A flexible artificial olfactory synapse and preparation method thereof

Abstract

The present invention relates to a flexible artificial olfactory synapse and a preparation method thereof. The flexible artificial olfactory synapse of the present invention comprises: a substrate, the substrate is formed by a polyethylene terephthalate film; an electrode, the electrode comprises a gate, a source and a drain, and the electrode is formed on the substrate; an organic channel, the organic channel is formed by poly (3,4-ethylenedioxythiophene)-poly (styrene sulfonic acid), and the organic channel is formed on the substrate; a porous solid electrolyte, the porous solid electrolyte is at least partially coated on the surface of the substrate. The flexible artificial olfactory synapse of the present invention has a lower response limit (0.2ppm) to H2S, a wider sensing range (0.2-100ppm) and excellent anti-interference performance, and has a memory capacity of cumulative effect, realizing the perception and memory function of imitating a neurobiological system.

Description

Technical Field

[0001] The invention relates to a flexible artificial olfactory synapse and a preparation method thereof, and belongs to the technical field of biological detection and medical detection. Background Art

[0002] The human brain is an extremely efficient computing system consisting of about 1011 neurons and about 1015 synapses. With its parallel interconnected structure, the brain is able to combine signal processing, memory and learning in an efficient way to process large amounts of complex information. Inspired by the human brain, artificial perceptual electronic devices based on neuromorphic morphology can respond to external stimuli (such as pressure, light, odor, etc.) and mimic the behavior of biological nervous systems (including perception and memory functions). In biological systems, information is transferred from the synapses of preneurons to the synapses of postneurons by transmitting electrical or chemical signals. Changes in the efficiency of connections between neurons are called synaptic plasticity, which is considered to be the basis of learning and memory. The realization of synaptic plasticity at the device level enables artificial synaptic electronics to mimic neurobiological behavior. Work that has been reported includes electronic skins (E-skins) that can simultaneously realize tactile perception and memory functions, artificial optic synapses that realize visual self-adjustment in real-life scenarios, and bimodal synapses that can perform cross-modal recognition and imagination.

[0003] The olfactory system is an extremely important sensory system that can recognize a large number of odor molecules, giving humans the ability to perceive their surroundings, evaluate food, and identify potential dangers. The biological olfactory recognition process begins with the chemical interaction between the inhaled odorant and the olfactory receptors of peripheral sensory neurons located in the olfactory epithelium at the dorsum of the nose. The resulting electrical signals are transmitted to neighboring neurons in the main olfactory bulb, where the information is pre-encoded and then transmitted to the olfactory cortex for further interpretation. The olfactory bulb plays an important role in the olfactory system because it exhibits neural plasticity, which is essential for olfactory learning and memory. Electronic devices that mimic olfactory functions, such as electronic noses (E-noses), have excellent odor recognition and high accuracy. However, synaptic olfactory electronics that integrate olfactory perception and memory functions have rarely been proposed.

[0004] Organic electrochemical transistors (OECTs) are excellent candidates for artificial synaptic devices due to their efficient ion-electron conversion, low operating voltage (≤1V) and good biocompatibility. Conductive polymers doped with polystyrene sulfonic acid (PEDOT:PSS) represent a typical organic channel material for OECTs. Since the voltage-controlled ion injection and extraction within the PEDOT:PSS channel are similar to the release and absorption of neurotransmitters in the synaptic cleft, organic electrochemical transistors based on PEDOT:PSS have been successfully demonstrated to have neuromorphic functions, including synaptic plasticity and neuromorphic computing.

