Gas or optical sensor comprising a graphene layer

Abstract

The present disclosure relates to a gas or optical sensor (100) comprising a graphene layer (110) whose first and second faces are decorated with metal nanoparticles or nanoobjects (115, 315) and covered by a first (120) and second (320) polymer layer.

Description

[0001] This application claims priority to European patent application No. EP23307373, filed on December 22, 2023, entitled “Gas sensor comprising a graphenelayer,” which is incorporated herein by reference to the fullest extent permitted by law. Technical Field

[0002] This disclosure generally relates to gas or optical sensors, and more specifically, to gas or optical sensors comprising a graphene layer. Background Technology

[0003] Gas concentration measurements are crucial for certain applications, such as conducting breath analysis, measuring levels of volatile organic compounds in the air, or verifying the toxicity or potential explosiveness of chemicals in the environment.

[0004] Traditional gas detection methods (such as gas chromatography and mass spectrometry) are limited by the large size of the required equipment, high maintenance costs, and long sampling and measurement times.

[0005] Resistive hydrogen sensors using metal-oxide-semiconductor (MOS) devices have been proposed. However, this method requires high temperatures to operate, posing a challenge for low-power applications. Furthermore, MOS-based resistive hydrogen sensors exhibit other drawbacks, including suboptimal selectivity and oxygen dependence of operation, meaning their operation is affected by changes in oxygen concentration. Other types of solid-state sensors based on electrochemical reactions with solid electrolytes have recently been proposed. However, they are expensive, consume high power (above 10 microwatts), and require a three-wire potentiostat for operation.

[0006] Therefore, compared to current technological solutions, there is a need for a gas sensor that has relatively low cost and / or relatively low power consumption while maintaining high sensitivity and selectivity.

[0007] In addition, a stable optical sensor with relatively high light sensitivity is needed. Summary of the Invention

[0008] According to one aspect, a gas sensor comprising a graphene layer is provided, at least a first side of said graphene layer being modified with metal nanoparticles and covered by a first polymer layer composed of parylene.

[0009] According to one embodiment, the second side of the graphene layer opposite to the first side is modified with metal nanoparticles and covered with a second polymer layer composed of phenelzine.

[0010] According to one embodiment, the gas sensor further includes:

[0011] - An electrolyte layer covering the second side of the graphene layer opposite the first side; and

[0012] - An electrode that is in contact with the electrolyte layer and is configured to apply a bias voltage to the electrolyte layer.

[0013] According to another aspect, a gas sensor is provided, comprising:

[0014] - A graphene layer, one or both sides of which are modified with metal nanoparticles;

[0015] - A first polymer layer covering the first side of the graphene layer; and

[0016] - A second polymer layer covering the second side of the graphene layer, the second side being opposite to the first side, the gas sensor being configured to detect gas penetrating the polymer layer on the first and / or second sides of the graphene layer.

[0017] According to one embodiment, the gas sensor is configured to detect hydrogen.

[0018] According to one embodiment, the metal nanoparticles include nanoparticles of one or more of the following materials: silver; platinum; palladium; or alloys of these materials.

[0019] According to one embodiment, the first polymer layer has a first side in contact with the graphene layer, and the gas sensor further includes a metal layer that covers a second side of the polymer layer, the second side of the polymer layer being opposite to the first side of the polymer layer.

[0020] According to another aspect, an electronic device is provided, comprising:

[0021] - A gas sensor comprising a graphene layer bonded to a first electrode and a second electrode;

[0022] - An electronic circuit comprising: a biasing circuit configured to bias the graphene layer by applying a voltage or current to the first electrode; and an analog-to-digital converter configured to convert a voltage between the first electrode and the second electrode into a digital value; and

[0023] - A transmission circuit configured to wirelessly transmit the digital value via the antenna of the electronic device.

[0024] According to one embodiment, the electronic circuit is configured to be powered by energy harvesting via received RF signals.

[0025] According to one embodiment, the gas sensor included in the electronic circuit is the aforementioned gas sensor.

[0026] According to another aspect, a system is provided, comprising:

[0027] - The aforementioned electronic devices; and

[0028] - A membrane that is attached to and surrounds the gas sensor of the electronic device, the membrane being adapted to be punctured by a straw to supply gas to the gas sensor.

[0029] According to another aspect, a system is provided, comprising:

[0030] - Including the first compartment at the entrance; and

[0031] - The aforementioned electronic devices located in the second compartment.

[0032] According to one embodiment, the system further includes: an input valve located at the interface between the first compartment and the second compartment; and an output valve on one side of the second compartment.

[0033] According to another aspect, a method for manufacturing a gas sensor is provided, the method comprising:

[0034] - Depositing metal nanoparticles on a graphene layer; and

[0035] - Deposit a first polymer layer composed of phenelzine, the first polymer layer being covered with a graphene layer modified with metal nanoparticles.

[0036] According to another aspect, a method for manufacturing a gas sensor is provided, the method comprising:

[0037] - Deposit metal nanoparticles on the first surface of the graphene layer;

[0038] - Form a first electrode in contact with the graphene layer, for example by printing the first electrode in a first region on a first side of the graphene layer using conductive ink;

[0039] - Deposit a first polymer layer covering the first side of the graphene layer;

[0040] - Deposit metal nanoparticles on the second surface of the graphene layer, the second surface being opposite to the first surface;

[0041] - Forming a second electrode in contact with the graphene layer, for example, by printing the second electrode in a second region on the second side of the graphene layer using conductive ink; and

[0042] - Deposit a second polymer layer covering the second side of the graphene layer.

[0043] According to another aspect, a sensor is provided, comprising:

[0044] - A graphene layer, wherein both sides of the graphene layer are modified with metal nanoparticles or nanoobjects;

[0045] - A first polymer layer covering the first side of the graphene layer; and

[0046] - A second polymer layer covering the second side of the graphene layer, the second side being opposite to the first side.

[0047] According to an implementation plan:

[0048] - The sensor is an optical sensor;

[0049] - The graphene layer is modified with nanomaterials, which are semiconductor nanowires or semiconductor quantum dots; and

[0050] - The first and second polymer layers have a transmittance of at least 50% for light in one or more wavelength ranges, and the optical sensor is configured to detect light penetrating the polymer layers on the first and / or second surfaces of the graphene layers.

[0051] According to one embodiment, the nanoobject is configured to allow light to be converted into electrical charge.

