阅读说明：本技术 一种基于有机-无机异质结的光伏自驱动柔性气体传感器及其制备方法 (Photovoltaic self-driven flexible gas sensor based on organic-inorganic heterojunction and preparation method thereof ) 是由 谢光忠 陈春旭 苏元捷 潘虹 姚明亮 杨叶 蒋亚东 于 2020-04-27 设计创作，主要内容包括：本发明涉及一种基于有机-无机异质结的光伏自驱动柔性气体传感器及其制备方法,气体传感器包括由气敏薄膜与导电聚合物纳米纤维构成的太阳能收集模块,气敏薄膜的背面贴有导电玻璃作为电极A,导电聚合物纳米纤维的基底为制备有金属电极B的柔性有机基底,并用导电银浆粘合导电聚合物纳米纤维和电极B。本发明不需要外加偏压驱动,且本设计中的有机-无机异质结可直接利用内建电场和光伏特性实现持续自主地检测环境中待测气体浓度；自驱动柔性气体传感器可以显著降低功耗,同时也可以减小集成所需的空间；器件结构制作简单、易于集成并且能够充分收集太阳能并转换成电输出信号使得气体传感器持续自主地正常工作。(The invention relates to a photovoltaic self-driven flexible gas sensor based on an organic-inorganic heterojunction and a preparation method thereof. The invention does not need external bias drive, and the organic-inorganic heterojunction in the design can continuously and autonomously detect the concentration of the gas to be detected in the environment by directly utilizing the built-in electric field and the photovoltaic characteristic; the self-driven flexible gas sensor can remarkably reduce power consumption and reduce the space required by integration; the device structure is simple to manufacture and easy to integrate, and can fully collect solar energy and convert the solar energy into an electric output signal so that the gas sensor continuously and autonomously works normally.)

1. The utility model provides a flexible gas sensor of photovoltaic self-driven based on organic-inorganic heterojunction which characterized in that, gas sensor includes the solar energy collection module that comprises gas-sensitive film and conducting polymer nanofiber, the back of gas-sensitive film is posted has electrically conductive glass as electrode A, the flexible organic base of conducting polymer nanofiber's base for preparing metal electrode B to with electrically conductive silver thick liquid bonding conducting polymer nanofiber and electrode B.

2. The photovoltaic self-driven flexible gas sensor based on the organic-inorganic heterojunction as claimed in claim 1, wherein the heterojunction of the solar energy collection module effectively separates the photo-generated electron-hole pairs through the built-in electric field, and the photo-generated electron-hole pairs are respectively accumulated on two sides of the heterojunction along with drift motion under the action of the built-in electric field, so that a potential difference appears on two sides of the heterojunction.

3. The photovoltaic self-driven flexible gas sensor based on the organic-inorganic heterojunction as claimed in claim 1, wherein the material of the gas-sensitive thin film is a two-dimensional semiconductor material sensitive to a target gas.

4. The photovoltaic self-driven flexible gas sensor based on the organic-inorganic heterojunction as claimed in claim 3, wherein the material of the gas-sensitive thin film comprises a composite film formed by one or more different materials selected from transition metal sulfides, boron nitride, III-VI layered compounds, IV main group single sulfur compounds, black phosphorus, perovskite and graphene two-dimensional structure materials.

5. The organic-inorganic heterojunction based photovoltaic self-driven flexible gas sensor according to claim 1, wherein the conductive polymer nanofibers are loose and porous nanofibers characterized by a thin film morphology, and comprise poly-3 hexylthiophene, polyaniline, poly (ethylenedioxythiophene) -poly (styrenesulfonate).

6. The preparation method of the photovoltaic self-driven flexible gas sensor based on the organic-inorganic heterojunction as claimed in claim 1, characterized in that a gas-sensitive film is formed by depositing a two-dimensional structure material on conductive glass by a stripping process in combination with a spin coating or a spray coating or a drop coating method, and noble metal nanoparticles are modified on the gas-sensitive film by a hydrothermal synthesis method; one side of the conductive polymer nanofiber is fixed on a flexible organic substrate with an electrode pattern by adopting an electrostatic spinning combined in-situ polymerization process, and the other side of the conductive polymer nanofiber is in full contact with a gas-sensitive material to form an organic-inorganic heterojunction.

