An organic field effect transistor and a method for manufacturing the same

Abstract

The application provides an organic field effect transistor and a preparation method thereof. The organic field effect transistor comprises a first conductive layer, an organic semiconductor layer, an insulating layer and a second conductive layer in sequence. The first conductive layer is made of conductive material with a work function of 4.5eV or above. The organic semiconductor layer is made of p-type organic semiconductor single crystal. The insulating layer is made of insulating material. The second conductive layer is made of material with an electrical conductivity of greater than 1S / m. The organic field effect transistor satisfies the following conditions: hole mobility μ p ≥0.5cm 2 V ‑1 s ‑1 , electron mobility μ n ≥0.5cm 2 V ‑1 s ‑1 , and balance coefficient B≤1, wherein the balance coefficient B is calculated by the formula: B=|lg(μ p / μ n |, and the organic field effect transistor has high and balanced hole mobility and electron mobility, and has a good application prospect in organic complementary circuits and light-emitting transistors.

Description

Technical Field

[0001] This invention relates to the field of organic semiconductor device technology, specifically to an organic field-effect transistor and its fabrication method. Background Technology

[0002] Organic semiconductor devices possess advantages such as low fabrication cost, flexibility, lightweight, and large-area fabrication, making them promising candidates for applications in flexible displays, flexible wearable devices, the Internet of Things (IoT), and biomedicine, and attracting widespread attention. The fabrication of high-performance organic semiconductor devices is a crucial process for their practical application. Among organic semiconductor devices, organic field-effect transistors (OFETs) are common and important fundamental components, forming the most important building blocks in organic integrated circuits.

[0003] Charge carriers, as the carriers of current in electronic devices, are charged particles that can move freely under the influence of an electric field. In semiconductor materials, there are two types of charge carriers: electrons and holes. Electrons carry a negative charge, while holes carry a positive charge. In the application of OFETs (Output-Focused Field-Controlled Transistors), the transport of both holes and electrons is crucial. For example, when an OFET is used in a complementary circuit, holes and electrons accumulate and transport in different transistors, allowing different transistors to be turned on or off systematically under the same control voltage, thereby realizing the function of logic operations.

[0004] Carrier mobility (abbreviated as mobility, denoted by μ, unit: cm) 2 V -1 s -1 The mobility (μ) refers to the migration rate of charge carriers under a unit electric field strength. For an OFET (Output Transmitter Field Sensor), mobility is a key parameter representing its performance, determining how quickly it turns on or off. Higher mobility means a faster turn-on or turn-off speed for the OFET, resulting in faster logic operations in logic circuits. Depending on the type of charge carrier, the carrier mobility μ can be expressed as hole mobility (μ0.05). p ) and electron mobility (μ n To characterize. μ p and μ n It can be obtained through the following formula:

[0005]

[0006]

[0007] The p-type and n-type transfer characteristic curves of the OFET were measured using a semiconductor analyzer, where L is the length of the OFET channel, W is the width of the OFET channel, and C... i The gate insulating layer capacitance, I, can be measured using a semiconductor parameter analyzer with capacitance analysis capabilities. DS When the OFET is operating, the current passing through the source and drain is V. G The voltage applied to the gate, It can be obtained by testing the transfer characteristic curve of a field-effect transistor operating in the saturation region. Figure 1 (a) and (b) are cross-sectional and top views of a common OFET structure, respectively. W and L can be measured by scale in the top view of the OFET taken with an optical microscope. Figure 1 (c) and (d) in the figure show the transfer characteristic curves of p-type OFET and n-type OFET, respectively, which can be measured by a semiconductor analyzer, and the I after processing the transfer characteristic curves. DS 1 / 2 -V G Curve, calculated by curve I DS 1 / 2 -V G The slope can be obtained

[0008] For OFETs, higher carrier mobility is better. Compared to field-effect transistors (FETs) made of inorganic semiconductor materials, OFETs generally have relatively low mobility. For example, FETs based on inorganic single-crystal silicon typically have a mobility of 10-1. 2 -10 3 cm 2 V -1 s -1 The mobility of OFETs is generally below 1 cm⁻¹. 2 V -1 s -1 To achieve practical application of OFETs, the mobility of both electrons and holes in an OFET must be no less than 0.1 cm⁻¹. 2 V -1 s -1 This is a basic requirement.

[0009] In common applications such as complementary circuits and light-emitting transistors, not only is the simultaneous transport of holes and electrons required for OFETs, but also μ... p and μ nThe voltage level is sufficiently high, and the balance between the two types of charge carrier transport is good. Taking complementary circuits as an example, for a long time, it has been necessary to use both p-type OFETs that transport holes and n-type OFETs that transport electrons, or to use bipolar OFETs that can transport both electrons and holes simultaneously, in order to achieve simultaneous electron and hole transport in the circuit and meet the fabrication requirements of complementary circuits. Complementary circuits cannot be obtained by using only p-type OFETs that can only transport holes, or by using only n-type OFETs that can only transport electrons.

[0010] Furthermore, in complementary circuits, the circuit performance is greatly affected by the balance of electron and hole transport; the side with poorer transport performance becomes a bottleneck that severely limits the circuit's operation. Even with extensive optimization in other aspects, improving hole mobility (μ) remains a significant challenge. p ) and electron mobility (μ n While both hole and electron mobilities are high, if the balance between hole and electron mobility is poor, circuit performance cannot be further improved. (I. Isakov, A. Paterson, O. Solomeshch, N. Tessler, Applied Physics Letters, 109, 26 (2016). This paper states: Although significant progress towards plastic-compatible, solution-processed hybrid logic has been achieved in the recent years, these circuits show moderate performance primarily due to the large imbalance in the hole and electron mobilities.) Therefore, improving the balance between hole and electron transport in semiconductor devices is of great significance for improving device performance.

[0011] The balance of hole and electron transport in semiconductor devices can be represented by μ. p and μ n The degree of proximity between the two is used to represent the balance between hole and electron transport; the closer they are, the better the balance between hole and electron transport. This balance can be measured by the balance coefficient B, which is calculated using the formula B = |lg(μ)|. p / μ n The smaller B is, the closer the hole mobility and electron mobility are, and the better the balance between hole and electron transport; ideally, when B = 0, μ p =μ nHole transport and electron transport are in perfect balance. A mobility difference of less than 10 times is considered an acceptable balance, i.e., within 0.1 μ. p ≤μ n ≤10μ p Within a certain range, the standard for balancing hole and electron transport is considered to be achieved, where the balance coefficient B ≤ 1. Therefore, the balance coefficient B ≤ 1 is the condition for balancing hole and electron transport.

[0012] Based on their ability to transport charge carriers in field-effect transistors (OFETs), organic semiconductor materials can be classified into three categories: p-type semiconductor materials, n-type semiconductor materials, and ambipolar semiconductor materials. P-type semiconductor materials primarily transport holes (μ) in OFETs. p >100μn); n-type semiconductor materials mainly transport electrons (μ) in FETs. n >100μ p Bipolar semiconductor materials in FETs can transport both holes and electrons, and μ p With μ n Approximately (0.01≤μ) p / μ n ≤100). p-type and n-type semiconductor materials are collectively referred to as unipolar semiconductor materials (or simply unipolar materials). For ease of distinction, the classification criteria for organic semiconductor materials here are based solely on the performance measured after the material is first fabricated into an OFET, rather than the performance measured after various modifications or optimizations. If only μ is measured in the initial report... p or μ n One of these characteristics indicates that the material tends to exhibit a single type of charge carrier transport performance, suggesting that it is a unipolar semiconductor rather than a bipolar semiconductor. For example, commonly used rubrene, pentacene, and pentacene derivatives (e.g., TIPS-pentacene) are all common p-type materials.

[0013] The aggregated state structure of organic semiconductors has a significant impact on the performance of organic electronic devices. Based on the orderliness of molecular arrangement, the aggregated state structures of organic semiconductors can be classified into single crystal, polycrystalline, and amorphous. Organic single crystals, often simply called organic single crystals, exhibit the highest orderliness among the three states. For the same organic semiconductor material, the single-crystal aggregated state has the highest orderliness, the fewest defects, and no grain boundaries, resulting in minimal scattering during carrier transport and the highest carrier transport performance. It has been proven that the long-range orderliness of organic single crystals is highly beneficial for improving carrier mobility and exciton diffusion length, thereby enhancing the performance of organic electronics. For example, carrier mobility μ is a crucial parameter determining the switching speed of an OFET (Optical Field-Controlled ... Taking fluorene as an organic semiconductor material as an example, the mobility of OFETs based on amorphous or polycrystalline fluorene is 10. -3 ~10 -4 cm 2 V -1 s -1 The mobility of red fluorene OFETs based on single-crystal morphology can reach up to 40 cm⁻¹. 2 V -1 s -1 This represents an improvement of nearly five orders of magnitude, resulting in faster semiconductor device operating speeds (J. Takeya, M. Yamagishi and Y. Tominari, R., Applied Physics Letters 90, 102120 (2007)).

[0014] Whether the aggregated structure of an organic semiconductor material is a single crystal can be determined by optical microscopy, selected area electron diffraction (SAED), and other methods. Among these, optical microscopy is a simple and effective method for observing the morphology of organic semiconductor single-crystal thin films. Organic single crystals exhibit anisotropy due to the highly ordered periodic arrangement of molecules within them. Under orthogonally polarized light under an optical microscope, anisotropic objects will exhibit birefringence. When the direction of crystal growth is perpendicular or parallel to the polarization angle, the presence of uniform color and brightness variations can be used to determine whether the crystal axes are highly oriented within the field of view, thereby determining its single crystallization (A. Yamamura, T. Okamoto and J. Takeya, Science Advances, 4, eaao5758, (2018)). In addition, the highly ordered molecular arrangement within organic single crystals results in regular edges and regular geometric morphologies. Based on the regular geometric morphology and the uniform brightness variations under orthogonally polarized light, it is easy to determine whether an organic single crystal has formed. Selected area electron diffraction (SAD) is also a commonly used method for single-crystal detection. When an electron beam acts on a material, the atoms in the material scatter electrons. Due to the wave nature of the electron beam, interference occurs between the scattered electron waves, causing the collected pattern to exhibit characteristics related to the material's structure. Within the selected area, the diffraction pattern of a single-crystal material consists of multiple neatly arranged spots, the diffraction pattern of a polycrystalline material is a series of concentric rings of different radii, while the diffraction pattern of an amorphous material has only a single diffuse central spot.

[0015] Complementary circuits cannot be obtained by using only p-type OFETs made of p-type materials or only n-type OFETs made of n-type materials. Bipolar materials can be used to obtain bipolar OFETs that can transport both holes and electrons. However, compared to unipolar materials, bipolar materials have more complex molecular structures, often requiring complex modifications, chemical linkages, and screenings based on unipolar material molecules. This increases the steps and difficulty of material synthesis and production, hindering industrial applications. Therefore, there are fewer material choices for bipolar semiconductors compared to unipolar semiconductors. For example, (Z.Cai, H.Luo, X.Chen, G.Zhang, Z.Liu, D.Zhang, Chem.-An Asian J.9(2014)1068–1075.) DPP (diketopyrrolopyrrole) is a p-type material (structure see the paper). Figure 2In (a) of the paper, DPP-F2 (a diketopyrrolopyrrole derivative containing E-(1,2-difluoro-vinyl) groups) with bipolar material was obtained only after complex modification of the DPP molecule (the structure is shown in the paper). Figure 2 (b) In this context, DPP-F2 molecules are more complex than DPP molecules, more difficult to synthesize, and have a more asymmetric structure, making it difficult to obtain single-crystal structures. Improper modification can even prevent the formation of bipolar materials. Therefore, bipolar materials are more difficult to obtain than unipolar materials, have less material selectivity, and are thus more difficult to apply in industrialization. Compared to bipolar semiconductor materials, unipolar semiconductor materials (p-type or n-type) have simpler molecular structures. The simpler molecular structure reduces the synthesis cost of unipolar semiconductor materials, provides a wider range of material choices, making them more suitable for industrial applications, and also makes unipolar semiconductor materials easier to crystallize, resulting in high-performance OFETs.

[0016] Among unipolar semiconductor materials, p-type materials have greater advantages in industrial applications compared to n-type semiconductor materials. This is because p-type materials generally outperform n-type materials in terms of mobility, air stability, and material selection when used in OFETs (Zhao Y, Guo Y, Liu Y. 25th Anniversary Article: Recent Advances in n-Type and Ambipolar Organic Field-Effect Transistors [J]. Advanced Materials, 2013. This article states: However, the overall development of n-type organic semiconductors still lags behind their p-type counterparts in terms of mobility, ambient stability, and so on. M. Hermann, R. Wu, DC Grenz, D. Kratzert, H. Li, B. Esser, J. Mater. Chem. C. 6 (2018) 5420–5426. Compared to p-type materials, fewer n-type or ambipolar OFET-materials exist.).