[0052] According to one implementation, the sensor is flexible.

[0053] According to an implementation plan:

[0054] - The sensor is a gas sensor;

[0055] - The graphene layer is modified with metal nanoparticles; and

[0056] - The first and second polymer layers are permeable to gas, and the gas sensor is configured to detect gas penetrating the polymer layers on the first and / or second surfaces of the graphene layer.

[0057] According to another aspect, a gas sensor is provided, comprising:

[0058] - A graphene layer, one or both sides of which are modified with metal nanoparticles;

[0059] - A first polymer layer covering the first side of the graphene layer;

[0060] - A second polymer layer covering a second side of the graphene layer, the second side being opposite to the first side, the second polymer layer being an electrolyte; and

[0061] - An electrode that is in contact with the second polymer layer and is configured to apply a bias voltage to the second polymer layer.

[0062] The gas sensor is configured to detect gas penetrating the polymer layer on the first and / or second sides of the graphene layer.

[0063] According to another aspect, a gas sensor is provided, comprising:

[0064] - A graphene layer, one or both sides of which are modified with metal nanoparticles;

[0065] - A first polymer layer covering the first side of the graphene layer; and

[0066] - A second polymer layer covering a second side of the graphene layer, the second side being opposite to the first side, wherein the first polymer layer has a first side in contact with the graphene layer, the gas sensor further comprising a metal layer covering the second side of the polymer layer, the second side of the polymer layer being opposite to the first side of the polymer layer, and the gas sensor being configured to detect gas penetrating the polymer layer on the first and / or second sides of the graphene layer.

[0067] According to one embodiment, the second polymer layer is an electrolyte and further includes an electrode in contact with the second polymer layer, the electrode being configured to apply a bias voltage to the second polymer layer.

[0068] According to one embodiment, the gas sensor is configured to detect hydrogen.

[0069] According to one embodiment, the metal nanoparticles comprise nanoparticles of one or more of the following materials:

[0070] - silver;

[0071] - Platinum;

[0072] - Palladium;

[0073] Or alloys of these materials.

[0074] According to one embodiment, the first polymer layer of the gas sensor has a first side in contact with the graphene layer, and the gas sensor further includes a metal layer that covers a second side of the polymer layer, the second side of the polymer layer being opposite to the first side of the polymer layer.

[0075] According to one embodiment, the graphene layer of the sensor is modified with metal nanoparticles or nanoobjects on both sides, and the first polymer layer and the second polymer layer are composed of phenelzine.

[0076] According to another aspect, an electronic device is provided, comprising:

[0077] - A gas or optical sensor comprising a graphene layer bonded to a first electrode and a second electrode;

[0078] - Electronic circuits, including:

[0079] A bias circuit configured to bias the graphene layer by applying a voltage or current to the first electrode; and

[0080] An analog-to-digital converter configured to convert the voltage between the first electrode and the second electrode into a digital value; and

[0081] - A transmission circuit configured to wirelessly transmit the digital value via the antenna of the electronic device.

[0082] According to one embodiment, the electronic circuit is configured to be powered by energy harvesting via received RF signals.

[0083] According to another aspect, a system is provided, comprising:

[0084] - The aforementioned electronic device, wherein the sensor is a gas sensor; and

[0085] - A membrane that is attached to and surrounds the gas sensor of the electronic device, the membrane being adapted to be punctured by a straw to supply gas to the gas sensor.

[0086] According to another aspect, a system is provided, comprising:

[0087] - Including the first compartment at the entrance; and

[0088] - The aforementioned electronic devices located in the second compartment.

[0089] According to one implementation, the system further includes:

[0090] - An input valve located at the interface between the first compartment and the second compartment; and

[0091] - An output valve on one side of the second compartment.

[0092] According to another aspect, a method for manufacturing a gas or optical sensor is provided, the method comprising:

[0093] - Deposit metal nanoparticles or nanoobjects on the first surface of the graphene layer;

[0094] - Form a first electrode in contact with the graphene layer, for example by printing the first electrode in a first region on a first side of the graphene layer using conductive ink;

[0095] - Deposit a first polymer layer covering the first side of the graphene layer;

[0096] - Deposit metal nanoparticles or nanoobjects on the second surface of the graphene layer, with the second surface opposite to the first surface;

[0097] - Forming a second electrode in contact with the graphene layer, for example, by printing the second electrode in a second region on the second side of the graphene layer using conductive ink; and

[0098] - Deposit a second polymer layer covering the second side of the graphene layer. Attached Figure Description

[0099] The foregoing features and advantages, as well as other features and advantages, will be described in detail below with reference to the accompanying drawings in the description of specific embodiments given in an illustrative and non-limiting manner, wherein:

[0100] Figure 1 This is a cross-sectional view of a gas sensor according to an exemplary embodiment of the present disclosure;

[0101] Figure 2 An exemplary embodiment according to this disclosure is shown. Figure 1 Cross-sectional views of the gas sensor during successive steps of the manufacturing process;

[0102] Figure 3 This is a cross-sectional view of a gas sensor according to another exemplary embodiment of this disclosure;

[0103] Figure 4 An exemplary embodiment according to this disclosure is shown. Figure 3 Cross-sectional views of the gas sensor during successive steps of the manufacturing process;

[0104] Figure 5 This is a cross-sectional view of a gas sensor according to yet another exemplary embodiment of the present disclosure;

[0105] Figure 6A An embodiment is shown. Figure 1 A cross-sectional view of a gas sensor during successive steps of a manufacturing process suitable for connecting two electrodes to the gas sensor.

[0106] Figure 6B An embodiment according to another implementation is shown. Figure 1A cross-sectional view of a gas sensor during successive steps of a manufacturing process suitable for connecting two electrodes to the gas sensor.

[0107] Figure 6C It has electrodes Figure 3 A cross-sectional view of the gas sensor;

[0108] Figure 7A A schematic illustration shows a measurement method according to an exemplary embodiment of the present disclosure. Figure 1 , Figure 3 or Figure 5 The electrical conductivity of the graphene layer in the gas sensor's electronic circuitry.

[0109] Figure 7B A schematic illustration shows a measurement method according to another exemplary embodiment of this disclosure. Figure 1 , Figure 3 or Figure 5 The electrical conductivity of the graphene layer in the gas sensor's electronic circuitry.

