Organic light-emitting field effect transistor and preparation method thereof

Abstract

The invention relates to the technical field of display, and particularly discloses an organic light-emitting field effect transistor and a preparation method thereof. The organic light-emitting field effect transistor comprises a grid electrode, a grid electrode insulating layer, a source electrode, an organic light-emitting function composite layer and a drain electrode which are sequentially stacked in the first direction, and the grid electrode insulating layer comprises a tunneling layer, a charge trapping layer and a barrier layer which are sequentially stacked in the first direction. According to the organic light-emitting field effect transistor, a gate insulation layer in a traditional organic light-emitting field effect transistor is arranged to be a tunneling layer, a charge trapping layer and a blocking layer which are sequentially stacked, namely, the organic light-emitting field effect transistor is combined with a storage device, so that the dual functions of light emitting and storage of the transistor can be achieved, the functions of the organic light-emitting field effect transistor are enriched, and the application range is widened. And the overall preparation process of each device is simplified.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to an organic light-emitting field effect transistor and a method for preparing the same. Background Art

[0002] Organic Light Emitting Transistor (OLET) has both the circuit modulation function of Organic Field-effect Transistor (OFET) and the light-emitting function of Organic Light-Emitting Diode (OLED). Theoretically, OLET can have higher carrier mobility, better luminous efficiency and luminous intensity than OLED. It will have great application value in the fields of flat panel display, optical communication, solid lighting, etc.

[0003] However, at present, there are still some problems in the application of OLET. Summary of the invention

[0004] Based on this, it is necessary to provide an organic light-emitting field effect transistor and a method for preparing the same in order to solve the above problems.

[0005] According to a first aspect of an embodiment of the present application, an organic light-emitting field effect transistor is provided, comprising a gate, a gate insulating layer, a source, an organic light-emitting functional composite layer and a drain stacked in sequence along a first direction, wherein the gate insulating layer comprises a tunneling layer, a charge capture layer and a blocking layer stacked in sequence along the first direction.

[0006] In one embodiment, the dielectric constant of the charge trapping layer is lower than the dielectric constant of the tunneling layer, and the dielectric constant of the charge trapping layer is lower than the dielectric constant of the blocking layer.

[0007] In one of the embodiments, the tunneling layer includes SiO2 or a high-k material.

[0008] In one of the embodiments, the charge trapping layer includes Al2O3 or SiN.

[0009] In one embodiment, the barrier layer comprises SiO2 or a high-k material, and the barrier layer is made of the same material or different material from the tunneling layer.

[0010] In one embodiment, the thickness of the tunneling layer is in the range of 1 nm to 30 nm.

[0011] In one embodiment, the charge capture layer has a thickness ranging from 1 nm to 50 nm.

[0012] In one embodiment, the barrier layer has a thickness ranging from 10 nm to 100 nm.

[0013] In one embodiment, the organic light-emitting functional composite layer includes a hole injection layer, a light-emitting layer, and an electron transport layer stacked in sequence along a first direction.

[0014] According to a second aspect of an embodiment of the present application, a method for preparing an organic light-emitting field effect transistor is provided, comprising:

[0015] forming a gate on the substrate;

[0016] forming a gate insulating layer on a surface of the gate away from the substrate and at least a portion of the surface of the substrate not covering the gate, wherein the gate insulating layer comprises a tunneling layer, a charge trapping layer and a blocking layer stacked in sequence;

[0017] A source electrode, an organic light-emitting functional composite layer and a drain electrode are sequentially formed on a side of the gate insulating layer away from the gate.

[0018] The organic light-emitting field effect transistor and the preparation method thereof provided in the embodiments of the present application configure the gate insulating layer in the traditional organic light-emitting field effect transistor to be a tunneling layer, a charge trapping layer, and a blocking layer stacked in sequence, that is, the organic light-emitting field effect transistor is combined with a storage device, thereby realizing the dual functions of transistor light emission and storage, enriching the functions of the organic light-emitting field effect transistor and simplifying the overall preparation process of each device. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the structure of an organic light-emitting field-effect transistor provided in one embodiment of the present application;

[0020] Figure 2 A schematic diagram of the structure of an organic light-emitting functional composite layer in an organic light-emitting field-effect transistor provided in an embodiment of the present application;

[0021] Figure 3 A schematic diagram of the structure of an organic light-emitting functional composite layer in an organic light-emitting field-effect transistor provided in an embodiment of the present application;

[0022] Figure 4 A flowchart of a method for preparing an organic light-emitting field effect transistor provided in one embodiment of the present application;

[0023] Figure 5 A diagram of a preparation process of an organic light-emitting field-effect transistor provided in one embodiment of the present application.

