KR20220022436A - Carbon-containing interdigitated electrode and device comprising the electrode - Google Patents

Abstract

The present invention relates to a shellac-derived carbon containing interdigitated electrode, an apparatus including the same, and a manufacturing method of the shellac-derived carbon containing interdigitated electrode. The shellac-derived carbon containing interdigitated electrode comprises a first electrode including a plurality of first finger units, a second electrode including a plurality of second finger units, and a shellac-derived carbon film disposed between the first electrode and the second electrode. The electrode can be used in a humidity sensor by having high selectivity and excellent reliability on humidity.

Description

Carbon-containing interdigitated electrode and device comprising the electrode

A shellac-derived carbon-containing interlocking electrode for humidity monitoring, and a device comprising the same.

Humidity monitoring can be used in various fields, such as agriculture, environment, and medicine. In particular, with the development of the Internet of Things (IoT), there is an increasing demand for a humidity sensor with improved operability and portability at low power and room temperature, along with durability, fast responsiveness, and high selectivity for humidity.

Various metal oxides are emerging as sensing materials due to their rapid reactivity, high selectivity to humidity, economic feasibility, and large surface area. .

Graphene oxide has a high surface area, contains many oxygen moieties, and can be operated at room temperature, so it can be used as a sensing material. However, the humidity sensor including graphene oxide has excessively high water absorption capacity, so the adsorption power of the active film containing graphene oxide to the substrate is low, and thus the reliability for moisture sensing is reduced, and the selectivity to humidity is somewhat The downside is that it is low.

Therefore, there is a need to develop a moisture sensor having high reliability for moisture sensing while having rapid response, high selectivity to humidity, and economical efficiency.

An object of the present invention is to provide a shellac-derived carbon-containing interlocking electrode and a device including the same, which is an electrode that can be used in a humidity sensor because it can operate at room temperature, has high selectivity to moisture, and has excellent reliability.

According to one aspect, a first electrode including a plurality of first finger parts; a second electrode including a plurality of second fingers; A shellac-derived carbon-containing interlocking electrode disposed on the first and second electrodes and comprising a shellac-derived carbon film is provided.

According to another aspect, there is provided a device comprising the shellac-derived carbon-containing interlocking electrode.

According to another aspect, there is provided a method of manufacturing the shellac-derived carbon-containing interlocking electrode.

The shellac-derived carbon-containing interlocking electrode can be used to fabricate a humidity sensor having excellent moisture sensitivity, rapid response rate and long lifespan.

1 is a schematic diagram illustrating a method of manufacturing a shellac-derived carbon-containing interlocking electrode according to an embodiment.
2 is a SEM image of a shellac-derived carbon-containing interlocking electrode according to an embodiment.
3 is an SEM image of a shellac-derived carbon film in a shellac-derived carbon-containing interlocking electrode according to an embodiment.
4A-4F are AFM images of a shellac-derived carbon film in a shellac-derived carbon-containing interlocking electrode (electrodes 1-3) according to an embodiment.
5 is a TGA measurement result of a shellac precursor.
6A and 6B are results of Raman spectrum and XPS spectrum measurement of shellac and a shellac-derived carbon-containing interlocking electrode (electrode 4) according to an embodiment.
7A to 7D are XPS spectra and Raman spectra measurement results of shellac-derived carbon-containing interlocking electrodes (electrodes 1 to 3) according to an embodiment.
8 is an IV curve measurement result of shellac-derived carbon-containing interlocking electrodes (electrodes 1 to 4) according to an embodiment.
9A to 9C are results of resistance measurement of shellac-derived carbon-containing interlocking electrodes (electrodes 1 to 3) according to an embodiment.
10A and 10B are performance measurement results of a humidity sensor including shellac-derived carbon-containing interlocking electrodes (electrodes 1 to 3) according to an exemplary embodiment.
11A and 11B are results of impedance measurement of a shellac-derived carbon-containing interlocking electrode (electrode 1) according to an exemplary embodiment.
12 is a measurement result of a contact angle of a shellac-derived carbon film with respect to water among shellac-derived carbon-containing interlocking electrodes (electrodes 1 to 3) according to an embodiment.
13A and 13B are results of Hall effect measurement of shellac-derived carbon-containing interlocking electrodes (electrodes 1 to 3) according to an exemplary embodiment.
14A to 14F are results of measurement of response of shellac-derived carbon-containing interlocking electrodes (electrodes 1 to 3) according to a change in humidity under a humidity condition of 0 to 70% according to an embodiment.
15A and 15B are results of measuring long-term durability and sensitivity of a humidity sensor including a shellac-derived carbon-containing interlocking electrode (electrode 1) according to an embodiment in order to test applicability in a real environment.

