Organic photovoltaic heterojunction passive multi-parameter gas sensor as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of gas sensing, and discloses an organic photovoltaic heterojunction passive multi-parameter gas sensor and a preparation method and application thereof, the organic photovoltaic heterojunction passive multi-parameter gas sensor comprises a bottom electrode, a hole transport layer, a heterojunction sensitive layer and a top electrode which are stacked in sequence; the heterojunction sensitive layer is an organic heterojunction sensitive layer formed by blending a donor and an acceptor; wherein the heterojunction sensitive layer adopts an organic photovoltaic polymer as an electron donor, adopts a non-fullerene small molecule as an electron acceptor, and is prepared by blending and spin-coating the organic photovoltaic polymer and the non-fullerene small molecule; the top electrode is a network-shaped silver nanowire electrode; the bottom electrode, the hole transport layer, the heterojunction sensitive layer and the top electrode are sequentially stacked to construct the gas sensor with an organic photovoltaic device structure, so that a multi-parameter gas sensing response mode is realized, and the sensitivity and selectivity of the sensor are remarkably improved; and accurate identification of types and concentrations of volatile organic compounds is realized.

Description

Technical Field

[0001] This invention belongs to the field of gas sensing technology, and specifically relates to an organic photovoltaic heterojunction passive multi-parameter gas sensor, its preparation method, and its application. Background Technology

[0002] Gas sensors play a crucial role in environmental monitoring, food quality control, medical and health care, aerospace, and military fields. Common gas sensors include metal-oxide-semiconductor (MOS) gas sensors, electrochemical gas sensors, and field-effect transistor (FET) gas sensors. Among them, MOS gas sensors are the most widely used, with advantages such as high sensitivity, simple manufacturing, and low cost. However, they have poor selectivity, usually require high temperatures to activate their gas-sensing characteristics, and the external heating unit also generates huge energy consumption. Although existing electrochemical gas sensors and FET gas sensors can be driven at room temperature, they all require an external power supply, resulting in increased energy consumption.

[0003] To address the aforementioned issues, self-powered gas sensors utilizing piezoelectric, triboelectric, or photovoltaic properties have been extensively studied. These sensors directly use piezoelectric voltage, triboelectric voltage, and photovoltaic current or voltage as gas-sensitive parameters to detect gases, aiming to reduce power consumption. Currently, although self-powered gas sensors based on piezoelectric, triboelectric, and photovoltaic effects have solved the energy consumption problem to some extent, they still suffer from limitations in sensitive materials and single gas-sensitive parameters, resulting in low selectivity. Specifically, existing self-powered gas sensors all employ a single-parameter response mode, such as open-circuit voltage or short-circuit current density, which is not conducive to constructing more accurate gas molecule "fingerprint" information and cannot solve the low selectivity problem caused by high cross-sensitivity of individual gas sensors. Summary of the Invention

[0004] To address the technical problems existing in the prior art, this invention provides an organic photovoltaic heterojunction passive multi-parameter gas sensor, its preparation method, and its application, in order to solve the technical problems of existing self-powered gas sensors having large limitations in sensitive materials and single gas-sensing parameters.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides an organic photovoltaic heterojunction passive multi-parameter gas sensor, comprising a bottom electrode, a hole transport layer, a heterojunction sensitive layer, and a top electrode stacked sequentially. The heterojunction sensitive layer is an organic heterojunction sensitive layer with donor and acceptor blends; wherein, the heterojunction sensitive layer uses an organic photovoltaic polymer as an electron donor and a non-fullerene small molecule as an electron acceptor, and is prepared by spin-coating a blend of organic photovoltaic polymer and non-fullerene small molecule. The top electrode is a network of silver nanowire electrodes.

[0006] Furthermore, the mass ratio of organic photovoltaic polymer to non-fullerene small molecules is 1:(1.2-2.0).

[0007] Furthermore, the organic photovoltaic polymer uses PM6, and the non-fullerene small molecule uses the Y-series small molecule acceptor; among them, the Y-series small molecule acceptor is one of Y5, Y6, BTP-4Cl, N3 and L8-BO.

[0008] Furthermore, both the hole transport layer and the top electrode are prepared by spin coating.

[0009] Furthermore, the hole transport layer has a thickness of 10-30 nm, the heterojunction sensitive layer has a thickness of 30-120 nm, and the top electrode has a thickness of 60-100 nm.

[0010] This invention also provides a method for fabricating an organic photovoltaic heterojunction passive multi-parameter gas sensor, comprising: A bottom electrode is fabricated on a pre-defined substrate to obtain a substrate with a bottom electrode; The substrate with the bottom electrode is pretreated to obtain the pretreated substrate with the bottom electrode. The transport layer solution is spin-coated onto the surface of the bottom electrode, annealed, and cooled to form a hole transport layer. The sensitive layer solution is spin-coated onto the surface of the hole transport layer, annealed, and cooled to form a heterojunction sensitive layer. A silver nanowire solution was spin-coated onto the surface of the heterojunction sensitive layer to form a top electrode, resulting in an organic photovoltaic heterojunction passive multi-parameter gas sensor.

[0011] Furthermore, the process of pretreating the substrate with the bottom electrode to obtain the pretreated substrate with the bottom electrode is as follows: The substrate with the bottom electrode was placed in acetone, detergent, deionized water and isopropanol solution in sequence for ultrasonic cleaning, and then dried to obtain the cleaned substrate with the bottom electrode. The cleaned substrate with the bottom electrode is subjected to O3 treatment or oxygen plasma treatment to obtain a pretreated substrate with the bottom electrode.

[0012] Furthermore, the transport layer solution is a poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) solution; the sensitive layer solution is formulated with organic photovoltaic polymers and non-fullerene small molecules.

[0013] Furthermore, the transport layer solution is spin-coated onto the surface of the bottom electrode, annealed, and cooled to form the hole transport layer. During this process, the annealing temperature is 120-150℃ and the annealing time is 10-20min. The sensitive layer solution is spin-coated onto the surface of the hole transport layer, annealed, and cooled to form a heterojunction sensitive layer. The annealing temperature is 80-150℃ and the annealing time is 10-20 minutes.

