Preparation process for realizing high-sensitivity organic field effect transistor gas sensor by using donor-acceptor type molecules

Abstract

The invention provides a process for preparing a high-sensitivity organic field effect transistor gas sensor by using donor-receptor type molecules, and belongs to the technical field of gas sensors. According to the invention, weak interaction force is generated when the D-A type molecular layer is in contact with the gas to be detected, so that intramolecular charge transfer occurs, the dipole distance of the D-A type molecules is changed, and the current flowing through the source and drain electrodes of the organic field effect transistor is changed, so that the response speed and sensitivity of the field effect transistor are enhanced. The result of the embodiment shows that the migration rate of the organic field effect transistor gas sensor provided by the invention is 0.3-2cm < 2 > V <-1 > s <-1 >, and the detection responsivity of the organic field effect transistor gas sensor to nitric oxide with the concentration of 1ppm can reach 21%.

Description

Technical Field

[0001] The present invention relates to the technical field of gas sensors, and in particular to a preparation process for realizing a high-sensitivity organic field-effect transistor gas sensor by utilizing donor-acceptor molecules. Background Art

[0002] To detect harmful gases in a timely manner, there is an increasing demand for efficient and portable gas sensors. Organic field-effect transistors (OFETs) have attracted widespread attention in the field of gas sensor research due to their small size, portability, and efficient signal conversion and amplification.

[0003] An organic field-effect transistor (OFET) consists of a gate, a dielectric layer, an organic semiconductor layer, and source and drain electrodes. The organic semiconductor layer (OSC) is the core layer and serves as the third working electrode in the OFET. It controls the current flowing between the source and drain electrodes in conjunction with the gate voltage, achieving electrical switching.

[0004] At present, people have studied and developed organic field-effect transistors with acene, thiophene, and phthalocyanine materials as organic semiconductor layers, and have realized the detection of various chemical gases such as nitrogen dioxide, DMMP, hydrogen sulfide, and hydrogen chloride. However, the mobility of these organic semiconductor layers is generally low, resulting in slow response speed and low sensitivity of organic field-effect transistors when used for gas detection. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation process for a high-sensitivity organic field-effect transistor gas sensor using donor-acceptor molecules. The organic field-effect transistor gas sensor provided by the present invention can detect the concentration and type of multiple gases with fast response speed and high sensitivity.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides an organic field-effect transistor gas sensor, comprising an organic field-effect transistor and a DA-type molecular layer; the organic field-effect transistor comprises a gate electrode, a dielectric layer, an organic semiconductor layer and a source-drain electrode; the DA-type molecular layer is located on the upper surface of one or more layers of the gate electrode, the dielectric layer, the organic semiconductor layer and the source-drain electrode.

[0008] Preferably, the DA type molecules in the DA type molecular layer include Nile red, polypyrrolopyrrole diketo-thiophene-thienothiophene, Nile blue, rhodamine dyes, boron-dipyrromethyl dyes or quinacridone.

[0009] Preferably, the DA type molecules in the DA type molecular layer include Nile Red or polypyrrolopyrrole diketo-thiophene-thienothiophene.

[0010] Preferably, it is characterized in that the number of layers of the DA type molecular layer is 1 to 4.

[0011] Preferably, the thickness of each DA type molecular layer is independently 3 to 100 nm.

[0012] Preferably, the DA type molecular layer is located on the upper surface of the dielectric layer and / or the organic semiconductor layer.

[0013] Preferably, the organic field effect transistor is of a bottom-gate top-contact type, a bottom-gate bottom-contact type, a top-gate top-contact type or a top-gate bottom-contact type.

[0014] The present invention also provides a method for preparing the organic field effect transistor gas sensor according to the above technical solution, comprising: depositing an organic field effect transistor structure and a DA type molecular layer on a substrate.

[0015] The present invention also provides the use of the organic field effect transistor gas sensor described in the above technical solution or the organic field effect transistor gas sensor prepared by the preparation method of the organic field effect transistor gas sensor described in the above technical solution in gas detection.

[0016] Preferably, the gas includes an environmental quality-related gas or a human health-indicative gas.