The present inventive concept described below can apply various transformations and can have various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present inventive concept to a specific embodiment, and should be understood to include all transformations, equivalents or substitutes included in the technical scope of the present inventive concept.

The terms used below are only used to describe specific embodiments, and are not intended to limit the present inventive concept. The singular expression includes the plural expression unless the context clearly dictates otherwise. Hereinafter, terms such as “comprising” or “having” are intended to indicate that a feature, number, step, operation, component, part, component, material, or combination thereof described in the specification exists, but one or the It should be understood that the above does not preclude the possibility of addition or existence of other features, numbers, steps, operations, components, parts, components, materials, or combinations thereof.

Also, throughout the specification, terms such as first, second, etc. may be used to describe various components, but the components should not be limited by the terms.

In order to clearly express the various layers and regions in the drawings, the thickness is enlarged or reduced. Throughout the specification, like reference numerals are assigned to similar parts. Throughout the specification, when a part, such as a layer, film, region, plate, etc., is referred to as “on” or “on” another part, it includes not only the case where it is directly on the other part, but also the case where there is another part in the middle. . The terms are used only for the purpose of distinguishing one component from another.

According to one aspect, a shellac-derived carbon-containing interlocking electrode includes: a first electrode including a plurality of first fingers; a second electrode including a plurality of second fingers; It is disposed on the first electrode and the second electrode, and may include a shellac-derived carbon film. The above "shellac-derived carbon film" means a carbon film made from a shellac precursor derived from shellac.

According to one embodiment, among the shellac-derived carbon-containing interlocking electrodes, the first electrode is an anode, and the second electrode is a cathode; The first electrode may be a cathode, and the second electrode may be an anode.

According to one embodiment, the shellac-derived carbon-containing interlocking electrode may be configured in a monolithic type. The term “monolithic” may have the same meaning as “integral” or “seamless”. That is, it may mean that the layer is a structure in which an interface between the layers does not exist and is integrated.

According to one embodiment, the plurality of first finger portions and the plurality of second finger portions among the shellac-derived carbon-containing interlocking electrode may be alternately disposed on the same plane.

According to an embodiment, the shellac-derived carbon film among the shellac-derived carbon-containing interlocking electrodes may be patterned to be exposed on the plurality of first finger portions and the plurality of second finger portions. For example, if the shellac-derived carbon film is patterned to be exposed on the plurality of first fingers and the plurality of second fingers, the entirety of the plurality of first fingers and the plurality of second fingers may be It may mean that the pattern is exposed to 50% or more of the area or the pattern is to be exposed to 50% or more of the area of each of the first and second finger parts.

According to one embodiment, the thickness of the shellac-derived carbon film in the shellac-derived carbon-containing interlocking electrode may be greater than 0 nm and less than or equal to 20 nm. For example, the thickness of the shellac-derived carbon film may be 5 nm or more and 15 nm or less, but is not limited thereto.

According to one embodiment, the content of oxygen-containing functional groups of the shellac-derived carbon film in the shellac-derived carbon-containing interlocking electrode may be greater than 0 wt% and less than or equal to 50 wt% with respect to a total of 100 wt% of the shellac-derived carbon film there is. For example, the content of oxygen-containing functional groups in the shellac-derived carbon film is greater than 0 wt% and less than or equal to 40 wt%, greater than 10 wt% and less than or equal to 40 wt%, greater than or equal to 20 wt% and less than or equal to 40 wt% or less than or equal to 30 wt% % and 40 wt% or less, but is not limited thereto.

