N-type organic electrochemical transistor comprising hydrophobic passivation layer and manufacturing method therefor

Abstract

Provided are an n-type organic electrochemical transistor comprising a hydrophobic passivation layer and a manufacturing method therefor. In the n-type organic electrochemical transistor, a passivation layer having hydrophobicity is formed on an active layer containing an n-type organic mixed ionic-electronic conductor to protect the surface of the active layer, thereby controlling the activity of oxygen in an electrolyte and the n-type organic mixed ionic-electronic conductor, thus improving the stability of a device.

Description

N-type organic electrochemical transistor including a hydrophobic passivation layer and method for manufacturing the same

[0001] The present invention relates to an organic electrochemical transistor, and more specifically, to an n-type organic electrochemical transistor comprising a hydrophobic passivation layer and a method for manufacturing the same.

[0002] Organic mixed ionic-electronic conductors (OMIECs) can carry both ionic and electronic charges through ionic-electronic coupling. Accordingly, OMIECs are being studied in a wide range of applications, including batteries, supercapacitors, chemical and biological sensors, actuators, and artificial muscles. In particular, because OMIECs have a large volumetric capacitance, they exhibit high transconductance (g m It is expected to be usefully applied as an active material for organic electrochemical transistors that require excellent stability in aqueous media.

[0003] Organic electrochemical transistors (OECTs) consist of an active layer, which is a channel implemented using a conductive polymer that can be electrochemically doped or de-doped, source and drain electrodes connected to it, and an electrolyte. These OECTs are receiving significant attention for their potential applications in bioelectronics and neuromorphic systems, as they can be miniaturized, utilize low-cost printing technologies, and possess various mechanical structures. In particular, OECTs are widely used as amplification devices due to their high transfer conductivity, and are also being studied as sensors for detecting ions, metabolites, DNA, or pathogens.

[0004] The development of organic electrochemical transistors has primarily focused on p-type transistors due to the degradation of the intrinsic stability of n-type transistors. However, the development of n-type transistors is also becoming important in terms of circuit development and cation sensing.

[0005] However, n-type organic electrochemical transistors have a problem in which the long-term stability of the device is compromised due to physical degradation caused by repetitive ion migration and the oxygen reduction reaction (ORR) of organic mixed ion-electron conductors in aqueous or oxygen-rich environments during device operation.

[0006] Accordingly, the technical problem to be solved by the present invention is to provide an n-type organic electrochemical transistor comprising a hydrophobic passivation layer capable of suppressing physical decomposition and chemical decomposition by oxygen reduction reaction of the n-type organic electrochemical transistor, and a method for manufacturing the same.

[0007] In addition, the present invention aims to provide an n-type organic electrochemical transistor comprising a hydrophobic passivation layer capable of improving the characteristics of the device, and a method for manufacturing the same.

[0008] The technical problems of the present invention are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below.

[0009] To achieve the above objective, one aspect of the present invention provides an n-type organic electrochemical transistor comprising: an active layer comprising an n-type organic mixed ion-electron conductor electrically connected to a source electrode and a drain electrode; a passivation layer formed on the active layer and having hydrophobicity; an electrolyte layer formed on the passivation layer; and a gate electrode disposed on the electrolyte layer.

[0010] The above n-type organic mixed ion-electron conductor may comprise one or more selected from monomers having polycyclic aromatic diimide or benzodithiophene units and polymers having polycyclic aromatic diimide or benzodithiophene units.

[0011] The above n-type organic mixed ion-electron conductor may include polybenzobisimidazobenzophenanthroline (BBL).

[0012] The above active layer may have peaks for the (100) crystal plane and the (010) crystal plane in the XRD spectrum.

[0013] The above passivation layer may include a low-molecular-weight organic semiconductor.

[0014] The above passivation layer may include a low-molecular-weight n-type organic semiconductor.

[0015] The above low-molecular-weight organic semiconductor may have a fullerene group.

[0016] The above low-molecular-weight organic semiconductor may further include side chains that have high solubility in organic solvents compared to the fullerene group.

[0017] The above side chain may include one or more selected from methyl ester, an alkyl chain having 1 to 30 carbon atoms, ethylene glycol, and a carboxylic acid.

[0018] The above passivation layer is C 60 Fullerene, C 70 Fullerene, C 76 Fullerene, C 84 Fullerene, PC 60 BM([6,6]-phenyl-C 61 butyric acid methyl ester), and PC 70 BM([6,6]-phenyl-C 71 It may include one or more selected from -butyric acid methyl ester.

[0019] The thickness of the active layer is 40 to 60 nm, and the thickness of the passivation layer may be 5 to 40 nm.

[0020] The above passivation layer can be formed so that the active layer is not exposed on the surface.

[0021] The surface roughness of the above passivation layer may be 1.5 nm or less.

[0022] The contact angle of the above passivation layer with respect to water may be 70° or more.

[0023] Another aspect of the present invention provides a method for manufacturing an n-type organic electrochemical transistor, comprising the steps of: forming a source electrode and a drain electrode on a substrate; forming an active layer formed on the substrate and electrically connected to the source electrode and the drain electrode and comprising an n-type organic mixed ion-electron conductor; forming a passivation layer formed on the active layer and having hydrophobicity; forming an electrolyte layer formed on the passivation layer; and placing a gate electrode on the electrolyte layer.