[0017] The present invention provides an organic field effect transistor gas sensor, comprising an organic field effect transistor and a DA type molecular layer; the organic field effect transistor comprises a gate electrode, a dielectric layer, an organic semiconductor layer and a source-drain electrode; the DA type molecular layer is located on the upper surface of one or more layers of the gate electrode, the dielectric layer, the organic semiconductor layer and the source-drain electrode. The present invention utilizes the weak interaction force generated when the DA type molecular layer contacts the gas to be measured, thereby causing intramolecular charge transfer, changing the dipole moment of the DA type molecule, causing the current flowing through the source-drain electrode of the organic field effect transistor to change, thereby enhancing the response speed and sensitivity of the field effect transistor. The results of the embodiment show that the mobility of the organic field effect transistor gas sensor provided by the present invention is 0.3 to 2 cm 2 V -1 s -1 The detection response of nitric oxide at a concentration of 1 ppm can reach 21%. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A cross-sectional view of an organic field effect transistor gas sensor according to Example 1 of the present invention;

[0019] Figure 2 Response curves of the organic field effect transistor gas sensors in Example 1 of the present invention and Comparative Example 1 to different concentrations of nitric oxide are shown. DETAILED DESCRIPTION

[0020] The invention provides an organic field effect transistor gas sensor, comprising an organic field effect transistor and a DA type molecular layer.

[0021] The organic field effect transistor gas sensor provided by the present invention comprises an organic field effect transistor, which comprises a gate electrode, a dielectric layer, an organic semiconductor layer and a source-drain electrode.

[0022] The present invention does not specifically limit the distribution of the gate electrode, dielectric layer, organic semiconductor layer, and source / drain electrode; appropriate types may be selected based on common knowledge in the art. In the present invention, the organic field-effect transistor is preferably a bottom-gate top-contact type, a bottom-gate bottom-contact type, a top-gate top-contact type, or a top-gate bottom-contact type.

[0023] In the present invention, the gate electrode preferably includes indium tin oxide, aluminum or P-type highly doped silicon doped with boron. The present invention improves the mobility of carriers by limiting the type of gate, thereby improving the responsiveness of the device.

[0024] In the present invention, the thickness of the gate electrode is preferably 10 to 150 nm. In specific embodiments of the present invention, the thickness of the gate electrode can be 10 nm, 20 nm, 30 nm, 50 nm, 100 nm, 120 nm, or 150 nm. By limiting the thickness of the gate electrode, the present invention further suppresses the tunneling effect and reduces leakage current, thereby improving the stability of the organic field-effect transistor.

[0025] In the present invention, the dielectric layer preferably includes polymethyl methacrylate, dichloroparaxylene dimer, polystyrene, polyvinyl alcohol or polyimide. The present invention limits the type of dielectric layer to ensure more effective prevention of gate electrode current leakage or short circuit.

[0026] In the present invention, the thickness of the dielectric layer is preferably 100 to 2000 nm. In specific embodiments of the present invention, the thickness of the dielectric layer can be 100 nm, 200 nm, 300 nm, 500 nm, 700 nm, 900 nm, 1200 nm, 1500 nm, 1700 nm, or 2000 nm. By limiting the thickness of the dielectric layer, the present invention achieves a more effective isolation effect while ensuring higher sensitivity of the organic field-effect transistor.

[0027] In the present invention, the organic semiconductor layer preferably includes pentacene, dinaphthothienothiophene, poly-3-hexylthiophene, 8-benzothiophene dimethylbenzothiophene, poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazole-4,8-diyl)], or copper phenol cyanine. By limiting the type of organic semiconductor material, the present invention achieves higher mobility and faster response of the organic field-effect transistor.

[0028] In the present invention, the thickness of the organic semiconductor layer is preferably 10 to 200 nm. In specific embodiments of the present invention, the thickness of the organic semiconductor layer can be 10, 50, 100, 150, or 200 nm. By limiting the thickness of the organic semiconductor layer, the present invention substantially reduces the carrier transmission path, thereby further improving the response speed of the organic field-effect transistor.

[0029] In the present invention, the source-drain electrodes preferably include gold, silver or aluminum. The present invention provides carriers and receives current more fully by limiting the types of source-drain electrodes.

[0030] In the present invention, the thickness of the source-drain electrode is preferably 20 to 200 nm. In specific embodiments of the present invention, the thickness of the source-drain electrode can be 20 nm, 50 nm, 100 nm, 150 nm, or 200 nm. By limiting the thickness of the source-drain electrode, the present invention further reduces the transmission distance of electrons in the transistor, thereby improving the response speed.