[0017] In summary, among the three types of organic semiconductor materials—p-type, n-type, and bipolar—p-type materials are the most diverse, the most thoroughly researched, and the most likely to be the first to achieve large-scale industrial applications.

[0018] High work function metals have the following advantages and problems when used in organic field-effect transistors:

[0019] Electrodes are an essential structural component of an OFET (Output Transistor). Depending on their function and the voltage applied during operation, the three electrodes in an OFET can be divided into the gate (G), source (S), and drain (D). The source and drain are the two electrodes that directly contact the semiconductor, used to drive the transistor and inject and extract charge carriers into the semiconductor layer. Electrode materials are generally composed of highly conductive materials, including metals, conductive metal oxides, alloys, and conductive polymers. Metals are the most common electrode materials, including gold, silver, aluminum, platinum, calcium, and magnesium.

[0020] The work function (WF) is an important physical parameter of electrode materials. The work function of a material refers to the difference between its vacuum level (VL) and Fermi level (E). F The energy difference between (WF = VL - E) F Based on their work function, electrode materials can be classified into high work function electrode materials and low work function electrode materials. Materials with a work function ≥ 4.5 eV are considered high work function electrode materials, such as gold (Au, 5.1 eV), platinum (Pt, 5.65 eV), copper (Cu, 4.65 eV), chromium (Cr, 4.6 eV), and indium tin oxide (ITO, 4.8 eV). Materials with a work function < 4.5 eV are considered low work function electrode materials, such as calcium (Ca, 2.87 eV), cesium (Cs, 2.14 eV), barium (Ba, 2.7 eV), magnesium (Mg, 3.66 eV), aluminum (Al, 4.28 eV), and silver (Ag, 4.26 eV). The work function of a material can be measured using ultraviolet photoelectron spectroscopy (UPS) or Kelvin probe microscopy (KPFM).

[0021] The degree of matching between the work function of the electrode material and the energy level of the organic semiconductor material has a significant impact on carrier transport in an OFET. High work function electrode materials, when used as source / drain electrodes in an OFET, are beneficial for the OFET to exhibit hole transport properties but detrimental to its electron transport properties; conversely, low work function electrode materials, when used as source / drain electrodes in an OFET, are beneficial for the OFET to exhibit electron transport properties but detrimental to its hole transport properties (J. Fidyk, W. Waliszewski, P. Sleczkowski, A. Kiersnowski, W. Pisula, T. Marszalek, Polymers (Basel). 12(2020) 1–14). This literature states: "Additionally, an alignment of the electrodework function with the HOMO and LUMO levels of the semiconductor is necessary for an efficient injection of electrons and holes into the..." activelayer.NBKotadiya,H.Lu,A.Mondal,Y.Ie,D.Andrienko,PWMBlom,GJAHWetzelaer,Nat.Mater.17(2018)329–334; stated in this document: Since the injected current depends exponentially on the injection barrier5, it is vital to find hole-injecting electrodes with a considerably higher work function.Y.Zhou,C.Fuentes-hernandez,J.Shim,J.Meyer,AJGiordano,H.Li,P.Winget,T.Papadopoulos,H.Cheun,J.Kim,M.Fenoll,A.Dindar, W.Haske,E.Najafabadi,TMKhan,H.Sojoudi,S.Barlow,S.Graham,J.Brédas,SRMarder,A.Kahn,B.Kippelen,Science(80-.).336(2012)327–332.The literature states that organic and printed electronics technologies require conductors with a sufficiently low work function to facilitate the transport of electrons in and out of various optoelectronic devices. For example, in a study (T. Takenobu, T. Takahashi, J. Takeya, Y. Iwasa, Appl. Phys. Lett. 90 (2007) 88–91.), p-type fluorene single crystals were used in OFETs. When gold, a high work function material, was used as the electrode, hole transport was good, but electron transport was poor; however, when calcium, a low work function material, was used as the electrode, electron transport in the OFET improved, but hole transport significantly deteriorated.

[0022] On the other hand, the work function of electrode materials, especially metallic materials, is related to the material's ability to lose electrons, i.e., its ability to be oxidized. The higher the work function, the less easily the material is oxidized, and the stronger its chemical stability when used as an electrode. From this perspective, the higher the work function of the electrode material, the better. For example, high work function electrode materials such as gold, platinum, and indium tin oxide also have excellent oxidation resistance, giving them a significant advantage in terms of air stability when used as electrodes; while low work function electrode materials such as calcium, cesium, barium, magnesium, aluminum, and silver are easily oxidized in air, causing problems such as decreased conductivity and increased resistance, and are therefore unsuitable for use as electrode materials in air.

[0023] In summary, high work function electrode materials exhibit good air stability, which extends their lifespan when used as electrodes, giving them an advantage in industrial applications. However, due to the unfavorable nature of high work function electrode materials for electron transport in OFETs, the following technical problems are currently prevalent: In OFETs composed of p-type materials, using high work function electrode materials as electrodes cannot achieve high μ values. p and μ n At the same time, it is impossible to make μ n With μ p quite.

[0024] In summary, to achieve good applications of complementary circuits and light-emitting transistors (LEDs), it is essential to achieve the coexistence of high hole mobility and high electron mobility in OFETs, as well as a good balance between the two. Currently, there are three main implementation methods:

[0025] 1. P-type and n-type materials are used to transport holes and electrons, respectively. However, compared with p-type materials, n-type materials generally have lower mobility and poorer air stability. Research on n-type materials is lagging behind, and there are fewer options available, which limits the development of applications such as complementary circuits and light-emitting transistors.

[0026] 2. Use bipolar materials that can simultaneously transport holes and electrons. However, bipolar materials have complex molecular structures, complicated synthesis steps, and a limited range of available materials, which increases the cost of industrial applications. Furthermore, the complex molecular structure is not conducive to the crystallization of bipolar material molecules, making it difficult to obtain high-performance single crystals to improve the mobility of OFETs.

[0027] 3. In OFETs using only p-type materials, low work function electrode materials, which are beneficial for electron transport, are used as source and drain electrodes to improve electron mobility. However, low work function electrode materials have poor air stability and are easily oxidized in air, affecting performance.

[0028] Using high work function electrode materials as source and drain electrodes, and employing only single-crystal p-type materials to obtain OFETs (this type of OFET is abbreviated as HM-p-OSC-FET), has significant advantages in application. HM-p-OSC-FETs have abundant material resources (p-type semiconductor materials are well-developed and diverse), excellent performance (single-crystal structure is conducive to high-performance carrier transport), and stable electrode performance, showing broad application prospects. However, due to the weak electron transport capability of p-type materials and the unfavorable effect of high work function electrode materials on electron transport in OFETs, HM-p-OSC-FETs generally suffer from low electron mobility and μ0. p and μ n Technical issues related to poor balance. Achieving high μ in HM-p-OSC-FET. n This can further expand its application scope, reduce the types of OFETs required in organic integrated circuits, thereby simplifying circuit design and fabrication processes, and improving circuit integration. This is of great significance for realizing the high integration, high performance and industrialization of organic integrated circuits.

[0029] The difficulty in achieving high electron mobility and balanced μ in HM-p-OSC-FETs p and μ n The existing technologies mainly address the following two problems:

[0030] Prior art 1:On the basis of a p-type organic semiconductor single crystal, an n-type semiconductor material capable of transporting electrons is deposited to form a double-layer heterojunction structure. (See Reference 1: Y. Zhang, H. Dong, Q. Tang, S. Ferrdous, F. Liu, SCB Mannsfeld, W. Hu, ALBriseno, Journal of the American Chemical Society. 132(2010) 11580–11584 and Reference 2: Fan C, Zoombelt AP, Hao J, et al. Advanced Materials, 2013, 25(40).) (The electron and hole mobilities in the above references are relatively low. In Reference 1, μ p and μ n They are only 0.07cm each. 2 V -1 s -1 and 0.05cm 2 V -1 s -1 In reference 2, μ p and μ n The highest value was only 0.29cm. 2 V -1 s -1 and 0.21cm 2 V -1 s -1However, this type of approach has the following problems: 1) It requires the deposition of two materials separately, which is complex and difficult to control; 2) Carrier transport in the upper material occurs at the heterojunction interface, which is difficult to control and is prone to various defects due to poor bonding between materials, affecting the performance of carrier transport and reducing the mobility of holes and electrons; 3) In addition, this method still uses n-type semiconductor materials, so the properties of n-type semiconductors still need to be studied, and the advantages of p-type semiconductors, which have many types and good performance, cannot be fully utilized. (X. Zhu, Y. Zhang, X. Ren, J. Yao, S. Guo, L. Zhang, D. Wang, G. Wang, is that the carrier mobilities are largely reduced in the bilayer p–njunctions due to the high density of defects and highroughness at the interface between the p-and n-type organic semiconductors, which is detrimental to charge transport).

[0031] Prior art 2: The work function of electrode materials can be altered by modifying electrodes with long-chain alkanes (self-assembled molecular monolayers, SAMs) containing reactive groups. (Cheng X, Noh YY, Wang J, et al. Advanced Functional Materials, 19.15(2009):2407-2415.) However, this method has the following problems: 1) It must be achieved through the reaction between the reactive groups and the electrode, and is only applicable when the electrode is deposited first and then the semiconductor is deposited; 2) The method of depositing the electrode first will affect the growth of the semiconductor single crystal, making it difficult to obtain high-quality organic single crystals and high-mobility OFETs. In the above case, the hole and electron mobilities of the FET are only 10. －3 cm 2 V-1 s -1 3) The reaction of self-assembled monolayers is complex and difficult to control, and the effect is easily affected by the generation of multiple modification layers or incomplete modification; 4) At present, it is only used in OFETs made of bipolar materials to improve the balance of carrier transport, and has not been used in OFETs made of p-type materials to improve electron mobility.

[0032] In summary, no existing technology has achieved high hole mobility and electron mobility, and a balance between hole mobility and electron mobility, such that the balance coefficient B ≤ 1, solely by using p-type organic semiconductor materials and high work function electrode materials. Summary of the Invention

[0033] To address the shortcomings of existing technologies, this invention provides an organic field-effect transistor and its fabrication method. The organic field-effect transistor features a simple structure, convenient fabrication, and low cost. It utilizes only well-developed p-type organic semiconductor materials and high work function electrode materials stable in air, avoiding the use of less developed n-type materials and low work function electrode materials easily oxidized by air. This organic field-effect transistor exhibits high hole and electron mobility, with a balanced ratio of B ≤ 1. It overcomes the technical bias that p-type organic semiconductor materials are unfavorable for electron transport and difficult to achieve high electron mobility. The use of high work function electrode materials extends the electrode's lifespan in air while maintaining high electron mobility. It also overcomes the technical bias that high work function conductive materials are unfavorable for improving electron mobility when used as OFET electrodes. This invention shows great promise for applications in organic complementary circuits and light-emitting transistors.

[0034] To address the existing problems of this invention, the present invention adopts the following technical solution:

[0035] This invention provides an organic field-effect transistor, which sequentially comprises a first conductive layer, an organic semiconductor layer, an insulating layer, and a second conductive layer;

[0036] The first conductive layer is composed of a conductive material with a work function of 4.5 eV or higher;

[0037] The organic semiconductor layer is composed of a p-type organic semiconductor single crystal;

[0038] The insulating layer is made of insulating material;

[0039] The second conductive layer is made of a material with a conductivity of 1 S / m or higher;

[0040] The organic field-effect transistor simultaneously satisfies: hole mobility μ p ≥0.5cm2 V -1 s -1 electron mobility μ n ≥0.5cm 2 V -1 s -1 And satisfying the balance coefficient B≤1, the formula for calculating the balance coefficient B is: B=|lg(μ p / μ n )|;

[0041] The organic field-effect transistor of this invention is composed of specific materials and a specific fabrication method to form a specific structure. To obtain an organic field-effect transistor with the technical effects of this invention, all of the following conditions must be strictly met: it sequentially comprises a first conductive layer, an organic semiconductor layer, an insulating layer, and a second conductive layer. The first conductive layer is composed of a conductive material with a work function of 4.5 eV or higher; the organic semiconductor layer is composed of a p-type organic semiconductor single crystal; the insulating layer is composed of an insulating material; and the second conductive layer is composed of a material with a conductivity of 1 S / m or higher. All of these conditions are indispensable. Only by simultaneously meeting all of these conditions can the overall synergistic effect be achieved to obtain the organic field-effect transistor of this invention, which uses a single p-type organic semiconductor material, and achieves good air stability in the first conductive layer and a hole mobility μ. p and electron mobility μ n At the same time ≥0.5cm 2 V -1 s -1 And the performance of the balance coefficient B≤1.

[0042] Furthermore, the first conductive layer, the insulating layer, and the second conductive layer are each independently selected from single-layer or multi-layer thin films.

