Organic field effect transistor and preparation method and application thereof

Abstract

The invention discloses an organic field effect transistor and a preparation method and application thereof. The organic field effect transistor structurally comprises a substrate, a gate electrode, a quantum dot layer, an organic active layer and source and drain electrodes from bottom to top in sequence, wherein the quantum dot layer is made of up-conversion quantum dots. According to the invention, the up-conversion quantum dots sensitive to near-infrared light are combined with the organic active substance in the organic active layer, and the organic active layer and the quantum dot layer sensitive to near-infrared light are constructed at the same time, so that the deficiency of near-infrared light response of the organic field effect transistor with a single component (only the organic active layer) can be supplemented; and the near-infrared light response performance of the organic field effect transistor is improved.

Description

Technical Field

[0001] The present invention relates to the field of electronic science and technology, and in particular to an organic field effect transistor and a preparation method and application thereof. Background Art

[0002] Advanced artificial vision systems play an indispensable role in cutting-edge applications such as smart homes, self-driving cars, and dynamic trajectory analysis. These systems are usually built on a complementary metal oxide semiconductor (CMOS) platform that integrates multiple components: image sensors dedicated to capturing visual input, memory for storing key information, and processors responsible for performing complex calculations. However, with the rapid growth of visual data, the separation of processors and memory units in the traditional von Neumann computer architecture has become a bottleneck that limits computing efficiency, introduces transmission delays and high power consumption, and has gradually been unable to keep up with the pace of processing massive amounts of data in the big data era.

[0003] However, the light absorption characteristics of organic materials are usually limited to the visible and ultraviolet regions, and their absorption capacity for near-infrared light is weak. Therefore, field-effect transistors based on organic materials have natural limitations in their response to near-infrared light. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide an organic field effect transistor and a preparation method and application thereof, aiming to solve the problem of the lack of near-infrared light response of the existing organic field effect transistor.

[0005] The technical solution of the present invention is as follows:

[0006] In a first aspect of the present invention, there is provided an organic field effect transistor, wherein the structure of the organic field effect transistor is, from bottom to top, a substrate, a gate electrode, a quantum dot layer, an organic active layer and a source-drain electrode;

[0007] Wherein, the material used in the quantum dot layer is up-conversion quantum dots.

[0008] Preferably, the thickness of the quantum dot layer is 5-20 nm, and the material used in the quantum dot layer is one or more of NaGdF4:Yb / Er, LaF3:Yb / Ho, and LaF3:Yb / Er.

[0009] Preferably, the thickness of the organic active layer is 30-50 nm, and the material used for the organic active layer is one or more of poly 3-hexylthiophene, pentacene, and tetracene.

[0010] Preferably, the substrate is selected from silicon wafer, plastic PET or glass, the gate electrode is made of a material selected from silicon, gold, aluminum, copper or silver, and the source and drain electrodes are made of a material selected from gold, aluminum, copper or silver.

[0011] A second aspect of the present invention provides a method for preparing an organic field effect transistor, the method comprising the following steps:

[0012] preparing an upconversion quantum dot solution and an organic active solution;

[0013] Coating the upconversion quantum dot solution on the surface of the substrate, performing a first annealing to form a quantum dot layer;

[0014] Coating the organic active solution on the surface of the quantum dot layer, and performing a second annealing to form an organic active layer;

[0015] Vapor depositing source and drain electrodes on the surface of the organic active layer;

[0016] The gate electrode is led out using a conductive copper tape at the bottom of the substrate.

[0017] Preferably, in the upconversion quantum dot solution, the concentration of the upconversion quantum dots is 0.2-0.6 mg / mL; in the organic active solution, the concentration of the organic active substance is 2-10 mg / mL.

[0018] Preferably, the step of coating the upconversion quantum dot solution on the surface of the substrate and performing a first annealing to form a quantum dot layer is specifically as follows: spin coating the upconversion quantum dot solution on the surface of the substrate at a spin coating speed of 2000-2500 r / min for 20-30s, and then annealing at a temperature of 70-150°C for 15-60min to form a quantum dot layer.