[0110] Figure 8 An electronic device according to an exemplary embodiment of the present disclosure is illustrated schematically;

[0111] Figure 9 This shows the effect for different hydrogen concentrations. Figure 1 A graph showing the relative change in resistance of the graphene layer in a hydrogen sensor over time.

[0112] Figure 10 This is a schematic cross-sectional view illustrating a gas detection system according to an exemplary embodiment of the present disclosure; and

[0113] Figure 11 This is a perspective view of a gas detection system according to another exemplary embodiment of the present disclosure. Detailed Implementation

[0114] In multiple figures, the same features are indicated by the same reference numerals. In particular, common structural and / or functional features in multiple embodiments may have the same reference numerals and may have the same structure, dimensions, and material properties.

[0115] For clarity, only the operations and components used to understand the embodiments described herein are shown and described in detail.

[0116] Unless otherwise stated, when referring to two elements connected together, it means that they are directly connected without any intermediate elements other than conductors, and when referring to two elements combined together, it means that the two elements can be connected or they can be combined by one or more other elements.

[0117] In the following disclosure, unless otherwise stated, when referring to absolute positional modifiers, such as the terms “front,” “back,” “top,” “bottom,” “left,” “right,” etc., or relative positional modifiers, such as the terms “above,” “below,” “higher than,” “lower than,” etc., or directional modifiers, such as “horizontal,” “vertical,” etc., refer to the directions shown in the accompanying drawings.

[0118] Unless otherwise stated, the expressions “around,” “approximately,” “basically,” and “in the order of” indicate within 10%, preferably within 5%.

[0119] Figure 1 This is a cross-sectional view of a gas sensor 100 according to an exemplary embodiment of the present disclosure. In some embodiments, the gas sensor 100 is a hydrogen sensor configured to detect the presence of hydrogen in the environment in which the sensor 100 is located.

[0120] Gas sensor 100 includes a substrate 105 configured to mechanically support the detection layer of the gas sensor. Substrate 105 is, for example, a polymer layer, such as a polyethylene terephthalate (PET) layer or a poly(p-xylene) (also known as n-xylene or phenelzine) layer, or a thermoplastic polyurethane (TPU) layer. In the case of phenelzine, substrate 105 is more specifically composed of phenelzine-C, phenelzine-N, phenelzine-D, or mixtures of these compounds.

[0121] The substrate 105 of the gas sensor 100 is covered by a graphene layer 110. In some embodiments, the graphene layer 110 is a single layer of graphene, i.e., a graphene layer with a thickness of only one atom. According to another embodiment, the graphene layer 110 is a multilayer comprising at least two layers of graphene. The graphene layer 110 is conductive.

[0122] The top surface of the graphene layer 110 is partially covered by metal nanoparticles 115. The metal nanoparticles 115 are composed, for example, palladium, platinum, silver, or alloys of these elements. In one embodiment, particularly in the case of a hydrogen sensor, the metal nanoparticles 115 are palladium or platinum. The diameter of the metal nanoparticles 115 is, for example, less than 5 nanometers, and for example, 1 to 2 nanometers. The metal nanoparticles 115 are in direct contact with the graphene layer 110. The electrical conductivity of the graphene layer 110 is altered by the interaction between the gas molecules to be detected and the metal nanoparticles. According to one embodiment, in the case of a hydrogen sensor, the metal nanoparticles 115 absorb hydrogen molecules located in their vicinity. The absorption of hydrogen molecules by the metal nanoparticles 115 affects the electronic interaction between the metal nanoparticles 115 and the graphene, and thus modulates the electrical conductivity of the graphene layer 110 through a field effect. Therefore, the conductivity of the graphene layer 110 varies as a function of the hydrogen concentration surrounding the metal nanoparticles, and the hydrogen sensor 100 acts as a chemielectric resistor, i.e., a variable resistor whose resistance is a function of the hydrogen concentration. Similar effects can be achieved for other gases to be detected.

[0123] The graphene layer 110 and the metal nanoparticles 115 are also covered by a polymer layer 120. In the case of a hydrogen sensor, the polymer layer 120 is, for example, a phenelin layer, such as phenelin-C, phenelin-N, phenelin-D, or a mixture of these compounds. Pphenelin is a porous material with pores large enough to allow hydrogen molecules to pass through, but small enough to prevent other larger molecules from passing through. For example, depending on its precise composition and thickness, the polymer layer 120 thus forms a molecular sieve in the gas sensor 100, thereby contributing to the gas selectivity of the sensor. In the case of a hydrogen sensor having a phenelin polymer layer 120, the phenelin layer 120 has, for example, a thickness of 100 nm to 10 μm.

[0124] According to one embodiment, a metal layer 125 is deposited on the surface of the polymer layer 120. The metal is, for example, palladium, platinum, silver, or a compound of these elements. The metal layer 125 is configured, for example, to filter molecules reaching the gas sensor 100 before they reach the surface of the polymer layer 120, thereby further increasing the selectivity of the gas sensor 100. In the case of a hydrogen sensor, the metal layer 125 has, for example, a thickness of 0.5 nm to 50 nm.

[0125] The composition of the polymer layer 120, its thickness, and the addition of a metal layer 125 to the surface of the polymer layer 120, for example, to adjust sensitivity and enhance the selectivity of the gas sensor 100 for a specific gas.

[0126] Figure 2 An exemplary embodiment according to this disclosure is shown. Figure 1A cross-sectional view of the hydrogen sensor 100 during successive steps of the manufacturing process.

[0127] During process step S1, a graphene layer 110 is grown on a temporary substrate layer 205, for example, made of copper, using chemical vapor deposition.

[0128] During process step S2 following step S1, metal nanoparticles 115 are deposited on the surface of graphene layer 110 to partially cover the surface, for example, using vacuum physical vapor deposition or electrochemical reduction of metal salts in water. For example, at least 5% of the surface of graphene layer 110 is not covered during step S2, and for example, at least 10% of the surface of graphene layer 110 is not covered during step S2.

[0129] During process step S3 following step S2, polymer layer 120 is deposited, for example, using chemical vapor deposition. The thickness of polymer layer 120 is adjusted, for example, according to the gas to be detected.

[0130] Although Figure 2 (Not shown in the diagram) According to one embodiment, after process step S3, a polymer layer 120 is deposited on its surface. Figure 1 Metal layer 125. For example, a palladium layer is deposited using physical vapor deposition or electrochemical deposition.