According to another embodiment, the oxygen-containing functional group may be a hydroxy group, a carboxy group, a formyl group, or any combination thereof.

For example, the oxygen-containing functional group may be a hydroxy group, a carboxy group, or any combination thereof.

According to one embodiment, the intensity of the D band compared to the intensity of the G band in the Raman spectrum of the shellac-derived carbon film of the shellac-derived carbon-containing interlocking electrode (I _D /I _G ) may be 0.6 or more and 0.9 or less. For example, I _D /I _G of the shellac-derived carbon film may be 0.7 or more and 0.9 or less, 0.8 or more and 0.9 or less, or 0.85 or more and 0.88 or less, but is not limited thereto.

According to one embodiment, the size of the shellac-derived carbon-containing interlocking electrode may be a sub-micrometer size. For example, the width of the shellac-derived carbon-containing interlocking electrode is 100 nm or more and 1000 nm or less, and the height is 100 nm or more and 500 nm or less.

The shellac-derived carbon-containing interlocking electrode comprises a first electrode comprising a plurality of first fingers and a second electrode comprising a plurality of second fingers, so that the electric power is achieved by the spacing between the fingers and a large area of the electrode portion. Conductivity may be excellent.

In addition, since the shellac-derived carbon-containing interlocking electrode includes the shellac-derived carbon film, it can be applied thinly and uniformly, thereby reducing resistance to the electrode.

In addition, when the shellac-derived carbon-containing interlocking electrode is monolithically configured, there is no boundary or crack between crystals, so the resistance between the shellac-derived carbon film and the interlocking electrode is low, so that electrical or thermal compatibility may be excellent. .

In addition, when the content of oxygen-containing functional groups of the shellac-derived carbon film in the shellac-derived carbon-containing interlocking electrode is greater than 0 wt% and less than or equal to 50 wt% of the total 100 wt% of the shellac-derived carbon film, the degree of hydrophilicity can be adjusted Therefore, the selectivity to moisture may be excellent.

Accordingly, a device including the electrode, for example, a humidity sensor may have excellent selectivity and reliability for moisture.

According to another aspect, there is provided a device comprising the shellac-derived carbon-containing interlocking electrode.

According to one embodiment, the device may be a humidity sensor.

According to another aspect, there is provided a method comprising: providing a carbon-containing interlocking electrode; and providing a shellac-derived coating layer on the carbon-containing interlocking electrode. A method for producing a shellac-derived carbon-containing interlocking electrode comprising:

According to one embodiment, the carbon-containing interlocking electrode in the method of manufacturing a shellac-derived carbon-containing interlocking electrode may be obtained by coating a photosensitive agent on a substrate and heat treatment.

For example, the photosensitizer may be a negative photosensitizer.

For example, the photosensitizer may be an acrylic resin, a polyester resin, a polyurethane resin, an epoxy resin, or any combination thereof.

For example, the photosensitizer may include a first photosensitizer and a second photosensitizer, and the first photosensitizer and the second photosensitizer may be different from each other.

For example, a thickness of the first photosensitizer may be smaller than a thickness of the second photosensitizer. When the thickness of the first photosensitizer is smaller than the thickness of the second photoresist, an electrical resistance between the interlocking electrode and the source meter may be reduced.

For example, the thickness of the first photosensitizer may be greater than 0 μm and less than or equal to 5 μm.

For example, the thickness of the second photosensitizer may be greater than 20 μm and less than or equal to 30 μm.

According to one embodiment, in the method for manufacturing the shellac-derived carbon-containing interlocking electrode, the heat treatment includes a first heat treatment step and a second heat treatment step, and the temperature of the first heat treatment step is the heat treatment temperature of the second heat treatment step may be lower.

According to another embodiment, the first heat treatment step may be performed at 300 °C to 800 °C.

According to another embodiment, the second heat treatment step may be performed at 900 °C to 1100 °C.

According to one embodiment, in the method for manufacturing the shellac-derived carbon-containing interlocking electrode, the shellac-derived coating layer may be obtained by spin-coating a shellac precursor solution dissolved in an alcohol-based solvent and then heat-treating it.