[0031] The organic field effect transistor gas sensor provided by the present invention further comprises a DA type molecular layer, which is located on the upper surface of one or more layers of the gate electrode, the dielectric layer, the organic semiconductor layer and the source / drain electrode.

[0032] The present invention limits the position of the DA-type molecular layer to ensure that the DA-type molecular layer can more fully contact the gas to be measured, generate a weak interaction force, cause intramolecular charge transfer, change the dipole moment of the DA-type molecules, and change the current flowing through the source and drain electrodes of the organic field-effect transistor, thereby enhancing the response speed and sensitivity of the field-effect transistor.

[0033] In the present invention, the DA-type molecules in the DA-type molecular layer preferably include Nile Red, polypyrrolopyrrole diketo-thiophene-thienothiophene, Nile Blue, rhodamine dyes, boron-dipyrromethyl dyes, or quinacridones, and more preferably Nile Red or polypyrrolopyrrole diketo-thiophene-thienothiophene. By limiting the types of DA-type molecules in the DA-type molecular layer, the present invention more fully generates weak interactions with harmful gases, causing intramolecular charge transfer and changing the dipole moment of the DA-type molecules, thereby changing the current flowing through the source and drain electrodes of the organic field-effect transistor and enhancing the response speed and sensitivity of the field-effect transistor.

[0034] In the present invention, the DA-type molecular layer is at least one layer, preferably at least two layers. As one embodiment of the present invention, the number of layers of the DA-type molecular layer is 1 to 4 layers. In a specific embodiment of the present invention, the DA-type molecular layer may be specifically 1 layer, 2 layers, 3 layers or 4 layers. In the present invention, the thickness of each layer of the DA-type molecular layer is independently 3 to 100 nm. As one embodiment of the present invention, the thickness of each layer of the DA-type molecular layer is independently 10 to 50 nm. In a specific embodiment of the present invention, the thickness of each layer of the DA-type molecular layer may be independently 10 nm, 20 nm, 30 nm, 40 nm or 50 nm. The present invention further improves the ability to generate sufficient weak interaction forces with harmful gases by limiting the number of DA-type molecular layers and the thickness of each layer of the DA-type molecular layer, causing intramolecular charge transfer, changing the dipole moment of the DA-type molecule, causing the current flowing through the source and drain electrodes of the organic field-effect transistor to change, and enhancing the response speed and sensitivity of the field-effect transistor.

[0035] As one embodiment of the present invention, the DA-type molecule layer can be located on the upper surface of the dielectric layer and / or the organic semiconductor layer. When the DA-type molecule layer is located on the upper surface of the dielectric layer, the DA-type molecules directly contact the harmful gas, resulting in a change in dipole moment due to weak interaction forces, intramolecular charge transfer, and enhanced current response of the semiconductor layer. When the DA-type molecule layer is located on the upper surface of the organic semiconductor layer, the harmful gas molecules pass through the semiconductor layer and interact with the DA-type molecules, generating intramolecular charge transfer, modulating the carrier transport channel, and improving the sensing response.

[0036] The present invention also provides a method for preparing the organic field effect transistor gas sensor described in the above technical solution, which comprises depositing an organic field effect transistor structure and a DA type molecular layer on a substrate.

[0037] In the present invention, the substrate is preferably a glass substrate or highly doped p-type silicon. The present invention limits the type of substrate to more fully support the manufactured organic field effect transistor gas sensor, making the manufactured organic field effect transistor gas sensor more stable.

[0038] In the present invention, the deposition method of the organic field effect transistor gas sensor is preferably vacuum coating.

[0039] The present invention also provides the application of the organic field effect transistor gas sensor described in the above technical solution in gas detection.

[0040] In the present invention, the gas preferably includes an environmental quality-related gas or a human health-indicating gas. In the present invention, the environmental quality-related gas preferably includes carbon dioxide, hydrogen, ammonia, hydrogen sulfide, sulfur dioxide, or nitrogen dioxide. In the present invention, the human health-indicating gas preferably includes ammonia, nitric oxide, oxygen, or carbon dioxide.