[0019] Preferably, the step of coating the organic active solution on the surface of the quantum dot layer and performing a second annealing to form an organic active layer is specifically as follows: spin coating the organic active solution on the surface of the quantum dot layer at a spin coating speed of 2000-2500 r / min for 20-30s, and then annealing at a temperature of 70-150°C for 15-60min to form an organic active layer.

[0020] Preferably, the step of evaporating the source-drain electrode on the surface of the organic active layer comprises: attaching a mask plate engraved with the source-drain electrode on the surface of the organic active layer, and then Evaporate source and drain electrodes.

[0021] The third aspect of the present invention provides the application of the organic long effect transistor in the field of photoelectric detection, imaging, sensor chip or neuromorphic computing technology.

[0022] Beneficial effects: The present invention provides an organic field effect transistor and its preparation method and application. The structure of the organic field effect transistor is a substrate, a gate electrode, a quantum dot layer, an organic active layer and a source-drain electrode from bottom to top; wherein the material used in the quantum dot layer is an up-conversion quantum dot. The present invention combines up-conversion quantum dots that are sensitive to near-infrared light with organic active substances, and constructs an organic active layer and a near-infrared light-sensitive quantum dot layer at the same time, which is conducive to supplementing the lack of near-infrared light response of a single-component (only organic active layer) organic field effect transistor and improving the near-infrared light response performance of the organic field effect transistor.

[0023] In addition, the organic field-effect transistor designed by the present invention can not only simulate common synaptic behaviors (such as excitatory postsynaptic current, double pulse facilitation, and pulse number-dependent plasticity) under near-infrared light illumination, but also demonstrates potential applications in identifying animal dynamic trajectories in dark environments. Compared with other monitoring technologies, the combination of single-component (only organic active layer) organic field-effect transistors and upconversion quantum dots has significant advantages, including near-infrared light response, efficient computing, and excellent stability and sensitivity, providing an experimental basis and design reference for the development of the next generation of intelligent dynamic image recognition systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 1 and 2 are a cross-sectional view and a top view of an organic field effect transistor prepared in accordance with an embodiment of the present invention.

[0025] Figure 2 This is an electrical test diagram of the organic field effect transistor prepared in the embodiment of the present invention.

[0026] Figure 3 This is a synapse-like current response diagram of the organic field effect transistor prepared in an embodiment of the present invention under the regulation of near-infrared light pulses. DETAILED DESCRIPTION

[0027] The present invention provides an organic field effect transistor and a preparation method and application thereof. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0028] Currently, existing organic field-effect transistors have problems such as lack of near-infrared light response and the "storage wall" caused by the von Neumann architecture.

[0029] Based on this, an embodiment of the present invention provides an organic field effect transistor, wherein the structure of the organic field effect transistor is, from bottom to top, a substrate, a gate electrode, a quantum dot layer, an organic active layer, and a source-drain electrode;

[0030] Wherein, the material used in the quantum dot layer is up-conversion quantum dots.

[0031] The embodiment of the present invention combines upconversion quantum dots with organic active substances. The upconversion quantum dots enhance the absorption performance of the organic field effect transistor to infrared light, and realize the charge capture and infrared sensing functions. In addition, the organic field effect transistor can also avoid the data transmission redundancy generated by the von Neumann structure, and the insufficient response of the single component (only organic active layer) organic field effect transistor to near-infrared light. At the same time, the organic field effect transistor avoids the use of the von Neumann structure, and can realize on-chip direct recognition of motion trajectories to a certain extent, which is of great significance to the development of the next generation of intelligent dynamic image recognition systems.

[0032] In some embodiments, the thickness of the quantum dot layer is 5-20 nm, and the material used for the quantum dot layer is one or more of NaGdF4:Yb / Er, LaF3:Yb / Ho, and LaF3:Yb / Er.

[0033] In some embodiments, the thickness of the organic active layer is 30-50 nm, and the material used for the organic active layer is one or more of poly 3-hexylthiophene, pentacene, and tetracene.