[0024] The above n-type organic mixed ion-electron conductor may include polybenzobisimidazobenzophenanthroline (BBL).

[0025] The above passivation layer may include a low-molecular-weight organic semiconductor.

[0026] The concentration of the above low-molecular-weight organic semiconductor may be 3 to 10 mg / mL.

[0027] The above passivation layer is C 60 Fullerene, C 70 Fullerene, C 76 Fullerene, C 84 Fullerene, PC 60 BM([6,6]-phenyl-C 61 butyric acid methyl ester), and PC 70 BM([6,6]-phenyl-C 71 It may include one or more selected from -butyric acid methyl ester.

[0028] The step of forming the passivation layer may include a process of dissolving a hydrophobic compound in an organic solvent to form a coating solution, a process of applying the coating solution onto the active layer to form a passivation coating layer, and a process of heat-treating the passivation coating layer.

[0029] The above organic solvent may include one or more selected from chloroform, chlorobenzene, dichlorobenzene, toluene, tetrahydrofuran, and anisole.

[0030] The process of forming the passivation coating layer above can be performed by one or more methods selected from spin coating, blade coating, spray coating, roll coating, and bar coating.

[0031] The active layer can be formed with a thickness of 40 to 60 nm, and the passivation layer can be formed with a thickness of 5 to 40 nm.

[0032] An n-type organic electrochemical transistor (OECT) according to one embodiment of the present invention can protect the surface of the active layer by having a hydrophobic passivation layer, thereby suppressing the physical decomposition of the active layer due to swelling and de-swelling caused by repeated ion movement within the active layer.

[0033] In addition, the n-type organic electrochemical transistor (OECT) of the present invention can reduce the surface roughness relative to the active layer through a hydrophobic passivation layer, thereby reducing the contact area with water. This allows for the suppression of chemical decomposition of the active layer caused by the oxygen reduction reaction (ORR) of the organic mixed ion-electron conductor resulting from dissolved oxygen in the aqueous electrolyte.

[0034] In addition, the n-type organic electrochemical transistor (OECT) of the present invention can be doped with an n-type organic mixed ion-electron conductor (OMIEC) through the entry and exit of ions into the active layer upon voltage application, but can block contact between the n-type organic mixed ion-electron conductor (OMIEC), which is charged through the entered and exiting ions, and oxygen in the electrolyte, thereby enabling stable operation.

[0035] In addition, when the n-type organic electrochemical transistor (OECT) of the present invention has conductivity when ions are doped into the active layer, the characteristics of the transistor (OECT) can be further improved through a hydrophobic passivation layer equipped with a material having a higher electron mobility than the active layer.

[0036] In addition, the n-type organic electrochemical transistor (OECT) of the present invention can easily introduce a low-molecular-weight n-type organic semiconductor as a passivation layer of the n-type organic electrochemical transistor (OECT) through a simple solution process.

[0037] The technical effects of the present invention are not limited to those mentioned above, and other unmentioned technical effects will be clearly understood by those skilled in the art from the description below.

[0038] FIG. 1 is a schematic diagram showing the structure of an n-type organic electrochemical transistor (OECT) according to one embodiment of the present invention.

[0039] FIG. 2 is a schematic diagram showing the structure of an n-type organic electrochemical transistor according to one embodiment of the present invention.

[0040] FIG. 3 is a schematic image illustrating the surface shape of the roughness of a BBL film according to the thickness of a PCBM film according to one embodiment of the present invention.

[0041] Figures 4 (a) to (d) are graphs showing consecutive transfer curves measured in multiple cycles of the OECTs of Preparation Examples 1 to 4 of the present invention.

[0042] FIG. 5 is a graph showing the continuous transfer curve of the OECT of Comparative Example 1 (BBL) of the present invention measured over multiple cycles.

[0043] FIG. 6 is a graph showing the continuous transfer curve of the OECT of Manufacturing Example 2 (PCBM(5) / BBL) of the present invention measured over multiple cycles.

[0044] FIG. 7 shows the first (1) of the OECT of Comparative Example 1 (BBL) of the present invention and the OECT of Manufacturing Example 2 (PCBM(5) / BBL). st ) Cycle and the last(50 th g between ) cycles m,norm This is a graph showing a comparison of ratios.

[0045] Figure 8(a) is a schematic cross-sectional view of the OECT measured after performing the 8th cycle of Comparative Example 1 (BBL) of the present invention and a planar SEM image observed with a scanning electron microscope (SEM), and (b) is a tilted-view SEM image of the upper part of the drain electrode, which is the red box area of ​​Figure 8(a), taken by tilting it 50° before and after the 8th cycle measurement.

[0046] Figure 9(a) is a schematic cross-sectional view of the OECT and a planar SEM image observed with a scanning electron microscope after performing the 8th cycle of the OECT of Manufacturing Example 2 (PCBM(5) / BBL) of the present invention, and (b) is an SEM image taken by tilting the upper part of the drain electrode, which is the red box area of ​​Figure 9(a), at 50° before and after the 8th cycle measurement.

[0047] Figure 10 (a) is a planar SEM image measured after performing the 15th cycle of Comparative Example 1 (BBL) of the present invention, and (b) is a planar SEM image of the OECT of Manufacturing Example 2 (PCBM(5) / BBL) of the present invention.