[0005] Hydrogen sulfide (H2S) is an endogenous gaseous transmitter that is involved in various physiological and pathological processes, including cell protection, vascular relaxation, and neuromodulation. However, inhalation of abnormal concentrations of H2S is highly toxic and can pose a significant threat to human health. It has been reported that low concentrations of H2S (such as an 8-hour time-weighted average concentration of 5 ppm) may cause adverse health effects, and high concentrations (>100 ppm) may even cause sudden death. Although the pungent odor of H2S can be detected by the human nose at very low concentrations (about 25 ppb), it cannot serve as a good warning for long-term or excessive H2S exposure due to olfactory fatigue caused by damage to epithelial cell receptors. Most conventional H2S gas sensors are also unable to record the cumulative adverse effects caused by frequent exposure to H2S. Therefore, it is very important to develop artificial olfactory synapses that can produce H2S sensation and memory functions. Summary of the invention

[0006] Problem that the invention aims to solve

[0007] Based on the above problems existing in the prior art, the present invention provides a flexible artificial olfactory synapse and a preparation method thereof. The flexible artificial olfactory synapse of the present invention shows excellent recognition ability and memory ability of cumulative effect of H2S. The flexible artificial olfactory synapse of the present invention realizes the perception and memory function of imitating the neural biological system, which lays a key foundation for completing the enhanced bionic olfactory system.

[0008] Solutions for solving problems

[0009] The present invention provides a flexible artificial olfactory synapse, comprising:

[0010] a substrate formed of a polyethylene terephthalate film;

[0011] Electrodes, the electrodes comprising a gate, a source and a drain, the electrodes being formed on the substrate;

[0012] An organic channel, wherein the organic channel is formed of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), and the organic channel is formed on the substrate;

[0013] A porous solid electrolyte is at least partially coated on the surface of the substrate.

[0014] According to the flexible artificial olfactory synapse of the present invention, the gate, source and drain are formed by a chromium layer and a gold layer.

[0015] According to the flexible artificial olfactory synapse of the present invention, the porous solid electrolyte is formed by polyvinylidene fluoride-hexafluoropropylene copolymer and 1-butyl-3-methylimidazole bistrifluoromethanesulfonyl imide salt.

[0016] According to the flexible artificial olfactory synapse of the present invention, the polyethylene terephthalate film has a thickness of 100-200 μm.

[0017] According to the flexible artificial olfactory synapse of the present invention, the thickness of the electrode is 5-15 nm for the chromium layer and 80-150 nm for the gold layer.

[0018] According to the flexible artificial olfactory synapse of the present invention, the thickness of the porous solid electrolyte is 30-100 μm.

[0019] According to the flexible artificial olfactory synapse of the present invention, the pore size of the porous solid electrolyte is 1-3 μm.

[0020] The present invention also provides a method for preparing the flexible artificial olfactory synapse according to the present invention, which comprises the following steps:

[0021] A polyethylene terephthalate film was attached as a substrate to a glass sheet coated with polydimethylsiloxane;

[0022] The substrate is subjected to magnetron sputtering and photolithography to form a gate, a source and a drain;

[0023] Spin coating poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) onto the substrate, annealing, and then forming an organic channel by photolithography and reactive ion etching to obtain a basic device;

[0024] The porous solid electrolyte is obtained by spin coating a blend of polyvinylidene fluoride-hexafluoropropylene copolymer and 1-butyl-3-methylimidazole bis(trifluoromethanesulfonyl)imide salt on the surface of the base device;

[0025] The basic device was mechanically peeled off from the glass slide to obtain a flexible artificial olfactory synapse.

[0026] According to the method for preparing the flexible artificial olfactory synapse of the present invention, spin coating is performed at a relative humidity of 60%-80% to obtain a porous solid electrolyte.

[0027] According to the method for preparing a flexible artificial olfactory synapse of the present invention, poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) is spin-coated onto the substrate and annealed at 100-150° C. for 30-60 min.

[0028] Effects of the Invention

[0029] The flexible artificial olfactory synapse of the present invention has a lower response limit (0.2ppm), a wider sensing range (0.2-100ppm) and excellent anti-interference performance to H2S. The flexible artificial olfactory synapse of the present invention has a cumulative memory ability, which can imitate the perception and memory functions of the neurobiological system, reveal the innovative strategy of the future electronic nose, and can imitate the perception and memory functions of the neurobiological system, which lays a key foundation for completing the enhanced bionic olfactory system. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of the process of the method for preparing the flexible artificial olfactory synapse of the present invention.

