in that: The mass fraction of DPHA monomer in the precursor solution of the photocurable polymer passivation dielectric layer material c-DPHA is 0.1-20wt.%, and the mass fraction of the photoinitiator is 0.01-2wt.%; the second solvent is any one or more of methanol, ethanol or isopropanol.

6. Use of the passivation-type polyelectrolyte composite dielectric film based on interfacial photocuring according to any one of claims 1 to 3 in the preparation of optoelectronic devices such as organic transistors, sensors, detectors, memories, capacitors, or electrical equipment.

7. An organic transistor, characterized in that: The organic transistor comprises a substrate, a gate and a semiconductor layer stacked in sequence, and a source electrode and a drain electrode formed on the surface of the semiconductor layer, wherein a conductive channel with a micro-nano scale spacing is formed between the source electrode and the drain electrode; It also includes the interfacial photocured passivation polyelectrolyte composite dielectric film according to any one of claims 1 to 3 located between the gate and the semiconductor layer.

8. A method for preparing an organic transistor, characterized in that: The method comprises the following steps: First, an organic transistor substrate is obtained, and a gate is formed on the surface of the substrate; Secondly, on the surface of the substrate and the gate, the interfacial photocured passivation type polyelectrolyte composite dielectric film according to claim 1 or 2 is formed by solution spin coating and photocuring; Next, on the surface of the interfacial photocured passivation polyelectrolyte composite dielectric film, an organic semiconductor material is processed by vacuum deposition, spin coating, scraping, drop coating or inkjet printing to form a semiconductor layer; Finally, a source electrode and a drain electrode are formed on the surface of the semiconductor layer by any one of magnetron sputtering, vacuum thermal evaporation, atomic layer deposition, inkjet printing or drop coating, and a conductive channel with a micro-nano scale spacing is formed between the source electrode and the drain electrode, thereby preparing the organic transistor.

9. The preparation method according to claim 8, characterized in that: When forming the interfacial photocured passivation polyelectrolyte composite dielectric film, the photocuring time is 2 to 30 minutes, and the photocuring environment is room temperature atmospheric environment; The material of the substrate is any one or more of polyethylene terephthalate, polyethylene naphthalate, polyimide, polydimethylsiloxane, polycarbonate, polyvinyl alcohol, glass, silicon dioxide / silicon or sapphire; The material of the gate is any one or more of gold, silver, aluminum, copper, chromium, platinum, titanium, nickel, indium tin oxide, fluorine-doped tin oxide, zinc aluminum oxide, carbon nanotubes, graphene or conductive polymer; The material of the semiconductor layer is any one of an organic conjugated polymer material, an organic small molecule semiconductor material, or a composite material of an organic conjugated polymer and an organic small molecule; The source and drain electrodes are made of any one or more of gold, silver, aluminum, copper, chromium, platinum, titanium, nickel, indium tin oxide, fluorine-doped tin oxide, zinc aluminum oxide, carbon nanotubes, graphene or conductive polymers.

10. Application of the interfacial photocured passivated polyelectrolyte composite dielectric film according to any one of claims 1 to 6 or the organic transistor according to any one of claims 7 to 8 in the fields of optoelectronic devices, sensor chips, flexible circuits, wearable devices, sensing, storage and computing integrated smart terminals or electrical equipment.

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