[0043] In this design, the first conductive layer serves as the electrode of the OFET, typically comprising two separate electrodes: a source and a drain. It connects to the external circuit, bears voltage, and injects holes and electrons into the organic semiconductor layer. The work function of the electrode material constituting the first conductive layer is highly dependent on its oxidation resistance: a higher work function indicates stronger oxidation resistance and better stability in air. To ensure air stability, the work function of the electrode material constituting the first conductive layer must be above 4.5 eV. The work function of the electrode material can be calculated using ultraviolet photoelectron spectroscopy (UPS) data. The calculation formula is: Φ = hν - (E cutoff -E F Where Φ is the work function of the conductive material; hν is the photon energy provided by the instrument, which is 21.22 eV; E cutoff E represents the secondary electron cutoff edge data of the material obtained from the UPS spectrum; FThe Fermi edge data for the material is obtained from the UPS spectrum. For conductive samples with good contact with the instrument, the Fermi edge data is 0. Therefore, the work function of the electrode material is 21.22 - E. cutoff Preferably, the first conductive layer is a single-layer or multi-layer thin film composed of a high work function conductive material (work function above 4.5 eV).

[0044] The organic semiconductor layer is the core structure in an OFET, serving as the channel for electron and hole transport and acting as a current conductor. P-type organic semiconductor materials generally outperform n-type semiconductor materials in terms of performance, stability, and material availability; therefore, p-type organic semiconductor materials are chosen to construct the organic semiconductor layer. For the same organic semiconductor material, single-crystal aggregates exhibit the highest order, fewest defects and grain boundaries, minimal scattering during carrier transport, and the highest carrier transport performance. It has been proven that the long-range order of organic single crystals is highly beneficial for improving carrier mobility and exciton diffusion length, thereby enhancing the performance of organic electronics. Therefore, p-type organic semiconductor single crystals are selected as the organic semiconductor layer.

[0045] The insulating layer in the OFET serves to isolate the second conductive layer, which acts as the gate, from the first conductive layer and the organic semiconductor layer used for charge transmission, preventing the formation of a composite structure between the first conductive layer and the organic semiconductor layer, and forming a conductive path between the second conductive layer, thereby ensuring the normal operation of the OFET (see structure). Figure 4 Therefore, the materials used for the insulating layer need to have good insulating properties, that is, the insulating layer needs to be made of insulating materials. The insulating layer is selected from at least one of insulating polymers, insulating metal oxides, insulating non-metallic oxides or nitrides, and self-assembled small molecules; more preferably, the insulating polymer is selected from at least one of polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), polyvinyl acetate, polyimide (PI), polyvinylidene fluoride, polyvinylidene fluoride copolymer, polyvinylidene fluoride-trifluoroethylene-chlorofluoroethylene, polystyrene, poly-α-methylstyrene, polyvinylpyrrolidone, polyvinylphenol, poly(p-xylene), polybenzocyclobutene, perfluoro(1-butenyl vinyl ether) polymer, and cyanoethylprolane; more preferably, the insulating metal oxide is selected from at least one of alumina, titanium oxide, tantalum oxide, and hafnium oxide; more preferably, the insulating non-metallic oxide or nitride is selected from at least one of silicon dioxide and silicon nitride; more preferably, the self-assembled small molecule is selected from at least one of silane-containing self-assembled small molecules, phosphate-containing self-assembled small molecules, and thiol-containing self-assembled small molecules; preferably, the insulating layer is a single-layer or multi-layer thin film.

[0046] The polymers mentioned herein refer to cross-linked or non-cross-linked insulating polymers, the insulating metal oxides refer to metal oxides with insulating properties, and the non-metal oxides or nitrides refer to non-metal oxides or nitrides with insulating properties. It should be noted that metal oxide materials can be used in the insulating layer, the first conductive layer, and the second conductive layer. However, the metal oxides used in the insulating layer are insulating metal oxides with insulating properties, such as aluminum oxide, titanium oxide, tantalum oxide, and hafnium oxide, while the metal oxides used in the first or second conductive layer are conductive metal oxides with conductive properties, such as indium tin oxide and tungsten oxide. This distinction should be carefully observed.

[0047] The second conductive layer forms the gate of the OFET, providing the gate voltage and controlling the OFET to turn on or off. To ensure good conductivity of the second conductive layer, the conductivity of the material constituting the second conductive layer is required to be above 1 S / m. The second conductive layer is selected from at least one of a second metal, a second conductive metal oxide, a second conductive polymer, and a conductive inorganic non-metal. Preferably, the second metal is selected from a second elemental metal or a second metal alloy. Preferably, the second elemental metal is selected from at least one of gold, silver, copper, iron, aluminum, zinc, tin, titanium, platinum, chromium, cobalt, palladium, manganese, nickel, magnesium, lead, and gallium. More preferably, the second metal alloy is selected from an alloy of at least two of gold, silver, copper, iron, aluminum, zinc, tin, titanium, platinum, chromium, cobalt, palladium, manganese, nickel, magnesium, lead, and gallium. More preferably, the second conductive metal oxide is selected from at least one of indium tin oxide, tungsten oxide, vanadium oxide, ruthenium oxide, iron oxide, nickel oxide, zinc oxide, and silver oxide. More preferably, the second conductive polymer is selected from poly(3,4-ethylenedioxythiophene):polystyrene sulfonic acid. More preferably, the conductive inorganic non-metal is selected from at least one of silicon, graphite, carbon fiber, and carbon nanotubes. More preferably, the second conductive layer is a single-layer or multi-layer thin film. The mobility of an OFET is an important parameter characterizing its turn-on or turn-off speed. Under the same conditions, a higher mobility indicates a faster turn-on or turn-off speed and better OFET performance. Mobility μ can be expressed as hole mobility μ0. p and electron mobility μ n To characterize it. To ensure the performance of the OFET, the μ value of the OFET is required. p and μ n All ≥0.5cm 2 V -1 s -1 The balance coefficient B is a characterizing factor of μ in OFET. p and μ n A parameter indicating the degree of closeness. The formula for calculating the balance coefficient is: B = |lg(μ) p / μ nThe smaller B is, the closer the hole mobility and electron mobility are, and the better the balance between hole and electron transport; ideally, when B = 0, μ p =μ n A perfect balance between hole and electron transport is achieved. To ensure that OFETs can fully perform in common applications such as complementary circuits and light-emitting transistors, the B-value of the OFET must be ≤1.

[0048] Furthermore, the organic semiconductor layer is a single-crystal thin film composed of organic materials with a HOMO energy level ≥ -5.5 eV and a band gap width ≥ 1.8 eV. The HOMO energy level, short for "highest occupied molecular orbital," is an important parameter in organic semiconductor materials. Holes are transported at the HOMO energy level of the organic semiconductor. Organic semiconductor materials with excessively low HOMO energy levels are not conducive to hole transport when used in OFETs; therefore, the selected organic material must have a HOMO energy level ≥ -5.5 eV. The band gap width is the energy difference between the guide band bottom and the valence band top, also known as the band gap width. A suitable band gap width ensures the intrinsic characteristics of the organic semiconductor and enables field-effect modulation. A single-crystal thin film is a thin film composed of a single crystal or a single-crystal array. It can be composed of a single continuous single crystal with a relatively small thickness, or it can be composed of a single-crystal array composed of multiple single crystals.

[0049] Furthermore, the first conductive layer and the organic semiconductor layer contain polar organic small molecules with a dipole moment greater than 1 Debye (D); preferably, there is a layer of polar organic small molecules with a dipole moment greater than 1 Debye (D) between the first conductive layer and the organic semiconductor layer; preferably, the polar organic small molecule layer can reduce the electron injection barrier between the first conductive layer and the organic semiconductor layer by more than 0.05 eV.

[0050] In an organic field-controlled FET (OFET), holes and electrons are injected from the first conductive layer into the organic semiconductor layer. The effectiveness of hole and electron injection directly affects the measured hole and electron mobilities in the OFET. The injection effect is influenced by the degree of energy level matching between the materials of the first conductive layer and the organic semiconductor. All other things being equal, a better energy level match results in better hole or electron injection, which is more beneficial for improving the OFET's mobility. For OFETs composed of p-type organic semiconductor materials and high work function conductive materials, hole injection is relatively good, while electron injection is very poor. Therefore, OFETs generally exhibit hole mobility much higher than electron mobility, and sometimes electron mobility is even unmeasurable. Polar organic small molecules play a role in regulating the energy level structure at the interface between the first conductive layer and the organic semiconductor layer, lowering the barrier for electron injection from the first conductive layer into the organic semiconductor layer, thereby enabling a more balanced injection of electrons and holes from the first conductive layer into the organic semiconductor layer. The dipole moment introduced by polar organic small molecules is a crucial factor in achieving energy level modulation. For effective energy level modulation, the dipole moment of polar organic small molecules must be greater than 1 Debye (D). The unit of dipole moment is [Debye, D], where 1 D = 3.33 × 10⁻⁶. -30 Kulen Mi.

[0051] Preferably, forming a polar organic small molecule layer between the first conductive layer and the organic semiconductor layer means introducing more polar organic small molecules, which is more conducive to achieving the effect of polar organic small molecules regulating the energy level structure between the first conductive layer and the organic semiconductor layer. The first conductive layer and the organic semiconductor layer refer to the interface where the first conductive layer and the organic semiconductor layer are in contact.

[0052] The role of polar organic small molecules is to lower the injection barrier for electrons to enter the organic semiconductor layer from the first conductive layer, making it easier for electrons to enter the organic semiconductor layer from the first conductive layer, thereby achieving a balanced hole and electron transport. Preferably, the polar organic small molecule layer can reduce the electron injection barrier between the first conductive layer and the organic semiconductor layer by more than 0.05 eV.

[0053] The reduction in the electron injection barrier can be measured using Kelvin probe microscopy (KPFM). The specific testing method is as follows: First, conductive layer films and organic semiconductor layer films are prepared using the first conductive layer material and the organic semiconductor layer material, respectively. The Fermi levels EF1 and EF2 on the surfaces of the conductive layer film and the organic semiconductor layer film are then measured using KPFM. Next, the surfaces of the conductive layer film and the organic semiconductor layer film are treated with polar organic small molecules (the treatment method is the same as the method for introducing polar organic small molecules into an OFET). Subsequently, the Fermi levels EF1' and EF2' on the surfaces of the conductive layer film and the organic semiconductor layer film are measured again using KPFM. The reduction in the injection barrier Δ is calculated using the formula Δ = (EF1' - EF1) + (EF2 - EF2').

[0054] Furthermore, the polar organic small molecules with a dipole moment greater than 1D have a molecular weight of less than 50 Da. The molecular weight of a polar organic small molecule can be expressed by the number of atoms constituting the polar small molecule. 50 Da means that the total number of atoms constituting one polar organic small molecule is 50.

[0055] Furthermore, the aforementioned polar organic small molecules have a freezing point of less than 25°C under one atmosphere of pressure. The freezing point represents the highest temperature required for a substance to solidify: below the freezing point, the substance is solid; above the freezing point, the substance is liquid. The freezing point of a substance is related to the pressure of its environment. The fact that polar organic small molecules have a freezing point of less than 25°C under one atmosphere of pressure means that under normal atmospheric pressure and at temperatures above 25°C, these polar organic small molecules will definitely be in a liquid state.

[0056] Furthermore, the polar organic small molecule is selected from at least one of polar organic small molecules containing hydroxyl, cyano, carboxyl, mercapto, carbonyl, or amide groups; more preferably, the polar organic small molecule is selected from at least one of methanol, ethanol, propanol, isopropanol, butanol, ethylene glycol, formic acid, acetic acid, propionic acid, acetonitrile, acetaldehyde, ethanethiol, propanethiol, acetone, tetrahydrofuran, and N'N-dimethylformamide.