[0034] The upconversion quantum dots have excellent near-infrared response. Specifically for NaGdF4:Yb / Er, it can absorb 980nm near-infrared light and excite light of about 520nm. The 520nm light corresponds to the maximum absorption peak of the organic active layer P3HT, which makes the organic field-effect transistor as a whole very sensitive to near-infrared light.

[0035] Setting the quantum dot layer and the organic active layer within this thickness range has the best photoelectric response characteristics.

[0036] In some embodiments, the substrate is selected from silicon wafer, plastic PET or glass, the material used for the gate electrode is selected from silicon, gold, aluminum, copper or silver, and the material used for the source and drain electrodes is selected from gold, aluminum, copper or silver.

[0037] An embodiment of the present invention provides a method for preparing an organic field effect transistor, the method comprising the following steps:

[0038] preparing an upconversion quantum dot solution and an organic active solution;

[0039] Coating the upconversion quantum dot solution on the surface of the substrate, performing a first annealing to form a quantum dot layer;

[0040] Coating the organic active solution on the surface of the quantum dot layer, and performing a second annealing to form an organic active layer;

[0041] Vapor depositing source and drain electrodes on the surface of the organic active layer;

[0042] The gate electrode is led out using a conductive copper tape at the bottom of the substrate.

[0043] In some embodiments, in the upconversion quantum dot solution, the concentration of upconversion quantum dots is 0.2-0.6 mg / mL; in the organic active solution, the concentration of organic active substances is 2-10 mg / mL.

[0044] When the concentration of upconversion quantum dots is set within this concentration range, the uniformity and photoelectric response characteristics of the organic field effect transistor are optimal. If the concentration of upconversion quantum dots is too low, the light response will be insensitive, while if the concentration is too high, the uniformity of the active layer film will deteriorate and the electrical performance will decrease.

[0045] In some preferred embodiments, in the upconversion quantum dot solution, the concentration of the upconversion quantum dots is 0.6 mg / mL; in the organic active solution, the concentration of the organic active substance is 6 mg / mL.

[0046] In some embodiments, the solvent in the upconversion quantum dot solution is selected from toluene or chlorobenzene, and the solvent in the organic active solution is selected from chlorobenzene, toluene or chloroform.

[0047] In some embodiments, the step of coating the upconversion quantum dot solution on the surface of the substrate and performing a first annealing to form a quantum dot layer is specifically as follows: spin coating the upconversion quantum dot solution on the surface of the substrate at a spin coating speed of 2000-2500 r / min for 20-30 seconds, and then annealing at a temperature of 70-150° C. for 15-60 minutes to form a quantum dot layer.

[0048] In some preferred embodiments, the step of coating the upconversion quantum dot solution on the surface of the substrate and performing a first annealing to form a quantum dot layer is specifically as follows: spin coating the upconversion quantum dot solution on the surface of the substrate at a spin coating speed of 2500 r / min for 30 seconds, and then annealing at a temperature of 100° C. for 40 minutes to form a quantum dot layer.

[0049] In some embodiments, the step of coating the organic active solution on the surface of the quantum dot layer and performing a second annealing to form an organic active layer is specifically as follows: spin coating the organic active solution on the surface of the quantum dot layer at a spin coating speed of 2000-2500 r / min for 20-30 seconds, and then annealing at a temperature of 70-150° C. for 15-60 minutes to form an organic active layer.

[0050] In some preferred embodiments, the step of spin coating the organic active solution on the surface of the quantum dot layer and performing a second annealing to form an organic active layer is specifically as follows: spin coating the organic active solution on the surface of the quantum dot layer at a spin coating speed of 2500 r / min for 30 seconds, and then annealing at a temperature of 100° C. for 40 minutes to form an organic active layer.

[0051] In some embodiments, the step of evaporating the source and drain electrodes on the surface of the organic active layer is specifically as follows: a mask plate engraved with the source and drain electrodes is attached to the surface of the organic active layer, and then Evaporate source and drain electrodes.

[0052] In some preferred embodiments, 50 nm source and drain electrodes are evaporated.