[0031] Figure 2 Schematic diagram of the working principle of the flexible artificial olfactory synapse of the present invention.

[0032] Figure 3 A graph showing the sensing performance test results of the flexible bionic olfactory synapse-I according to Example 1 of the present invention.

[0033] Figure 4 Graph showing the bending performance test results of the flexible bionic olfactory synapse-I of Example 1 of the present invention.

[0034] Figure 5 A graph showing the test results of the bionic olfactory synapse plasticity mediated by trace H2S of the flexible artificial olfactory synapse-I of Example 1 of the present invention.

[0035] Figure 6 Test results of H2S (1-100 ppm)-mediated biomimetic olfactory synapse plasticity of the flexible artificial olfactory synapse-I of Example 1 of the present invention DETAILED DESCRIPTION

[0036] The following is a detailed description of the present invention. The following description of the technical features is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

[0037] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints A and B.

[0038] In this specification, unless otherwise specified, the word "multiple" in "multiple", "multiple", "plurality", etc. means a numerical value of 2 or more.

[0039] In the present specification, the term “substantially”, “substantially” or “essentially” means that the error is less than 5%, less than 3% or less than 1% compared with the relevant perfect standard or theoretical standard.

[0040] In this specification, unless otherwise specified, "%" means mass percentage.

[0041] In this specification, the word "may" means both performing a certain process and not performing a certain process.

[0042] In the present specification, "optional" or "optionally" means that the event or situation described below may or may not occur, and the description includes cases where the event occurs and cases where it does not occur.

[0043] In this specification, the references to "some specific / preferred embodiments", "other specific / preferred embodiments", "embodiments", etc., mean that the specific elements (e.g., features, structures, properties and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein, and may or may not exist in other embodiments. In addition, it should be understood that the elements may be combined in various embodiments in any suitable manner.

[0044] The present invention provides a flexible artificial olfactory synapse, comprising:

[0045] a substrate formed of a polyethylene terephthalate film;

[0046] Electrodes, the electrodes comprising a gate, a source and a drain, the electrodes being formed on the substrate;

[0047] An organic channel, wherein the organic channel is formed of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), and the organic channel is formed on the substrate;

[0048] A porous solid electrolyte is at least partially coated on the surface of the substrate.

[0049] According to the flexible artificial olfactory synapse of the present invention, the thickness of the polyethylene terephthalate film is 1 to 3 microns.

[0050] According to the flexible artificial olfactory synapse of the present invention, the gate, source and drain are formed by a chromium layer and a gold layer.

[0051] In the electrode with a stacked structure, the Cr layer is mainly used as an adhesion layer to improve the adhesion between the gold layer and the substrate. The Au layer is used as a functional layer. The work function of Au is close to that of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), and an ohmic contact can be formed. In the flexible artificial olfactory synapse of the present invention, Au mainly plays a conductive role, and its electrochemical and mechanical properties are stable. The above-mentioned electrode structure can prevent the electrode from falling off due to poor adhesion between the metal and the substrate, and prevent the sensitivity and stability of the prepared sensor from decreasing.

[0052] According to the flexible artificial olfactory synapse of the present invention, the porous solid electrolyte is formed by polyvinylidene fluoride-hexafluoropropylene copolymer and 1-butyl-3-methylimidazole bistrifluoromethanesulfonyl imide salt.

[0053] According to the flexible artificial olfactory synapse of the present invention, the polyethylene terephthalate film has a thickness of 100-200 μm.

[0054] According to the flexible artificial olfactory synapse of the present invention, the thickness of the electrode is 5-15 nm for the chromium layer and 80-150 nm for the gold layer.

[0055] According to the flexible artificial olfactory synapse of the present invention, the thickness of the porous solid electrolyte is 30-100 μm, and more preferably, the pore size of the porous solid electrolyte is 1-3 μm.