[0041] In the present invention, the method for detecting environmental quality-related gases or human health-indicative gases by the organic field-effect transistor gas sensor preferably includes: connecting the source, drain, and gate of the organic field-effect transistor gas sensor to the probes of a semiconductor current-voltage tester, respectively, and then applying a voltage to the gate electrode and drain after contact with the gas to be measured, and recording the current change value of the semiconductor current-voltage tester.

[0042] In the present invention, the applied voltage is preferably 0 to 100 V. As an embodiment, the applied voltage may be 2 to 80 V. In an embodiment of the present invention, the applied voltage may specifically be 2 V, 10 V, 20 V, 30 V, 40 V, 50 V, 60 V, 70 V, 80 V, 90 V, or 100 V.

[0043] The present invention utilizes the weak interaction force generated when the DA-type molecular layer contacts harmful gases, thereby causing intramolecular charge transfer, changing the dipole moment of the DA-type molecules, and causing the current flowing through the source and drain electrodes of the organic field-effect transistor to change, thereby enhancing the response speed and sensitivity of the field-effect transistor.

[0044] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0045] Example 1

[0046] An organic field effect transistor gas sensor, such as Figure 1 As shown, the bottom-gate, top-contact organic field-effect transistor (FOET) and a DA-type molecular layer are composed of a 200nm thick indium tin oxide (ITO) gate electrode, a 500nm thick dichloro-p-xylene dimer dielectric layer, a 50nm thick dinaphthothienothiophene organic semiconductor layer, and a 50nm thick gold source / drain electrode, all arranged sequentially on the upper surface of the substrate. The 3nm thick Nile Red DA-type molecular layer is located on the upper surface of the organic semiconductor layer. The mobility of the organic field-effect transistor gas sensor in Example 1 was measured using an LCR digital bridge and a semiconductor current-voltage tester to be 1.20cm2 V -1 s -1 The preparation method of the above-mentioned organic field effect transistor gas sensor is as follows: using a glass substrate as a substrate, vacuum sputtering depositing a 200nm indium tin oxide gate electrode on the substrate, then using a CO2 laser cutting machine to cut the glass substrate with the deposited indium tin oxide gate electrode into 20mm×20mm pieces, and then vacuum evaporating the indium tin oxide gate electrode. A 500 nm thick dichloroparaxylene dimer dielectric layer, a 50 nm thick dinaphthothienothiophene organic semiconductor layer, a 3 nm thick Nile Red DA type molecular layer and a 50 nm thick gold source and drain electrode were sequentially deposited at a rate of 100 nm to obtain an organic field effect transistor gas sensor.

[0047] The organic field-effect transistor gas sensor was connected to a semiconductor current-voltage tester. The semiconductor current-voltage tester was then placed in 1-20 ppm hydrogen sulfide gas. A voltage of -10 V was applied to the gate and drain electrodes, and the current change of the semiconductor current-voltage tester was recorded. The results showed that the organic field-effect transistor gas sensor prepared by the present invention exhibited current changes in 1-20 ppm hydrogen sulfide gas, with a response of 12.1% to 1 ppm hydrogen sulfide gas and a detection limit of 100 ppb. Therefore, the organic field-effect transistor gas sensor prepared by the present invention can accurately detect 1-20 ppm hydrogen sulfide gas with high sensitivity.

[0048] Example 2

[0049] An organic field-effect transistor gas sensor comprises a bottom-gate, top-contact organic field-effect transistor and a DA-type molecular layer. The bottom-gate, top-contact organic field-effect transistor comprises: a 200nm-thick indium tin oxide gate electrode, a 500nm-thick polymethyl methacrylate dielectric layer, a 30nm-thick pentacene organic semiconductor layer, and a 50nm-thick gold source-drain electrode, sequentially disposed on the upper surface of a substrate; and a 20nm-thick polypyrrolopyrrole-diketone-thiophene-thienothiophene DA-type molecular layer located on the upper surface of the dielectric layer.