[0024] Description of reference numerals:

[0025] 100, substrate; 200, gate; 300, gate insulating layer; 310, tunneling layer; 320, charge capture layer; 330, blocking layer; 400, source; 500, organic light-emitting functional composite layer; 510, hole injection layer; 520, hole transport layer; 530, light-emitting layer; 540, electron transport layer; 550, electron injection layer; 600, drain. DETAILED DESCRIPTION

[0026] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to understand the disclosure of the present application more thoroughly and comprehensively.

[0027] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0028] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0030] Organic Light Emitting Transistor (OLET) has both the circuit modulation function of Organic Field-effect Transistor (OFET) and the light-emitting function of Organic Light-Emitting Diode (OLED). Theoretically, OLET can have higher carrier mobility, better luminous efficiency and luminous intensity than OLED. It will have great application value in the fields of flat panel display, optical communication, solid lighting, etc.

[0031] However, there are still some problems in the application of OLET. For example, OLET and storage devices exist independently to realize their respective functions, so there are problems such as single device function and complex overall process.

[0032] In response to the above problems, the embodiments of the present application provide an organic light-emitting field effect transistor and a method for preparing the same, which can combine the structures of traditional organic light-emitting field effect transistors and storage devices, so that flat panel display technology can achieve static display with simpler processes and higher integration.

[0033] In one embodiment, an organic light emitting field effect transistor is provided.

[0034] Reference Figure 1 The organic light-emitting field effect transistor provided in this embodiment includes a gate 200, a gate insulating layer 300, a source 400, an organic light-emitting functional composite layer 500 and a drain 600 stacked in sequence along a first direction, and the gate insulating layer 300 includes a tunneling layer 310, a charge trapping layer 320 and a blocking layer 330 stacked in sequence along the first direction.

[0035] The first direction may be a vertical direction from bottom to top. A substrate 100 is disposed on one side of the gate 200 away from the gate insulating layer 300, and the material of the substrate 100 may include at least one of glass, polyimide, or polyvinyl pyrrolidone, polyvinyl pyrrolidone, etc. The gate insulating layer 300 covers the surface of the gate 200 away from the substrate 100 and the surface of the substrate 100 where the gate 200 is not disposed. The source electrode 400 is disposed on the surface of the gate insulating layer 300 away from the gate 200. The organic light-emitting functional composite layer 500 is disposed on the surface of the source electrode 400 away from the gate insulating layer 300. The drain electrode 600 is disposed on the surface of the organic light-emitting functional composite layer 500 away from the source electrode 400.

[0036] In this embodiment, the gate insulating layer 300 is not the gate insulating layer 300 in the conventional organic light-emitting field effect transistor (e.g., a single-layer Al2O3 structure), but a stacked structure composed of a tunneling layer 310, a charge trapping layer 320, and a blocking layer 330. When a positive voltage is applied to the gate 200, electrons tunnel through the tunneling layer 310 to discrete electron traps in the charge trapping layer 320, thereby increasing the threshold voltage. When a negative voltage is applied to the gate 200, electrons tunnel back from the charge trapping layer 320, thereby decreasing the threshold voltage. Thus, the signals of "1" and "0" can be distinguished according to the magnitude of the threshold voltage. Therefore, the stacked structure composed of the tunneling layer 310, the charge trapping layer 320, and the blocking layer 330 is equivalent to combining a memory structure with the structure of the organic light-emitting field effect transistor, so that it has both a light-emitting function and a storage function.

[0037] In this embodiment, an organic light-emitting field effect transistor is combined with a memory device, thereby realizing the dual functions of transistor light emission and memory, enriching the functions of the organic light-emitting field effect transistor and simplifying the overall preparation process of each device.

[0038] In one embodiment, the dielectric constant of the charge trapping layer 320 is lower than the dielectric constant of the tunneling layer 310 , and the dielectric constant of the charge trapping layer 320 is lower than the dielectric constant of the blocking layer 330 .

[0039] Specifically, the tunneling layer 310 may be made of materials with high dielectric constant and good film quality, such as SiO2 or high-k materials, the charge capture layer 320 may be made of materials with low dielectric constant and poor film quality, such as Al2O3 or SiN, and the blocking layer 330 may be made of materials with high dielectric constant and good film quality, such as SiO2 or high-k materials. The materials of the blocking layer 330 and the tunneling layer 310 may be the same or different.

[0040] In a specific example, the material of the tunneling layer 310 is SiO2, the material of the charge capture layer 320 is Al2O3, and the material of the blocking layer 330 is SiO2, that is, the gate insulating layer 300 is a SiO2 / Al2O3 / SiO2 stacked structure.

[0041] In one embodiment, the thickness of the tunnel layer 310 is in the range of 1 nm to 30 nm. Specifically, the thickness of the tunnel layer 310 can be 1 nm, 15 nm, 25 nm, 30 nm, etc., and can be set according to actual needs.