For example, the heat treatment after the spin coating may be performed at 500 °C to 700 °C.

According to one embodiment, the method of manufacturing the shellac-derived carbon-containing interlocking electrode may further include etching the shellac-derived coating layer on the shellac-derived carbon-containing interlocking electrode using UV to expose the shellac-derived coating layer.

Hereinafter, for example, a shellac-derived carbon-containing interlocking electrode according to an embodiment of the present invention will be described in more detail.

[Example - Synthesis of Shellac-derived Carbon-Containing Interlocking Electrodes]

Raw material

Shellac flakes were purchased from Shellac Shack. Isopropanol (99.5%) was purchased from Sigma-Aldrich. Two types of negative photosensitizers (SU-8 2002 and 2025) are described in MicroChem. Corp. was purchased from

Synthesis Example 1: Synthesis of electrode 1 (SDC-600)

1) Preparation of interlocking electrodes

1 is a schematic diagram illustrating a method of manufacturing a shellac-derived carbon-containing interlocking electrode according to an embodiment.

A thin layer of negative photoresist (SU-8 2002, 2 μm) was spin-coated on a silicon wafer (6 inch) and insulated with a 1 μm-thick thermally grown SiO ₂ layer. The photosensitizer layer was exposed to UV using a mask aligner (MA/BA6-8, SUSS MicroTec SE, Germany) and grown using SU-8 Developer to form an IDE-shaped polymer structure (FIG. 1a). A thick photoresist pad structure (SU-8 2025, 25 μm) was patterned on the IDE-shaped polymer structure to form a carbon pad ( FIG. 1B ).

To convert the carbon pad into a monolithically constructed carbon electrode, a two-step thermal process was performed in a vacuum. The first was a vacuum pyrolysis step, in which the carbon pad was pyrolyzed in a vacuum furnace. In order to prevent a sudden decrease in volume, the temperature of the furnace was raised to 350° C. and then maintained for 1 hour. Thereafter, the temperature of the furnace was raised to 700° C. and maintained for 1 hour. The pyrolyzed carbon pad was naturally cooled. The second is a rapid heat treatment step, wherein the carbon pad was heat treated at 1000° C. for 1 minute using an RTA system to obtain an interlocking electrode.

2) Application of shellac-derived carbon film

Shellac flakes (4 g) and isopropanol (100 mL) were stirred at 60° C. for 1 hour to obtain a solution. The solution was uniformly coated on the interlocking electrode using a manual spray coater to obtain a spray-coated electrode. After drying the spray-coated electrode at 25° C. for 30 minutes, heat treatment was performed by increasing the annealing temperature to 600° C. at a rising rate of 3° C. min ⁻¹ at low pressure for 30 minutes, and interlocking with a shellac-derived carbon film electrode was obtained.

3) patterning of electrodes

After patterning a photoresist (NR9-8000, Futurrex Inc., USA) etch mask using photolithography on the interlocking electrode coated with the shellac-derived carbon film, oxygen plasma etching was selectively performed and photoresist removal solution Electrode 1 (SDC-600) was prepared by removing the polymer patterned using and rinsing with deionized water.

Examples 2 to 4: Synthesis of electrodes 2 to 4

Electrode 2 (SDC-650) in the same manner as in Example 1, except that, instead of heating the shellac-derived carbon film by raising the annealing temperature to 600 ° C. ), electrode 3 (SDC-700) and electrode 4 (SDC-550) were prepared.

[Evaluation Example 1: Physical/chemical properties of electrodes]

(Assessment Methods)

To measure the structure of the electrode, an SEM image (Quanta 200 FEG, FEI, USA) was measured.

The thickness of the film was measured by AFM (Multimode V, Bruker, USA).

X-ray photoelectron spectroscopy (XPS) was measured with a K-alpha spectrometer (Thermo Fisher Scientific, UK).

Raman spectra were measured with Al-pha300R (WITec, Germany).