[0014] The present invention also provides an application of an organic photovoltaic heterojunction passive multi-parameter gas sensor for the detection of volatile organic compound gases.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: The organic photovoltaic heterojunction passive multi-parameter gas sensor provided by this invention constructs a gas sensor with an organic photovoltaic device structure by sequentially stacking a bottom electrode, a hole transport layer, a heterojunction sensitive layer, and a top electrode, thereby combining the functions of a solar organic cell and a gas sensor. The heterojunction sensitive layer is an organic heterojunction sensitive layer with donor-acceptor co-processing, which has non-covalent interactions with the gas to be measured. Based on the synergistic effect of the induced dipole moment caused by the adsorption of polar gas molecules by the heterojunction sensitive layer and the polymer swelling effect, the electrotransport capabilities such as carrier transport and interfacial barriers are affected, causing changes in the photoelectric conversion performance of the device. This allows for the extraction of short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency from the device's current density-voltage curve, representing... By inducing changes in the type or concentration of the gas to be detected, a multi-parameter gas sensing response mode is achieved, significantly improving the sensor's sensitivity and selectivity, and enabling accurate identification of the type and concentration of volatile organic compounds. Specifically, by introducing bottom and top electrodes, photoelectron-hole pairs are generated due to the photovoltaic effect. These photoelectron-hole pairs move under the influence of the built-in electric field between the bottom and top electrodes, and separate at the electron donor and electron acceptor of the heterojunction sensitive layer to form electrons and holes, i.e., charge carriers. During transport, some of the charge carriers recombine, while others move to the corresponding electrodes to form a current. Furthermore, by directly stacking the top electrode and the heterojunction sensitive layer, and using a network of silver nanowire electrodes for the top electrode, the diffusion resistance of gas molecules is reduced, the permeation rate is increased, and the response time of the gas sensor is effectively shortened.

[0016] The method for fabricating and applying the organic photovoltaic heterojunction passive multi-parameter gas sensor provided by this invention possesses all the advantages of the aforementioned organic photovoltaic heterojunction passive multi-parameter gas sensor. Attached Figure Description

[0017] Figure 1 A cross-sectional view of the structure of the organic photovoltaic heterojunction passive multi-parameter gas sensor provided by the present invention; Figure 2 This is a structural diagram of PM6 in this invention; Figure 3 This is a structural diagram of the Y-series small molecule receptor in this invention; Figure 4 A flowchart illustrating the fabrication method of the organic photovoltaic heterojunction passive multi-parameter gas sensor provided by the present invention; Figure 5 A schematic diagram illustrating the gas detection principle of the organic photovoltaic heterojunction passive multi-parameter gas sensor provided by the present invention in a passive multi-parameter state; Figure 6 This is a schematic diagram of the test chamber in Example 1; Figure 6 The attached diagram on the left shows the internal structure of the test chamber. Figure 6 The attached diagram on the right shows the front and back structural diagrams of the test chamber; Figure 7 The graph shows the JV curve changes of the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 1 before and after the introduction of 200 ppm formic acid gas. Figure 8 The graph shows the changes in multiple parameters of the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 1 in formic acid gas of different concentrations. Figure 9 The graph shows the changes in multiple parameters of the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 1 in different gases at 200 ppm. Figure 10 The graph shows the current variation of the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 1 under a 1V bias voltage for different concentrations of formic acid gas from 0 to 200 ppm. Figure 11 The current variation of the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 1 under 0V bias voltage for different concentrations of formic acid gas from 0 to 200 ppm is shown in the graph. Figure 12 The graph shows the changes in multiple parameters of the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 2 in different gases at 200 ppm. Figure 13 The graph shows the changes in multiple parameters of the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 3 in different gases at 200 ppm. Figure 14 The graph shows the multi-parameter variation of the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 4 in different gases at 200 ppm. Figure 15 This is a graph showing the multi-parameter variations of the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 5 in different gases at 200 ppm. Figure 16 The images show principal component analysis of different volatile organic compounds by the organic photovoltaic heterojunction passive multi-parameter gas sensors prepared in Examples 1-5.

[0018] The structure consists of 1 bottom electrode, 2 hole transport layer, 3 heterojunction sensitive layer, and 4 top electrode. Detailed Implementation

[0019] To make the technical problems solved by the present invention, the technical solutions, and the beneficial effects clearer, the following specific embodiments provide a further detailed description of the present invention. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention.

[0020] As attached Figure 1 As shown, the present invention provides an organic photovoltaic heterojunction passive multi-parameter gas sensor, comprising a bottom electrode 1, a hole transport layer 2, a heterojunction sensitive layer 3, and a top electrode 4 stacked sequentially; specifically, the hole transport layer 2 is disposed on the surface of the bottom electrode 1, the heterojunction sensitive layer 3 is disposed on the surface of the hole transport layer 2, and the top electrode 4 is disposed on the surface of the heterojunction sensitive layer 3.

[0021] In this invention, the hole transport layer 2, the heterojunction sensitive layer 3, and the top electrode 4 are all prepared by spin coating; wherein, the thickness of the hole transport layer 2 is 10-30 nm, the thickness of the heterojunction sensitive layer 3 is 30-120 nm, and the thickness of the top electrode 4 is 60-100 nm.

[0022] It should be noted that the heterojunction sensitive layer 3 is an organic heterojunction sensitive layer with a donor-acceptor blend. The heterojunction sensitive layer 3 uses an organic photovoltaic polymer as the electron donor and a non-fullerene small molecule as the electron acceptor, and is prepared by spin-coating a blend of the organic photovoltaic polymer and the non-fullerene small molecule. The mass ratio of the organic photovoltaic polymer to the non-fullerene small molecule is 1:(1.2-2.0). Preferably, the organic photovoltaic polymer is PM6, as shown in the attached figure. Figure 2 As shown; non-fullerene small molecules utilize Y-series small molecule acceptors, as shown in the attached image. Figure 3 As shown; among them, the Y-series small molecule receptors are one of Y5, Y6, BTP-4Cl, N3 and L8-BO.