[0050] The preparation method of the above-mentioned organic field effect transistor gas sensor is as follows: using highly doped p-type silicon as a substrate, vacuum sputtering depositing a 200nm thick indium tin oxide gate electrode on the substrate, then using a laser cutting machine to cut the glass substrate with the deposited indium tin oxide gate electrode into 20mm×20mm pieces, and then using a sol-gel method to prepare a 500nm thick polymethyl methacrylate dielectric layer on the indium tin oxide gate electrode, and then using a vacuum evaporation method to A polypyrrolopyrrole diketo-thiophene-thienothiophene DA type molecular layer with a thickness of 20 nm, a pentacene organic semiconductor layer with a thickness of 30 nm and a gold source-drain electrode with a thickness of 50 nm were sequentially deposited at a rate to obtain an organic field-effect transistor gas sensor.

[0051] The mobility of the organic field effect transistor gas sensor of Example 2 was measured to be 0.50 cm-1 using an LCR digital bridge and a semiconductor current-voltage tester. 2 V -1 s -1 .

[0052] The organic field-effect transistor gas sensor was connected to a semiconductor current-voltage tester. The semiconductor current-voltage tester was then placed in 1-20 ppm nitrogen dioxide gas. A voltage of -10 V was applied to the gate and drain electrodes, and the current change value of the semiconductor current-voltage tester was recorded. The results showed that the organic field-effect transistor gas sensor prepared by the present invention exhibited current changes in 1-20 ppm nitrogen dioxide gas. The response to 1 ppm nitrogen dioxide gas reached 35.3%, and the detection limit reached the 100 ppb level. Therefore, the organic field-effect transistor prepared by the present invention can accurately detect 1-20 ppm nitrogen dioxide gas with high sensitivity.

[0053] Example 3

[0054] The difference between this embodiment and embodiment 2 is that the Nile Red DA type molecule layer with a thickness of 10 nm is located on the upper surface of the organic semiconductor layer.

[0055] The mobility of the organic field effect transistor gas sensor of Example 3 was measured to be 0.80 cm-1 using an LCR digital bridge and a semiconductor current-voltage tester. 2 V -1 s -1 .

[0056] The organic field-effect transistor gas sensor was connected to a semiconductor current-voltage tester. The semiconductor current-voltage tester was then placed in 1-20 ppm ammonia gas. A voltage of -10 V was applied to the gate and drain electrodes, and the current change of the semiconductor current-voltage tester was recorded. The results showed that the organic field-effect transistor gas sensor prepared by the present invention exhibited current changes in 1-20 ppm ammonia gas, with a response of 8.1% to 1 ppm ammonia gas and a detection limit of 100 ppb. Therefore, the organic field-effect transistor prepared by the present invention can accurately detect 1-100 ppm ammonia gas with high sensitivity.

[0057] Example 4

[0058] The difference between this embodiment and embodiment 1 is that the dinaphthothienothiophene organic semiconductor layer is replaced by a pentacene organic semiconductor layer, and the rest is the same as embodiment 1.

[0059] The mobility of the organic field effect transistor gas sensor of Example 4 was measured to be 2.00 cm-1 using an LCR digital bridge and a semiconductor current-voltage tester. 2 V -1 s -1 .

[0060] The organic field-effect transistor gas sensor was connected to a semiconductor current-voltage tester. The semiconductor current-voltage tester was then placed in 1-20 ppm sulfur dioxide gas. A voltage of -10 V was applied to the gate and drain electrodes, and the current change value of the semiconductor current-voltage tester was recorded. The results showed that the organic field-effect transistor gas sensor prepared by the present invention exhibited current changes in sulfur dioxide gas concentrations of 1-20 ppm, with a response of 18.6% to 1 ppm sulfur dioxide gas and a detection limit of 100 ppb. Therefore, the organic field-effect transistor prepared by the present invention can accurately detect sulfur dioxide gas concentrations of 1-20 ppm with high sensitivity.

[0061] Example 5

[0062] The difference between this embodiment and embodiment 1 is that the dinaphthothienothiophene organic semiconductor layer is replaced by a poly (3-hexylthiophene) organic semiconductor layer, and the rest is the same as embodiment 1.

[0063] The mobility of the organic field effect transistor gas sensor of Example 5 was measured to be 0.30 cm-1 using an LCR digital bridge and a semiconductor current-voltage tester. 2 V -1 s -1 .