[0056] like Figure 2 As shown, the flexible artificial olfactory synapse of the present invention draws on the human olfactory mechanism and system architecture. Gas molecules bind to specific receptors in epithelial cells, and the receptors are activated to generate an action potential signal, which is then transmitted to the olfactory bulb, where the information is further compiled and decoded. The present invention draws on the above mechanism and architecture. The transistor gate and the coupled porous solid electrolyte are similar to the presynaptic domain, and the PEDOT:PSS organic channel between the drain and the source is similar to the postsynaptic domain. The PEDOT:PSS is electrochemically doped and dedoped by injecting and extracting cations in the porous solid electrolyte to simulate the release and uptake of neurotransmitters, and a bionic artificial olfactory synapse that simulates the biological olfactory structure is constructed, which can realize a flexible bionic olfactory system with the functions of olfactory information perception, transmission, and storage.

[0057] The present invention also provides a method for preparing the flexible artificial olfactory synapse of the present invention, which comprises the following steps:

[0058] A polyethylene terephthalate film was attached as a substrate to a glass sheet coated with polydimethylsiloxane;

[0059] The substrate is subjected to magnetron sputtering and photolithography to form a gate, a source and a drain;

[0060] The substrate is subjected to magnetron sputtering and photolithography to form a gate, a source, and a drain; preferably, when the gate, the source, and the drain are formed by magnetron sputtering, the sputtering voltage is 350-400V, the working current is 0.03-0.09A, and the sputtering rate is

[0061] Spin coating poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) onto the substrate, annealing, and then forming an organic channel by photolithography and reactive ion etching to obtain a basic device;

[0062] Preferably, poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) is coated on the substrate, annealed, and then an organic channel is formed by photolithography and reactive ion etching. Preferably, poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) is coated on the substrate by spin coating. Preferably, the spin coating is carried out in two steps, the first step has a spin coating speed of 500-600 rpm, the spin coating time is 6-9 s, the second step has a spin coating speed of 2000-3500 rpm, the spin coating time is 30-40 s, the annealing temperature is 120-150 degrees Celsius, and the annealing time is 30-60 min. Most preferably, the first step has a spin coating speed of 600 rpm, the spin coating time is 6 s, the second step has a spin coating speed of 2500 rpm, the spin coating time is 30 s, the annealing temperature is 120 degrees Celsius, and the annealing time is 60 min.

[0063] There is no particular limitation on photolithography and reactive ion etching, as long as the desired morphology can be obtained. Particularly preferably, reactive ion etching is performed at a pressure of 90 mTorr, 100 sccm O2, 5 sccm SF6, and a power of 100 W for 100 to 150 s, most preferably 120 s.

[0064] Spin coating a blend of polyvinylidene fluoride-hexafluoropropylene copolymer and 1-butyl-3-methylimidazole bis(trifluoromethanesulfonyl)imide salt on the surface of the base device, and annealing to obtain a porous solid electrolyte;

[0065] Preferably, the polyvinylidene fluoride-hexafluoropropylene copolymer is dissolved in a mixture of DMF and acetone at a mass ratio of 1:10 at 60°C, and 1-butyl-3-methylimidazole bistrifluoromethanesulfonyl imide salt is added at a mass ratio of 2:1 (1-butyl-3-methylimidazole bistrifluoromethanesulfonyl imide salt: polyvinylidene fluoride-hexafluoropropylene copolymer), and stirred at room temperature. The obtained mixture is stirred at 60°C for at least 1 hour, and then spin-coated on the basic device, the first step of the spin coating speed is 600rpm, the spin coating time is 6-9s, and the second step of the spin coating speed is 2000rpm, and the spin coating time is 30s. Subsequently, the obtained basic device is thermally annealed in a vacuum at 50°C for 3 hours.

[0066] The basic device was mechanically peeled off from the glass slide to obtain a flexible artificial olfactory synapse.