[0023] The top electrode 4 is a network-shaped silver nanowire electrode; wherein the diameter of the silver nanowire is 15-30nm, so that the network formed on the heterojunction sensitive layer 3 is denser but the gap pore size is larger, and the top electrode and the heterojunction sensitive layer are directly stacked, so that the diffusion resistance of the gas molecules to be measured (such as formaldehyde, toluene and other VOCs) is small, the permeation rate is fast, and the response time of the gas sensor is effectively shortened.

[0024] Preparation method: As attached Figure 4 As shown, the method for fabricating an organic photovoltaic heterojunction passive multi-parameter gas sensor according to the present invention includes the following steps: Step 1: Fabricate a bottom electrode 1 on a pre-defined substrate to obtain a substrate with bottom electrode 1; pre-treat the substrate with bottom electrode 1 to obtain a pre-treated substrate with bottom electrode 1. Specifically, the process is as follows: Step 11: On a preset substrate, a bottom electrode 1 is prepared by vapor deposition process to obtain a substrate with bottom electrode 1.

[0025] Step 12: Place the substrate with bottom electrode 1 in acetone, detergent, deionized water and isopropanol solution in sequence for ultrasonic cleaning, and dry it after cleaning to obtain the cleaned substrate with bottom electrode 1; wherein, the ultrasonic cleaning with deionized water is repeated more than 5 times, and each cleaning is 15 minutes.

[0026] Step 13: Treat the cleaned substrate with bottom electrode 1 with O3 or oxygen plasma for 15-20 minutes to obtain the pretreated substrate with bottom electrode 1.

[0027] Step 2: Spin-coat the transport layer solution onto the surface of the bottom electrode 1, anneal and cool to form the hole transport layer 2. The transport layer solution is a poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) (PEDOT:PSS) solution.

[0028] Specifically, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) and deionized water are mixed in a mass ratio of 1:1 to obtain a transport layer solution. Then, the transport layer solution is spin-coated onto the surface of the bottom electrode 1 at a spin-coating speed of 3000-4500 r / min for 40-60 s. Next, it is annealed at 120-150℃ for 15-20 min and then cooled to room temperature to form the hole transport layer 2.

[0029] Step 3: Spin-coat the sensitive layer solution onto the surface of hole transport layer 2, anneal and cool to form heterojunction sensitive layer 3. The sensitive layer solution is formulated from organic photovoltaic polymers and non-fullerene small molecules.

[0030] Specifically, an organic photovoltaic polymer and non-fullerene small molecules are dissolved in chloroform to obtain a sensitive layer solution; wherein the total concentration of the organic photovoltaic polymer and non-fullerene small molecules in the sensitive layer solution is 8.8-13.2 mg / mL; then, the sensitive layer solution is spin-coated onto the surface of hole transport layer 2 at a spin-coating speed of 2000-4500 r / min for 20 s; then, it is annealed at 80-150℃ for 10-20 min, and then cooled to room temperature to form a heterojunction sensitive layer 3.

[0031] Step 4: Spin-coat the silver nanowire solution onto the surface of the heterojunction sensitive layer 3 to form the top electrode 4, thus obtaining the organic photovoltaic heterojunction passive multi-parameter gas sensor. Specifically, in a glove box under a nitrogen or argon atmosphere, spin-coat the isopropanol solution of Ag NWs onto the surface of the heterojunction sensitive layer to form the top electrode 4, thus obtaining the organic photovoltaic heterojunction passive multi-parameter gas sensor; wherein, the concentration of the isopropanol solution of Ag NWs is 7-9 mg / mL; the spin-coating speed is 1000-1500 r / min, and the time is 30-60 s.

[0032] Gas detection principle: The organic photovoltaic heterojunction passive multi-parameter gas sensor described in this invention detects volatile organic compound gases. It utilizes the photovoltaic effect of electron donors and acceptors in the heterojunction sensitive layer under illumination, combined with the synergistic effect of induced dipole moment caused by adsorbed polar gas molecules and polymer swelling, to influence carrier transport and interfacial barrier electrotransport capabilities. This causes changes in the device's photoelectric conversion performance, allowing the extraction of short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency from the device's current density-voltage curve. This characterizes the type or concentration change of the detected volatile organic compound gas, achieving a multi-parameter gas sensing response mode.

[0033] Specifically, as shown in the appendix Figure 5As shown, volatile organic compound (VOC) gas molecules easily permeate through the high porosity and high conductivity of the network-like silver nanowire electrode, smoothly entering the heterojunction sensitive layer, which is composed of donor and acceptor blends. When polar VOC molecules specifically adsorb onto the surface of the heterojunction sensitive layer, two core physicochemical effects are triggered simultaneously: first, the induced dipole moment effect, where the uneven charge distribution of polar gas molecules induces a local dipole field on the polymer molecular chain, which directly changes the mobility of charge carriers (electron-hole), interfering with their directional transport efficiency; second, the polymer swelling effect, where VOC molecules penetrate into the polymer network, increasing the inter-chain spacing and altering the conformation, thereby lengthening the charge carrier transport path and reducing its transport probability. Based on the synergistic effect of the induced dipole moment and polymer swelling, the regulation mechanism of electrical transport characteristics includes two aspects: in terms of charge carrier transport, the direction and intensity of the induced dipole field directly affect the drift velocity of the charge carriers, while the inter-chain spacing change induced by polymer swelling... Increasing carrier scattering probability leads to significant fluctuations in carrier mobility. At the interface barrier level, the contact interface between the heterojunction sensitive layer and the network of silver nanowire electrodes undergoes structural changes due to dipole field superposition and swelling, resulting in an upward or downward adjustment of the Schottky barrier height, directly affecting the injection efficiency of carriers from the electrode to the heterojunction sensitive layer. The combined changes in the aforementioned electrical transport characteristics directly affect the photoelectric conversion process of the device, as well as the separation, transport, and collection efficiency of photogenerated carriers, all of which undergo regular changes, ultimately manifesting as a shift in the shape of the device's current density-voltage curve. By extracting short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency from the device's current density-voltage curve, the type or concentration change of the gas to be detected can be characterized, realizing a multi-parameter gas sensing response mode. Simultaneously, the device can detect gas type and concentration under illumination without external bias voltage, achieving a passive multi-parameter state, significantly reducing energy consumption, simplifying the fabrication process, and enabling direct conversion of photovoltaic characteristics into electrical signals for continuous operation under illumination.