[0064] The organic field-effect transistor gas sensor was connected to a semiconductor current-voltage tester. The semiconductor current-voltage tester was then placed in 1-20 ppm ammonia gas. A voltage of -10 V was applied to the gate and drain electrodes, and the current change of the semiconductor current-voltage tester was recorded. The results showed that the organic field-effect transistor gas sensor prepared by the present invention exhibited current changes in 1-20 ppm ammonia gas, with a response of 7.1% to 1 ppm ammonia gas and a detection limit of 100 ppb. Therefore, the organic field-effect transistor prepared by the present invention can accurately detect 1-20 ppm ammonia gas with high sensitivity.

[0065] Example 6

[0066] The difference between this embodiment and embodiment 1 is that the dinaphthothienothiophene organic semiconductor layer is replaced by an 8-benzothiophenedimethylbenzothiophene organic semiconductor layer, and the rest is the same as embodiment 1.

[0067] The mobility of the organic field effect transistor gas sensor of Example 6 was measured to be 0.75 cm-1 using an LCR digital bridge and a semiconductor current-voltage tester. 2 V -1 s -1 .

[0068] The organic field-effect transistor gas sensor was connected to a semiconductor current-voltage tester. The semiconductor current-voltage tester was then placed in 1-20 ppm hydrogen sulfide gas. A voltage of -10 V was applied to the gate and drain electrodes, and the current change value of the semiconductor current-voltage tester was recorded. The results showed that the organic field-effect transistor gas sensor prepared by the present invention exhibited current changes in 1-20 ppm hydrogen sulfide gas. The response to 1 ppm hydrogen sulfide gas reached 11.8%, and the detection limit reached the 100 ppb level. Therefore, the organic field-effect transistor prepared by the present invention can detect 1-20 ppm hydrogen sulfide gas with high sensitivity.

[0069] Example 7

[0070] The difference between this embodiment and embodiment 1 is that the dinaphthothienothiophene organic semiconductor layer is replaced by a poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alternative-(benzo[2,1,3]thiadiazole-4,8-diyl)] organic semiconductor layer, and the rest is the same as embodiment 1.

[0071] The mobility of the organic field effect transistor gas sensor of Example 7 was measured to be 0.43 cm-1 using an LCR digital bridge and a semiconductor current-voltage tester. 2 V -1 s -1 .

[0072] The organic field-effect transistor gas sensor was connected to a semiconductor current-voltage tester. The semiconductor current-voltage tester was then placed in 1-20 ppm sulfur dioxide gas. A voltage of -10 V was applied to the gate and drain electrodes, and the current change value of the semiconductor current-voltage tester was recorded. The results showed that the organic field-effect transistor gas sensor prepared by the present invention exhibited current changes in sulfur dioxide gas concentrations of 1-20 ppm, with a response of 10.1% to 1 ppm sulfur dioxide gas and a detection limit of 100 ppb. Therefore, the organic field-effect transistor prepared by the present invention can accurately detect sulfur dioxide gas concentrations of 1-20 ppm with high sensitivity.

[0073] Example 8

[0074] The difference between this embodiment and embodiment 2 is that the pentacene organic semiconductor layer is replaced by a dinaphthothienothiophene organic semiconductor layer, and the rest is the same as embodiment 2.

[0075] The mobility of the organic field effect transistor gas sensor of Example 8 was measured to be 0.50 cm 2 V -1 s -1 .

[0076] The organic field-effect transistor gas sensor was connected to a semiconductor current-voltage tester. The semiconductor current-voltage tester was then placed in 1-20 ppm ammonia gas. A voltage of -10 V was applied to the gate and drain electrodes, and the current change value of the semiconductor current-voltage tester was recorded. The results showed that the organic field-effect transistor gas sensor prepared by the present invention exhibited current changes in 1-20 ppm ammonia gas, with a response of 8.6% to 1 ppm ammonia gas and a detection limit of 100 ppb. Therefore, the organic field-effect transistor prepared by the present invention can accurately detect 1-20 ppm ammonia gas with high sensitivity.

[0077] Comparative Example 1

[0078] The difference between this comparative example and Example 1 is that the DA type molecular layer is not used, and the rest is the same as Example 1.

[0079] The mobility of the organic field effect transistor gas sensor prepared in Comparative Example 1 was tested using an LCR digital bridge measurement and a semiconductor current-voltage tester, and the mobility was found to be 1.0 cm 2 V -1 s -1 .