[0057] Further, the conductivity of the first conductive layer is greater than 1 S / m; preferably, the first conductive layer is selected from at least one of a first metal, a first conductive metal oxide, and a first conductive polymer; more preferably, the first metal is selected from at least one of a first elemental metal and a first metal alloy; more preferably, the first elemental metal is selected from at least one of gold, copper, platinum, chromium, cobalt, and palladium; more preferably, the first metal alloy is selected from an alloy of at least two of gold, copper, platinum, chromium, cobalt, and palladium; more preferably, the first conductive metal oxide is selected from at least one of indium tin oxide, tungsten oxide, vanadium oxide, and ruthenium oxide; more preferably, the first conductive polymer is selected from poly(3,4-ethylenedioxythiophene):polystyrene sulfonate;

[0058] Furthermore, the organic field-effect transistor may also include: an insulating substrate and / or a packaging layer; the insulating substrate is a surface-insulated substrate that serves as a support structure during the fabrication and use of the OFET, and can be a rigid or flexible structure. To avoid mutual interference caused by multiple OFETs fabricated on the same substrate, the substrate surface needs to be insulated. In some special cases, when the second conductive layer itself has a certain mechanical strength and can serve as a support, it may not contain an insulating substrate. For example, when using a heavily doped silicon wafer or a thick copper foil (which can conduct electricity) as the second conductive layer, since the second conductive layer itself is rigid and can serve as a support, an additional insulating substrate may not be needed. It should be noted that when using a heavily doped silicon wafer with an insulating oxide layer (the oxide layer is composed of silicon dioxide) on its surface, there are two situations. The first situation is that the conductive part of the heavily doped silicon wafer serves as the second conductive layer, and its surface oxide layer serves as an insulating layer, used as an electrical functional component of the OFET (distinct from the mechanical functional part that only serves as support). The second scenario involves using only a heavily doped silicon wafer containing an oxide layer as an insulating substrate. A conductive material and an insulating material are then deposited on this insulating substrate to form a second conductive layer and an insulating layer. Both of these scenarios are common. The insulating substrate is selected from at least one of the following: silicon wafers containing an oxide layer, glass, ceramics, insulating metal oxides, paper, or polymers. Preferably, the polymer is selected from at least one of polyethylene naphthalate, polyethylene terephthalate, polyetheretherketone, polyimide, polycarbonate, polyethersulfone resin, polyarylate, and polycyclic olefins. The encapsulation layer, being a polymer material, serves to protect the OFET.

[0059] The present invention also provides a method for fabricating an organic field-effect transistor, comprising the following steps:

[0060] 1) A second conductive layer and an insulating layer are sequentially deposited on the surface of an insulating substrate, and an organic semiconductor layer is deposited on the insulating layer;

[0061] The deposition method of the second conductive layer is selected from one or more of vapor deposition and solution deposition; the deposition method of the insulating layer is selected from one or more of vapor deposition, solution deposition, atomic layer deposition, and in-situ oxidation.

[0062] 2) The insulating substrate with the second conductive layer, insulating layer and organic semiconductor layer deposited is placed in a polar organic small molecule atmosphere for 10s to 2h to allow the polar organic small molecule liquid or vapor to fully contact the surface of the organic semiconductor layer. Then the insulating substrate with the second conductive layer, insulating layer and organic semiconductor layer deposited is separated from the polar organic small molecule atmosphere.

[0063] 3) A first conductive layer with a thickness of 30-1000 nm is deposited on the surface of the organic semiconductor layer as an electrode to obtain the organic field-effect transistor;

[0064] The first conductive layer is composed of a conductive material with a work function of 4.5 eV or higher;

[0065] The organic semiconductor layer is composed of a p-type organic semiconductor single crystal;

[0066] The insulating layer is made of insulating material;

[0067] The second conductive layer is made of a material with a conductivity of 1 S / m or higher;

[0068] Because p-type materials are not conducive to electron transport, and high work function electrode materials are not conducive to electron injection in OFETs, p-type organic field-effect transistors have low electron mobility and poor μp and μn balance. This invention precisely controls the overall preparation conditions, including the deposition order of the first conductive layer, organic semiconductor layer, insulating layer, and second conductive layer, selecting a high work function material as the first conductive layer, a p-type organic semiconductor single crystal as the semiconductor layer, an insulating material as the insulating layer, a material with a conductivity of 1 S / m or higher as the second conductive layer, and controlling the deposition thickness of the first conductive layer. Combined with the effects of polar organic small molecule treatment and precise control of the treatment time on the p-type organic semiconductor single crystal, an overall synergistic effect is formed to prepare the organic field-effect transistor with high hole mobility and high electron mobility, and a balance coefficient ≤1 as described in this invention.

[0069] Furthermore, the first conductive layer, the insulating layer, and the second conductive layer are each independently selected from single-layer or multi-layer thin films;

[0070] Preferably, in step 3), the deposition thickness is 30–100 nm; more preferably, the deposition thickness is 100 nm.

[0071] In step 1), the second conductive layer can be a metal, alloy, conductive metal oxide, or inorganic non-metal deposited by vapor deposition; it can also be metal nanoparticles or conductive polymers deposited by solution deposition; it can be highly doped silicon; or a combination of the above materials. The insulating layer can be an insulating metal oxide, non-metal oxide, or nitride deposited by chemical vapor deposition, atomic layer deposition, or in-situ oxidation; it can also be a polymer deposited by solution deposition or vapor deposition; it can also be a self-assembled small molecule obtained by solution deposition or vapor deposition; or a combination of the above materials. The insulating substrate surface refers to the smooth and flat side of the insulating substrate that has insulating properties. For insulating substrates with two identical surfaces (since the insulating substrates used are generally thin, only the two main surfaces are considered, not the side surfaces), any surface can be selected for material deposition and device fabrication; for insulating substrates with two different surfaces, the surface with better insulation and lower roughness should be selected for material deposition and device fabrication. In the same complete OFET structure, the second conductive layer, the insulating layer, the organic semiconductor layer, and the first conductive layer are all deposited on the same side surface of the insulating substrate; while when fabricating multiple OFETs, different OFETs can be fabricated on different surfaces of the same insulating substrate.

[0072] Both the second conductive layer and the insulating layer can be single-layer or multi-layer structures. When using heavily doped silicon with an oxide layer on its surface, an insulating substrate can be omitted, and the conductive portion of the heavily doped silicon can be used directly as the second conductive layer. The oxide layer (silicon dioxide) on the surface of the heavily doped silicon can be used as the insulating layer. Polymers and self-assembled small molecular layers can also be modified on the silicon dioxide surface to form a multi-layer insulating layer. p-type organic semiconductor single crystals can be directly deposited on the substrate surface through in-situ growth, or they can be grown elsewhere first and then transferred to the substrate surface through a transfer method. p-type organic semiconductor single crystals can be obtained through solution methods and vapor phase methods.

[0073] In step 2), to ensure the presence of polar organic molecules on the surface of the p-type organic semiconductor single crystal, the polar organic molecules must first come into contact with the surface of the organic semiconductor single crystal before the polar organic molecule liquid on the surface of the organic semiconductor single crystal is removed. Methods for bringing the polar organic molecules into contact with the surface of the organic semiconductor single crystal include droplet contact and vapor contact. Droplet contact involves adding the polar organic molecule liquid to the surface of the organic semiconductor single crystal through methods such as dripping, spraying, printing, soaking, or rinsing, ensuring the surface of the organic semiconductor single crystal is completely covered by the polar organic molecule liquid to achieve sufficient contact. Vapor contact involves evaporating the polar organic molecule liquid into vapor, placing the organic semiconductor single crystal in a vapor atmosphere of polar organic molecules, thus ensuring sufficient contact between the surface of the organic semiconductor single crystal and the polar organic molecules. For the droplet contact method, the organic semiconductor single crystal and the polar organic small molecule atmosphere can be separated by spin coating, natural drying, gas purging, etc.; for the vapor contact method, the organic semiconductor single crystal and the polar organic small molecule atmosphere can be separated by removing the organic semiconductor single crystal from the vapor atmosphere and then naturally drying.

[0074] In step 3), the first conductive layer can be directly deposited on the surface of an organic semiconductor single crystal by physical vapor deposition (including vacuum evaporation, sputtering, ion plating), chemical vapor deposition, solution printing, or indirectly deposited by transferring an existing conductive material film to the surface of an organic semiconductor single crystal.

[0075] Because p-type materials are not conducive to electron transport, and high work function electrode materials are not conducive to electron injection in OFETs, p-type organic field-effect transistors have low electron mobility and poor μp and μn balance. This invention focuses on the overall fine control of the deposition order of the first conductive layer, organic semiconductor layer, insulating layer, and second conductive layer. It selects high work function material as the first conductive layer, p-type organic semiconductor single crystal as the semiconductor layer, insulating material as the insulating layer, material with conductivity above 1 S / m as the second conductive layer, and controls the deposition thickness of the first conductive layer. Combined with the treatment of polar organic small molecules and the precise control of the treatment time to regulate the p-type organic semiconductor single crystal, the organic field-effect transistor with high hole mobility and high electron mobility and balance coefficient ≤1 described in this invention can be prepared.

[0076] The present invention also provides an optoelectronic device: the optoelectronic device includes an organic field-effect transistor as described above, and the optoelectronic device is selected from light-emitting transistors, memory, sensors, and displays.

[0077] The present invention also provides an organic circuit: the organic circuit includes organic field-effect transistors as described above, and the organic circuit is selected from at least one circuit combination of gate circuits, combinational logic circuits, sequential logic circuits, and amplifier circuits.

[0078] The present invention also provides an optoelectronic integrated array, which includes one or more optoelectronic devices and organic circuits as described above. (e.g.) Figure 3 (As shown).

[0079] Furthermore, the organic field-effect transistors, the organic field-effect transistor fabrication methods, the optoelectronic devices, the organic circuits, and the optoelectronic integrated arrays described above are used in semiconductor devices, transportation and logistics, mining and metallurgy, environment, medical devices, explosion-proof detection, food, water treatment, pharmaceuticals, and biological fields.

[0080] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0081] 1) Overcoming technological bias, for the first time, an organic field-effect transistor with high hole mobility and electron mobility in balance was obtained using p-type organic semiconductor single crystals and high work conductivity materials, resulting in a hole mobility μ p ≥0.5cm 2 V -1 s -1 electron mobility μ n ≥0.5cm 2 V -1 s -1 And satisfy the balance coefficient B≤1;

[0082] 2) The use of mature, diverse, and high-performance p-type organic semiconductor single crystal materials enables organic field-effect transistors to achieve high hole mobility and high electron mobility with convenient material availability, and achieves a balance between hole and electron transport, overcoming the technical bias that p-type organic semiconductor materials are not conducive to electron transport and are difficult to obtain high electron mobility.

[0083] 3) High work function conductive materials with good stability in air are used as electrodes, which achieves high electron mobility while extending the service life of the electrodes in the air environment. This overcomes the technical bias that high work function conductive materials are not conducive to improving electron mobility when used as OFET electrodes. Attached Figure Description

[0084] Figure 1 The diagram shows the OFET structure and its transfer characteristics. Figure 1 (a) in the diagram is a cross-sectional view showing the OFET structure; Figure 1(b) is a top view of the OFET, from which the channel length L and channel width W can be measured; Figure 1 (c) in the figure is the n-type transfer characteristic curve, which can be used to calculate the electron mobility μ. n ; Figure 1 (d) in the figure represents the p-type transfer characteristic curve, which can be used to calculate the hole mobility μ. p ;

[0085] Figure 2 The diagram shows the structures of organic semiconductor molecules DPP(a) and DPP-F2(b) (Cai, Z., Luo, H., Chen, X., Zhang, G., Liu, Z., & Zhang, D. Chemistry–An Asian Journal, 2017, 9(4), 1068-1075.). It can be seen that the DPP-F2 molecule is obtained by complex modification of DPP.

[0086] Figure 3 This is a schematic diagram illustrating the effect of the optoelectronic integrated array of the present invention;

[0087] Figure 4 This is a schematic diagram of an organic field-effect transistor, which sequentially includes a first conductive layer, an organic semiconductor layer, an insulating layer, and a second conductive layer.

[0088] Figure 5 The measured ultraviolet photoelectron spectrum of gold;

[0089] Figure 6 The images show (a) an optical microscope image and (b) a microscope image under orthogonally polarized light of the TIPS-pentacene single crystal array of Example 1.

[0090] Figure 7 (a) is an optical microscope image of the OFET in Example 1, which can be used to calculate the channel length L and channel width W; Figure 7 (b) in the figure shows the case where the semiconductor layer does not completely cover the electrode confinement area. In this case, W should be based on the actual semiconductor range.

[0091] Figure 8 This is a graph showing the transfer characteristics of Example 1. Figure 8 (a) in the figure is a p-type transfer characteristic curve, which can be used to calculate hole mobility. Figure 8 (b) in the figure is the transfer characteristic curve under n-channel, which can be used to calculate electron mobility;

[0092] Figure 9 This is a single-crystal optical microscope image of TIPS-pentacene from Example 2;

[0093] Figure 10 The graph shows the change in resistance of the first conductive layer material in Comparative Example 1 and Example 1 before and after exposure to air. Figure 10 In Figure (a), the resistance of the first conductive layer (calcium) in Comparative Example 1 before exposure to air is 22 Ω. Figure 10 In Figure (b), the resistance of the first conductive layer in Comparative Example 1 after 5 minutes of exposure to air is 8810 Ω. Figure 10 In Figure (c), the resistance of the first conductive layer (gold) before being exposed to air in Example 1 is 15Ω. Figure 10 In the figure (d), the resistance of the first conductive layer after 5 minutes of exposure to air in Example 1 is 17Ω;

[0094] Figure 11 This is an optical microscope image of the organic semiconductor single crystal in Comparative Example 2. Figure 11 (a) shows TIPS-pentacene single crystal and C60 single crystal. Figure 11 (b) in the figure represents a C60 single crystal that has not been exposed to TIPS-pentacene solution;

[0095] Figure 12 Image (a) in the image is an optical microscope image of the TIPS-pentacene polycrystalline thin film in Comparative Example 3. Figure 12 (b) in the figure is the transfer characteristic curve of the OFET in Comparative Example 3;

[0096] Figure 13 (a) in the figure is the p-type transfer characteristic curve of the OFET in Comparative Example 4; Figure 13 (b) in the figure is the n-type transfer characteristic curve of the OFET in Comparative Example 4. Detailed Implementation

[0097] The present invention will now be described in detail with reference to the embodiments and accompanying drawings. It should be noted that the following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0098] It should be noted that the thickness of the material used in the following embodiments is an optimized thickness or a commercially available material specification, and is not the only choice, nor is it intended to limit the scope of the present invention.