[0131] During process step S4 following step S3, the temporary substrate layer 205 is removed, for example, by chemical etching with ferric chloride or sodium persulfate, or by delamination by oxidation of copper in hot water, or by electrochemical action and formation of a gas film at the copper / graphene interface.

[0132] Process steps after step S4 ( Figure 2 During (not shown), for example, deposition on graphene layer 110 Figure 1 The substrate layer 105 is used instead of the temporary substrate layer 205 to obtain Figure 1 The gas sensor 100. According to one embodiment, the substrate 105 is composed of phenelzine and is deposited using chemical vapor deposition in a manner similar to process step S3. According to another embodiment, the substrate 105 contains an additional PET film covered with ethylene-vinyl acetate copolymer (EVA), and is deposited directly onto the graphene layer 110 or directly onto the substrate 105, for example, using thermal lamination, which utilizes the thermal melting properties of EVA. The substrate 105 protects the graphene layer and provides support for the gas sensor 100.

[0133] Figure 2Some of the methods and steps are described in more detail in the applicant’s patent publications FR3131076A1 and WO2023118723, the contents of which are incorporated herein by reference in their entirety to the extent permitted by law.

[0134] Although Figure 2 In one embodiment, the substrate is a temporary substrate layer 205; however, in an alternative embodiment, the substrate layer can be changed to a layer of another material before steps S2 to S4. In such a case, after step S1, a polymer substrate layer, for example composed of phenelzine, is deposited on the graphene layer 110, and the temporary substrate layer 205 is removed as described in step S4. Then, according to step S2, metal nanoparticles 115 are deposited on the exposed surface of the graphene layer 110. Then, according to step S3, a phenelzine layer 120 is deposited on top of the metal nanoparticles 115.

[0135] Figure 3 This is a cross-sectional view of a gas sensor 300 according to another exemplary embodiment of the present disclosure.

[0136] Figure 3 The gas sensor 300 does not include Figure 1 The substrate 105. The gas sensor 300 includes metal nanoparticles 115 and a first polymer layer 120 on one side of the graphene layer 110, and metal nanoparticles 315 and a second polymer layer 320 on the opposite side of the graphene layer 110.

[0137] Metal nanoparticles 315 are composed, for example, of palladium, platinum, silver, or compounds of these elements. Metal nanoparticles 115 and 315 have, for example, the same composition as each other. In an alternative embodiment, metal nanoparticles 115 and 315 have different compositions.

[0138] The diameter of the metal nanoparticles 315 is, for example, less than 5 nanometers, and for example, 1 to 2 nanometers.

[0139] Metal nanoparticles 315 are in direct contact with graphene layer 110.

[0140] According to one embodiment, metal nanoparticles 315 are used for gas detection. According to another embodiment, metal nanoparticles 315 are used as a dopant to dope polymer layer 320 and to set the potential of graphene layer 110 to tune gas sensor 300 to operate at relatively high sensitivity.

[0141] In the alternative implementation plan, Figure 3 Chemical components, not shown, are mixed in polymer layer 320 to dope polymer layer 320 and to set the potential of graphene layer 110 to adjust gas sensor 300 to operate at a relatively high maximum sensitivity.

[0142] Polymer layers 120 and 320 are, for example, pyreline layers, such as pyreline-C, pyreline-N, pyreline-D, or mixtures of these compounds, or any other suitable polymer. Polymer layers 120 and 320 have, for example, the same composition as each other. In alternative embodiments, layers 120 and 320 have different compositions. Layer 120 or layer 320, for example, constitutes the substrate of gas sensor 300.

[0143] Polymer layers 120 and 320 are porous layers, for example, acting as polymer molecular sieve membranes, configured to filter particles small enough to pass through polymer layers 120 and 320 and reach metal nanoparticles 115 and 315. The metal nanoparticles 115 and 315 are chosen such that their conductivity can be adjusted according to the concentration of a specific gas. Adjustment of the conductivity of the metal nanoparticles 115 and 315 results in adjustment of the conductivity of the graphene layer they contact. Therefore, the device 300 can be used as a gas sensor, for example, for hydrogen, ammonia, ethanol, methane, etc.

[0144] The composition of polymer layers 120 and 320, their thickness, and the addition of metal layers 125 and 125' to the surfaces of polymer layers 120 and 320, for example, are used to adjust the sensitivity and selectivity of gas sensor 300 to a specific gas.

[0145] One advantage of having metal nanoparticles 115, 315 and polymer layers 120, 320 on both sides of the graphene layer 110 is that it increases the surface area on which gases can be detected, thereby increasing the sensitivity of the gas sensor 300.

[0146] Figure 4 An exemplary embodiment according to this disclosure is shown. Figure 3 A cross-sectional view of the gas sensor 300 during the continuous steps of the manufacturing process.

[0147] For example, by conducting Figure 2 Steps S1 to S4 are obtained Figure 4 The apparatus shown in the first step S4. The graphene layer 110 is partially covered by metal nanoparticles 115 on the first surface of the graphene layer 110, and a polymer layer 120 has been deposited on the first surface of the graphene layer 110. The temporary substrate layer 205 has been removed, leaving the uncovered second surface of the graphene layer 110.

[0148] exist Figure 2 Step S4 and beyond Figure 4 During process step S5, for example, with Figure 2In a similar manner to step S2, such as using physical vapor deposition or electrochemistry, metal nanoparticles 315 are deposited on the surface of the second side of the graphene layer 110 to partially cover the second side. For example, at least 5% of the surface of the second side of the graphene layer is not covered during step S5, and for example, at least 10% of the surface of the second side of the graphene layer is not covered during step S5.

[0149] During process step S6 following step S5, for example, a polymer layer 320 is deposited on the second surface of the graphene layer 110 to obtain... Figure 3 Gas sensor 300. For example, according to similar... Figure 2 The process of step S3, for example, using chemical vapor deposition, deposits a polymer layer 320.

[0150] Although Figure 4 (Not shown in the diagram) According to one embodiment, after process step S3, a polymer layer 120 is deposited on its surface. Figure 3 The metal layer 125 is deposited on the surface of the polymer layer 320 after process step S6.

[0151] Figure 5 This is a cross-sectional view of a gas sensor 500 according to yet another exemplary embodiment of the present disclosure.