[0034] In this invention, the functions of organic solar cells and gas sensors are combined. Utilizing the existing photovoltaic effect, the organic solar cell generates photoelectron-hole pairs under illumination. Under the influence of the built-in electric field, the electron-hole pairs separate into electrons and holes, i.e., charge carriers, at the electron donor and electron acceptor interface. Subsequently, during the transport process, some of the charge carriers recombine, while the other part is transported to the corresponding electrode to form a current. In order not to affect the permeation of gas molecules, a porous network of silver nanowire electrodes is used as the top electrode, and the heterojunction sensitive layer is directly stacked with the network of silver nanowire electrodes, so that gas molecules can quickly contact the heterojunction sensitive layer.

[0035] It is worth noting that when the organic photovoltaic heterojunction passive multi-parameter gas sensor described in this invention is placed in a gas-sensitive chamber and illuminated by LEDs pre-installed in the chamber, the device also exhibits a photovoltaic effect due to the presence of light, which is reflected in the rectification characteristics of the current density-voltage curve. Its characteristic photovoltaic parameters can be obtained from the rectification curve and used as response parameters for gas sensing. During gas sensing testing, the gas molecules to be measured pass through the network of silver nanowire electrodes into the lower layer and come into contact with the heterojunction sensitive layer. Due to the influence of the gas molecules, the photovoltaic curve of the device changes under illumination, which is ultimately reflected in changes in photovoltaic parameters such as short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency.

[0036] During gas sensitivity testing, the organic photovoltaic heterojunction passive multi-parameter gas sensor can represent the characteristic signal of the gas to be detected as a change in the optical signal. Since it also has the photovoltaic effect, the optical signal can be converted into an electrical signal output at the same time. Compared with traditional metal oxide gas sensors, the organic photovoltaic heterojunction passive multi-parameter gas sensor can identify the differences in gas type and concentration not only through changes in current value, but also through more parameters with varying degrees of change, thus enhancing the accuracy of gas identification.

[0037] Optionally, non-fullerene small molecules such as Y5, Y6, BTP-4Cl, N3, or L8-BO can be selected as electron acceptors to construct different sensors and form sensor arrays of different types of sensors. This allows for the establishment of the relationship between the sensitive material, the morphology of the heterojunction sensitive layer, photovoltaic parameters, and the gas to be measured, thereby obtaining the sensitive mechanism of gas sensing and achieving accurate identification of different types and concentrations of volatile organic compounds. Secondly, without applying an external bias voltage, a single-stage constant voltage test is performed on the organic photovoltaic heterojunction passive multi-parameter gas sensor under illumination. The test results show that the current-time curve of the organic photovoltaic heterojunction passive multi-parameter gas sensor changes in the presence of volatile organic compounds, indicating that the gas sensor can operate for a long time in a passive multi-parameter state and has the advantage of low power consumption.

[0038] The following specific embodiments further explain and illustrate the organic photovoltaic heterojunction passive multi-parameter gas sensor provided by the present invention: Example 1 This embodiment 1 provides an organic photovoltaic heterojunction passive multi-parameter gas sensor, comprising an ITO electrode, a hole transport layer, a heterojunction sensitive layer, and a top electrode stacked sequentially; wherein, the ITO electrode serves as the bottom electrode, and the hole transport layer, the heterojunction sensitive layer, and the top electrode are sequentially prepared on the surface of the ITO electrode by spin coating, thereby obtaining the organic photovoltaic heterojunction passive multi-parameter gas sensor.

[0039] In this embodiment 1, the area of ​​the ITO electrode is 0.06 cm². 2 The hole transport layer has a thickness of 30 nm; the heterojunction sensitive layer has a thickness of 30 nm; PM6 is used as an electron donor and Y6 as an electron acceptor in the heterojunction sensitive layer, with a mass ratio of PM6 to Y6 of 1:1.2; the top electrode has a thickness of 100 nm.

[0040] Preparation process: The fabrication process of the organic photovoltaic heterojunction passive multi-parameter gas sensor described in Example 1 is as follows: Step 1: ITO electrodes are prepared on a transparent glass substrate by vapor deposition process to obtain a substrate with ITO electrodes.

[0041] Step 2: Place the substrate with the ITO electrode in acetone, detergent, deionized water and isopropanol solution in sequence for ultrasonic cleaning, and dry it after cleaning to obtain the cleaned substrate with the ITO electrode; the ultrasonic cleaning with deionized water is repeated more than 5 times, and each cleaning is 15 minutes.

[0042] Step 3: Treat the cleaned substrate with bottom electrode 1 with O3 for 20 minutes to obtain a pretreated substrate with ITO electrode.

[0043] Step 4: Mix poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) and deionized water at a mass ratio of 1:1 to obtain a transport layer solution; then, spin-coat the transport layer solution onto the surface of the ITO electrode at a spin coating speed of 4500 r / min for 40 s; next, anneal at 150 °C for 15 min, and then cool to room temperature to form a hole transport layer.

[0044] Step 5: Dissolve PM6 and Y6 in chloroform at a mass ratio of 1:1.2 to obtain a sensitive layer solution; wherein the total concentration of PM6 and Y6 in the sensitive layer solution is 13.2 mg / mL; then, spin-coat the sensitive layer solution onto the surface of the hole transport layer at a spin-coating speed of 4500 r / min for 20 s; then, anneal at 100℃ for 10 min, and cool to room temperature after annealing to form a heterojunction sensitive layer.