7. The preparation method of the photovoltaic self-driven flexible gas sensor based on the organic-inorganic heterojunction as claimed in claim 6, wherein the stripping process comprises an intercalation stripping method, a hydrothermal template assembly method and an ultrasonic stripping method.

8. The method for preparing the photovoltaic self-driven flexible gas sensor based on the organic-inorganic heterojunction as claimed in claim 6, wherein the noble metal comprises Au, Ag and Pd.

9. The preparation method of the photovoltaic self-driven flexible gas sensor based on the organic-inorganic heterojunction as claimed in any one of claims 1 to 8, is characterized by comprising the following steps:

(1) cleaning conductive glass and a flexible organic substrate by using a chemical reagent, drying and storing, and treating by using an ultraviolet cleaning machine before use:

(2) dispersing a two-dimensional semiconductor material in a mixed solution of ethanol and deionized water, processing by using an ultrasonic wall breaking machine of 285W to strip nano-sheets, and finally repeatedly cleaning by using the deionized water and the ethanol;

(3) adding chloroauric acid and methanol into deionized water dispersion liquid of the two-dimensional semiconductor material nanosheets, modifying the surfaces of the two-dimensional semiconductor material nanosheets by hydrothermally synthesizing noble metal nanoparticles, and finally repeatedly cleaning the nanosheets with deionized water and ethanol;

(4) depositing a two-dimensional material on conductive glass to form a gas-sensitive film by a spin coating or spray coating or drip coating method on a two-dimensional semiconductor material nanosheet modified by the noble metal nanoparticles, and drying and storing the gas-sensitive film;

(5) preparing a nanofiber framework from PPY and PVP materials through electrostatic spinning, preparing conductive polymer nanofibers through in-situ polymerization, and drying and storing;

(6) cutting out a flexible organic substrate by a laser cutting machine, and preparing a metal electrode pattern on the flexible organic substrate by evaporation;

(7) brushing a conductive silver paste thin layer on one side of an electrode pattern of the flexible organic substrate, transferring the conductive polymer nanofiber layer to one side coated with the conductive silver paste, and finally attaching the conductive glass to the flexible organic substrate to enable the gas sensitive material to be in contact with the conductive polymer material to form a heterojunction.

Technical Field

The invention relates to the technical field of energy collection technology, two-dimensional semiconductor materials and conductive polymer materials, in particular to a photovoltaic self-driven flexible gas sensor based on an organic-inorganic heterojunction and a preparation method thereof.

Background

With the rapid growth of industrial production and road transport, toxic gases entering the atmosphere have increased rapidly in recent years. Air pollution can harm the human brain by impairing cognitive ability, causing problems in decision making and daily routine. Furthermore, the world health organization has reported that millions of people die each year as a result of inhalation of contaminated air, which fact has caused widespread attention to air quality monitoring in the past few years.

The gas sensor is used for detecting harmful inorganic gas (NO)₂、NO、NH₃、H₂、CO₂Etc.) and volatile organic compounds (methane, triethylamine, benzene, etc.). In addition, gas sensors are also widely used in military, medical diagnostics, aerospace, industrial and agricultural processes, and other fields. Over the past several decades, various sensor technologies have been used for gas sensing, such as electrical conductance, optics, electrochemistry, thermoelectricity, and acoustics. With the increasing global demand for energy, solar energy obtained through various forms has attracted considerable interest due to its reliable, abundant and sustainable nature, including solar photovoltaic cells (PVC), solar heat and solar thermal power.

Among various gas detection technologies, the conventional chemiresistive gas sensor is operated at a high temperature, which limits its wide application. Furthermore, high temperature operation can also lead to instability of the sensor, inaccurate test results, and the risk of gas explosion. Therefore, it is urgent to lower the operating temperature of the gas sensor. And the existing gas sensor needs additional bias drive and has high energy consumption.