[0067] According to the method for preparing the flexible artificial olfactory synapse of the present invention, the porous solid electrolyte is obtained by spin coating at a relative humidity of 60%-80%. Figure 1 As shown, spin coating is performed at a relative humidity of 60%-80%. When water vapor in a humid environment contacts a colder surface, condensation forms water droplets. Pores are formed at the locations where the water droplets are condensed after evaporation. The formation of pores in the porous solid electrolyte depends on the spontaneous condensation and evaporation of water droplets in a high humidity environment. The process is simple and easy and does not require complex equipment or the introduction of other organic matter.

[0068] According to the method for preparing a flexible artificial olfactory synapse of the present invention, poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) is spin-coated onto the substrate and annealed at 100-120° C. for 30-60 min.

[0069] Example

[0070] Example 1

[0071] A polyethylene terephthalate film (125 μm) was attached to a glass sheet coated with polydimethylsiloxane to form a substrate; chromium (Cr) and gold (Au) sputtering targets were used to form electrodes, including a gate electrode, a counter electrode, and a reference electrode, by magnetron sputtering. The sputtering voltage was 380 V, the operating current was 0.06 A, and the sputtering rate was The step profiler test shows that the thickness of the electrode is 10 nm for chromium and 100 nm for gold;

[0072] Poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) was spin-coated on a substrate and annealed, followed by photolithography and reactive ion etching to form an organic channel, the spin-coating parameters were 600rpm / 2500rpm, 6s / 30s, the annealing temperature was 120°C, and the annealing time was 1h; the step profiler test showed that the thickness of the organic channel was about 180nm; the reactive ion etching parameters were: pressure 90mtorr, gas flow rate 100sccm O2, 5sccm SF6, power 100w, and duration 120s;

[0073] Polyvinylidene fluoride-hexafluoropropylene copolymer was dissolved in a mixture of DMF and acetone in a mass ratio of 1:10 at 60°C, and 1-butyl-3-methylimidazole bistrifluoromethanesulfonyl imide salt was added in a mass ratio of 2:1 (1-butyl-3-methylimidazole bistrifluoromethanesulfonyl imide salt: polyvinylidene fluoride-hexafluoropropylene copolymer). The mixture was stirred with a magnetic stirrer and stirred at 60°C for at least 1 hour, and then spin-coated on the base device with spin coating parameters of 2000 rpm for 40 seconds. In order to obtain a porous structure, the relative humidity was maintained at about 60% during spin coating and solvent evaporation, followed by thermal annealing in a vacuum at 50°C for 3 hours.

[0074] The device was mechanically peeled off from the glass substrate to obtain a flexible artificial olfactory synapse-I.

[0075] Comparative Example 1

[0076] During the spin coating and solvent evaporation process, the relative humidity was maintained at about 25% to obtain a non-porous solid electrolyte. Otherwise, a flexible artificial olfactory synapse-II was obtained in the same manner as in Example 1.

[0077] Performance Test Results

[0078] Sensing performance test of flexible bionic olfactory synapse

[0079] The flexible artificial olfactory synapse-I was tested under different H2S concentrations (5ppm, 10ppm, 15ppm, 20ppm, 25ppm), among which, Figure 3 a shows the transfer characteristic curve of the flexible artificial olfactory synapse-I; Figure 3 b shows the transconductance curve of the flexible artificial olfactory synapse-I, where the exposure duration of each concentration is 10 minutes; Figure 3 c shows the normalized response of the flexible artificial olfactory synapse-I to H2S concentrations (5ppm, 10ppm, 15ppm, 20ppm, 25ppm), the exposure duration for each concentration was 10 minutes, the drain voltage was -0.2V, and the gate bias was +0.4V during the test; Figure 3 d shows the anti-interference performance of the flexible artificial olfactory synapse-I against H2S.