(Evaluation results)

2 is a SEM image of a shellac-derived carbon-containing interlocking electrode according to an embodiment. The volume decreased by about 90% during pyrolysis, resulting in a micrometer-sized interlocking electrode structure (1 μm wide, 2 μm high) resulting in a sub-micrometer-sized shellac-derived carbon-containing interlocking electrode (600 nm wide, 300 nm high, electrode). interval of 1.5 μm). As such, the electrode size is small, and the total length of the facing electrodes can be extended up to 100 mm, and the surface area of the sensing region of the shellac-derived carbon-containing interlocking electrode is increased to 100 μm x 2 mm. Accordingly, the electrical resistance of the film positioned at the finger portion among the shellac-derived carbon-containing interlocking electrodes was reduced, making it possible to effectively measure the electrical resistance even in electrodes with relatively low electrical conductivity. In addition, it can be confirmed that the shellac-derived carbon-containing interlocking electrode can be used as a humidity sensor by patterning the sensing region to be clear.

3 is an SEM image of a shellac-derived carbon film in a shellac-derived carbon-containing interlocking electrode according to an embodiment. It can be seen that the shellac-derived carbon-containing interlocking electrode is formed in a monolithic structure, so that there is no inter-crystal boundary or crack.

4A-4F are AFM images of a shellac-derived carbon film in a shellac-derived carbon-containing interlocking electrode (electrodes 1-3) according to an embodiment. The thickness of the shellac-derived carbon film among electrodes 1 to 3 was about 10 nm or less. In addition, the centerline surface roughness (R _a ) was about 0.25 nm or less. It was found that the thickness of the shellac-derived carbon film had a similar thickness regardless of the heat treatment temperature of the electrode coated with the solution containing the shellac precursor. This is due to the process of dehydration (below 150 °C) and dehydrogenation (below 450 °C) of the shellac precursor, as can be seen from the TGA results of the shellac precursor (FIG. 5). That is, it can be seen that at 550 °C, about 76% of the total weight of the shellac precursor is carbonized, but at 600 °C or higher, there is no decrease in weight, so that most of the shellac precursor is carbonized at 400 °C to 600 °C. This was also confirmed through the Raman spectrum (Fig. 6a) and the high-resolution C-1s XPS spectrum (Fig. 6b) of the shellac precursor. Therefore, it can be seen that when the annealing temperature is 600° C. or higher, the thicknesses of the shellac-derived carbon films are similar to each other.

7A to 7D are XPS spectra and Raman spectra measurement results of shellac-derived carbon-containing interlocking electrodes (electrodes 1 to 3) according to an embodiment. The XPS spectrum (Fig. 7a) shows four distinct peaks in the carbon-containing bond: (C=C) 284.2 eV, (C-OH) 285.3 eV, (C=O) 288.1 eV and π-π bond satellite peak according to 291 eV. The (C=C) peak may appear due to the graphitization process starting at 600 °C. As the annealing temperature increased from 600 °C to 700 °C, it can be seen that the sp ² hybridized carbon network increased from 55% to 80%, and the content of oxygen-containing functional groups decreased ( FIG. 7c ).

It was confirmed that the Raman spectrum (FIG. 7b) had a D band and a G band. This is due to the defect site of the sp ³ site and the sp ² carbon atom with in-plane oscillations, respectively. As the annealing temperature increased, the G band exhibited a red shift, which was due to the increase of the sp ² hybridized carbon network (Fig. 7d). In addition, it can be seen that the intensity of the D band compared to the intensity of the G band (I _D /I _G ) decreases from 0.88 (electrode 1, SDC-600) to 0.63 (electrode 3, SDC-700), which increases the annealing temperature It indicates that there are fewer defects or structural inconsistencies.

[Evaluation Example 2: Measurement of electrode humidity sensing performance]

(Assessment Methods)

To measure the I-V properties, the ohmic contact between the coated shellac-derived carbon film and the interlocking electrode was measured with a Keithley-2450 source meter (Keithley Instruments Inc., USA).

The resistance of the humidity sensor was measured using a Keithley-2450 source meter.