[0099] like Figure 4As shown, this invention provides an organic field-effect transistor, comprising, in sequence, a first conductive layer, an organic semiconductor layer, an insulating layer, and a second conductive layer. The first conductive layer is composed of a conductive material with a work function of 4.5 eV or higher. The organic semiconductor layer is composed of a p-type organic semiconductor single crystal. The insulating layer is composed of an insulating material. The second conductive layer is composed of a material with a conductivity of 1 S / m or higher. The organic field-effect transistor simultaneously satisfies the following conditions: hole mobility μ... p ≥0.5cm 2 V -1 s -1 Electron migration μ n ≥0.5cm 2 V -1 s -1 And satisfying the balance coefficient B≤1, the formula for calculating the balance coefficient B is: B=|lg(μ p / μ n )|.

[0100] Furthermore, the organic semiconductor layer is selected from any one of polycyclic aromatic hydrocarbons, sulfur-containing heterocyclic aromatic hydrocarbons, nitrogen-containing heterocyclic aromatic hydrocarbons, and their respective derivatives; more preferably, the polycyclic aromatic hydrocarbon is selected from any one of benzo[a]benzene, dinaphthalene-benzene, diphenylanthracene, and red fluorene; the sulfur-containing heterocyclic aromatic hydrocarbon is selected from any one of oligothiophene, benzothiophene, and tetrathiofulvalene; the nitrogen-containing heterocyclic aromatic hydrocarbon is selected from any one of metal phthalocyanine and metal porphyrin; more preferably, the organic semiconductor layer is a thin film made of an organic single crystal material with a HOMO energy level ≥ -5.5 eV and a band gap width ≥ 1.8 eV.

[0101] Further, the insulating layer is selected from at least one of insulating polymers, insulating metal oxides, insulating non-metallic oxides or nitrides, and self-assembled small molecules; more preferably, the insulating polymer is selected from at least one of polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), polyvinyl acetate, polyimide (PI), polyvinylidene fluoride, polyvinylidene fluoride copolymer, polyvinylidene fluoride-trifluoroethylene-chlorofluoroethylene, polystyrene, poly-α-methylstyrene, polyvinylpyrrolidone, polyvinylphenol, poly(p-xylene), polybenzocyclobutene, perfluoro(1-butenyl vinyl ether) polymer, and cyanoethylprolane; more preferably, the insulating metal oxide is selected from at least one of alumina, titanium oxide, tantalum oxide, and hafnium oxide; more preferably, the insulating non-metallic oxide or nitride is selected from at least one of silicon dioxide and silicon nitride; more preferably, the self-assembled small molecule is selected from at least one of silane-containing self-assembled small molecules, phosphate-containing self-assembled small molecules, and thiol-containing self-assembled small molecules;

[0102] Further, the second conductive layer is selected from at least one of a second metal, a second conductive metal oxide, a second conductive polymer, and a conductive inorganic non-metal; preferably, the second metal is selected from a second elemental metal or a second metal alloy; preferably, the second elemental metal is selected from at least one of gold, silver, copper, iron, aluminum, zinc, tin, titanium, platinum, chromium, cobalt, palladium, manganese, nickel, magnesium, lead, and gallium; more preferably, the second metal alloy is selected from an alloy of at least two of gold, silver, copper, iron, aluminum, zinc, tin, titanium, platinum, chromium, cobalt, palladium, manganese, nickel, magnesium, lead, and gallium; more preferably, the second conductive metal oxide is selected from at least one of indium tin oxide, tungsten oxide, vanadium oxide, ruthenium oxide, iron oxide, nickel oxide, zinc oxide, and silver oxide; more preferably, the second conductive polymer is selected from poly(3,4-ethylenedioxythiophene):polystyrene sulfonic acid; more preferably, the conductive inorganic non-metal is selected from at least one of silicon, graphite, carbon fiber, and carbon nanotubes; more preferably, the second conductive layer is a single-layer or multi-layer thin film.

[0103] The polar organic small molecule is selected from at least one of polar organic small molecules containing hydroxyl, cyano, carboxyl, mercapto, carbonyl, and amide groups; more preferably, the polar organic small molecule is selected from at least one of methanol, ethanol, propanol, isopropanol, butanol, ethylene glycol, formic acid, acetic acid, propionic acid, acetonitrile, acetaldehyde, ethanethiol, propanethiol, acetone, tetrahydrofuran, and N'N-dimethylformamide; more preferably, a polar organic small molecule layer with a dipole moment greater than 1D exists between the first conductive layer and the organic semiconductor layer; more preferably, the polar organic small molecule layer can reduce the electron injection barrier between the first conductive layer and the organic semiconductor layer by more than 0.05 eV.

[0104] Organic single-crystal thin films can be detected using instruments that analyze fine structures, such as optical microscopes with orthogonal polarizers, atomic force microscopes, scanning electron microscopes, transmission electron microscopes, laser confocal Raman spectrometers, and single-crystal diffractometers. The energy level structures of conductive materials and organic semiconductor materials can be analyzed using instruments such as Kelvin probe microscopes, ultraviolet photoelectron spectrometers, angle-resolved photoelectron spectrometers, ultraviolet absorption spectroscopy, conductivity methods, and functional theory calculations. The structures of semiconductor devices can be detected using optical microscopes, atomic force microscopes, scanning electron microscopes, and transmission electron microscopes. The relevant performance of semiconductor devices can be detected using instruments that analyze photoelectric properties, such as semiconductor parameter analyzers, Hall effect testers, scanning probe microscopes, ferroelectric testers, quantum efficiency testers, transient spectrometers, solar cell testers, photoelectric detection systems, micro-fluorescence spectrometers, spectrometers, and conductivity measurement systems.

[0105] To characterize the work function of the first conductive layer, ultraviolet photoelectron spectroscopy was used. To characterize the morphology of the organic semiconductor single crystal, optical microscopy was used. To characterize the hole mobility, electron mobility, and equilibrium coefficient of the fabricated OFET, characteristic curves of the OFET were obtained using a semiconductor parameter analyzer, and calculations were performed using the mobility and equilibrium coefficient calculation formulas.

[0106] Example 1

[0107] An organic field-effect transistor based on p-type organic semiconductor single crystal 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) single crystal and gold, and its fabrication method, comprising the following steps:

[0108] (1) Take a p-type heavily doped material with a thickness of 525 μm. <100> Silicon wafer (with 300nm thick silicon dioxide on it).

[0109] A 10 nm PMMA polymer film was obtained by spin-coating a PMMA solution onto a silicon dioxide surface; TIPS-pentacene single crystals were then deposited on the silicon wafer surface with the deposited PMMA polymer film using a solution method.

[0110] (2) Add ethanol to the silicon wafer with deposited TIPS-pentacene single crystals to make the ethanol cover the crystal surface; spin coat to remove the ethanol liquid.

[0111] (3) A 100 nm gold layer was deposited on the crystal surface as the first conductive layer using vacuum evaporation. An OFET based on TIPS-pentacene single crystal as the semiconductor layer and gold as the source and drain electrodes was fabricated.

[0112] In this embodiment, heavily doped silicon can be directly used as the second conductive layer, and a bilayer structure (SiO2-PMMA) consisting of a 300nm thick silicon dioxide layer (SiO2) on the silicon wafer surface and a spin-coated PMMA polymer film serves as the insulating layer. TIPS-pentacene single crystal serves as the organic semiconductor layer, and a 100nm thick gold layer obtained by vacuum evaporation serves as the first conductive layer.

[0113] The work function of gold, used as the first conductive layer, was measured using ultraviolet photoelectron spectroscopy (UV PES). A gold thin film was first deposited on a substrate with good conductivity, and then the UV PES spectrum was measured using a UV PES spectrometer. The cutoff edge energy E can be obtained from the spectrum. cutoff and Fermi edge energy E F ,like Figure 5 As shown. The work function Φ of a metal can be calculated using the following formula: Φ = hν - (E cutoff -E FWhere hv is the ultraviolet light energy emitted by the instrument, which is 21.22 eV. For metal samples with good electrical contact with the instrument, E... F =0. From Figure 5 The work function of gold, obtained from the ultraviolet photoelectron spectrum and combined with the formula, is calculated to be Φ = 21.22 - 16.14 = 5.08 eV. Using KPFM to test the injection barrier change, the electron injection barrier decreased by 0.1 eV before and after treatment of the organic semiconductor single crystal and the gold surface with ethanol.

[0114] The identification and morphology of organic semiconductor single crystals can be characterized using an optical microscope equipped with orthogonal polarizers. The highly ordered molecular arrangement in organic semiconductor single crystals gives them regular edges and geometric morphologies, and they often exhibit anisotropy in optical and other properties, with uniform color changes observable under orthogonally polarized light. Figure 6 (a) shows a single-crystal array composed of multiple TIPS-pentacene single crystals, exhibiting regular edges and a regular geometric morphology, and displaying [unclear] under orthogonally polarized light. Figure 6 The uniform color change shown in (b) indicates that it is an organic single crystal array.

[0115] The dipole moments of the polar organic small molecules used are basic structural parameters of the polar organic small molecules, which can be easily obtained by consulting literature or solvent handbooks. The results are shown in Table 1.

[0116] The mobility μ of an OFET can be calculated using the following formula:

[0117]

[0118] Where L is the length of the OFET channel and W is the width of the OFET channel, which can be obtained from an OFET image obtained by an optical microscope (e.g., ...). Figure 7 (as shown in (a)). When the semiconductor layer does not completely cover the area between the electrodes, W should be taken as the actual width of the semiconductor layer (e.g., ...). Figure 7 (as shown in (b)). C i The gate insulating layer capacitance can be measured using a semiconductor parameter analyzer with capacitance analysis capabilities. The transfer characteristic curves of the field-effect transistor operating in the saturation region can be obtained by testing them. The p-type and n-type transfer characteristic curves of the OFET in Example 1, measured by a semiconductor analyzer, are shown below. Figure 8 As shown in (a) and (b) in the figure. The transfer characteristic curves are used to obtain... Curve, and then according to The slope of the curve can be obtained for both p-type and n-type curves. Finally, by combining the relevant parameters of the OFET, μ can be calculated.p =0.85cm 2 V -1 s -1 μ n =1.05cm 2 V -1 s -1 ;

[0119] According to μ p and μ n We can use B = |lg(μ) p / μ n The calculated balance parameter B for this OFET is 0.09. It should also be noted that... Figure 8 The transfer characteristic curves shown exhibit a distinct V-shape. The appearance of a V-shaped curve is an indicator that the OFET can exhibit both hole and electron transport. When the curve lacks a V-shaped characteristic, it can be determined that the OFET can only transport one type of carrier.

[0120] Example 2

[0121] An organic field-effect transistor based on p-type organic semiconductor single crystal 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) single crystal and gold, and its fabrication method, comprising the following steps:

[0122] (1) Take a p-doped material with a thickness of 525 μm. <100> A silicon wafer (with a 300nm thick silicon dioxide layer) is used. A 50nm aluminum layer is deposited on the silicon wafer surface as a second conductive layer; subsequently, a 300nm poly(p-xylene) thin film is deposited on the substrate surface using vapor deposition; and TIPS-pentacene single crystals are deposited on the pentacene surface using a solution method.

[0123] (2) Add methanol to the silicon wafer on which TIPS-pentacene single crystals are deposited, so that the methanol covers the crystal surface; use nitrogen to purge the substrate surface to remove the residual methanol liquid.

[0124] (3) A 100 nm gold layer was deposited on the crystal surface as the first conductive layer using vacuum evaporation. An OFET based on TIPS-pentacene single crystal as the semiconductor layer and gold as the source and drain electrodes was fabricated.

[0125] Example 2 demonstrates the use of a TIPS-pentacene single crystal with a morphology different from that in Example 1, as shown in the figure. Figure 9 As shown. The regular edges and consistent geometric shape make it easily identifiable as a single crystal. It should be noted that, regardless of... Figure 6 The single-crystal array in the middle is composed of multiple organic semiconductor single crystals, or... Figure 9All individual organic semiconductor single crystals mentioned above fall within the scope of organic semiconductor single crystals. The characterization method for the structure and performance of the OFET constructed from TIPS-pentacene single crystals is the same as that used in Example 1. The obtained device-related parameters and performance are shown in Table 1.