[0048] Figure 11 (a) is an Auger electron spectroscopy (AES) image after performing the 8th cycle (period) of the OECT of Comparative Example 1 (BBL) of the present invention, and (b) is a graph showing the differential AES spectra for the white aggregate (indicated by the red box) and the dark background (indicated by the blue box) shown in (a).

[0049] Figure 12(a) is a graph showing the XPS results when a voltage bias is applied (BBL-biased) and when no voltage bias is applied (BBL) to a BBL film thermally deposited on a gold (Au) substrate of Comparative Example 3 of the present invention, (b) is an enlarged graph of (a) for the analysis of Au 4f binding energy plotted together with the XPS analysis of a pristine gold (Au) substrate, and Figure 12(c) is a normalized graph of (b).

[0050] FIG. 13 (a) and (b) show the OH of Comparative Example 3 (BBL) OECT of the present invention in the original electrolyte (0.1M NaCl) and a degraded electrolyte (0.1M NaOH). - Images showing the results of a rapid strip test to detect H2O2, where (a) is a pH test strip and (b) is a peroxide test strip.

[0051] Figures 14 (a) to (c) are optical microscopy images of Comparative Example 3 (BBL) OECT of the present invention after being immersed for one day in (a) a 0.1M NaCl aqueous solution, (b) a 0.1M NaOH aqueous solution, and (c) a 0.1M NaCl aqueous solution containing 1 mM H2O2, and Figure 14 (d) is an optical microscopy image of the Au-deposited substrate of Comparative Example 4 after being immersed for one day in a 0.1M NaCl aqueous solution containing 1 mM H2O2.

[0052] FIG. 15 is the result of surface analysis using an atomic force microscope (AFM) of the BBL film of Comparative Example 1 of the present invention, the PCBM (3) / BBL film of Preparation Example 1, and the PCBM (5) / BBL film of Preparation Example 2, where (a) is an image of the topography and (b) is an image of the phase.

[0053] FIG. 16 is the result of surface analysis using an atomic force microscope (AFM) of the PCBM (7) / BBL film of Preparation Example 3 of the present invention, the PCBM (10) / BBL film of Preparation Example 4, and the PCBM (5) film of Comparative Example 2, where (a) is an image of the topography and (b) is an image of the phase.

[0054] FIG. 17 shows the root-mean-square surface roughness (R) for the BBL film of Comparative Example 1 of the present invention, the PCBM (5) film of Comparative Example 2, and the PCBM (3-10) / BBL films of Preparation Examples 1 to 4. q This is a graph showing the measurement results.

[0055] FIG. 18 shows Comparative Example 1 (BBL) and Preparation Example 2 (PC) of the present invention. 60 BM(5) / BBL), Preparation Example 6 (PC 70 BM(5) / BBL), and Preparation Example 7 (C 60(5) / BBL) This is a topographic image of the active layer of the OECT surface analyzed by an atomic force microscope (AFM).

[0056] FIG. 19 shows Comparative Example 1 (BBL) and Manufacturing Example 2 (PC) of the present invention. 60 BM(5) / BBL), Preparation Example 6 (PC 60 BM(5) / BBL), and Preparation Example 7 (C 60 (5) This is a graph showing the relative on-currents according to the cycle number of OECTs in 0.1M NaCl of the OECT of BBL.

[0057] Figures 20 (a) to (c) are images showing the water contact angle of the active layer of Comparative Example 1 (BBL), Comparative Example 2 (PCBM (5)), and Preparation Example 2 (PCBM (5) / BBL) OECT of the present invention.

[0058] FIG. 21 is a graph showing the results of measuring the water contact angle for the active layer of Comparative Example 1 (BBL), Comparative Example 2 (PCBM (5)), and Manufacturing Examples 1 to 4 (PCBM (3~10) / BBL) OECTs of the present invention.

[0059] FIG. 22 is a graph showing the results of two-dimensional grazing incident X-ray diffraction (2D-GIXD) analysis of the active layer of the OECT of Comparative Example 1 (BBL), Comparative Example 2 (PCBM (5)), and Preparation Examples 1 to 4 (PCBM (3~10) / BBL) of the present invention.

[0060] FIG. 23 is a line-scan profile of the 2D-GIXD of FIG. 22, where (a) is out-of-plane (q z ), (b) is in the plane (in-plane, q xy These are images based on the direction.

[0061] Figure 24 (a) is a graph showing the CV curves of the OECT of Comparative Example 1 (BBL) and Preparation Example 2 (PCBM(5) / BBL) of the present invention, measured using 0.1M NaCl electrolyte under Ar-purged conditions (Ar-purged) and (b) under O2-purged conditions (O2-purged).

[0062] Figure 25 (a) is a graph showing the cumulative charge (top), current (middle), and voltage (bottom) profiles in an Ar-purged 0.1M NaCl electrolyte of the BBL film of Comparative Example 1 and the PCBM (5) / BBL film of Preparation Example 2, which underwent the 10th CV cycle in Figure 24.

[0063] Figure 26 is a graph of the films of Figure 25 measured in an O2-purged 0.1M NaCl electrolyte.