To measure the performance of the humidity sensor, electrical resistance was measured in a constant humidity and temperature chamber (TH-ME-065, JEIO Tech., Korea). Humidity was controlled from 0% to 90% RH, and the temperature was maintained at 25°C. The reactivity (%) of the humidity sensor was calculated by the following <Equation 1>, and the sensitivity (S) to moisture of the humidity sensor was calculated by the following <Equation 2>:

<Equation 1>

In Equation 1, R is the resistance value of the humidity sensor in dry air (0% RH), and R _h is the resistance value of the humidity sensor in the humidity condition to be measured.

<Equation 2>

S=

In Equation 2, ΔRH is a range of humidity conditions during measurement.

To measure the impedance action according to various humidity, it was measured with a potentiometer (Ivium Stat, Ivium Technologies, Netherlands; 1 V, 100 Hz-1 MHz).

To measure the charge carrier properties of the shellac-derived carbon-containing interlocking electrode, the Hall effect of the electrode was measured. P-type and n-type silicon wafers were calibrated for hole measurements.

To measure the response/recovery time, a humidity/temperature-control system was set up that allowed immediate humidity control from high humidity conditions (70% relative humidity) to dry conditions (0% relative humidity, RH). The system consists of a solenoid valve (S10MM20-24-2, Pneumadyne Inc., USA), a humidity/temperature meter (SHT15, Sensirion), a regulator (Arduino Uno, Arduino cc), and a microscope incubator (CU-501, Live Cell Instrument). was composed of The solenoid valve was programmed using LabVIEW software (National Instruments).

In order to measure the sensitivity to moisture, the sensitivity to moisture was measured in the presence of NO ₂ , H ₂ , and CH ₄ gases at atmospheric pressure. The gas concentration was controlled by a mass flow controller (GMC1200, ATOVAC, Korea).

(Evaluation results)

8 is an I-V curve measurement result of shellac-derived carbon-containing interlocking electrodes (electrodes 1 to 4) according to an embodiment. Since the electrode of the present invention exhibits excellent ohmic performance, it can be seen that the electrical or thermal compatibility between the shellac-derived carbon film and the interlocking electrode is excellent. The finger portion of the electrode of the present invention is connected to a thick and wide carbon pad (Figs. 2c and 2d, width = 2 mm, thickness = 6 μm), which can have the effect of reducing the resistance of the shellac-derived carbon film to the electrode. there is. Electrode 4 (SDC-550) has a relatively higher resistance than electrodes 1 to 3, and from this, it can be seen that electrode 4 contains many defects because carbonization is not sufficient.

9A to 9C are results of resistance measurement of shellac-derived carbon-containing interlocking electrodes (electrodes 1 to 3) according to an embodiment. It can be seen that as the distance between the electrodes decreases, the resistivity of the film also decreases linearly. That is, it indicates that the film is uniformly coated on the electrode.

10A and 10B are performance measurement results of a humidity sensor including shellac-derived carbon-containing interlocking electrodes (electrodes 1 to 3) according to an exemplary embodiment. 10A is a graph of reactivity (%) with respect to a relative humidity (RH) of 0% to 90%, and FIG. 10B is a graph of sensitivity (S) to moisture according to annealing temperature. It can be seen that the lower the annealing temperature, the higher the reactivity (%) and sensitivity (S) of the humidity sensor. That is, electrode 1 (SDC-600) has more than 20 times higher sensitivity than electrode 3 (SDC-700), because the amount of oxygen-containing functional groups on the surface of electrode 1 (SDC-600) is greater (Fig. 7c). ).

11A and 11B are results of impedance measurement of a shellac-derived carbon-containing interlocking electrode (electrode 1) according to an embodiment. 11A is a Bode plot, and FIG. 11B is a Nyquist plot. It can be seen from FIG. 11a that the impedance of electrode 1 is significantly lower as the relative humidity (RH) is higher at a low frequency (less than 200 kHz). However, it can be seen that the change in impedance according to humidity at high frequency is smaller than the change at low frequency. This is because water molecules absorbed by the sensor are difficult to align with the direction of the electric field. In Fig. 11b, the Nyquist plot of electrode 1 shows a semicircle without Warburg impedance under high humidity conditions (~90% RH). This is because, due to the low hydrophilicity of the film, the amount of water molecules absorbed on the electrode surface is not sufficient to form a continuous layer, thereby remaining in an isolated state.