[0152] The gas sensor 500 includes metal nanoparticles 115 on one side of a graphene layer 110 and a polymer layer 120. According to one embodiment, the metal layer 125 is present on the surface of the polymer layer 120.

[0153] The second side of the graphene layer 110 is covered by an electrolyte layer 520 in contact with the graphene layer 110. The electrolyte layer 520 is, for example, a liquid (e.g., a gel) or a solid. The electrolyte 520 is, for example, a solid polymer electrolyte, such as one made of polyvinyl acetate (PVA) and magnesium perchlorate.

[0154] Electrode 530 is in contact with electrolyte 520 and is configured to bias electrolyte 520, for example, with a fixed voltage. A bias voltage is applied to electrolyte layer 520 to bias graphene layer 110 in contact with it, thereby allowing the operating point of gas sensor 500 to be set.

[0155] Gas sensor 500, for example, is made of Figure 1The process steps S1 to S4 are performed, followed by deposition of the electrolyte layer 520 on the exposed surface of the graphene layer 110. In some embodiments, particularly when the electrolyte is liquid, it is sealed within a housing (not shown), such that it is trapped between the housing and the graphene layer 110. In some embodiments, for example, if the electrolyte is solid, a substrate polymer layer is deposited on the surface of the electrolyte layer 520. For example, the substrate polymer layer includes a pyrene layer, a PET layer, or a PET layer covered with EVA.

[0156] Figure 6A An embodiment is shown. Figure 1 Cross-sectional views of gas sensors 100, 300, and 500 during successive steps of a manufacturing process suitable for connecting two electrodes 640 and 642 to the gas sensor.

[0157] Gas concentration is measured using gas sensors 100, 300, and 500, for example, by connecting the two edges of graphene layer 110 to electrodes 640 and 642 to bias graphene layer 110 and / or to perform the measurement.

[0158] For example, change Figure 2 The process step S3 is used to integrate the deposition of electrodes 640 and 642.

[0159] exist Figure 2 During process step S3' following step S2, electrodes 640, 642 are deposited on the graphene layer 110 partially covered by metal nanoparticles, for example by ink printing using conductive ink, such as ink containing silver particles.

[0160] During process step S3'b following step S3', according to Figure 2 In process step S3, a polymer layer 120 is deposited on the surface of the graphene layer 110 and the surfaces of the electrodes 640 and 642. The polymer layer 120 protects the electrodes 640 and 642 and / or the metal nanoparticles 115 from corrosion, especially when the polymer layer 120 is formed of pyrene, particularly for electrodes and / or metal nanoparticles 115 made of silver.

[0161] Figure 6B An embodiment according to another implementation is shown. Figure 1 Cross-sectional views of gas sensors 100, 300, and 500 during successive steps of a manufacturing process suitable for connecting two electrodes 640 and 642 to the gas sensor.

[0162] In a preferred embodiment, Figure 2In process step S3'a following the deposition of the metal nanoparticles 115 described in process step S2, electrodes 640 and 642 are printed onto an EVA-coated PET sheet using conductive ink, such as ink containing silver particles. The EVA-coated PET sheet includes openings, for example, in areas between electrodes where polymer layers 120 are deposited. Electrodes 640 and 642 and PET layers 645 and 647 are deposited on the surface of graphene layer 110, for example, using a hot-melt lamination process. The hot-melt lamination process step is performed, for example, according to the process detailed in European patent application EP23305773 filed on May 15, 2023, in the name of the applicant, the contents of which are incorporated herein by reference in their entirety to the extent permitted by law.

[0163] During process step S3'b following step S3'a, according to Figure 2 In process step S3, a polymer layer 120 is deposited on the surface of the graphene layer 110, located in the opening of the PET sheet.

[0164] For example, it can be adopted Figure 6B The method to make electrodes 640 and 642 contact Figure 3 The graphene layer 110 in the gas sensor 300. In such a case, step S2 is applied, for example, to... Figure 2 The structure of step S4 is used to deposit metal nanoparticles 315 on the exposed surface of the graphene layer 110. Then, steps S3'a and S3'b are performed, for example, as described above.

[0165] Now refer to Figure 6C Describe a form of contact Figure 3 An alternative method for the electrodes of the graphene layer 110 in the gas sensor 300.

[0166] Figure 6C It has electrodes 640, 642, 650, and 652. Figure 3 A cross-sectional view of the gas sensor;

[0167] Similar to Figure 6A The connection of the two electrodes 640, 642 on one side of the graphene layer 100, as detailed in the description, is, for example, in... Figure 3 Two additional electrodes 650 and 652 are deposited on the other side of the graphene layer 110 in the gas sensor 300.

[0168] According to one implementation, in order to form these electrodes, for example, instead of Figure 4 Step S6, repeat Figure 6A Steps S3' and S3'b.

[0169] Electrodes 640 and 650 at one edge of graphene layer 110 and electrodes 642 and 652 at the other edge of graphene layer 110 are connected to each other to form two contacts, one on each edge of graphene layer 110.

[0170] Figure 7A A schematic illustration shows a measurement method according to an exemplary embodiment of the present disclosure. Figure 1 , Figure 3 or Figure 5 The electrical conductivity of the graphene layer in the gas sensor is 100, 300, or 500, and the electronic circuit is 700.

[0171] Electronic circuit 700 includes respectively Figure 1 , Figure 3 and Figure 5 Any one of the gas sensors 100, 300, and 500, the gas sensor including connections between two electrodes (e.g. Figure 6A The graphene layer 110 is between electrodes 640 and 642. The voltage source 705 is connected between the ground of the electronic circuit 700 and the first node 710 of the Wheatstone bridge.

[0172] The Wheatstone bridge includes a first resistor R1 with a fixed resistance value connected between node 710 and the second node 715. The Wheatstone bridge also includes a second resistor R2 with a variable resistance value connected between node 715 and the third node 720. The Wheatstone bridge also includes a third resistor R3 with a fixed resistance value connected between node 710 and the fourth node 725. The Wheatstone bridge also includes gas sensors 100, 300, and 500 connected between nodes 725 and 720.

[0173] The analog-to-digital converter (ADC) 730 has two input nodes IN1, IN2, which are, for example, combined with nodes 710 and 720 of a Wheatstone bridge, and is configured to measure the voltage between these nodes and convert the voltage into a digital output value at its output node OUT.