[0080] In order to detect the response speed of the organic field effect transistor gas sensors prepared in Example 1 and Comparative Example 1, the prepared organic field effect transistor gas sensors were connected to a semiconductor current-voltage tester, and then the semiconductor current-voltage tester was placed in 1 ppm, 2 ppm, 5 ppm, 10 ppm, 15 ppm and 20 ppm nitric oxide gas, respectively. A voltage of -10 V was applied to the gate electrode and the drain electrode, and the current change value of the semiconductor current-voltage tester was recorded. The response curves of the organic field effect transistor gas sensors to different concentrations of nitric oxide were plotted, as shown in Tables 1 and Figure 2 As shown in the figure, it can be seen that the response value of the organic field effect transistor gas sensor prepared in the present invention to different concentrations of nitric oxide is much higher than that of comparative example 1, indicating that the organic field effect transistor gas sensor prepared in the present invention has a fast response speed.

[0081] Table 1 Response data of organic field effect transistor gas sensors prepared in Example 1 and Comparative Example 1 to different concentrations of nitric oxide gas

[0082] 1ppm 2ppm 5ppm 10ppm 15ppm 20ppm Example 1 21％ 101％ 325％ 636％ 1211％ 1988％ Comparative Example 1 6％ 25％ 125％ 266％ 489％ 889％

[0083] As can be seen from Table 1, the response values ​​of the organic field effect transistor gas sensor prepared in the present invention in nitric oxide gas at 1ppm, 2ppm, 5ppm, 10ppm, 15ppm and 20ppm are 21%, 101%, 325%, 636%, 1211% and 1988%, respectively. The response values ​​of the organic field effect transistor gas sensor prepared in Comparative Example 1 in nitric oxide gas at 1ppm, 2ppm, 5ppm, 10ppm, 15ppm and 20ppm are 6%, 25%, 125%, 266%, 489% and 889%, respectively. The response values ​​of the organic field effect transistor gas sensor prepared in the present invention to different concentrations of nitric oxide are much higher than those in Comparative Example 1, indicating that the organic field effect transistor gas sensor prepared in the present invention has a fast response speed.

[0084] In summary, the organic field-effect transistor gas sensor provided by the present invention can detect the concentrations and types of various gases, and has a fast response speed and high sensitivity.

[0085] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. An organic field-effect transistor gas sensor, comprising an organic field-effect transistor and a DA-type molecular layer; the organic field-effect transistor comprises a gate electrode, a dielectric layer, an organic semiconductor layer, and a source-drain electrode; the DA-type molecular layer is located on the upper surface of one or more layers of the gate electrode, dielectric layer, organic semiconductor layer, and source-drain electrode.

2. The organic field effect transistor gas sensor according to claim 1, characterized in that: The DA type molecules in the DA type molecular layer include Nile red, polypyrrolopyrrole diketo-thiophene-thienothiophene, Nile blue, rhodamine dyes, boron-dipyrromethyl dyes or quinacridone.

3. The organic field effect transistor gas sensor according to claim 1, characterized in that: The DA type molecules in the DA type molecular layer include Nile Red or polypyrrolopyrrole diketo-thiophene-thienothiophene.

4. The organic field effect transistor gas sensor according to any one of claims 1 to 3, characterized in that: The number of layers of the DA type molecular layer is 1 to 4.

5. The organic field effect transistor gas sensor according to claim 4, characterized in that: The thickness of each DA type molecular layer is independently 3 to 100 nm.

6. The organic field effect transistor gas sensor according to any one of claims 1 to 3, characterized in that: The DA type molecular layer is located on the upper surface of the dielectric layer and / or the organic semiconductor layer.

7. The organic field effect transistor gas sensor according to any one of claims 1 to 3, characterized in that: The organic field effect transistor is of bottom gate top contact type, bottom gate bottom contact type, top gate top contact type or top gate bottom contact type.

8. The method for preparing the organic field effect transistor gas sensor according to any one of claims 1 to 7, comprising: A field effect transistor structure and a DA type molecular layer are deposited on a substrate.

9. Use of the organic field effect transistor gas sensor according to any one of claims 1 to 7 or the organic field effect transistor gas sensor prepared by the preparation method according to claim 8 in gas detection.

10. The use according to claim 9, characterized in that The gas includes a gas related to environmental quality or a gas indicative of human health.

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