12 is a measurement result of a contact angle of a shellac-derived carbon film with respect to water among shellac-derived carbon-containing interlocking electrodes (electrodes 1 to 3) according to an embodiment. It can be seen that the film of the present invention has a relatively low hydrophilicity. In addition, it can be seen that the higher the annealing temperature, the higher the contact angle increases, and thus the hydrophobicity of the film increases. This is because the amount of oxygen-containing functional groups decreases as the annealing temperature increases.

13A and 13B are results of Hall effect measurement of shellac-derived carbon-containing interlocking electrodes (electrodes 1 to 3) according to an exemplary embodiment. 13A is a schematic diagram of a Hall effect measurement setup, and FIG. 13B is a graph of Hall voltage versus magnetic field. Since the charge carrier properties of the electrode of the present invention are p-type, water molecules form ion-dipole interactions on the thin carbon film surface. The absorbed water molecules act as oxidizing agents and affect the electronic conduction of the thin carbon film. In addition, the thin carbon film exhibits a relatively low electrical resistivity, which is due to the narrow gap between the fingers of the carbon interlocking electrode and the large area of the electrode portion. Therefore, the current flows mostly through the thin film portion, so the electrical conductivity is excellent.

14A to 14F are results of measurement of response of shellac-derived carbon-containing interlocking electrodes (electrodes 1 to 3) according to a change in humidity under a humidity condition of 0 to 70% according to an embodiment. It can be seen that the humidity sensor of the present invention exhibits constant and rapid response and recovery performance even in repeated cycles of humidity change. It can be seen that because the electrode has a thin thickness, the movement of water molecules occurs on the surface of the electrode, so that it can be quickly detached from the surface. The humidity sensor including electrode 1 showed a response rate of 140 ms. This is because the amount of sp ² hybridized carbon and the amount of oxygen-containing functional groups included in the electrode vary according to the annealing temperature. The greater the amount of hydroxyl groups, the greater the affinity for moisture and the faster the reaction rate. On the other hand, as the amount of sp ² hybridized carbon increases, hydrophobicity increases, indicating fast recovery performance. In addition, it can be seen that the desorption rate is slower than the adsorption rate of water molecules, because the electrode has hydrophilicity, which limits the effective desorption of water molecules.

15A and 15B are results of measuring long-term durability and sensitivity to moisture of a humidity sensor including a shellac-derived carbon-containing interlocking electrode (electrode 1) according to an embodiment in order to test applicability in a real environment; . 14A is a result of measuring the dynamic response and response/recovery time of the humidity sensor at 70% RH for 4 weeks. 14b is a result of measuring the dynamic response of the humidity sensor in the presence of 30% RH and various gases (1000 ppm H ₂ , 5 ppm NO ₂ , 1000 ppm CH ₄ ). It can be seen from FIG. 14A that the dynamic response and response/recovery time of the humidity sensor did not change during 4 weeks. In addition, the power consumption of the humidity sensor was also maintained at 1 mW or less at 1 V. It can be seen from FIG. 14B that even if various gases exist at high concentrations, the effect on the dynamic response of the humidity sensor to moisture is low. This indicates that the accuracy and reliability of the humidity sensor can be high even in the presence of other gases.

Table 1 shows the humidity range (% RH), response / recovery time (s), dynamic response (%) and This is a table comparing sensitivity to moisture (1/%RH).

matter Humidity range
(% RH) Response/Recovery Time (s) Dynamic response (%) Sensitivity (1/%RH) TiO ₂ -PSS composite 30-90 2/80 - - VO ₂ nanoparticles 10-90 5/13 20 0.25 SiC nanowires 15-90 85/105 - 0.38 Multilayer Graphene (CVD) 1-96 0.6/0.4 4.5 0.31 2-Layer Graphene (CVD) 20-100 0.7/0.3 1.1 0.93 rGO 10-70 16/47 17.6 0.02 N-doped rGO 6-100 -- 5 0.32 rGO/PU 10-70 3.5/7 9 0.53 GO (Hummer's) 20-70 0.032/0.032 - - Li-Doped GO 11-97 4/25 97 0.25 electrode 1 0-90 0.14/1.7 50 0.54

From Table 1, it can be seen that the humidity sensor including electrode 1 of the present invention has a wide humidity measurement range, high dynamic response, quick response time, and high sensitivity to moisture.