[0064] FIG. 27 is a graph showing the LSV curves measured at various rotor speeds of the OECT of Comparative Example 1 (BBL) and Manufacturing Example 2 (PCBM(5) / BBL) of the present invention.

[0065] FIG. 28 is a Koutecky-Levich plot derived from the results of FIG. 27 for the OECT of (a) Comparative Example 1 (BBL) and (b) Preparation Example 2 (PCBM(5) / BBL) of the present invention, and (c) is a graph showing the number of electron transfers (n) of the BBL film at each potential (vs. Ag / AgCl) extracted from the slope of the Koutecky-Levich plot.

[0066] FIG. 29 shows (a) a schematic diagram and (b) an image at the site of a UV-vis-NIR measurement setup according to one embodiment of the present invention.

[0067] FIG. 30 is a graph showing the UV-vis-NIR absorption spectra of OECTs of Comparative Example 1 (BBL), Comparative Example 2 (PCBM (5)), and Preparation Example 2 (PCBM (5) / BBL) of the present invention.

[0068] FIG. 31 is a graph showing the UV-vis-NIR absorption spectra in the field of (a) Comparative Example 2 (PCBM(5)), (b) Comparative Example 1 (BBL), and Preparation Example 2 (PCBM(5) / BBL) OECTs of the present invention.

[0069] FIG. 32 is a graph showing the UV-vis-NIR absorption spectra in the field of (a) Comparative Example 1 (BBL), (b) Manufacturing Example 1 (PCBM(3) / BBL), (c) Manufacturing Example 2 (PCBM(5) / BBL), (d) Manufacturing Example 3 (PCBM(7) / BBL), (e) Manufacturing Example 5 (PCBM(9) / BBL) OECT, and (f) Comparative Example 2 (PCBM(5)) OECT of the present invention.

[0070] FIG. 33 is a graph showing the mass change (top), current density (middle), and voltage (bottom) profiles obtained from coupled QCM measurements of the CV cycle for Comparative Example 1 (BBL), Comparative Example 2 (PCBM (5)), and Manufacturing Example 2 (PCBM (5) / BBL) of the present invention.

[0071] FIG. 34 is a graph of QCM fitted by galvanostatic deposition of silver (Ag) on ​​a quartz crystal according to one embodiment of the present invention.

[0072] FIG. 35 shows the μC of Comparative Example 1 (BBL) and Preparation Example 2 (PCBM(5) / BBL) OECT of the present invention. * g for extracting m vs. This is a plot showing channel geometry and operating conditions.

[0073] FIG. 36 shows the C of Comparative Example 1 (BBL) and Manufacturing Example 2 (PCBM(5) / BBL) OECT of the present invention. * This is a plot showing capacitance vs. layer volume for extracting.

[0074] Figure 37 (a) is a Nyquist plot of Comparative Example 1 (BBL) and Manufacturing Example 2 (PCBM(5) / BBL) OECT of the present invention measured by electrochemical impedance spectroscopy (EIS), (b) is an enlarged graph of (a) for determining charge transfer resistance, and (c) and (d) are Bode plots of Comparative Example 1 (BBL) and Manufacturing Example 2 (PCBM(5) / BBL) OECT of the present invention applied to Randles equivalent circuits, respectively.

[0075] FIG. 38 shows the extracted τ of Comparative Example 1 (BBL) and Preparation Example 2 (PCBM(5) / BBL) OECT of the present invention. e I with a value D transient vs. I G It is a plot.

[0076] FIG. 39 shows the I of Comparative Example 1 (BBL) and Manufacturing Example 2 (PCBM(5) / BBL) OECT of the present invention. D This is a graph showing the transient response.

[0077] FIG. 40 is a schematic diagram showing the role of the PCBM layer in the ion doping of Comparative Example 1 (BBL) and Preparation Example 2 (PCBM(5) / BBL) OECTs of the present invention.

[0078] FIG. 41 shows the I of Comparative Example 1 (BBL) and Manufacturing Example 2 (PCBM(5) / BBL) OECT of the present invention. D This is a graph showing the pulse responses.

[0079] FIG. 42 shows the I of Comparative Example 1 (BBL) and Manufacturing Example 2 (PCBM(5) / BBL) OECT of the present invention. D This is a graph showing the pulse responses.

[0080] FIG. 43 is a graph showing the continuous transfer curves measured over multiple cycles under basic electrolyte (0.1 M NaOH) conditions of Comparative Example 1 (BBL) and Preparation Example 2 (PCBM(5) / BBL) OECTs of the present invention (V D = 0.7V).

[0081] FIG. 44 shows the conventional electrolyte (0.1 M NaCl) and the extended V range of -0.7V to 0.7V of Comparative Example 1 (BBL) and Preparation Example 2 (PCBM(5) / BBL) OECTs of the present invention. G This is a graph showing the continuous transfer curve measured over multiple cycles under sweep conditions (V D = 0.7V).

[0082] Hereinafter, embodiments according to the present invention will be described in detail with reference to the attached drawings.

[0083] While the present invention allows for various modifications and variations, specific embodiments are illustrated in the drawings and will be described in detail below. However, it is not intended to limit the invention to the particular forms disclosed, but rather the invention includes all modifications, equivalents, and substitutions consistent with the spirit of the invention as defined by the claims.