[0042] In one embodiment, the thickness of the charge capture layer 320 is in the range of 1 nm to 50 nm. Specifically, the thickness of the charge capture layer 320 can be 1 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, etc., which can be set according to actual needs.

[0043] In one embodiment, the thickness of the barrier layer 330 is in the range of 10 nm to 100 nm. Specifically, the thickness of the barrier layer 330 can be 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, or 100 nm, etc., which can be set according to actual needs.

[0044] In one embodiment, referring to Figure 2 The organic light-emitting functional composite layer 500 includes a hole injection layer 510 (HIL), an emitting layer 530 (EML), and an electron transport layer 540 (ETL) which are sequentially stacked along a first direction.

[0045] In other embodiments, reference Figure 3 A hole transport layer 520 (HTL) may be included between the hole injection layer 510 and the light emitting layer 530 , and an electron injection layer 550 (EIL) may be provided on the side of the electron transport layer 540 away from the light emitting layer 530 .

[0046] The light-emitting layer 530 may be made of a light-emitting material, specifically a small molecule, a polymer, or a mixture of a small molecule and a polymer.

[0047] The material of the hole injection layer 510 may include but is not limited to the following commonly used HIL materials:

[0048] N,N'-bis-(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine(NPB)、4,4',4"-tris(3-methylphenylphenylamino)-trip henylamine(m-MTDATA), Poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonate)(PEDOT:PSS), polyvinylcarbazole(PVK).

[0049] The material of the hole transport layer 520 may include paired coupled diamine compounds such as TPD, TAPC, NPB, β-NPB, α-NPD; triphenylamine compounds such as TDAB, TDAPB, PTDATA, spiro-mTTB; or some triarylamine polymers, carbazole compounds.

[0050] The material of the electron injection layer 550 may include lithium oxide, lithium boron oxide, potassium silicon oxide, cesium carbonate or alkali metal fluoride, such as one of lithium fluoride, potassium fluoride and cesium fluoride.

[0051] The material of the electron transport layer 540 may include one of oxazole derivatives, metal chelate quinoline derivatives, oxaline derivatives, diazanthracene derivatives, diazanthracene derivatives, and silicon-containing heterocyclic compounds.

[0052] Specifically, the specific structure of the organic light-emitting functional composite layer 500 can be set according to the conditions of carrier migration.

[0053] In this embodiment, the material of the gate 200 can be selected from indium tin oxide (ITO), aluminum zinc oxide (AZO), poly (3,4-ethylenedioxythiophene)-poly (styrene sulfonic acid) (PEDOT:PSS), silver nanowires or graphene.

[0054] In this embodiment, the material of the source electrode 400 can be a high work function material, and the high work function material can include gold, platinum, copper, selenium, indium tin oxide (ITO), graphene, etc. In this embodiment, the source electrode 400 can be a high work function material doped with FeCl3. Exemplarily, the source electrode 400 can be a single layer of graphene doped with FeCl3.

[0055] In this embodiment, the material of the drain electrode 600 may be a low work function material, and the low work function material may include silver, aluminum, lithium, calcium or magnesium.

[0056] In one embodiment, a method for preparing an organic light-emitting field effect transistor is provided, which can be used to prepare the organic light-emitting field effect transistor provided in the above embodiment.

[0057] Reference Figure 4 and Figure 5 The method for preparing an organic light-emitting field effect transistor provided in this embodiment comprises the following steps:

[0058] Step S200 , forming a gate 200 on the substrate 100 .

[0059] First, a substrate 100 is provided, and the substrate 100 can be a glass substrate 100 or a substrate 100 of other materials. Then, a gate 200 is formed on one side of the substrate 100 , and specifically, the gate 200 can be formed by depositing on the substrate 100 through a PVD (physical vapor deposition) process.

[0060] The material of the gate 200 may be indium tin oxide (ITO), aluminum zinc oxide (AZO), poly (3,4-ethylenedioxythiophene)-poly (styrene sulfonic acid) (PEDOT:PSS), silver nanowire or graphene.

[0061] Step S400, forming a gate insulating layer 300 on a surface of the gate 200 away from the substrate 100 and on at least a portion of the surface of the substrate 100 not covering the gate 200, wherein the gate insulating layer 300 includes a tunneling layer 310, a charge trapping layer 320 and a blocking layer 330 stacked in sequence.

[0062] After forming the gate 200, a gate insulating layer 300 may be formed on a surface of the gate 200 away from the substrate 100 and at least a portion of the surface of the substrate 100 not covering the gate 200. The step of forming the gate insulating layer 300 includes sequentially forming a tunneling layer 310, a charge trapping layer 320, and a blocking layer 330.