In the above, a preferred embodiment according to the present invention has been described with reference to the drawings and examples, but this is merely an example, and various modifications and equivalent other embodiments are possible by those skilled in the art. will be able to understand Accordingly, the protection scope of the present invention should be defined by the appended claims.

Claims (20)

a first electrode including a plurality of first fingers;
a second electrode including a plurality of second fingers;
A shellac-derived carbon-containing interlocking electrode disposed on the first and second electrodes and comprising a shellac-derived carbon film. According to claim 1,
the first electrode is an anode and the second electrode is a cathode;
wherein the first electrode is a cathode and the second electrode is an anode. According to claim 1,
wherein the shellac-derived carbon-containing interlocking electrode is monolithically constructed. According to claim 1,
wherein the plurality of first finger portions and the plurality of second finger portions are alternately disposed on the same plane. According to claim 1,
and the shellac-derived carbon-containing interlocking electrode is patterned such that the shellac-derived carbon film is exposed on the plurality of first fingers and the plurality of second fingers. According to claim 1,
wherein the thickness of the shellac-derived carbon film is greater than 0 nm and less than or equal to 20 nm. According to claim 1,
wherein the content of oxygen-containing functional groups in the shellac-derived carbon film is greater than 0 wt% and less than or equal to 50 wt% with respect to a total of 100 wt% of the shellac-derived carbon film. According to claim 1,
The shellac-derived carbon-containing interlocking electrode, wherein the intensity of the D band compared to the intensity of the G band in the Raman spectrum of the shellac-derived carbon film (I _D /I _G ) is 0.6 or more and 0.9 or less. According to claim 1,
and the size of the shellac-derived carbon-containing interlocking electrode is sub-micrometer in size. 10. A device comprising the shellac-derived carbon-containing interlocking electrode of any one of claims 1-9. 11. The method of claim 10,
wherein the device is a humidity sensor. providing a carbon-containing interlocking electrode; and
providing a shellac-derived coating layer on the carbon-containing interlocking electrode; A method for producing a shellac-derived carbon-containing interlocking electrode comprising: 13. The method of claim 12,
The method for producing a shellac-derived carbon-containing interlocking electrode, wherein the carbon-containing interlocking electrode is obtained by coating a photosensitive agent on a substrate and performing heat treatment. 14. The method of claim 13,
The photosensitizer comprises a first photosensitizer and a second photosensitizer,
wherein the first photosensitizer and the second photosensitizer are different from each other. 14. The method of claim 13,
The heat treatment includes a first heat treatment step and a second heat treatment step,
The temperature of the first heat treatment step is lower than the heat treatment temperature of the second heat treatment step, the method of manufacturing a shellac-derived carbon-containing interlocking electrode. 16. The method of claim 15,
Wherein the first heat treatment step is performed at 300 °C to 800 °C, shellac-derived carbon-containing interlocking electrode manufacturing method. 16. The method of claim 15,
Wherein the second heat treatment step is performed at 900 °C to 1100 °C, a method of manufacturing a shellac-derived carbon-containing interlocking electrode. 13. The method of claim 12,
wherein the shellac-derived coating layer is obtained by spin-coating a shellac precursor solution dissolved in an alcohol-based solvent and then heat-treating the shellac-derived carbon-containing interlocking electrode. 13. The method of claim 12,
The heat treatment is carried out at 500 °C to 700 °C, a method for producing a shellac-derived carbon-containing interlocking electrode. 13. The method of claim 12,
The method of claim 1, further comprising: etching the shellac-derived carbon-containing interlocking electrode using UV to expose the shellac-derived coating layer on the shellac-derived carbon-containing interlocking electrode.

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