[0080] First, if Figure 3 a and Figure 3 As shown in b, the transfer characteristic curves of the flexible artificial olfactory synapse-I before and after exposure to different concentrations of H2S gas molecules (5ppm, 10ppm, 15ppm, 20ppm, 25ppm, with pure N2 as the balance gas) for 10 minutes ( Figure 3 a) and the corresponding transconductance curve (g m , Figure 3 b). During the test, the drain voltage is fixed at V d =-0.2V, gate voltage V g Sweep from +0.2V to +1.0V. Blank response ( Figure 3 The dashed lines in a and b are obtained by exposing the device to pure N2 gas. As the H2S concentration increases, the transfer characteristic curve gradually shifts to the left and reaches the maximum g m V g The maximum difference can reach 200mV. Furthermore, the normalized response (NR) of the channel current is used to evaluate the sensing performance of the flexible artificial olfactory synapse-I. Figure 3 As shown in Figure c, as the H2S concentration increases, the corresponding NR increases immediately, and when the H2S gas is replaced by N2, the NR recovers slightly. In addition, at all H2S concentrations, the sensitivity of the device with porous solid electrolyte is higher than that of the device with non-porous solid electrolyte (about 3 to 4 times). For example, after exposure to 10ppm H2S, the NR of flexible artificial olfactory synapse-I is 0.27, while the NR of flexible artificial olfactory synapse-II is only 0.07. In order to evaluate the selectivity of the device for H2S, potential interfering gases [50ppm formaldehyde (HCHO), 50ppm ethylbenzene (C8H 10 ), 25ppm sulfur dioxide (SO2), 25ppm ammonia (NH3) and 25ppm nitric oxide (NO)]. The device showed a stronger response to H2S than other gases. The results are shown in Figure 3 d, indicating excellent selectivity.

[0081] Bending performance test

[0082] first, Figure 4 a shows a photograph of a flexible bionic synaptic device (bending radius: 1 mm). Figure 4 b shows the H2S sensing properties of the flexible artificial olfactory synapse-I in the unbent and bent states.

[0083] There is almost no difference in the consistent normalized response of the flexible artificial olfactory synapse-I to H2S in the planar and bent states, indicating that the device has good flexibility.

[0084] Trace H2S-mediated biomimetic olfactory synaptic plasticity test

[0085] Figure 5 The figure shows the test results of biomimetic olfactory synaptic plasticity mediated by trace H2S of flexible artificial olfactory synapse-I. Figure 5 As shown in a, a gate pulse (gate voltage V g= +0.4 V, pulse interval = 60 s, pulse duration = 30 s) to perform short-term regulation on the flexible artificial olfactory synapse-I, by passing N2 in the first 1200 s, and then passing H2S with concentrations ranging from 200 ppb to 1000 ppb. Figure 5 b shows the H2S stimulation for 300 s and the H2S and V g The changes in synaptic weight (ΔW) after 300 s of removal showed the short-term memory (STM) behavior associated with trace H2S.

[0086] Figure 6 The figure shows the test results of H2S (1-100ppm) mediated biomimetic olfactory synapse plasticity of flexible artificial olfactory synapse-I. Figure 6 As shown in a, a gate pulse (gate voltage V g = +0.4 V, pulse interval = 60 s, pulse duration = 30 s) to perform short-term and long-term regulation on the flexible artificial olfactory synapse-I. N2 was introduced in the first 1200 s, and then H2S stimulation with concentrations ranging from 1 ppm to 100 ppm was introduced, where ΔW represents the change in synaptic weight. Figure 6 b shows the relationship between H2S and V before and 300s after H2S stimulation. g The change in synaptic weight (ΔW) 300 s after removal, indicating the STM to LTM transition associated with the increase in H2S concentration; Figure 6 c shows the real-time response current (I ds ) test results; Figure 6 d shows the corresponding synaptic weight (ΔW) changes with the voltage pulse width in the range of 5 to 300 s; Figure 6 e shows the paired pulse depression (PPD) index of the flexible artificial olfactory synapse-I when the pulse voltage is +0.4Ve, where the dotted line is the fitting result.