Disclosure of Invention

The invention aims to: the photovoltaic self-driven flexible gas sensor based on the organic-inorganic heterojunction and the preparation method thereof are provided, the unified functional module of solar energy collection and gas sensitivity test is realized, the sensor can realize self-driven gas detection at room temperature, and no external power supply is needed. The built-in electric field of the heterojunction in the sensor structure can widen a depletion region and separate photo-generated electron-hole pairs, and finally open-circuit voltage (Voc) appears at two ends of a p-n junction under illumination, so that continuous independent and autonomous work is realized without external power supply drive. Meanwhile, no current flows under the condition of zero bias voltage, and the signal response does not reflect the change of the conductivity characteristic of the gas sensitive material, namely the open circuit voltage (Voc) only reflects the change of the property of the p-n heterojunction. The surface of the gas sensitive material reacts with adsorbed gas molecules to cause the change of the concentration of majority molecules in the gas sensitive material, so that the width of a depletion region of a p-n heterojunction, namely a built-in electric field, is influenced, and finally, the output open-circuit voltage Voc is correspondingly changed along with the change of the chemical property and the concentration of the gas to be detected in the environment under the zero-bias test condition.

The technical scheme adopted by the invention is as follows:

the utility model provides a flexible gas sensor of photovoltaic self-driven based on organic-inorganic heterojunction, the gas sensor includes the solar energy collection module that comprises gas-sensitive film and conducting polymer nanofiber, the back of gas-sensitive film is pasted conductive glass as electrode A, the flexible organic base of conducting polymer nanofiber's base for preparing there is metal electrode B to with conductive silver thick liquid bonding conducting polymer nanofiber and electrode B.

The solar energy collecting function and the gas sensitive function are integrated in a unit and a device, and the gas sensitive film is combined with the conductive polymer nano-fiber to form the solar energy collecting module. The back of the gas-sensitive film is pasted with conductive glass as an electrode, and sunlight or working light is irradiated from the side. The substrate of the conductive polymer nanofiber is a flexible organic substrate prepared with a metal electrode pattern, and the conductive polymer nanofiber and the electrode are bonded by conductive silver paste. The output signal of the self-driven sensor is an open-circuit voltage Voc generated on the heterojunction by the sunlight collection module, and meanwhile, the surface of the gas sensitive material can react with adsorbed gas molecules to cause the change of the concentration of majority molecules in the gas sensitive material, so that the width of a depletion region of the p-n heterojunction, namely a built-in electric field, is influenced, and finally the output open-circuit voltage Voc is correspondingly changed under the test condition of 0 bias voltage.

Furthermore, the heterojunction of the solar energy collection module effectively separates the photo-generated electron-hole pairs through a built-in electric field, and the photo-generated electron-hole pairs are respectively accumulated on two sides of the heterojunction along with drift motion under the action of the built-in electric field, so that potential difference appears on two sides of the heterojunction.

Further, the material of the gas-sensitive film is a two-dimensional semiconductor material sensitive to the target gas.

Further, the material of the gas-sensitive thin film includes a transition metal sulfide (e.g., molybdenum disulfide (MoS)₂) Boron nitride, III-VI layered compounds, IV main group single sulfur compounds, black phosphorus, perovskite, graphene and the like, or a composite film formed by any one or more different materials.

Further, the conductive polymer nanofiber is a loose and porous nanofiber characterized by a film shape, and comprises poly-3 hexylthiophene, polyaniline and poly (ethylenedioxythiophene) -poly (styrenesulfonate).