[0063] Specifically, a CVD (chemical vapor deposition) process may be used to sequentially deposit a tunneling layer 310, a charge trapping layer 320, and a blocking layer 330. The tunneling layer 310 may be made of a material with a relatively high dielectric constant and good film quality, such as SiO2 or a high-k material, the charge trapping layer 320 may be made of a material with a relatively low dielectric constant and poor film quality, such as Al2O3 or SiN, and the blocking layer 330 may be made of a material with a relatively high dielectric constant and good film quality, such as SiO2 or a high-k material. The materials of the blocking layer 330 and the tunneling layer 310 may be the same or different.

[0064] In a specific example, the material of the tunneling layer 310 is SiO2, the material of the charge trapping layer 320 is Al2O3, and the material of the blocking layer 330 is SiO2, that is, the formed gate insulating layer 300 is a SiO2 / Al2O3 / SiO2 stacked structure.

[0065] Step S600 , forming a source electrode 400 , an organic light-emitting functional composite layer 500 and a drain electrode 600 in sequence on a side of the gate insulating layer 300 away from the gate 200 .

[0066] After the gate insulating layer 300 is formed, a source electrode 400 can be deposited on the surface of the gate insulating layer 300 away from the gate 200, and then an organic light-emitting functional composite layer 500 can be deposited on the surface of the source electrode 400 away from the gate insulating layer 300, and then a drain electrode 600 can be deposited and patterned on the surface of the organic light-emitting functional composite layer 500 away from the source electrode 400.

[0067] The material of the source 400 may be a high work function material, which may include gold, platinum, copper, selenium, indium tin oxide (ITO), etc. In this embodiment, the source 400 may be a high work function material doped with FeCl3. Exemplarily, the source 400 may be a single layer of graphene doped with FeCl3. The material of the drain 600 may be a low work function material, which may include silver, aluminum, lithium, calcium or magnesium, etc.

[0068] In this embodiment, forming the organic light-emitting functional composite layer 500 may include sequentially depositing a hole injection layer 510 , a light-emitting layer 530 , and an electron transport layer 540 along a first direction.

[0069] In other embodiments, forming the organic light-emitting functional composite layer 500 may include sequentially depositing a hole injection layer 510 , a hole transport layer 520 , a light-emitting layer 530 , an electron transport layer 540 , and an electron injection layer 550 along a first direction.

[0070] Regarding the material composition of the hole injection layer 510 , the hole transport layer 520 , the light emitting layer 530 , the electron transport layer 540 and the electron injection layer 550 , reference may be made to the specific description of the organic light emitting field effect transistor provided in the above embodiments, which will not be repeated here.

[0071] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0072] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent. It should be noted that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. An organic light-emitting field effect transistor, characterized in that: It comprises a gate, a gate insulating layer, a source electrode, an organic light-emitting functional composite layer and a drain electrode which are sequentially stacked along a first direction, and the gate insulating layer comprises a tunneling layer, a charge trapping layer and a blocking layer which are sequentially stacked along the first direction.

2. The organic light-emitting field effect transistor according to claim 1, characterized in that: The dielectric constant of the charge trapping layer is lower than the dielectric constant of the tunneling layer, and the dielectric constant of the charge trapping layer is lower than the dielectric constant of the blocking layer.

3. The organic light-emitting field effect transistor according to claim 2, characterized in that: The tunneling layer includes SiO2 or a high-k material.

4. The organic light-emitting field effect transistor according to claim 2, characterized in that: The charge trapping layer includes Al2O3 or SiN.

5. The organic light-emitting field effect transistor according to claim 1, characterized in that: The barrier layer includes SiO2 or a high-k material, and the barrier layer and the tunnel layer may be made of the same material or different material.

6. The organic light emitting field effect transistor according to claim 1, characterized in that: The thickness of the tunneling layer is in the range of 1 nm to 30 nm.

7. The organic light emitting field effect transistor according to claim 1, characterized in that: The charge capture layer has a thickness ranging from 1 nm to 50 nm.

8. The organic light emitting field effect transistor according to claim 1, characterized in that: The thickness of the barrier layer is in the range of 10 nm to 100 nm.

9. The organic light emitting field effect transistor according to claim 1, characterized in that: The organic light-emitting functional composite layer comprises a hole injection layer, a light-emitting layer and an electron transport layer which are sequentially stacked along a first direction.

10. A method for preparing an organic light-emitting field effect transistor, characterized in that: include: forming a gate on the substrate; forming a gate insulating layer on a surface of the gate away from the substrate and at least a portion of the surface of the substrate not covering the gate, wherein the gate insulating layer comprises a tunneling layer, a charge trapping layer and a blocking layer stacked in sequence; A source electrode, an organic light-emitting functional composite layer and a drain electrode are sequentially formed on a side of the gate insulating layer away from the gate.

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