[0087] Figure 5 and Figure 6 The gaseous transmitter-mediated plasticity and the corresponding short-term memory (STM) and long-term memory (LTM) behaviors of the flexible artificial olfactory synapse-I were demonstrated. g = +0.4V, 30s), simulating the input stimulation of the presynaptic neuron, thereby triggering the corresponding inhibitory postsynaptic current (IPSC), which is one of the most important synaptic behaviors. In the absence of H2S stimulation, the pulse signal does not affect the drain current (I ds) and does not affect the change in bionic synaptic weight (ΔW). Once H2S is introduced, the amplitude of the channel current (IPSC) and the change in channel conductance (ΔW) increase simultaneously. Specifically, in the presence of trace amounts of H2S (0.2-1ppm), the channel current first increases; after the stimulus (H2S and gate pulse) is removed, the channel current then slowly returns to its initial value, and ultimately the synaptic weight does not change (ΔW=0), indicating the presence of STM behavior. Figure 5 As shown in b, after 300s of H2S stimulation, the H2S concentration (0.2-1ppm) is linearly related to the intermediate change of the synaptic weight. The results show that the response limit of the flexible artificial olfactory synapse-I to H2S is 200ppb, and the STM behavior of the flexible artificial olfactory synapse-I can simulate the human body's metabolism of low-concentration harmful gases.

[0088] like Figure 6 As shown in a, as the H2S concentration increases, the channel current cannot return to its initial state, indicating that the H2S-induced changes in synaptic weights are stored by the biomimetic olfactory synapse. The persistent ΔW represents a non-volatile behavior that can mimic the long-term damage to the olfactory system caused by overexposure to H2S, also known as LTM. Figure 6 b summarizes the ΔW after H2S stimulation for 300 s, removal of H2S, and pulse gate voltage for 300 s. As the H2S concentration increases (from 5 ppm to 100 ppm), both the ΔW after H2S stimulation and the final stored ΔW (after both H2S and pulse gate voltage are removed) increase, indicating that STM gradually transforms to LTM. Figure 6 c shows the real-time response of the flexible artificial olfactory synapse-I to 20 ppm H2S at different pulse durations (5, 10, 60, 120, 180 and 300 s). The corresponding time-ΔW relationship is shown in Figure 6 d. The transition from STM to LTM was successfully demonstrated by adjusting the pulse duration. Figure 6 As shown in Figure e, the flexible artificial olfactory synapse-I exhibits typical paired pulse depression (PPD) behavior, which is crucial for decoding temporal information in the olfactory system. PPD behavior refers to a pair of presynaptic excitations triggering two peak channel currents, with the second current peak being larger than the previous one. When the pulse interval between the two presynaptic peaks is shorter, the difference between the two current peaks becomes larger. This PPD behavior can be described by a double exponential function ( Figure 6 e). Figure 6 As shown in e, the PPD exponentially increases while the spike interval decreases, which is similar to the behavior of biological synapses.

Claims

1. Use of a flexible artificial olfactory synapse in detecting H2S, characterized in that: The flexible artificial olfactory synapse comprises: A substrate, wherein the substrate is formed of a polyethylene terephthalate film, and the thickness of the polyethylene terephthalate film is 100-200 μm; Electrodes, the electrodes comprising a gate, a source and a drain, the electrodes being formed on the substrate; An organic channel, wherein the organic channel is formed of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), and the organic channel is formed on the substrate; A porous solid electrolyte, wherein the porous solid electrolyte is at least partially coated on the surface of the substrate, the pore size of the porous solid electrolyte is 1-3 μm, and the porous solid electrolyte is formed by polyvinylidene fluoride-hexafluoropropylene copolymer and 1-butyl-3-methylimidazole bistrifluoromethanesulfonyl imide salt.

2. The use according to claim 1, wherein The gate, source and drain are formed of chromium and gold layers.

3. The use according to claim 1 or 2, wherein The thickness of the electrode is 5-15 nm for the chromium layer and 80-150 nm for the gold layer.

4. The use according to claim 1 or 2, wherein The thickness of the porous solid electrolyte is 30-100 μm.

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