[0045] Step 6: In a glove box under nitrogen or argon atmosphere, spin-coat a 9 mg / mL solution of Ag NWs in isopropanol onto the surface of the heterojunction sensitive layer to form a top electrode, thereby obtaining the organic photovoltaic heterojunction passive multi-parameter gas sensor; wherein the spin-coating speed is 1000 r / min and the time is 30 s.

[0046] Performance testing: The organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 1 was placed in a test chamber for performance testing; the structure of the test chamber is shown in the attached figure. Figure 6 As shown; from the appendix Figure 6 As can be seen, LED lights are installed on the top cover of the test chamber to provide illumination.

[0047] Specifically, the testing process is as follows: In a glove box under nitrogen or argon atmosphere, the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 1 was scraped to expose the bottom ITO electrode. The ITO electrode and the top electrode were used as positive and negative electrodes, respectively, and tested with silver paste leads. In the test chamber, formic acid gas at concentrations of 30 ppm, 50 ppm, 100 ppm, 150 ppm, 200 ppm, 250 ppm, and 300 ppm was introduced sequentially. The JV curves of the device before and after the gas introduction were obtained, and the photovoltaic parameters were extracted. The changes before and after were compared, and the response value was calculated.

[0048] As attached Figure 7 As shown, attached Figure 7 The figure shows the JV curve changes of the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 1 before and after the introduction of 200 ppm formic acid gas; from the appendix Figure 7 As can be seen, the JV curve changed significantly before and after the introduction of 200 ppm formic acid gas. The changes in short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency can be directly obtained from the JV curve.

[0049] As attached Figure 8 As shown, attached Figure 8 The figure shows the multi-parameter variation of the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 1 under different concentrations of formic acid gas; from the appendix Figure 8 As can be seen, the four parameters—short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency—show differentiated changes with different concentrations of formic acid gas. All parameters decrease in a formic acid atmosphere. When pure N2 is introduced, all four parameters recover, and the changes in each parameter exhibit a certain linear relationship with the formic acid concentration. This indicates that the device can be used as a gas sensor.

[0050] As attached Figure 9 As shown, attached Figure 9 The figure shows the multi-parameter variation of the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 1 in different gases at 200 ppm; from the appendix Figure 9As can be seen, for the same gas at different concentrations, Example 1 can provide four response parameters with different degrees of variation, including short-circuit current density, open-circuit voltage, fill factor and photoelectric conversion efficiency, and the response recovery speed is relatively fast; for different types of gases, their differences can be demonstrated from multiple dimensions.

[0051] As attached Figure 10-11 As shown, attached Figure 10 The paper presents a graph showing the current variation of the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 1 under a 1V bias voltage for formic acid gas at concentrations of 0-200 ppm. (See attached graph.) Figure 11 The figure shows the current variation of the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 1 under 0V bias for different concentrations of formic acid gas from 0-200 ppm; from the attached figure... Figure 11 As can be seen, under a 1V bias voltage, the current response value detected in the passive multi-parameter state is reduced somewhat, but it can still detect volatile organic compounds at the ppm level, and the energy consumption is greatly reduced. Under a 0V bias voltage, the invention continuously and dynamically detected formic acid at different concentrations of 0-200 ppm. It can be seen that the device can detect formic acid gas in the passive multi-parameter state, and the detection sensitivity is high.

[0052] Example 2 This embodiment 2 provides an organic photovoltaic heterojunction passive multi-parameter gas sensor, comprising an ITO electrode, a hole transport layer, a heterojunction sensitive layer, and a top electrode stacked sequentially; wherein, the ITO electrode serves as the bottom electrode, and the hole transport layer, the heterojunction sensitive layer, and the top electrode are sequentially prepared on the surface of the ITO electrode by spin coating, thereby obtaining the organic photovoltaic heterojunction passive multi-parameter gas sensor.

[0053] In this embodiment 2, the area of ​​the ITO electrode is 0.06 cm². 2 The hole transport layer has a thickness of 15 nm; the heterojunction sensitive layer has a thickness of 50 nm; PM6 is used as an electron donor and Y5 as an electron acceptor in the heterojunction sensitive layer, with a mass ratio of PM6 to Y5 of 1:1.6; the top electrode has a thickness of 90 nm.

[0054] Preparation process: The fabrication process of the organic photovoltaic heterojunction passive multi-parameter gas sensor described in Example 2 is as follows: Step 1: ITO electrodes are prepared on a flexible substrate by vapor deposition process to obtain a substrate with ITO electrodes.

[0055] Step 2: Place the substrate with the ITO electrode in acetone, detergent, deionized water and isopropanol solution in sequence for ultrasonic cleaning, and dry it after cleaning to obtain the cleaned substrate with the ITO electrode; the ultrasonic cleaning with deionized water is repeated more than 5 times, and each cleaning is 15 minutes.

[0056] Step 3: Treat the cleaned substrate with bottom electrode 1 with O3 for 18 minutes to obtain a pretreated substrate with ITO electrode.

[0057] Step 4: Mix poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) and deionized water at a mass ratio of 1:1 to obtain a transport layer solution; then, spin-coat the transport layer solution onto the surface of the ITO electrode at a spin coating speed of 4000 r / min for 50 s; next, anneal at 140 °C for 18 min, and then cool to room temperature to form a hole transport layer.

[0058] Step 5: Dissolve PM6 and Y5 in chloroform at a mass ratio of 1:1.6 to obtain a sensitive layer solution; wherein the total concentration of PM6 and Y5 in the sensitive layer solution is 11.0 mg / mL; then, spin-coat the sensitive layer solution onto the surface of the hole transport layer at a spin-coating speed of 3000 r / min for 20 s; then, anneal at 150℃ for 20 min, and cool to room temperature after annealing to form a heterojunction sensitive layer.