[0126] Example 3

[0127] An organic field-effect transistor based on p-type organic semiconductor single crystal pentacene single crystal and platinum, and its fabrication method, includes the following steps:

[0128] (1) A 50 nm aluminum layer was deposited as a second conductive layer on a smooth glass insulating substrate. Subsequently, a 30 nm aluminum oxide film was deposited on the aluminum-deposited insulating substrate using atomic layer deposition. The substrate was then placed in a solution of phosphate-based self-assembled small molecules, allowing the self-assembled small molecules to react with the aluminum oxide surface to form a self-assembled layer. The pentacene single crystals grown by physical vapor transport were transferred to the substrate surface using a microprobe.

[0129] (2) Place the glass substrate with pentacene single crystals deposited on its surface in a sealed container filled with acetone vapor atmosphere and leave it for 2 hours to allow acetone molecules to fully contact the pentacene single crystal surface. Remove the substrate and let it stand in the air for 2 minutes to dry.

[0130] (3) A 100 nm platinum layer was deposited on the crystal surface as the first conductive layer using vacuum sputtering. An OFET based on pentacene single crystal as the semiconductor layer and platinum as the source and drain electrodes was fabricated.

[0131] The characterization methods for structure and performance are the same as those in Example 1. The obtained device-related parameters and performance are shown in Table 1.

[0132] Example 4

[0133] An organic field-effect transistor based on p-type organic semiconductor single-crystal red fluorene and platinum, and its fabrication method, comprising the following steps:

[0134] (1) Take a p-type heavily doped material with a thickness of 525 μm. <100> A silicon wafer (with 300 nm thick silicon dioxide) is used. A 2 nm titanium and a 50 nm gold layer are deposited on the silicon wafer surface as a second conductive layer. Subsequently, a 200 nm layer containing cross-linked polystyrene monomer is deposited on the surface of the silicon wafer with deposited titanium and gold using a solution method. Then, the single crystal is cross-linked by thermal cross-linking to obtain a cross-linked polystyrene insulating layer. Red fluorene single crystals are grown using physical vapor transport and transferred to the surface of the insulating layer using microprobe manipulation.

[0135] (2) Immerse the substrate with the deposited red fluorene single crystal in ethanethiol for 10 seconds and then remove it quickly. Allow the substrate to air dry.

[0136] (3) A 100 nm platinum layer was deposited on the crystal surface as the first conductive layer using vacuum sputtering. An OFET based on rubrene single crystal as the semiconductor layer and platinum as the source and drain electrodes was fabricated.

[0137] The characterization methods for structure and performance are the same as those in Example 1. The obtained device-related parameters and performance are shown in Table 1.

[0138] Example 5

[0139] An organic field-effect transistor based on p-type organic semiconductor single crystal tetrathiofulvalene and gold, and its fabrication method, includes the following steps:

[0140] (1) Using a smooth polyimide flexible film as an insulating substrate, a 30 nm gold layer was deposited on the substrate surface as a second conductive layer; subsequently, a 300 nm polyvinyl alcohol film was deposited on the substrate surface using a solution method, and a 20 nm PMMA film was then deposited using a solution method. Tetrathiofulvalene single crystals were grown using physical vapor transport, and the single crystals were transferred to the substrate surface on which the second conductive layer and the insulating layer were deposited by microprobe manipulation.

[0141] (2) Acetaldehyde droplets are sprayed onto the surface of tetrathiofulvalene single crystal by spraying. Spin coating is performed at the same time as spraying so that the spray droplets can be evenly distributed on the single crystal surface, fully contact the single crystal surface, and dry quickly.

[0142] (3) A 100 nm gold layer was deposited on the crystal surface as the first conductive layer using vacuum evaporation. An OFET based on tetrathiofulvalene single crystal as the semiconductor layer and gold as the source and drain electrodes was fabricated.

[0143] The characterization methods for structure and performance are the same as those in Example 1. The obtained device-related parameters and performance are shown in Table 1.

[0144] Example 6

[0145] An organic field-effect transistor based on p-type organic semiconductor single-crystal copper phthalocyanine single crystal and gold, and its fabrication method, comprising the following steps:

[0146] (1) Using glass as an insulating substrate, indium tin oxide was deposited on the glass as a second conductive layer. A 500 nm polyimide film was deposited on the substrate surface using a solution thermal crosslinking method. Copper phthalocyanine single crystals were grown using a physical vapor transport method and transferred to the surface of the polyimide film using a microprobe.

[0147] (2) Drop formic acid onto the surface of copper phthalocyanine single crystal, so that the liquid covers the surface of the single crystal, and spin-coat to dry the formic acid droplets.

[0148] (3) A 30 nm gold layer was deposited on the crystal surface using vacuum evaporation as the first conductive layer. An OFET based on copper phthalocyanine single crystal as the semiconductor layer and gold as the source and drain electrodes was fabricated.

[0149] The characterization methods for structure and performance are the same as those in Example 1. The obtained device-related parameters and performance are shown in Table 1.

[0150] Example 7

[0151] An organic field-effect transistor based on p-type organic semiconductor single crystal 2,7-dioctyl[1]benzothiophene[3,2-b][1]benzothiophene (C8-BTBT) single crystal and gold, and its fabrication method, comprising the following steps:

[0152] (1) A 50 nm silver layer was deposited on a glass surface, and a PMMA solution containing dispersed titanium dioxide nanoparticles was spin-coated onto the silver-deposited glass surface to obtain a 500 nm titanium dioxide / PMMA hybrid insulating layer. A C8-BTBT single crystal array was directly grown on the substrate surface by solution method.

[0153] (2) Add propanol droplets onto the C8-BTBT single crystal to cover the surface of the single crystal, and spin-coat to dry the propanol droplets.

[0154] (3) A 100 nm gold layer was deposited on the crystal surface as the first conductive layer using vacuum evaporation. An OFET based on C8-BTBT single crystal as the semiconductor layer and gold as the source and drain electrodes was fabricated.

[0155] The characterization methods for structure and performance are the same as those in Example 1. The obtained device-related parameters and performance are shown in Table 1.

[0156] Example 8

[0157] An organic field-effect transistor based on p-type organic semiconductor single crystal perylene and copper, and its fabrication method, comprising the following steps:

[0158] (1) Take a p-type heavily doped material with a thickness of 525 μm. <100> A silicon wafer (with 300 nm thick silicon dioxide) is used. A polyvinylpyrrolidone solution containing a crosslinking agent is spin-coated onto the silicon dioxide surface, and thermal crosslinking is performed to obtain a 50 nm crosslinked polyvinylpyrrolidone film. A perylene single crystal array is grown on the crosslinked polyvinylpyrrolidone film using a solution method.

[0159] (2) Add tetrahydrofuran to the silicon wafer with perylene single crystal deposited, so that the tetrahydrofuran covers the crystal surface; spin-coat to remove dimethyl sulfoxide liquid.

[0160] (3) A 100 nm copper layer was deposited on the crystal surface using vacuum evaporation as the first conductive layer. An OFET based on perylene single crystal as the semiconductor layer and gold as the source and drain electrodes was fabricated.

[0161] The characterization methods for structure and performance are the same as those in Example 1. The obtained device-related parameters and performance are shown in Table 1.

[0162] Example 9

[0163] An organic field-effect transistor based on p-type organic semiconductor single crystal TIPS-pentacene single crystal and PEDOT:PSS and its fabrication method thereof includes the following steps:

[0164] (1) A smooth, flexible polyester film was used as an insulating substrate. A PEDOT:PSS film was deposited on the surface of the polyester film using solution printing. A 200 nm thick polyvinylphenol film was deposited on the substrate using solution spin coating. Subsequently, a PMMA solution containing a crosslinking agent was spin-coated, and a 100 nm thick crosslinked PMMA film was obtained by thermal crosslinking. A TIPS-pentacene single-crystal array was grown on the surface of the PMMA film using solution processing.

[0165] (2) Add acetonitrile to the substrate on which TIPS-pentacene single crystals are deposited, so that the acetonitrile covers the crystal surface; spin-coat to remove the acetonitrile liquid.

[0166] (3) PEDOT:PSS was deposited on the crystal surface as the first conductive layer using solution printing. An OFET based on TIPS-pentacene as the semiconductor layer and PEDOT:PSS as the source and drain electrodes was fabricated.

[0167] The characterization methods for structure and performance are the same as those in Example 1. The obtained device-related parameters and performance are shown in Table 1.

[0168] Example 10

[0169] An organic field-effect transistor based on p-type organic semiconductor single crystal 2,9-disacyldinaphthalene-[2,3-b:2,3-f]thiophene[3,2-b]thiophene (C10-DNTT) single crystal and gold, and its fabrication method, comprising the following steps:

[0170] (1) Glass was used as an insulating substrate, and gold was deposited on the substrate surface as a second conductive layer by vacuum evaporation. A 200 nm polyvinylidene fluoride copolymer was deposited on the gold surface as an insulating layer by solution spin coating. A C10-DNTT single crystal array was obtained by solution growth, and then the C10-DNTT single crystal array was transferred to the surface of the insulating substrate on which gold and polyvinylidene fluoride copolymer were deposited by template transfer.

[0171] (2) Add methanol to the substrate on which C10-DNTT single crystal array is deposited, so that methanol covers the crystal surface; spin-coat to remove the methanol liquid.

[0172] (3) A 1000 nm gold layer was deposited on the crystal surface using vacuum deposition as the first conductive layer. An OFET based on C10-DNTT single crystal as the semiconductor layer and gold as the source and drain electrodes was fabricated.

[0173] The characterization methods for structure and performance are the same as those in Example 1. The obtained device-related parameters and performance are shown in Table 1.

[0174] Example 11

[0175] An organic field-effect transistor based on p-type organic semiconductor single crystal perylene and gold / tungsten oxide and its fabrication method.

[0176] The organic field-effect transistor fabrication method in Example 11 is the same as in Example 3. The structural and performance characterization methods are the same as in Example 1. The material selection formulations are shown in Table 2, and the resulting OFET performance is shown in Table 3. Gold / tungsten oxide was deposited using a vacuum evaporation method.

[0177] Example 12

[0178] An organic field-effect transistor based on p-type organic semiconductor single crystal TIPS-pentacene single crystal and platinum / vanadium oxide and its fabrication method.

[0179] The organic field-effect transistor fabrication method in Example 12 is the same as in Example 3. The structural and performance characterization methods are the same as those in Example 1. The material selection and formulation are shown in Table 2, and the performance of the obtained OFET is shown in Table 3.

[0180] Example 13

[0181] An organic field-effect transistor based on p-type organic semiconductor single crystal and tetraphenylene single crystal and indium tin oxide and its fabrication method.

[0182] The organic field-effect transistor fabrication method in Example 13 is the same as in Example 6. The structural and performance characterization methods are the same as in Example 1. The material selection formulations are shown in Table 2, and the resulting OFET performance is shown in Table 3. Indium tin oxide was deposited by a transfer method.

[0183] Example 14

[0184] An organic field-effect transistor based on p-type organic semiconductor single crystal 2,8-difluoro-5,11-bis[2-(triethylsilyl)ethynyl]-anthraquinone dithiophene single crystal and cobalt, and its fabrication method.

[0185] The fabrication method of the organic field-effect transistor in Example 14 is the same as that in Example 8. The structural and performance characterization methods are the same as those in Example 1. The material selection and formulation are shown in Table 2, and the performance of the obtained OFET is shown in Table 3.

[0186] Example 15

[0187] An organic field-effect transistor based on p-type organic semiconductor single-crystal red fluorene single crystal and palladium and its fabrication method.

[0188] The organic field-effect transistor fabrication method in Example 15 is the same as in Example 6. The structural and performance characterization methods are the same as those in Example 1. The material selection and formulation are shown in Table 2, and the performance of the obtained OFET is shown in Table 3.

[0189] Example 16

[0190] An organic field-effect transistor based on p-type organic semiconductor single crystal copper phthalocyanine and chromium-gold alloy and its fabrication method.

[0191] The organic field-effect transistor fabrication method in Example 16 is the same as in Example 8. The structural and performance characterization methods are the same as in Example 1. The material selection and formulation are shown in Table 2, and the performance of the obtained OFET is shown in Table 3.

[0192] Examples 17-30

[0193] An organic field-effect transistor and its fabrication method.

[0194] The fabrication methods for organic field-effect transistors in Examples 17-30 are the same as in Example 8. The structural and performance characterization methods are the same as in Example 5. The material selection and formulation are shown in Table 2, and the performance of the obtained OFETs is shown in Table 3.

[0195] Examples 31-33

[0196] An organic field-effect transistor and its fabrication method.

[0197] The organic field-effect transistors (OFETs) in Examples 31-33 were fabricated using the same methods as in Example 8. The structural and performance characterization methods were the same as in Example 9. The material selection and formulation are shown in Table 2, and the resulting OFET performance is shown in Table 3.