[0053] In some embodiments, the method for preparing the organic field effect transistor comprises the following steps:

[0054] The upconversion quantum dot NaGdF4:Yb / Er was dissolved in toluene to prepare an upconversion quantum dot solution with a concentration of 0.6 mg / mL, and poly 3-hexylthiophene was dissolved in chlorobenzene to prepare an organic active solution with a concentration of 6 mg / mL;

[0055] Spin coating the upconversion quantum dot solution on the surface of the substrate at a rotation speed of 2500 r / min for 30 seconds, and annealing at 100° C. for 40 minutes to form a quantum dot layer with a thickness of 40 nm;

[0056] Spin coating the surface of the quantum dot layer with an organic active solution at a speed of 2500 r / min for 30 seconds, and annealing at 100° C. for 40 minutes to form an organic active layer with a thickness of 40 nm;

[0057] A mask having source and drain electrode patterns is attached to the surface of the organic active layer, and the organic active layer is placed in an air-isolated state. 50nm gold was evaporated at an evaporation rate of;

[0058] A 1.5 cm copper conductive tape was pasted on the bottom of the substrate to lead out the gate electrode.

[0059] The embodiments of the present invention also provide applications of the organic long-effect transistor in the fields of photoelectric detection, imaging, sensor chips or neuromorphic computing technology.

[0060] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, and are only for illustrating the present invention but not limiting the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0061] Example

[0062] The preparation of an organic field effect transistor comprises the following steps:

[0063] Preparation of quantum dot layer and organic active layer: 100nm oxide layer silicon wafer was selected as substrate, the silicon wafer was cut into small squares of 2cm×2cm, 3mg upconversion quantum dot NaGdF4:Yb / Er was poured into 5mL toluene, and mechanical stirring was performed for 10 minutes to evenly disperse the upconversion quantum dots in toluene to obtain 0.6mg / mL upconversion quantum dot solution. After that, the upconversion quantum dot solution was spin-coated on the silicon wafer at a speed of 2500r / min, the spin-coating time was 30s, and then it was annealed in a nitrogen atmosphere at an annealing temperature of 100℃. The annealing time was 40 minutes, and a quantum dot layer with a thickness of 40nm was obtained; 6mg poly 3-hexylthiophene was poured into 1mL chlorobenzene, and ultrasonic vibration was performed for 15 minutes to evenly disperse poly 3-hexylthiophene in chlorobenzene to obtain 6mg / mL poly 3-hexylthiophene solution. Afterwards, the poly (3-hexylthiophene) solution was spin-coated on the quantum dot layer at a speed of 2500 r / min for 30 seconds, and then annealed in a nitrogen atmosphere at a temperature of 100° C. The annealing time was 40 minutes, and an organic active layer with a thickness of 40 nm was obtained.

[0064] Prepare electrodes: Stick the mask with source and drain electrode patterns on the organic active layer with high-temperature conductive tape. The gold was evaporated at a rate of 1.50 nm and the thickness of gold was controlled at 50 nm. After the evaporation was completed, a 1.5 cm long copper conductive tape was attached to the bottom of the silicon wafer and the gate electrode was led out to complete the organic field effect transistor. The cross section and top view of the obtained organic field effect transistor are shown in the figure below. Figure 1 shown.

[0065] Comparative Example

[0066] The preparation of an organic field effect transistor comprises the following steps:

[0067] Preparation of organic active layer: Use 100nm oxide layer silicon wafer as substrate, cut the silicon wafer into 2cm×2cm small squares; pour 6mg poly 3-hexylthiophene into 1mL chlorobenzene, and perform ultrasonic vibration for 15 minutes to evenly disperse poly 3-hexylthiophene in chlorobenzene to obtain 6mg / mL poly 3-hexylthiophene solution. After that, spin coat the poly 3-hexylthiophene solution on the silicon wafer at a speed of 2500r / min for 30s, and then anneal it in a nitrogen atmosphere at 100℃. The annealing time is 40 minutes, and an organic active layer with a thickness of 40nm is obtained.

[0068] Prepare electrodes: Stick the mask with source and drain electrode patterns on the organic active layer with high-temperature conductive tape. The gold was evaporated at a rate of 50 nm. After the evaporation was completed, a 1.5 cm long copper conductive tape was attached to the bottom of the silicon wafer, and the gate electrode was led out to complete the organic field effect transistor.