[0059] Step 6: In a glove box under nitrogen or argon atmosphere, spin-coat a 7 mg / mL solution of Ag NWs in isopropanol onto the surface of the heterojunction sensitive layer to form a top electrode, thereby obtaining the organic photovoltaic heterojunction passive multi-parameter gas sensor; wherein the spin-coating speed is 1500 r / min and the time is 45 s.

[0060] Performance testing: In a glove box under nitrogen or argon atmosphere, the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 1 was scraped to expose the bottom ITO electrode. The ITO electrode and the top electrode were used as positive and negative electrodes respectively, and silver paste leads were used for testing; as shown in the attached figure. Figure 12 As shown, attached Figure 12 The figure shows the multi-parameter variation of the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 2 in different gases at 200 ppm; from the appendix Figure 12 As can be seen, significant differences in multiple parameters can be observed. The response values ​​are significantly higher for highly polar acid gases, which is related to the stronger interaction between acidic organic compounds and donor-acceptor molecules in the heterojunction sensitive layer.

[0061] Example 3 This embodiment 3 provides an organic photovoltaic heterojunction passive multi-parameter gas sensor, comprising an ITO electrode, a hole transport layer, a heterojunction sensitive layer, and a top electrode stacked sequentially; wherein, the ITO electrode serves as the bottom electrode, and the hole transport layer, the heterojunction sensitive layer, and the top electrode are sequentially prepared on the surface of the ITO electrode by spin coating, thereby obtaining the organic photovoltaic heterojunction passive multi-parameter gas sensor.

[0062] In this embodiment 3, the area of ​​the ITO electrode is 0.06 cm². 2 The hole transport layer has a thickness of 20 nm; the heterojunction sensitive layer has a thickness of 70 nm; PM6 is used as an electron donor and BTP-4Cl is used as an electron acceptor in the heterojunction sensitive layer, with a mass ratio of PM6 to BTP-4Cl of 1:1.8; the top electrode has a thickness of 80 nm.

[0063] Preparation process: The fabrication process of the organic photovoltaic heterojunction passive multi-parameter gas sensor described in Example 3 is as follows: Step 1: ITO electrodes are prepared on a transparent glass substrate by vapor deposition process to obtain a substrate with ITO electrodes.

[0064] Step 2: Place the substrate with the ITO electrode in acetone, detergent, deionized water and isopropanol solution in sequence for ultrasonic cleaning, and dry it after cleaning to obtain the cleaned substrate with the ITO electrode; the ultrasonic cleaning with deionized water is repeated more than 5 times, and each cleaning is 15 minutes.

[0065] Step 3: Treat the cleaned substrate with bottom electrode 1 with O3 for 16 minutes to obtain a pretreated substrate with ITO electrode.

[0066] Step 4: Mix poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) and deionized water at a mass ratio of 1:1 to obtain a transport layer solution; then, spin-coat the transport layer solution onto the surface of the ITO electrode at a spin coating speed of 3500 r / min for 40 s; next, anneal at 130 °C for 16 min, and then cool to room temperature to form a hole transport layer.

[0067] Step 5: Dissolve PM6 and BTP-4Cl in chloroform at a mass ratio of 1:1.8 to obtain a sensitive layer solution; wherein the total concentration of PM6 and BTP-4Cl in the sensitive layer solution is 8.8 mg / mL; then, spin-coat the sensitive layer solution onto the surface of the hole transport layer at a spin-coating speed of 2000 r / min for 20 s; then, anneal at 80℃ for 10 min, and cool to room temperature after annealing to form a heterojunction sensitive layer.

[0068] Step 6: In a glove box under nitrogen or argon atmosphere, spin-coat an isopropanol solution of Ag NWs with a concentration of 8 mg / mL onto the surface of the heterojunction sensitive layer to form a top electrode, thereby obtaining the organic photovoltaic heterojunction passive multi-parameter gas sensor; wherein, the spin-coating speed is 1000 r / min and the time is 60 s.

[0069] Performance testing: In a glove box under nitrogen or argon atmosphere, the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 3 was scraped to expose the bottom ITO electrode. The ITO electrode and the top electrode were used as positive and negative electrodes respectively, and silver paste leads were used for testing. (See attached...) Figure 13 As shown, attached Figure 13 The figure shows the multi-parameter variation of the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 3 in different gases at 200 ppm; from the appendix Figure 13 As can be seen, significant differences in multiple parameters can be observed. The response values ​​are significantly higher for highly polar acid gases, which is related to the stronger interaction between acidic organic compounds and donor-acceptor molecules in the heterojunction sensitive layer.

[0070] Example 4 This embodiment 4 provides an organic photovoltaic heterojunction passive multi-parameter gas sensor, comprising an ITO electrode, a hole transport layer, a heterojunction sensitive layer, and a top electrode stacked sequentially; wherein, the ITO electrode serves as the bottom electrode, and the hole transport layer, the heterojunction sensitive layer, and the top electrode are sequentially prepared on the surface of the ITO electrode by spin coating, thereby obtaining the organic photovoltaic heterojunction passive multi-parameter gas sensor.

[0071] In this embodiment 4, the area of ​​the ITO electrode is 0.06 cm². 2 The hole transport layer has a thickness of 10 nm; the heterojunction sensitive layer has a thickness of 90 nm; PM6 is used as an electron donor and N3 is used as an electron acceptor in the heterojunction sensitive layer, with a mass ratio of PM6 to N3 of 1:2.0; the top electrode has a thickness of 70 nm.

[0072] Preparation process: The fabrication process of the organic photovoltaic heterojunction passive multi-parameter gas sensor described in Example 4 is as follows: Step 1: ITO electrodes are prepared on a transparent glass substrate by vapor deposition process to obtain a substrate with ITO electrodes.

[0073] Step 2: Place the substrate with the ITO electrode in acetone, detergent, deionized water and isopropanol solution in sequence for ultrasonic cleaning, and dry it after cleaning to obtain the cleaned substrate with the ITO electrode; the ultrasonic cleaning with deionized water is repeated more than 5 times, and each cleaning is 15 minutes.