[0084] When an element such as a layer, region, or substrate is referred to as existing "on" another component, it can be understood that this exists directly on the other element, or that an intermediate element may exist between them.

[0085] Although terms such as first, second, etc., may be used to describe various elements, components, regions, layers, and / or regions, it will be understood that these elements, components, regions, layers, and / or regions should not be limited by these terms.

[0086] Examples

[0087] One aspect of the present invention may provide an n-type organic electrochemical transistor (OECT). The n-type organic electrochemical transistor (OECT) may include a hydrophobic passivation layer.

[0088] FIG. 1 is a schematic diagram showing the structure of an n-type organic electrochemical transistor (OECT) according to one embodiment of the present invention.

[0089] Referring to FIG. 1, the n-type organic electrochemical transistor (OECT) may include a source electrode (110) and a drain electrode (130), an active layer (200) comprising an n-type organic mixed ion-electron conductor electrically connected to the source electrode (110) and the drain electrode (130), a passivation layer (300) formed on the active layer (200) and having hydrophobicity, an electrolyte layer (400) formed on the passivation layer (300), and a gate electrode (500) disposed on the electrolyte layer (400).

[0090] When a positive voltage greater than the threshold voltage is applied to the gate electrode (500) of the n-type organic electrochemical transistor (OECT), cations in the electrolyte layer (400) penetrate through the passivation layer (300) and infiltrate into the active layer (200), thereby doping the active layer (200) and increasing the conductivity of the active layer (200). As a result, the n-type organic electrochemical transistor (OECT) can be turned on.

[0091] As shown in FIG. 1, the source electrode (110) and the drain electrode (130) can be formed on a substrate (10). The substrate (10) can be any material applicable to an organic electrochemical transistor (OECT). Specifically, for example, the substrate (10) can be one or more selected from a silicon wafer (Si wafer), a glass substrate, a polyethylene terephthalate (PET), and a polymer substrate such as polyimide (PI), but is not limited thereto.

[0092] The source electrode (110) and the drain electrode (130) are positioned on the substrate (10) in electrically separated regions spaced apart from each other and may be formed in a horizontal direction relative to each other. The source electrode (110) and the drain electrode (130) may be composed of a metal or a conductive polymer electrode. The metal may include one or more selected from gold (Au), silver (Ag), aluminum (Al), nickel (Ni), molybdenum (Mo), tungsten (W), indium tin oxide (ITO), and indium zinc oxide (IZO), and the conductive polymer electrode may be PEDOT:PSS, etc., but is not limited thereto.

[0093] The active layer (200) may be provided to be electrically connected to the source electrode (110) and the drain electrode (130), and in one embodiment as shown in FIG. 1, the active layer (200) may be formed on the substrate (10) and arranged to be connected to the source electrode (110) and the drain electrode (130). That is, the active layer (200) may be formed in a portion of the substrate (10) and in a portion of the source electrode (110) and the drain electrode (130).

[0094] The active layer (200) can function as a channel of an n-type organic electrochemical transistor (OECT). Cations contained in the electrolyte layer (400) can be injected into the active layer (200). In the n-type organic electrochemical transistor of the present invention, the channel length (L) of the effective channel may be the distance between the source electrode (110) and the drain electrode (130), and the channel width (W) of the effective channel may be the width between the source electrode (110) and the drain electrode (130).

[0095] The active layer (200) may include an n-type organic mixed ionic-electronic conductor (OMIEC). The n-type organic mixed ionic-electronic conductor may be a polymer or a monomer. In one embodiment, the n-type organic mixed ionic-electronic conductor may be a trapezoidal n-type organic polymer.

[0096] Specifically, the n-type organic mixed ion-electron conductor (OMIEC) may comprise one or more selected from a monomer having a polycyclic aromatic diimide or benzodithiophene unit and a polymer having a polycyclic aromatic diimide or benzodithiophene unit. That is, it may comprise one or more selected from a monomer having a polycyclic aromatic diimide unit, a polymer having a polycyclic aromatic diimide unit, a monomer having a benzodithiophene unit, and a polymer having a benzodithiophene unit. The polycyclic aromatic diimide unit may comprise one or more selected from perylenediimide and naphthalenediimide.

[0097] More specifically, the n-type organic mixed ion-electron conductor (OMIEC) may be poly(benzimidazobenzophenanthroline); BBL. The poly(benzimidazobenzophenanthroline) (BBL) may exhibit excellent stability in air and water due to its deep LUMO level.

[0098] The passivation layer (300) may be provided on the active layer (200) and may be positioned so as not to come into direct contact with the source electrode (110) and the drain electrode (130). As the passivation layer (300) is formed to protect the surface of the active layer (200), it can suppress contact between the active layer (200) and oxygen (O2) or water (H2O) and suppress physical decomposition caused by repeated ion movement within the active layer (200).

[0099] Specifically, the passivation layer (300) may be formed on the active layer (200) to passivate the active layer (200) without hindering the entry and exit of ions into the active layer (200). To this end, the passivation layer (300) may be composed of a material capable of allowing ion penetration during the operation of the transistor.