[0174] By adjusting the value of resistor R2 and measuring the voltage between nodes 710 and 720, the resistance values ​​of gas sensors 100, 300, and 500 can be derived.

[0175] The graphene layer 110 is biased at a fixed voltage. Since the conductivity of the graphene layer 110 varies with the concentration of the surrounding gas, the current flowing through the graphene layer 110 varies as a function of the surrounding gas concentration. According to one embodiment, the gas sensors 100, 300, and 500 have a resistance of 1 to 5 kiloohms, and advantageously, the energy consumption of the electronic circuitry 700 is in the submicrowatt range.

[0176] Figure 7B A schematic illustration shows a measurement method according to another exemplary embodiment of this disclosure. Figure 1 , Figure 3 or Figure 5 The graphene layer 110 of the gas sensor has high conductivity, and the electronic circuit 750 provides, for example, an electronic circuit 750. Figure 7A An alternative to the 700 circuit.

[0177] Electronic circuit 750 includes respectively Figure 1 , Figure 3 and Figure 5 Any one of the gas sensors 100, 300, and 500, the gas sensor including connections between two electrodes (e.g. Figure 6A The graphene layer 110 is located between the electrodes 640, 642. For example, a constant current source 755, implemented by a constant current device, is integrated between the ground of the electronic circuit 750 and the first electrode 640 of the gas sensors 100, 300, 500, and is configured to deliver a constant current to the gas sensors. In some embodiments, the level of the constant current generated by the current source 755 is adjustable.

[0178] The second electrode 642 of gas sensors 100, 300, and 500 is connected to the ground of electronic circuit 750.

[0179] The analog-to-digital converter (ADC) 730 has, for example, two input nodes IN1 and IN2, which are coupled to the first electrode 640 and the second electrode 642 of the gas sensors 100, 300, and 500, respectively, and is configured to measure the voltage across the gas sensors and convert the voltage into a digital output value at its output node OUT.

[0180] For example, a constant current with a known value is driven by a current source 755 through gas sensors 100, 300, and 500, and the resistance of gas sensors 100, 300, and 500 is derived, for example, from the voltage measured between their electrodes 640 and 642.

[0181] Figure 8 An electronic device 800 according to an exemplary embodiment of the present disclosure is illustrated schematically.

[0182] Electronic device 800 includes components connected to electronic circuit 810. Figure 1 , Figure 3 and Figure 5 Any one of the gas sensors 100, 300, and 500. Electronic circuitry 810 is configured, for example, to communicate with external devices (in [the specified location] via antenna 820 through NFC communication (“NFC Com”). Figure 8In some cases, communication is conducted via a mobile phone or smartphone. Alternatively, the external device could be another type of electronic device, such as a laptop or tablet.

[0183] Electronic circuit 810 includes, for example, Figure 7A Electronic circuit 700 or Figure 7B The electronic circuit 750 is configured to estimate the concentration of a specific gas in the environment of the gas sensors 100, 300, and 500.

[0184] According to one embodiment, antenna 820 is configured to wirelessly transmit and receive data at frequencies in the range of 13 MHz to 14 MHz (corresponding to the near field communication (NFC) frequency range). For example, electronic circuitry for estimating the concentration of a specific gas is... Figure 7B The electronic circuit 750.

[0185] According to another embodiment, antenna 820 is configured to wirelessly transmit and receive data at frequencies of 300 MHz and 3 GHz (which correspond to the ultra-high frequency (UHF) radio frequency identification (RFID) frequency range). For example, electronic circuitry for estimating the concentration of a specific gas is... Figure 7A 700 electronic circuits.

[0186] According to one embodiment, and in accordance with standard practices known to those skilled in the art, electronic circuitry 810 is configured to harvest energy via antenna 820 to power electronic device 800. One advantage of gas sensors 100, 300, and 500, which include a graphene layer, is that they consume a sufficiently small amount of energy to operate solely on the harvested energy, without requiring a separate power source such as a battery.

[0187] Figure 9 This shows the initial conditions relative to the gas sensor 100 being surrounded by air, for different hydrogen concentrations. Figure 1 The graph shows the relative change in resistance of the graphene layer of the hydrogen sensor 100 over time.

[0188] The relative change in resistance of the hydrogen sensor 100, for example, using Figure 7A Electronic circuit 700 or Figure 7B Electronic circuit 750 and Figure 8 The electronic device 800 is used for measurement. Relative changes are measured, for example, as voltage changes.

[0189] During the first time period between t1 and t2 (where t1 is 44 seconds and t2 is 5 minutes and 11 seconds), a hydrogen flux of 25 parts per million (ppm) (“H2 flow (25 ppm)”) is delivered toward gas sensor 100. The hydrogen concentration near gas sensor 100 increases and is measured to decrease by 5% by the gas sensor.

[0190] During the second time period between t2 and t3 (where t3 is 17 minutes and 25 seconds), an air flux (“airflow”) is delivered toward the gas sensor 100. The hydrogen concentration near the gas sensor 100 decreases and is measured by the gas sensor to be an increase of approximately 3.3%, resulting in a relative change of approximately -1.7%.

[0191] During the time interval between t3 and t4 (where t4 is approximately 25 minutes), a hydrogen flux of 25 ppm (“H2 flow (25 ppm)”) is delivered toward gas sensor 100. The hydrogen concentration near gas sensor 100 increases and is measured by the gas sensor to be a decrease of approximately 5.5%, resulting in a relative change of approximately -7.2%.

[0192] During the time interval between t4 and t5 (where t5 is 25 minutes and 50 seconds), the hydrogen flux was stopped (“no flow”), and the hydrogen concentration remained stable. The voltage drop continued to decrease at a similar decay rate, reaching a relative change of approximately -7.5%.

[0193] During the time interval between t5 and t6 (where t6 is 50 minutes and 25 seconds), an air flux (“airflow”) is delivered toward gas sensor 100. The hydrogen concentration near gas sensor 100 decreases and is measured by the gas sensor to be an increase of approximately 6.1%, resulting in a relative change of approximately -1.4%.

[0194] During the final time period between t6 and t7 (where t7 is 1 hour and 8 minutes), the gas flow is stopped and the heating system is turned on (“heating + open air”). The heating system causes air movement, and the gas sensor 100 measures a sudden change. The relative change reaches 0 at t7 because the gas around the sensor 100 has a composition similar to the initial conditions at t1.