[0074] Step 3: Perform oxygen plasma treatment on the cleaned substrate with bottom electrode 1 for 15 minutes to obtain a pretreated substrate with ITO electrode.

[0075] Step 4: Mix poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) and deionized water at a mass ratio of 1:1 to obtain a transport layer solution; then, spin-coat the transport layer solution onto the surface of the ITO electrode at a spin coating speed of 3000 r / min for 55 s; next, anneal at 120 °C for 20 min, and then cool to room temperature to form a hole transport layer.

[0076] Step 5: Dissolve PM6 and N3 in chloroform at a mass ratio of 1:2.0 to obtain a sensitive layer solution; wherein the total concentration of PM6 and N3 in the sensitive layer solution is 13.2 mg / mL; then, spin-coat the sensitive layer solution onto the surface of the hole transport layer at a spin-coating speed of 3800 r / min for 20 s; then, anneal at 150 °C for 12 min, and cool to room temperature after annealing to form a heterojunction sensitive layer.

[0077] Step 6: In a glove box under nitrogen or argon atmosphere, spin-coat a 9 mg / mL solution of Ag NWs in isopropanol onto the surface of the heterojunction sensitive layer to form a top electrode, thereby obtaining the organic photovoltaic heterojunction passive multi-parameter gas sensor; wherein the spin-coating speed is 1200 r / min and the time is 45 s.

[0078] Performance testing: In a glove box under nitrogen or argon atmosphere, the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 4 was scraped to expose the bottom ITO electrode. The ITO electrode and the top electrode were used as positive and negative electrodes, respectively, and tested with silver paste leads; as shown in the attached figure. Figure 14 As shown, attached Figure 14 The figure shows the multi-parameter variation of the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 4 in different gases at 200 ppm; from the appendix Figure 14 As can be seen, significant differences in multiple parameters can be observed. Similarly, the response value is significantly higher for highly polar acid gases, which is related to the stronger interaction between acid organic compounds and donor-acceptor molecules in the heterojunction sensitive layer.

[0079] Example 5 This embodiment 5 provides an organic photovoltaic heterojunction passive multi-parameter gas sensor, comprising an ITO electrode, a hole transport layer, a heterojunction sensitive layer, and a top electrode stacked sequentially; wherein, the ITO electrode serves as the bottom electrode, and the hole transport layer, the heterojunction sensitive layer, and the top electrode are sequentially prepared on the surface of the ITO electrode by spin coating, thereby obtaining the organic photovoltaic heterojunction passive multi-parameter gas sensor.

[0080] In this embodiment 5, the area of ​​the ITO electrode is 0.06 cm². 2 The hole transport layer has a thickness of 20 nm; the heterojunction sensitive layer has a thickness of 120 nm; PM6 is used as an electron donor and L8-BO is used as an electron acceptor in the heterojunction sensitive layer, with a mass ratio of PM6 to L8-BO of 1:1.2; the top electrode has a thickness of 60 nm.

[0081] Preparation process: The fabrication process of the organic photovoltaic heterojunction passive multi-parameter gas sensor described in Example 4 is as follows: Step 1: ITO electrodes are prepared on a transparent glass substrate by vapor deposition process to obtain a substrate with ITO electrodes.

[0082] Step 2: Place the substrate with the ITO electrode in acetone, detergent, deionized water and isopropanol solution in sequence for ultrasonic cleaning, and dry it after cleaning to obtain the cleaned substrate with the ITO electrode; the ultrasonic cleaning with deionized water is repeated more than 5 times, and each cleaning is 15 minutes.

[0083] Step 3: Perform oxygen plasma treatment on the cleaned substrate with bottom electrode 1 for 20 minutes to obtain a pretreated substrate with ITO electrode.

[0084] Step 4: Mix poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) and deionized water at a mass ratio of 1:1 to obtain a transport layer solution; then, spin-coat the transport layer solution onto the surface of the ITO electrode at a spin coating speed of 4500 r / min for 40 s; next, anneal at 150 °C for 15 min, and then cool to room temperature to form a hole transport layer.

[0085] Step 5: Dissolve PM6 and L8-BO in chloroform at a mass ratio of 1:1.2 to obtain a sensitive layer solution; wherein the total concentration of PM6 and L8-BO in the sensitive layer solution is 11 mg / mL; then, spin coat the sensitive layer solution onto the surface of the hole transport layer at a spin coating speed of 3000 r / min for 20 s; then, anneal at 80℃ for 20 min, and cool to room temperature after annealing to form a heterojunction sensitive layer.

[0086] Step 6: In a glove box under nitrogen or argon atmosphere, spin-coat an isopropanol solution of Ag NWs with a concentration of 8 mg / mL onto the surface of the heterojunction sensitive layer to form a top electrode, thereby obtaining the organic photovoltaic heterojunction passive multi-parameter gas sensor; wherein, the spin-coating speed is 1500 r / min and the time is 30 s.

[0087] Performance testing: In a glove box under nitrogen or argon atmosphere, the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 5 was scraped to expose the bottom ITO electrode. The ITO electrode and the top electrode were used as positive and negative electrodes, respectively, and tested with silver paste leads; as shown in the attached diagram. Figure 15 As shown, attached Figure 15 The figure shows the multi-parameter variation of the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Example 5 in different gases at 200 ppm; from the appendix Figure 15 As can be seen, significant differences in multiple parameters can be observed. The response values ​​are significantly higher for highly polar acid gases, which is related to the stronger interaction between acidic organic compounds and donor-acceptor molecules in the heterojunction sensitive layer.

[0088] As attached Figure 16 As shown, attached Figure 16 The appendix provides principal component analysis (PCA) plots for different volatile organic compounds obtained using the organic photovoltaic heterojunction passive multi-parameter gas sensors prepared in Examples 1-5; from the appendix... Figure 16 As can be seen from the data, the different parameter changes of different gases at 200 ppm in Examples 1-5 were extracted and used as feature values ​​for principal component analysis. The calculation showed that the organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in Examples 1-5 achieved a 100% accuracy in distinguishing eight different volatile organic compounds in the range of 30-300 ppm.