[0100] The passivation layer (300) may be hydrophobic. That is, the passivation layer (300) may include a hydrophobic compound. As the passivation layer (300) is composed of a hydrophobic material, the passivation layer (300) can reduce surface roughness relative to the active layer (200), thereby reducing the contact area with water. In addition, the hydrophobic passivation layer (300) can cover the active layer (200) to suppress the penetration of water or dissolved oxygen in the water into the active layer (200). Accordingly, OH by the oxygen reduction reaction (ORR)- Alternatively, damage to the active layer (200) can be suppressed by radicals from H2O2. This can increase the reliability of the n-type organic electrochemical transistor of the present invention.

[0101] The passivation layer (300) can be formed so that the active layer (200) is not exposed on its surface. That is, the passivation layer (300) can completely cover the active layer (200) so that a portion of the active layer (200) does not protrude on the passivation layer (300). In this way, as the passivation layer (300) increases the degree of passivation of the active layer (200), the surface roughness of the passivation layer (300) formed on the active layer (200) can be reduced, and the contact angle with water can be increased. As a result, the penetration of water or dissolved oxygen in the water into the active layer (200) can be further suppressed.

[0102] When the penetration of water, etc. into the active layer (200) is inhibited, the injection of ions hydrated by water into the active layer (200) is inhibited, and thus g m There may be a disadvantage of lower transconductance. However, the reliability of the n-type organic electrochemical transistor of the present invention can be improved. In addition, ions absorbed within the active layer (200) can contribute to the electrochemical reduction of the passivation layer (300) to form an anionic state of fullerene units, thereby improving electron conductivity (see FIG. 30).

[0103] The surface roughness of the passivation layer (300) may be 1.5 nm or less, specifically 0.54 to 1.5 nm, and more specifically 0.80 to 1.5 nm. Preferably, the surface roughness of the passivation layer (300) may be 0.80 to 1.42 nm. For details, refer to FIG. 17 and the description thereof.

[0104] The contact angle of the passivation layer (300) with respect to water may be 70° or greater, specifically 70 to 90.9°, and more specifically 70 to 86.3°. Preferably, the contact angle of the passivation layer (300) with respect to water may be 70 to 75°. Refer to FIG. 21 for this.

[0105] The signal (q) of the amorphous ring of the passivation layer (300) xy ) is 1.33–1.34 Å -1 It may appear in. Specifically, refer to Fig. 23.

[0106] In addition, since the passivation layer (300) can reduce the doping efficiency of the active layer (200), it may be composed of a material capable of achieving high carrier mobility to compensate for this.

[0107] The hydrophobic passivation layer (300) may include a low-molecular-weight organic semiconductor. The low-molecular-weight organic semiconductor may refer to an organic semiconductor that is not a high-molecular-weight organic semiconductor. Specifically, the low-molecular-weight organic semiconductor may refer to an organic semiconductor having a molecular weight of about 1,000 daltons or less. For example, the low-molecular-weight organic semiconductor may have a molecular weight of 100 to 2,000 g / mol. Preferably, the passivation layer (300) may include a low-molecular-weight n-type organic semiconductor. When the passivation layer (300) includes the low-molecular-weight n-type organic semiconductor, the process of ion absorption in the active layer (200) contributes to the electrochemical reduction of the passivation layer (300), so that the low-molecular-weight n-type organic semiconductor constituting the passivation layer (300) may become an anionic state. Through this, the passivation layer (300) can further increase electron mobility while promoting electron transport when the n-type organic electrochemical transistor operates.

[0108] The above low-molecular-weight organic semiconductor may have a fullerene group. For example, the above low-molecular-weight organic semiconductor having a fullerene group is C 60 Fullerene, C 70 Fullerene, C 76 Fullerene, C 84 Fullerene, PC 60 BM([6,6]-phenyl-C 61 butyric acid methylester), and PC 70 BM([6,6]-phenyl-C 71 It may include one or more selected from -butyric acid methyl ester.

[0109] At this time, the passivation layer (300) may be composed of a material that does not damage other material layers within the transistor, including the active layer (200). Specifically, the passivation layer (300) may use an organic solvent with low solubility for the active material within the active layer (200) as the organic solvent used to form it. Accordingly, even if the passivation layer (300) is provided on the active layer (200), the active material within the active layer (200) can maintain a crystallized state.

[0110] In one embodiment, when the active layer (200) is composed of polybenzobisimidazobenzophenanthroline (BBL), the active layer (200) may have peaks for the (100) crystal plane and the (010) crystal plane in the X-ray diffraction (XRD) spectrum. That is, even after the passivation layer (300) is provided on the active layer (200), the peaks for the unique crystal planes of the active layer (200) may be maintained.

[0111] That is, since the passivation layer (300) must be soluble in an organic solvent due to the characteristics of its manufacturing process, an organic solvent can be used that has low solubility for the active material of the active layer (200) and can effectively dissolve the hydrophobic compound constituting the passivation layer (300), specifically a low-molecular-weight organic semiconductor. At the same time, the hydrophobic compound constituting the passivation layer (300), specifically a low-molecular-weight organic semiconductor, can also be composed of a material that is well soluble in an organic solvent.

[0112] Specifically, the low molecular weight organic semiconductor may have a fullerene group and may have a side chain having a higher solubility in an organic solvent compared to the fullerene group. That is, the low molecular weight organic semiconductor may have a side chain that enhances the solubility of the low molecular weight organic semiconductor having the fullerene group in an organic solvent. For example, the side chain may include one or more selected from methyl ester, an alkyl chain having 1 to 30 carbon atoms, ethylene glycol, and a carboxylic acid.