[0198] Examples 34-36

[0199] An organic field-effect transistor and its fabrication method.

[0200] The organic field-effect transistors (OFETs) in Examples 34-36 were fabricated using the same methods as in Example 8. The structural and performance characterization methods were the same as in Example 5. The material selection and formulation are shown in Table 2, and the resulting OFET performance is shown in Table 3.

[0201] Comparative Example 1

[0202] An organic field-effect transistor based on p-type organic semiconductor single crystal TIPS-pentacene single crystal and calcium, and its fabrication method, includes the following steps:

[0203] (1) Take a p-type heavily doped material with a thickness of 525 μm. <100> Silicon wafer (with 300nm thick silicon dioxide on it). A 10nm PMMA polymer film was obtained by spin-coating a PMMA solution onto the silicon dioxide surface to modify the substrate; TIPS-pentacene single crystals were deposited by solution method.

[0204] (2) Add ethanol to the substrate on which TIPS-pentacene single crystals are deposited, so that the ethanol covers the crystal surface; spin-coat to remove the ethanol liquid.

[0205] (3) A 100 nm layer of calcium was deposited on the crystal surface as the first conductive layer using vacuum evaporation. An OFET based on TIPS-pentacene single crystal as the semiconductor layer and gold as the source and drain electrodes was fabricated.

[0206] To illustrate the advantages of using a high work function material as the first conductive layer, Comparative Example 1 used a low work function material, calcium, as the first conductive layer. After the OFET was placed in air for 5 minutes, the resistance of the first conductive layer increased from the original 22Ω to 8810Ω (e.g., ...). Figure 10 As shown in (a) and (b) above, the resistance increased by 400 times, indicating that calcium, when used as the first conductive layer, is easily oxidized by air, causing a decrease in conductivity, i.e., poor air stability. Oxidation of the electrode will severely affect the performance of the semiconductor device. In contrast, after the OFET in Example 1 was placed in air for 5 minutes, the resistance of the first conductive layer changed from 15Ω to 17Ω, remaining essentially unchanged (as shown in (a)). Figure 10 As shown in (c) and (d) in the figure, gold has good air stability when used as the first conductive layer. When the placement time in air is extended to 2 hours, the resistance of the first conductive layer in Comparative Example 1 increases to 50 kΩ, while the resistance of the first conductive layer in Example 1 becomes 18 Ω, which is basically unchanged. This further illustrates that the high work function material has good air stability as the first conductive layer and can extend the service life of the electrode in the air environment.

[0207] Comparative Example 2

[0208] An organic field-effect transistor based on p-type organic semiconductor single crystal TIPS-pentacene single crystal, n-type organic semiconductor single crystal fullerene (C60) single crystal, and gold, and its fabrication method, comprising the following steps:

[0209] (1) Take a p-type heavily doped material with a thickness of 525 μm. <100> A silicon wafer (with a 300nm thick silicon dioxide layer) is used. A 50nm aluminum layer is deposited on the silicon wafer surface as a second conductive layer. Subsequently, a 300nm poly(p-xylene) film is deposited on the aluminum-deposited silicon wafer surface using vapor deposition. A C60 single crystal is then deposited on the pentacene film surface using a solution method, followed by a TIPS-pentacene single crystal deposited using a solution method.

[0210] (3) A 100 nm gold layer was deposited on the crystal surface as the first conductive layer using vacuum evaporation. An OFET was fabricated with C60 and TIPS-pentacene single crystals as semiconductor layers and gold as source and drain electrodes.

[0211] To illustrate the advantages of constructing an OFET using only a single p-type semiconductor crystal as the semiconductor layer, Comparative Example 2 uses TIPS-pentacene single crystal (p-type) and C-type single crystal, respectively. 60 Single-crystal (n-type) OFET fabrication. Firstly, when depositing two single crystals using a solution method, the order of crystal deposition is critical. This is because benzene solvents that dissolve C60 have high solubility for TIPS-pentacene. If the TIPS-pentacene single crystal is deposited first, the growth of the C60 single crystal will severely damage the underlying TIPS-pentacene single crystal. Therefore, the only viable option is to deposit the C60 single crystal first, followed by the TIPS-pentacene single crystal. The resulting bilayer single-crystal structure is shown below. Figure 11 As shown in (a), the lower layer is a C60 single crystal, and the upper layer is a TIPS-pentacene single crystal. It can be seen that although the TIPS-pentacene solution did not completely dissolve the C60, it still affected the C60. 60 Significant damage was observed on the surface of the single crystal. Figure 11 In Figure (b), the surface of a complete C60 single crystal is shown to be very smooth and flat. However, the C60 single crystal surface after TIPS-pentacene growth becomes rough. This will severely affect the interface between the two semiconductors, resulting in poor performance of the final OFET.

[0212] The characterization methods for structure and performance are the same as those in Example 1. The obtained device-related parameters and performance are shown in Table 1.

[0213] Comparative Example 3

[0214] An organic field-effect transistor based on p-type organic semiconductor 6,13-bis(triisopropylsilylethynyl)pentacene polycrystalline thin film and gold, and its fabrication method, comprising the following steps:

[0215] (1) Take a p-type heavily doped material with a thickness of 525 μm. <100> A silicon wafer (with a 300nm thick silicon dioxide layer) is used. A 50nm aluminum layer is deposited on the silicon wafer surface as a second conductive layer. Subsequently, a 300nm poly(p-xylene) film is deposited on the aluminum-coated silicon wafer surface using vapor deposition. A TIPS-pentacene polycrystalline film is then deposited using a solution spin-coating method.

[0216] (2) Add methanol to the substrate on which TIPS-pentacene polycrystalline film is deposited, so that methanol covers the surface of the polycrystalline film; purge the substrate surface with nitrogen to remove the residual methanol liquid.

[0217] (3) A 100 nm gold layer was deposited on the surface of the polycrystalline thin film as the first conductive layer using vacuum evaporation. An OFET based on a TIPS-pentacene polycrystalline thin film as the semiconductor layer and gold as the source and drain electrodes was fabricated.

[0218] To illustrate the advantages of using organic single crystals as organic semiconductor layers, Comparative Example 3 used spin-coated TIPS-pentacene polycrystalline films as organic semiconductor layers to construct TIPS-pentacene. Figure 12 As can be seen in (a), unlike the regular and smooth appearance of organic single crystals, polycrystalline thin films have a rough surface composed of many grains. The grain boundaries between these grains severely impede carrier transport. From... Figure 12 Figure (b) shows the p-type transfer characteristic curve of the obtained OFET. It can be seen that the hole mobility of the OFET composed of TIPS-pentacene polycrystalline thin film is low, only 0.367 cm⁻¹. 2 V -1 s -1 Furthermore, the transfer characteristic curve is significantly different from that of Example 1, and the V-shaped transition cannot be observed. Therefore, it can be determined that the obtained OFET has no electron transport performance (electron mobility is 0). Thus, the balance coefficient B is infinite, which cannot meet the requirement of B=1.

[0219] Comparative Example 4

[0220] An organic field-effect transistor based on p-type organic semiconductor single crystal 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) single crystal and gold, and its fabrication method, comprising the following steps:

[0221] (1) Take a p-type heavily doped material with a thickness of 525 μm. <100> A silicon wafer (with 300 nm thick silicon dioxide on it). A 10 nm PMMA polymer film was obtained by spin-coating a PMMA solution onto the silicon dioxide surface; a TIPS-pentacene single crystal was then deposited on the PMMA film surface using a solution method.

[0222] (2) A 100 nm gold layer was deposited on the crystal surface as the first conductive layer using vacuum evaporation. An OFET based on TIPS-pentacene single crystal as the semiconductor layer and gold as the source and drain electrodes was fabricated.

[0223] To illustrate the importance of the presence of polar organic small molecules for achieving high electron mobility and a balance between hole and electron mobility, Comparative Example 4 used TIPS-pentacene single crystals that had not undergone polar organic small molecule treatment to prepare OFETs. Figure 13 To compare the p-type and n-type transfer characteristic curves of the OFET in Example 4, it can be seen that although the OFET still has a high hole mobility (1.93 cm⁻¹), it still exhibits high hole mobility. 2 V -1 s -1 However, its electron mobility μ is low, only 1.08 × 10⁻⁶. -2 cm 2 V -1 s -1 The calculated equilibrium coefficient B = 2.25, which does not meet the requirement of B = 1. This indicates that the presence of polar organic small molecules plays an important role in improving the electron mobility of OFETs with p-type organic semiconductor single crystals as the semiconductor layer and high work function conductive materials as the first conductive layer.

[0224] Comparative Example 5

[0225] An organic field-effect transistor based on p-type organic semiconductor single crystal 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) single crystal and gold, and its fabrication method, comprising the following steps:

[0226] (1) Take a p-type heavily doped material with a thickness of 525 μm. <100> Silicon wafer (with 300nm thick silicon dioxide). A 50nm aluminum layer is deposited on the silicon wafer as a second conductive layer; then, 300nm gold is deposited on the aluminum-coated silicon wafer surface using vapor deposition; and TIPS-pentacene single crystals are deposited using a solution method.

[0227] (2) Add ethanol to the substrate on which TIPS-pentacene single crystals are deposited, so that the ethanol covers the crystal surface; purge the substrate surface with nitrogen to remove the residual ethanol liquid.

[0228] (3) A 100 nm gold layer was deposited on the crystal surface as the first conductive layer using vacuum evaporation. An OFET based on TIPS-pentacene single crystal as the semiconductor layer and gold as the source and drain electrodes was fabricated.

[0229] To illustrate that an insulating layer made of insulating material is a necessary structure for the organic field-effect transistor, in Comparative Example 5, compared to Example 2, the 300nm pyrene insulating layer (insulating material) was replaced with 300nm gold (conductive material). Because it lacked an insulating layer, the resulting device remained in a short-circuit state and could not function properly. This demonstrates that an insulating layer made of insulating material is a necessary structure for the organic field-effect transistor.

[0230] Comparative Example 6

[0231] An organic field-effect transistor based on p-type organic semiconductor single crystal 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) single crystal and gold, and its fabrication method, comprising the following steps:

[0232] (1) Take a p-type heavily doped material with a thickness of 525 μm. <100> Silicon wafer (with 300nm thick silicon dioxide). 50nm aluminum oxide is deposited on the silicon wafer surface; subsequently, a 300nm pentacene insulating layer is deposited on the substrate surface using vapor deposition; TIPS-pentacene single crystals are deposited on the pentacene insulating layer using a solution method.

[0233] (2) Add ethanol to the substrate on which TIPS-pentacene single crystals are deposited, so that the ethanol covers the crystal surface; purge the substrate surface with nitrogen to remove the residual ethanol liquid.

[0234] (3) A 100 nm gold layer was deposited on the crystal surface as the first conductive layer using vacuum evaporation. An OFET based on TIPS-pentacene single crystal as the semiconductor layer and gold as the source and drain electrodes was fabricated.

[0235] To illustrate that the use of a second conductive layer made of conductive material is a necessary structure for the organic field-effect transistor, in Comparative Example 6, compared with Example 2, 50 nm of aluminum (conductive material) was replaced with 50 nm of alumina (insulating material, resistivity of approximately 0.004 S / m, [1] Bai Xiaoping, Chen Yan. Study on the influence of alumina filler conductivity on casting performance [J]. Electrical Manufacturing, 2014(11):62-65.). Since it lacks a conductive second layer, the device cannot provide a gate voltage to control the switching on and off of the organic field-effect transistor and cannot function properly. This demonstrates that a second conductive layer made of conductive material is a necessary structure for the organic field-effect transistor.

[0236] Comparative Example 7

[0237] The organic field-effect transistor of Comparative Example 7 was fabricated using the same method as in Example 1, except that the thickness of the deposited first conductive layer was 15 nm. The structural and performance characterization methods were the same as those in Example 1.

[0238] Comparative Example 8

[0239] The organic field-effect transistor of Comparative Example 8 was fabricated using the same method as in Example 1, except that the thickness of the deposited first conductive layer was 1500 nm. The structural and performance characterization methods were the same as those in Example 1.

[0240] To illustrate the impact of the thickness of the first conductive layer on the performance of the organic field-effect transistor, Comparative Examples 7 and 8 selected metals with thicknesses less than 30 nm and greater than 1000 nm, respectively, as the first conductive layer. In Comparative Example 7, due to the excessively thin first conductive layer and the influence of the underlying organic semiconductor layer morphology, the first conductive layer was discontinuous and could not function as an electrode, causing the device to malfunction. In Comparative Example 8, due to the excessively thick first conductive layer, short circuits occurred between the electrodes, also causing the device to malfunction. This demonstrates that the thickness of the first conductive layer needs to be controlled within the range of 30-1000 nm.