[0089] The organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in this invention uses a transparent glass substrate, on which ITO electrodes are deposited by vapor deposition. A hole transport layer and a heterojunction sensitive layer are sequentially coated on the ITO electrodes. Silver nanowires are coated on the heterojunction sensitive layer as the top electrode. The heterojunction sensitive layer uses an organic photovoltaic polymer as an electron donor and a non-fullerene small molecule as an electron acceptor, and is prepared by spin-coating a blend of the organic photovoltaic polymer and the non-fullerene small molecule. By observing the changes in multiple organic photovoltaic parameters of the organic photovoltaic heterojunction gas sensor under illumination with the introduction of volatile organic compounds, the sensor can detect different volatile organic compound gases with a 100% accuracy in distinguishing between different organic volatile gases. The organic photovoltaic heterojunction passive multi-parameter gas sensor prepared in this invention can detect unknown gases in a passive multi-parameter state without any bias voltage. The manufacturing process is simple, significantly reducing energy consumption, and it can directly utilize photovoltaic properties to convert into electrical signals and operate continuously under illumination.

[0090] In this invention, a gas sensor with an organic solar cell structure is constructed, which simplifies the fabrication process. It also functions as a solar cell device, enabling photovoltaic effects while sensing gas, generating photocurrent from which four photovoltaic parameters can be extracted as gas response parameters, thus achieving multi-parameter output. Furthermore, it can function as a gas sensor, achieving 100% accuracy in distinguishing various volatile organic compounds, effectively broadening the range of gas-sensitive materials, and enabling long-term operation in a passive multi-parameter state.

[0091] The above embodiments are merely one of the implementation methods for achieving the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention.

Claims

1. An organic photovoltaic heterojunction passive multi-parameter gas sensor, characterized in that, It includes a bottom electrode (1), a hole transport layer (2), a heterojunction sensitive layer (3), and a top electrode (4) stacked in sequence. The heterojunction sensitive layer (3) is an organic heterojunction sensitive layer with donor and acceptor blends; wherein, the heterojunction sensitive layer (3) uses an organic photovoltaic polymer as an electron donor and a non-fullerene small molecule as an electron acceptor, and is prepared by spin coating of organic photovoltaic polymer and non-fullerene small molecule blends. The top electrode (4) is a network of silver nanowire electrodes.

2. The organic photovoltaic heterojunction passive multi-parameter gas sensor according to claim 1, characterized in that, The mass ratio of organic photovoltaic polymer to non-fullerene small molecules is 1:(1.2-2.0).

3. The organic photovoltaic heterojunction passive multi-parameter gas sensor according to claim 1, characterized in that, The organic photovoltaic polymer uses PM6, and the non-fullerene small molecules use Y-series small molecule acceptors; among them, the Y-series small molecule acceptors are one of Y5, Y6, BTP-4Cl, N3 and L8-BO.

4. The organic photovoltaic heterojunction passive multi-parameter gas sensor according to claim 1, characterized in that, The hole transport layer (2) and the top electrode (4) are both prepared by spin coating.

5. The organic photovoltaic heterojunction passive multi-parameter gas sensor according to claim 1, characterized in that, The hole transport layer (2) has a thickness of 10-30 nm, the heterojunction sensitive layer (3) has a thickness of 30-120 nm, and the top electrode (4) has a thickness of 60-100 nm.

6. The method for fabricating an organic photovoltaic heterojunction passive multi-parameter gas sensor as described in any one of claims 1-5, characterized in that, include: A bottom electrode (1) is fabricated on a preset substrate to obtain a substrate with the bottom electrode (1); The substrate with bottom electrode (1) is pretreated to obtain a pretreated substrate with bottom electrode (1); The transport layer solution was spin-coated onto the surface of the bottom electrode (1), annealed, and cooled to form a hole transport layer (2). The sensitive layer solution was spin-coated onto the surface of the hole transport layer (2), annealed, and cooled to form a heterojunction sensitive layer (3). A silver nanowire solution was spin-coated onto the surface of the heterojunction sensitive layer (3) to form a top electrode (4), thus obtaining an organic photovoltaic heterojunction passive multi-parameter gas sensor.

7. The method for fabricating an organic photovoltaic heterojunction passive multi-parameter gas sensor according to claim 6, characterized in that, The process of pretreating the substrate with bottom electrode (1) to obtain the pretreated substrate with bottom electrode (1) is as follows: The substrate with bottom electrode (1) was placed in acetone, detergent, deionized water and isopropanol solution for ultrasonic cleaning in sequence. After cleaning, it was dried to obtain the cleaned substrate with bottom electrode (1). The cleaned substrate with bottom electrode (1) is subjected to O3 treatment or oxygen plasma treatment to obtain a pretreated substrate with bottom electrode (1).

8. The method for fabricating an organic photovoltaic heterojunction passive multi-parameter gas sensor according to claim 6, characterized in that, The transport layer solution is a poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) solution; the sensitive layer solution is formulated with organic photovoltaic polymer and non-fullerene small molecules.

9. The method for fabricating an organic photovoltaic heterojunction passive multi-parameter gas sensor according to claim 6, characterized in that, During the process of spin-coating the transport layer solution onto the surface of the bottom electrode (1), annealing, and cooling to form the hole transport layer (2), the annealing temperature is 120-150℃ and the annealing time is 10-20min. During the process of spin-coating the sensitive layer solution onto the surface of the hole transport layer (2), annealing, and cooling to form the heterojunction sensitive layer (3), the annealing temperature is 80-150℃ and the annealing time is 10-20min.

10. The application of the organic photovoltaic heterojunction passive multi-parameter gas sensor as described in any one of claims 1-5, characterized in that, Used for the detection of volatile organic compound gases.

Images