In order to realize the purpose, the invention also provides a preparation method of the photovoltaic self-driven flexible gas sensor based on the organic-inorganic heterojunction, the two-dimensional structure material is deposited on the conductive glass by adopting a stripping process combined with a spin coating or spray coating or drop coating method to form a gas-sensitive film, and noble metal nano particles are modified on the gas-sensitive film by a hydrothermal synthesis method; one side of the conductive polymer nanofiber is fixed on a flexible organic substrate with an electrode pattern by adopting an electrostatic spinning combined in-situ polymerization process, and the other side of the conductive polymer nanofiber is in full contact with a gas-sensitive material to form an organic-inorganic heterojunction.

Further, the stripping process comprises an intercalation stripping method, a hydrothermal template assembly method and an ultrasonic stripping method.

Further, the noble metal comprises Au, Ag and Pd. The modification of the two-dimensional material can enhance the light absorption capability of the visible light wave band of the sensor.

The preparation method of the photovoltaic self-driven flexible gas sensor based on the organic-inorganic heterojunction specifically comprises the following steps:

(1) cleaning conductive glass and a flexible organic substrate by using a chemical reagent, drying and storing, and treating by using an ultraviolet cleaning machine before use;

(2) dispersing a two-dimensional semiconductor material in a mixed solution of ethanol and deionized water, processing by using an ultrasonic wall breaking machine of 285W to strip nano-sheets, and finally repeatedly cleaning by using the deionized water and the ethanol;

(3) adding chloroauric acid and methanol into deionized water dispersion liquid of the two-dimensional semiconductor material nanosheets, modifying the surfaces of the two-dimensional semiconductor material nanosheets by hydrothermally synthesizing noble metal nanoparticles, and finally repeatedly cleaning the nanosheets with deionized water and ethanol;

(4) depositing a two-dimensional material on conductive glass to form a gas-sensitive film by a spin coating or spray coating or drip coating method on a two-dimensional semiconductor material nanosheet modified by the noble metal nanoparticles, and drying and storing the gas-sensitive film;

(5) preparing a nanofiber framework from PPY (polypyrrole composite membrane) and PVP (crosslinked polyvinylpyrrolidone) materials through electrostatic spinning, preparing conductive polymer nanofibers through in-situ polymerization, and drying and storing;

(6) cutting out a flexible organic substrate by a laser cutting machine, and preparing a metal electrode pattern on the flexible organic substrate by evaporation;

(7) brushing a conductive silver paste thin layer on one side of an electrode pattern of the flexible organic substrate, transferring the conductive polymer nanofiber layer to one side coated with the conductive silver paste, and finally attaching the conductive glass to the flexible organic substrate to enable the gas sensitive material to be in contact with the conductive polymer material to form a heterojunction.

In summary, compared with the prior art, the invention has the following beneficial effects:

(1) the invention does not need external bias drive, and the organic-inorganic heterojunction in the design can continuously and autonomously detect the concentration of the gas to be detected in the environment by directly utilizing the built-in electric field and the photovoltaic characteristic;

(2) the self-driven flexible gas sensor provided by the invention can obviously reduce the power consumption and can also reduce the space required by integration;

(3) the device provided by the invention has the advantages of simple structure and easy integration, and can fully collect solar energy and convert the solar energy into an electric output signal so that the gas sensor continuously and autonomously works normally.

Drawings

FIG. 1 is a schematic diagram of a photovoltaic self-driven flexible gas sensor based on an organic-inorganic heterojunction according to the present invention;

FIG. 2 is a diagram of an energy collection mechanism of a photovoltaic self-driven flexible gas sensor based on an organic-inorganic heterojunction;

FIG. 3 is a diagram of a gas sensing mechanism of a photovoltaic self-driven flexible gas sensor based on an organic-inorganic heterojunction in an oxidizing gas (NO2) environment;

FIG. 4 shows a photovoltaic self-driven flexible gas sensor based on organic-inorganic heterojunction in reducing gas (CH)₃CH₂OH) environment.

The reference signs are: 1-electrode A, 2-electrode B, 3-gas-sensitive film, 4-conductive polymer nanofiber, 5-conductive glass and 6-flexible organic substrate.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.

The invention will be further described with reference to the accompanying figures 1-4 and examples.