[0113] Preferably, the low-molecular-weight organic semiconductor is a PC 60 BM, and PC 70 It may include one or more selected from BMs. PCBM exhibits high electron mobility and high hydrophobicity and may possess excellent solution processability, which can provide a uniform thin film surface with a simple solution-based coating process.

[0114] The thickness of the active layer (200) may be 40 to 60 nm, and the thickness of the passivation layer (300) may be 5 to 40 nm. That is, by providing the active passivation layer (300) with a thickness within the above-described range relative to the thickness of the active layer (200), the movement of ions injected into the active layer (200) through the passivation layer (300) can be facilitated, and the active layer (200) can be uniformly passivated. Specifically, this can be understood by referring to the following experimental examples and drawings.

[0115] The electrolyte layer (400) may be formed on the passivation layer (300) and configured to be in contact with the passivation layer (300). The electrolyte layer (400) may be an electrolyte in the form of an aqueous solution containing a compound having ionic bonds, and may include water, cations, and anions. Alternatively, the electrolyte layer (400) may be an electrolyte in the form of a hydrogel containing a compound having ionic bonds, and may include a hydrophilic polymer matrix such as polyvinyl alcohol (PVA), water, cations, and anions. Specifically, for example, the compound having the ionic bond may include one or more selected from sodium chloride (NaCl), potassium chloride (KCl), sodium hexafluorophosphate (NaPF6), potassium hexafluorophosphate (KPF6), 1-ethyl-3-methylimidazole ethyl sulfate (EMIM EtSO4), and calcium chloride (CaCl2), but is not limited thereto, and any material applicable to an n-type organic electrochemical transistor may be used.

[0116] A gate electrode (500) may be disposed on the electrolyte layer (400). The gate electrode (500) may use any material applicable as a gate electrode for an n-type organic electrochemical transistor.

[0117] As described above, the n-type organic electrochemical transistor comprising the hydrophobic passivation layer of the present invention can easily control the activity of oxygen in the electrolyte and the n-type organic mixed ion-electron conductor, thereby effectively resolving technical limitations such as reduced stability due to side reactions during the operation of conventional n-type organic electrochemical transistors. Accordingly, the hydrophobic passivation layer of the present invention can be extended to other types of n-type organic semiconductor devices and is expected to be utilized in various fields for developing ion-operating sensors, such as bio-devices and agricultural devices.

[0118] Another aspect of the present invention may provide a method for manufacturing an n-type organic electrochemical transistor. That is, the manufacturing method may be a method for manufacturing an n-type organic electrochemical transistor comprising a hydrophobic passivation layer. This may be a method for manufacturing the n-type organic electrochemical transistor described above.

[0119] The method for manufacturing the above-described n-type organic electrochemical transistor may include the steps of forming a source electrode and a drain electrode on a substrate; forming an active layer formed on the substrate and electrically connected to the source electrode and the drain electrode and comprising an n-type organic mixed ion-electron conductor; forming a passivation layer formed on the active layer and having hydrophobicity; forming an electrolyte layer formed on the passivation layer; and placing a gate electrode on the electrolyte layer.

[0120] As shown in FIG. 1, in one embodiment, a substrate (10) can be prepared first. Specifically, for example, the substrate (10) may be one or more selected from a silicon wafer (Si wafer), a glass substrate, and a polymer substrate such as polyethylene terephthalate (PET) and polyimide (PI).

[0121] A source electrode (110) and a drain electrode (130) can be formed on the substrate (10). At this time, the source electrode (110) and the drain electrode (130) are placed in electrically separated regions on the substrate (10) and can be formed in a horizontal direction relative to each other. That is, the source electrode (110) can be formed at one end of the substrate (10), and the drain electrode (130) can be formed at the other end of the substrate (10) oriented with the source electrode (130), but their arrangement may vary depending on the embodiment. For example, the source electrode (110) and the drain electrode (130) can be formed using vacuum deposition, but are not limited thereto. The source electrode (110) and the drain electrode (130) may be composed of a metal or a conductive polymer electrode, but are not limited thereto.

[0122] Referring to FIG. 1, an active layer (200) can be formed on the substrate (10). In one embodiment, the active layer (200) can be formed with a thickness of 40 to 60 nm, but is not limited thereto and can be formed with various thicknesses depending on the embodiment.

[0123] The active layer (200) can be formed to be electrically connected to the source electrode (110) and the drain electrode (130). Specifically, the active layer (200) can be formed to be in contact with a portion of the substrate (10), and simultaneously formed to be in contact with the source electrode (110) and the drain electrode (130). The step of forming the active layer (200) may include a process of forming a first solution by mixing the n-type organic mixed ion-electron conductor and an acidic solvent, a process of forming a first solution layer by coating the first solution onto the substrate (10), a process of neutralizing the substrate (10) on which the first solution layer is formed by immersing it in a neutralizing solution, and a process of heat-treating the neutralized substrate (10) on which the first solution layer is formed.

[0124] The above n-type organic mixed ion-electron conductor may comprise one or more selected from monomers having polycyclic aromatic diimide or benzodithiophene units and polymers having polycyclic aromatic diimide or benzodithiophene units. Specifically, the above n-type organic mixed ion-electron conductor may use polybenzobisimidazobenzophenanthroline (BBL).