[0069] Performance testing experiment

[0070] The photoelectric response performance of the embodiment is improved compared with that of the comparative example. The light-induced postsynaptic current change of the embodiment is about 5.5 nA, while the light-induced postsynaptic current of the comparative example is almost unchanged.

[0071] Specifically, the performance test of the organic field effect transistor prepared in this embodiment is carried out by using a Keysight B2902A digital source meter, a commercial near-infrared light source (980 nm) and an optical power meter (Thorlabs).

[0072] The electrical performance test results of the organic field effect transistor prepared in this embodiment are as follows: Figure 2 As can be seen from the figure, the organic long-effect transistor prepared in this embodiment has a good on-off ratio in a wide voltage range.

[0073] The photoelectric test results of the organic field effect transistor prepared in this embodiment are as follows: Figure 3 As can be seen from the figure, the organic long-effect transistor prepared in this embodiment has a synaptic-like current response under the regulation of near-infrared light pulses.

[0074] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. An organic field effect transistor, characterized in that: The structure of the organic field effect transistor is, from bottom to top, a substrate, a gate electrode, a quantum dot layer, an organic active layer and a source-drain electrode; Wherein, the material used in the quantum dot layer is up-conversion quantum dots.

2. The organic field effect transistor according to claim 1, characterized in that: The thickness of the quantum dot layer is 5-20 nm, and the material used in the quantum dot layer is one or more of NaGdF4:Yb / Er, LaF3:Yb / Ho, and LaF3:Yb / Er.

3. The organic field effect transistor according to claim 1, characterized in that: The thickness of the organic active layer is 30-50 nm, and the material used in the organic active layer is one or more of poly 3-hexylthiophene, pentacene, and tetracene.

4. The organic field effect transistor according to claim 1, characterized in that: The substrate is selected from silicon wafer, plastic PET or glass, the gate electrode is made of a material selected from silicon, gold, aluminum, copper or silver, and the source and drain electrodes are made of a material selected from gold, aluminum, copper or silver.

5. A method for preparing an organic field effect transistor according to claim 1, characterized in that: The preparation method comprises the following steps: preparing an upconversion quantum dot solution and an organic active solution; Coating the upconversion quantum dot solution on the surface of the substrate, performing a first annealing to form a quantum dot layer; Coating the organic active solution on the surface of the quantum dot layer, and performing a second annealing to form an organic active layer; Vapor depositing source and drain electrodes on the surface of the organic active layer; The gate electrode is led out using a conductive copper tape at the bottom of the substrate.

6. The method for preparing an organic field effect transistor according to claim 5, characterized in that: In the upconversion quantum dot solution, the concentration of upconversion quantum dots is 0.2-0.6 mg / mL; In the organic active solution, the concentration of the organic active substance is 2-10 mg / mL.

7. The method for preparing an organic field effect transistor according to claim 5, characterized in that: The step of coating the upconversion quantum dot solution on the surface of the substrate and performing a first annealing to form a quantum dot layer is specifically as follows: spin coating the upconversion quantum dot solution on the surface of the substrate at a spin coating speed of 2000-2500 r / min for 20-30 seconds, and then annealing at a temperature of 70-150° C. for 15-60 minutes to form a quantum dot layer.

8. The method for preparing an organic field effect transistor according to claim 5, characterized in that: The step of coating the organic active solution on the surface of the quantum dot layer and performing a second annealing to form an organic active layer is specifically as follows: spin coating the organic active solution on the surface of the quantum dot layer at a spin coating speed of 2000-2500 r / min for 20-30 seconds, and then annealing at a temperature of 70-150° C. for 15-60 minutes to form an organic active layer.

9. The method for preparing an organic field effect transistor according to claim 5, characterized in that: The step of evaporating the source and drain electrodes on the surface of the organic active layer is specifically as follows: a mask plate engraved with the source and drain electrodes is attached to the surface of the organic active layer, and then Evaporate source and drain electrodes.

10. Application of the organic field effect transistor according to claim 1 in the field of photoelectric detection, imaging, sensor chip or neuromorphic computing technology.

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