[0241] Table 1. Relevant parameters and performance of Examples 1-10 and Comparative Examples 1-8

[0242]

[0243] Table 2. Material Selection for Examples 11-36

[0244]

[0245]

[0246]

[0247] Table 3. Performance Tests of Examples 11-36

[0248]

[0249]

[0250] Through the analysis of embodiments and comparative examples, it is evident that the organic field-effect transistor of the present invention is composed of specific materials and fabrication methods to form a specific structure. To obtain an organic field-effect transistor with the technical effects of the present invention, all of the following conditions must be strictly met: it sequentially comprises a first conductive layer, an organic semiconductor layer, an insulating layer, and a second conductive layer; the first conductive layer is composed of a conductive material with a work function of 4.5 eV or higher; the organic semiconductor layer is composed of a p-type organic semiconductor single crystal; the insulating layer is composed of an insulating material; and the second conductive layer is composed of a material with a conductivity of 1 S / m or higher. All of these conditions are indispensable. Only by simultaneously meeting all of these conditions can the overall synergistic effect be achieved to obtain the organic field-effect transistor of the present invention, constructed using a single p-type organic semiconductor material, achieving good air stability in the first conductive layer and a hole mobility μ. p and electron mobility μ n At the same time ≥0.5cm 2 V -1 s -1 And the performance of the balance coefficient B≤1.

Claims

1. An organic field-effect transistor, characterized in that, The organic field-effect transistor comprises, in sequence, a first conductive layer, an organic semiconductor single crystal layer, an insulating layer, and a second conductive layer; The first conductive layer is composed of a conductive material with a work function of 4.5 eV or higher; The organic semiconductor single crystal layer is composed of p-type organic semiconductor single crystals; The insulating layer is made of insulating material; The second conductive layer is made of a material with a conductivity of 1 S / m or higher; The organic field-effect transistor simultaneously satisfies: hole mobility μ p ≥0.5cm 2 V -1 s -1 electron mobility μ n ≥0.5cm 2 V -1 s -1 And satisfying the equilibrium coefficient B≤1, the formula for calculating the equilibrium coefficient B is: B=|lg(μ p / μ n )|; where, after depositing p-type organic semiconductor single crystals, An insulating substrate with the second conductive layer, insulating layer and organic semiconductor single crystal layer deposited on it is placed in a polar organic small molecule atmosphere for 10s to 2h to allow the polar organic small molecule liquid or vapor to fully contact the surface of the organic semiconductor single crystal layer. Then the insulating substrate with the second conductive layer, insulating layer and organic semiconductor single crystal layer deposited on it is separated from the polar organic small molecule atmosphere.

2. The organic field-effect transistor according to claim 1, characterized in that, The first conductive layer, insulating layer, and second conductive layer are each independently selected from single-layer or multi-layer thin films.

3. The organic field-effect transistor according to claim 1, characterized in that, The organic semiconductor single crystal layer is a thin film made of organic single crystal material with a HOMO energy level ≥ -5.5eV and a band gap width ≥ 1.8eV.

4. The organic field-effect transistor according to claim 1, characterized in that, The conductivity of the first conductive layer is greater than 1 S / m.

5. The organic field-effect transistor according to claim 1, characterized in that, The first conductive layer is selected from at least one of a first metal, a first conductive metal oxide, and a first conductive polymer.

6. The organic field-effect transistor according to claim 5, characterized in that, The first metal is selected from at least one of a first metallic element and a first metallic alloy.

7. The organic field-effect transistor according to claim 6, characterized in that, The first metallic element is selected from at least one of gold, copper, platinum, chromium, cobalt, and palladium.

8. The organic field-effect transistor according to claim 6, characterized in that, The first metal alloy is selected from at least two alloys of gold, copper, platinum, chromium, cobalt, and palladium.

9. The organic field-effect transistor according to claim 5, characterized in that, The first conductive metal oxide is selected from at least one of indium tin oxide, tungsten oxide, vanadium oxide, and ruthenium oxide.

10. The organic field-effect transistor according to claim 5, characterized in that, The first conductive polymer is selected from poly(3,4-ethylenedioxythiophene):polystyrene sulfonate.

11. The organic field-effect transistor according to claim 1, characterized in that, The insulating layer is selected from at least one of insulating polymers, insulating metal oxides, insulating non-metallic oxides or nitrides, and self-assembled small molecules.

12. The organic field-effect transistor according to claim 11, characterized in that, The insulating polymer is selected from at least one of polymethyl methacrylate, polyvinyl alcohol, polyvinyl acetate, polyimide, polyvinylidene fluoride, polyvinylidene fluoride copolymer, polyvinylidene fluoride-trifluoroethylene-chlorofluoroethylene, polystyrene, poly-α-methylstyrene, polyvinylpyrrolidone, polyvinylphenol, poly(p-xylene), polybenzocyclobutene, perfluoro(1-butenyl vinyl ether) polymer, and cyanoethylprolane.

13. The organic field-effect transistor according to claim 11, characterized in that, The insulating metal oxide is selected from at least one of aluminum oxide, titanium oxide, tantalum oxide, and hafnium oxide.

14. The organic field-effect transistor according to claim 11, characterized in that, The insulating non-metallic oxide or nitride is selected from at least one of silicon dioxide and silicon nitride.

15. The organic field-effect transistor according to claim 11, characterized in that, The self-assembled small molecule is selected from at least one of silane-containing self-assembled small molecules, phosphate-containing self-assembled small molecules, and thiol-containing self-assembled small molecules.

16. The organic field-effect transistor according to claim 1, characterized in that, The second conductive layer is selected from at least one of a second metal, a second conductive metal oxide, a second conductive polymer, and a conductive inorganic non-metal.

17. The organic field-effect transistor according to claim 16, characterized in that, The second metal is selected from a second elemental metal or a second alloy of metals.

18. The organic field-effect transistor according to claim 17, characterized in that, The second metallic element is selected from at least one of gold, silver, copper, iron, aluminum, zinc, tin, titanium, platinum, chromium, cobalt, palladium, manganese, nickel, magnesium, lead, and gallium.

19. The organic field-effect transistor according to claim 17, characterized in that, The second metal alloy is selected from at least two alloys of gold, silver, copper, iron, aluminum, zinc, tin, titanium, platinum, chromium, cobalt, palladium, manganese, nickel, magnesium, lead, and gallium.

20. The organic field-effect transistor according to claim 16, characterized in that, The second conductive metal oxide is selected from at least one of indium tin oxide, tungsten oxide, vanadium oxide, ruthenium oxide, iron oxide, nickel oxide, zinc oxide, and silver oxide.

21. The organic field-effect transistor according to claim 16, characterized in that, The second conductive polymer is selected from poly(3,4-ethylenedioxythiophene):polystyrene sulfonic acid.

22. The organic field-effect transistor according to claim 16, characterized in that, The conductive inorganic non-metal is selected from at least one of silicon, graphite, carbon fiber, and carbon nanotubes.

23. The organic field-effect transistor according to claim 1, characterized in that, The organic semiconductor single crystal layer is selected from any one of polycyclic aromatic hydrocarbons, sulfur-containing heterocyclic aromatic hydrocarbons, nitrogen-containing heterocyclic aromatic hydrocarbons, and their respective derivatives.

24. The organic field-effect transistor according to claim 23, characterized in that, The polycyclic aromatic hydrocarbon is selected from any one of benzo[a]benzene, dinaphthalene, diphenylanthracene, and rubrene.

25. The organic field-effect transistor according to claim 23, characterized in that, The sulfur-containing heterocyclic ring is selected from any one of oligothiophene, benzothiophene, and tetrathiofulvalene.

26. The organic field-effect transistor according to claim 23, characterized in that, The nitrogen-containing heterocyclic ring is selected from any one of metal phthalocyanine and metal porphyrin.

27. The organic field-effect transistor according to claim 1, characterized in that, The first conductive layer and the organic semiconductor single crystal layer contain polar organic small molecules with a dipole moment greater than 1D; the molecular weight of the polar organic small molecules is less than 50 Da.

28. The organic field-effect transistor according to claim 27, characterized in that, The polar organic small molecules described herein have a freezing point of less than 25°C under one atmosphere of pressure.

29. The organic field-effect transistor according to claim 27, characterized in that, The polar organic small molecule is selected from at least one of polar organic small molecules containing hydroxyl, cyano, carboxyl, thiol, carbonyl, and amide groups.

30. The organic field-effect transistor according to claim 27, characterized in that, The polar organic small molecule is selected from at least one of methanol, ethanol, propanol, isopropanol, butanol, ethylene glycol, formic acid, acetic acid, propionic acid, acetonitrile, acetaldehyde, ethanethiol, propanethiol, acetone, tetrahydrofuran, and N'N-dimethylformamide.

31. The organic field-effect transistor according to claim 1, characterized in that, Between the first conductive layer and the organic semiconductor single crystal layer, there exists a polar organic small molecule layer with a dipole moment greater than 1D.

32. The organic field-effect transistor according to claim 31, characterized in that, The polar organic small molecule layer reduces the electron injection barrier between the first conductive layer and the organic semiconductor single crystal layer by more than 0.05 eV.

33. The organic field-effect transistor according to any one of claims 1-32, characterized in that, include: An insulating substrate and / or an encapsulation layer; wherein the insulating substrate is selected from at least one of silicon wafers containing an oxide layer, glass, ceramics, insulating metal oxides, paper, or polymers, and the encapsulation layer is a polymer material.

34. The organic field-effect transistor according to claim 33, characterized in that, The polymer is selected from at least one of polyethylene naphthalate, polyethylene terephthalate, polyetheretherketone, polyimide, polycarbonate, polyethersulfone resin, polyarylate, and polycyclic olefin.

35. A method for fabricating an organic field-effect transistor, characterized in that, Includes the following steps: 1) A second conductive layer and an insulating layer are sequentially deposited on the surface of an insulating substrate, and an organic semiconductor single crystal layer is deposited on the insulating layer; the deposition method of the second conductive layer is selected from one or more of vapor deposition and solution deposition; the deposition method of the insulating layer is selected from one or more of vapor deposition, solution deposition, atomic layer deposition, and in-situ oxidation. 2) The insulating substrate with the second conductive layer, insulating layer and organic semiconductor single crystal layer deposited is placed in a polar organic small molecule atmosphere for 10s to 2h to allow the polar organic small molecule liquid or vapor to fully contact the surface of the organic semiconductor single crystal layer. Then the insulating substrate with the second conductive layer, insulating layer and organic semiconductor single crystal layer deposited is separated from the polar organic small molecule atmosphere. 3) A first conductive layer with a thickness of 30-1000 nm is deposited on the surface of an organic semiconductor single crystal layer as an electrode to obtain the organic field-effect transistor; The first conductive layer is composed of a conductive material with a work function of 4.5 eV or higher; The organic semiconductor single crystal layer is composed of p-type organic semiconductor single crystals; The insulating layer is made of insulating material; The second conductive layer is made of a material with a conductivity of 1 S / m or higher; The organic field-effect transistor simultaneously satisfies: hole mobility μ p ≥0.5cm 2 V -1 s -1 electron mobility μ n ≥0.5cm 2 V -1 s -1 And satisfying the equilibrium coefficient B≤1, the formula for calculating the equilibrium coefficient B is: B=|lg(μ p / μ n )|.

36. The preparation method according to claim 35, characterized in that, The first conductive layer, insulating layer, and second conductive layer are each independently selected from single-layer or multi-layer thin films.

37. The preparation method according to claim 35, characterized in that, In step 3), the deposition thickness is 30–100 nm.

38. The preparation method according to claim 35, characterized in that, The deposition thickness is 100 nm.

39. An optoelectronic device, characterized in that, The optoelectronic device comprises an organic field-effect transistor as described in any one of claims 1-34 or an organic field-effect transistor prepared by the preparation method as described in any one of claims 35-38.

40. The optoelectronic device according to claim 39, characterized in that, The optoelectronic devices are selected from light-emitting transistors, memory, sensors, and displays.

41. An organic circuit, characterized in that, The organic circuit comprises an organic field-effect transistor as described in any one of claims 1-34 or an organic field-effect transistor prepared by the preparation method as described in any one of claims 35-38.

42. The organic circuit according to claim 41, characterized in that, The organic circuit is selected from at least one combination of gate circuits, combinational logic circuits, sequential logic circuits, and amplifier circuits.

43. An optoelectronic integrated array, characterized in that, The optoelectronic integrated array comprises one or more optoelectronic devices as described in any one of claims 39-40 and organic circuits as described in any one of claims 41-42.

44. An application of an organic field-effect transistor as described in any one of claims 1-34, an organic field-effect transistor prepared by the preparation method described in any one of claims 35-38, an optoelectronic device as described in any one of claims 39-40, an organic circuit as described in any one of claims 41-42, or an optoelectronic integrated array as described in claim 43, wherein the application refers to its use in the fields of semiconductor devices, transportation and logistics, mining and metallurgy, environment, medical devices, explosion-proof detection, food, water treatment, pharmaceuticals, and biology.

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