[0195] The gas sensor 100 is capable of detecting changes in hydrogen concentration below 25 ppm and has, for example, a detection threshold of 5 ppm.

[0196] Figure 10 This is a schematic cross-sectional view of a gas detection system 1000 according to an exemplary embodiment of the present disclosure.

[0197] System 1000 includes Figure 8Electronic device 800, said electronic device 800 includes Figure 1 , 3 Gas sensors 100, 300, or 500. System 1000 also includes, for example, a membrane 1010, which is attached to the electronic device 800 and forms a blister surrounding the gas sensors 100, 300, or 500 of the electronic device 800.

[0198] According to one embodiment, a user blows air into a chamber 1025 defined by a membrane 1010 using a straw 1015, allowing the air to pass through gas sensors 100, 300, and 500. The gas sensors are used, for example, to measure the concentration of a given gas in the user's breath, such as hydrogen, ethanol, methane, ammonia, etc. In some embodiments, the electronics 800 includes gas sensors 100, 300, and 500 fixed downwards to the bottom surface of a substrate 1005, such as a PCB (printed circuit board) or inlay. An inlet 1020 passes through the substrate 1005 and communicates with the chamber 1025. The inlet 1020 is connected, for example, to the straw 1015, thereby allowing air to be blown into the chamber 1025. An outlet 1030 is also provided, for example, passing through the substrate 1005 and communicating with the chamber 1025, thereby allowing air to exit the chamber 1025.

[0199] The advantage of providing a chamber 1025 beneath the substrate 1005 to house the gas sensors 100, 300, and 500 is that this allows for better detection of certain gases lighter than air, such as hydrogen. In fact, lighter gases will accumulate at the top of the chamber 1025 where the gas sensors are located. Furthermore, water condensate formed in the chamber 1025 and caused by moisture in the user's exhaled breath will fall to the bottom of the chamber 1025, away from the gas sensors.

[0200] The concentration of hydrogen in a user's breath can be used, for example, to diagnose digestive conditions.

[0201] Figure 11 This is a perspective view of a gas detection system 1100 according to another exemplary embodiment of the present disclosure.

[0202] System 1100 includes a first compartment 1110 and a second compartment 1120, and the first compartment 1110 and the second compartment 1120 are configured to contain and guide air. According to one embodiment, system 1100 includes a third compartment 1130 in contact with the second compartment 1120, and the third compartment 1130 is configured to guide air.

[0203] The first compartment 1110 includes an inlet 1140 for the gas to be analyzed to enter. For example, the compartment 1110 is a cylinder with an internal cavity, into which a user can blow air to analyze their breath. The shape of the first compartment 1110 is not limited to having a circular cross-section, but can have other forms, such as a rectangular cross-section.

[0204] In some embodiments, the inlet valve 1145 is located at the interface between the first compartment 1110 and the second compartment 1120. The inlet valve 1145 is configured to allow gas to enter if the gas velocity is high enough to open the valve, and to contain the gas in the second compartment 1120 during analysis. In other embodiments, there is no valve at the interface between the first compartment 1110 and the second compartment 1120.

[0205] In some embodiments, the output valve 1150 is located on the wall of the second compartment 1120. The output valve 1150 is configured to allow gas to exit the first compartment 1110 if the gas velocity is high enough to open the valve, and to retain the gas in the second compartment 1120 during analysis. In other embodiments, there is no output valve.

[0206] According to one implementation, when a user blows air into the first compartment 1110 using inlet 1140, inlet valve 1145 and outlet valve 1150 open, and the gas previously in the second compartment 1120 is blown out and replaced by the user's exhalation.

[0207] The third compartment 1130 is in contact with the second compartment 1120, for example, at the location of the output valve 1150.

[0208] Figure 8 Electronic device 800 is fixed in the second compartment. The gas sensor of electronic device 800 analyzes the concentration of gas in compartment 1120 over time, and the data can be transmitted to an external device (not shown) via antenna 820.

[0209] The advantages of the implementation scheme described in this article are that it can produce a gas sensor with relatively low power consumption and relatively low cost.

[0210] The advantage of using conductive ink to print the graphene layer 110 on the electrodes is that it avoids the need for specific metal deposition steps and has a process compatible with roll-to-roll manufacturing.

[0211] Various implementation schemes and variations have been described. Those skilled in the art will understand that certain features of these implementation schemes can be combined, and other variations will be readily apparent to them.

[0212] In particular, although gas sensors 100, 300, and 500 have been described in detail in this specification, in other embodiments, the sensor may be an optical sensor instead of a gas sensor.

[0213] Specifically, although the metal nanoparticles 115 have been described in detail for gas sensors 100, 300, and 500 in this specification, in other embodiments, the metal nanoparticles 115 are replaced by nanomaterials to obtain optical sensors. For example, the nanomaterials have optical properties.

[0214] According to one embodiment, the nanoobject is a semiconductor nanowire or a semiconductor quantum dot. The nanoobject is deposited on the graphene layer 110, for example, by drop casting, spin coating, dipping, spraying, or the like.

[0215] Nanoobjects located on the surface of graphene layer 110 are configured, for example, to allow light to be converted into electrical charge. Therefore, the light flux incident on the nanoobjects is converted into a charge flow, for example, flowing along the graphene layer. Because these nanoobjects are encapsulated by graphene and polymer layers such as phenelzine, they are well protected from environmental influences and oxidation.

[0216] In the embodiments described herein, polymer layer 120 and substrate layer 105, or polymer layer 120 and second polymer layer 320, are configured to encapsulate nanoobjects and protect them from environmental influences and oxidation.

[0217] According to one embodiment, the optical sensor is flexible. For example, polymer layer 120 and substrate layer 105, or polymer layer 120 and second polymer layer 320, are made of flexible material.

[0218] According to one embodiment, polymer layer 120 and / or second polymer layer 320 have relative transmittance to light, for example, at least 50% transmittance for a relevant wavelength, depending on the application. For example, the nanoobject is sensitive to light in the visible and / or infrared and / or near-infrared and / or ultraviolet ranges, and polymer layer 120 and / or second polymer layer 320 have relative transmittance in one or more of these wavelength ranges. The sensor is configured to detect light penetrating the polymer layers on the first and / or second sides of the graphene layer.

[0219] For those skilled in the art, how to replace the metal nanoparticles 115 with nanomaterials will be related to... Figures 1 to 4 and Figures 6A to 8 It is obvious that the relevant description applies to optical sensors. Specifically, in Figure 2 During step S2 and Figure 4During step S5, nanomaterials are deposited on the graphene layer 110, for example, by drop casting, spin coating, dipping, spraying, etc. Figure 2 During step S3 and Figure 4 During step S6, polymer layer 120 is deposited, for example, using chemical vapor deposition. The thickness and composition of polymer layer 120 are adjusted, for example, according to the wavelength range to be detected and the desired transmittance.

[0220] Finally, based on the functional description provided above, the actual implementation of the embodiments and variations described herein is within the capabilities of those skilled in the art. Specifically, a gas sensor for measuring hydrogen concentration has been described, but the gas sensor is also applicable to hydrogen. Although this specification describes the manufacture of a single gas sensor in detail, it will be apparent to those skilled in the art that multiple gas sensors can be used to infer the gas concentration based on a linear combination of the responses of the multiple gas sensors.

Claims

1. A sensor (300) comprising: - A graphene layer (110), both sides of which are modified with metal nanoparticles (115, 315) or nano-objects; - A first polymer layer (120) covering the first side of the graphene layer; and - A second polymer layer (320) covering the second side of the graphene layer, the second side being opposite to the first side.

2. The sensor according to claim 1, wherein: - The sensor is an optical sensor; - The graphene layer (110) is modified with nanomaterials (115, 315), which are semiconductor nanowires or semiconductor quantum dots; as well as - The first and second polymer layers have a transmittance of at least 50% for light in one or more wavelength ranges, and the optical sensor is configured to detect light penetrating the polymer layers on the first and / or second surfaces of the graphene layers.

3. The sensor of claim 2, wherein the nanoobject is configured to allow light to be converted into electrical charge.

4. The sensor according to claim 2 or 3, wherein the sensor is flexible.

5. The sensor according to claim 1, wherein: - The sensor is a gas sensor; - The graphene layer (110) is modified with metal nanoparticles (115, 315); and - The first and second polymer layers are permeable to gas, and the gas sensor is configured to detect gas penetrating the polymer layers on the first and / or second surfaces of the graphene layer.

6. A gas sensor (300) comprising: - A graphene layer (110), one or both sides of which are modified with metal nanoparticles (115, 315); - A first polymer layer (120) covering the first side of the graphene layer; - A second polymer layer (320) covering the second side of the graphene layer, the second side being opposite to the first side, the second polymer layer being an electrolyte (520); and - An electrode (530) that is in contact with the second polymer layer and is configured to apply a bias voltage to the second polymer layer. The gas sensor is configured to detect gas penetrating the polymer layer on the first and / or second sides of the graphene layer.

7. A gas sensor (300) comprising: - A graphene layer (110), one or both sides of which are modified with metal nanoparticles (115, 315); - A first polymer layer (120) covering the first side of the graphene layer; and - A second polymer layer (320) covering the second side of the graphene layer, the second side being opposite to the first side. The first polymer layer (120) has a first side in contact with the graphene layer, and the gas sensor further includes a metal layer (125) covering a second side of the polymer layer, the second side of the polymer layer being opposite to the first side of the polymer layer, and the gas sensor being configured to detect gas penetrating the first and / or second sides of the polymer layer.

8. The gas sensor of claim 7, wherein the second polymer layer is an electrolyte (520) and further comprises an electrode (530) in contact with the second polymer layer, and the electrode is configured to apply a bias voltage to the second polymer layer.

9. The gas sensor according to any one of claims 5 to 8, configured to detect hydrogen.

10. The gas sensor according to any one of claims 5 to 9, wherein the metal nanoparticles (115, 315) comprise nanoparticles of one or more of the following materials: - silver; - Platinum; - Palladium; Or alloys of these materials.

11. The gas sensor according to any one of claims 5, 6 and 8 to 10, wherein the first polymer layer (120) has a first side in contact with the graphene layer, and the gas sensor further includes a metal layer (125) covering a second side of the polymer layer, the second side of the polymer layer being opposite to the first side of the polymer layer.

12. The sensor according to any one of claims 1 to 11, wherein the graphene layer is modified with metal nanoparticles or nanoobjects on both sides, and the first polymer layer and the second polymer layer are composed of phenelzine.

13. An electronic device (800) comprising: - Gas or optical sensors (100, 300, 500) comprising a graphene layer (110) bonded to a first electrode (640, 650) and a second electrode (642, 652); - Electronic circuit (810), comprising: Bias circuits (705, 755) configured to bias the graphene layer by applying a voltage or current to the first electrode; and An analog-to-digital converter (730) configured to convert the voltage between the first electrode and the second electrode into a digital value; and - A transmission circuit configured to wirelessly transmit the digital value via the antenna (820) of the electronic device.

14. The electronic device of claim 13, wherein the electronic circuit (810) is configured to be powered by energy harvesting through receiving RF signals.

15. A system (1000) comprising: - The electronic device (800) according to claim 13 or 14, wherein the sensor is a gas sensor; as well as - A membrane (1010) which is attached to and surrounds the gas sensor (100, 300, 500) of the electronic device, the membrane being adapted to be punctured by a straw to supply gas to the gas sensor.

16. A system (1100) comprising: - The first compartment (1110) including the entrance (1140); as well as - The electronic device (800) according to claim 13 or 14 located in the second compartment.

17. The system of claim 16, further comprising: - An input valve (1145) located at the interface between the first compartment and the second compartment (1120); as well as - Output valve (1150) on one side of the second compartment.

18. A method for manufacturing a gas or optical sensor, the method comprising: - Deposit metal nanoparticles or nanoobjects (115) on the first surface of the graphene layer (110); - Form a first electrode (640, 650) in contact with the graphene layer, for example by printing the first electrode in a first region on a first side of the graphene layer (110) using conductive ink; - Deposit a first polymer layer (120) covering the first side of the graphene layer; - Deposit metal nanoparticles or nanoobjects (315) on the second surface of the graphene layer, the second surface being opposite to the first surface; - Form a second electrode (642, 652) in contact with the graphene layer, for example by printing the second electrode in a second region on the second side of the graphene layer (110) using conductive ink; as well as - Deposit a second polymer layer (320) covering the second side of the graphene layer.

Images