[0125] First, the n-type organic mixed ion-electron conductor may be mixed with an acidic solvent such as methanesulfonic acid, and then stirred at a temperature of 5 to 40°C for 10 to 15 hours to form a first solution. The concentration of the n-type organic mixed ion-electron conductor in the first solution may be 1 to 20 mg / mL, specifically 5 to 15 mg / mL, and more specifically 8 to 10 mg / mL. Preferably, it may be 9 mg / mL.

[0126] Then, the first solution can be coated onto the substrate (10) to form a first solution layer. The method of coating the first solution onto the substrate (10) may utilize one or more methods selected from spin coating, blade coating, spray coating, roll coating, and bar coating, but is not limited thereto. Specifically, the coating of the first solution may be performed using spin coating, and more specifically, at 2000 rpm for 40 to 50 seconds.

[0127] Then, the substrate (10) on which the first solution layer is formed can be immersed in a neutralizing solution, such as ethanol containing triethylamine, to neutralize the acidic solution contained in the first solution layer. Specifically, for example, the immersion time may be 40 to 80 minutes.

[0128] Afterwards, the substrate (10) on which the neutralized first solution layer is formed can be heat-treated at a temperature of 180 to 220°C for 5 to 40 minutes. Through this, an active layer (200) having high crystallinity can be formed. Then, the substrate on which the active layer (200) is formed can be cooled at room temperature.

[0129] Referring to FIG. 1, a hydrophobic passivation layer (300) can be formed on the active layer (200). The passivation layer (300) may include a hydrophobic compound, specifically a low-molecular-weight organic semiconductor, more specifically a low-molecular-weight n-type organic semiconductor. The passivation layer (300) can be formed to uniformly cover the surface of the active layer (200).

[0130] In the step of forming the passivation layer (300), the concentration of the hydrophobic compound, specifically a low-molecular-weight organic semiconductor, more specifically a low-molecular-weight n-type organic semiconductor, can be formed at a concentration of 0.01 to 30 mg / mL. This may vary depending on the limiting solubility of the organic solvent and the roughness of the active layer disposed below it.

[0131] Specifically, for example, the concentration of the low molecular weight n-type organic semiconductor in the step of forming the passivation layer (300) may be 1 to 10 mg / ml, and more specifically, the concentration of the low molecular weight n-type organic semiconductor may be 3 to 10 mg / ml, and preferably 5 to 7 mg / ml. This may be the optimal concentration range of the passivation layer (300) relative to the concentration of the active layer (200). By configuring the passivation layer (300) within the concentration range described above, the electrical characteristics of the n-type organic electrochemical transistor can be improved by allowing electrons to move smoothly through the passivation layer (300) while improving stability by passivating the active layer (200).

[0132] In one embodiment, based on the active layer (200) being formed with a thickness of 40 to 60 nm, the passivation layer (300) can be formed with a thickness of 5 to 40 nm. That is, based on the thickness of the active layer (200), the thickness of the passivation layer (300) can be adjusted in a ratio within the range described above. This is intended to facilitate the movement of ions injected into the active layer (200) through the passivation layer (300), and at the same time, to uniformly passivate the active layer (200).

[0133] The step of forming the passivation layer (300) may include a process of dissolving a hydrophobic compound in an organic solvent to form a coating solution, a process of applying the coating solution onto the active layer to form a passivation solution layer, and a process of heat-treating the passivation coating layer.

[0134] First, a hydrophobic compound constituting the passivation layer (300) can be dissolved in an organic solvent to form a coating solution for forming the passivation layer. For example, the hydrophobic compound, specifically a low-molecular-weight organic semiconductor, can be mixed with the organic solvent and stirred at room temperature at about 500 to 700 rpm for 20 to 40 minutes.

[0135] In this case, the above low-molecular-weight organic semiconductor may use a material having a fullerene group. For example, the above low-molecular-weight organic semiconductor having a fullerene group is C 60 Fullerene, C 70 Fullerene, C 76 Fullerene, C 84 Fullerene, PC 60 BM([6,6]-phenyl-C 61 butyric acid methylester), and PC 70 BM([6,6]-phenyl-C 71 It may include one or more selected from -butyric acid methyl ester.

[0136] More specifically, the low molecular weight organic semiconductor may further include a side chain having a fullerene group and high solubility in an organic solvent. That is, the low molecular weight organic semiconductor may further include a side chain that enhances the solubility of the low molecular weight organic semiconductor in the organic solvent. For example, the side chain may include one or more selected from methyl ester, an alkyl chain having 1 to 30 carbon atoms, ethylene glycol, and a carboxylic acid. Preferably, the low molecular weight organic semiconductor is PC 60 BM, and PC 70 It may include one or more selected from BMs.

[0137] The above organic solvent may be an organic solvent capable of effectively dissolving a hydrophobic compound, specifically a low-molecular-weight organic semiconductor, constituting the passivation layer (300) without dissolving the active material of the active layer (200), thereby forming a uniform passivation layer (300). The above organic solvent may be a non-polar solvent.

[0138] Specifically, for example, when the active layer (200) includes polybenzobisimidazobenzophenanthroline (BBL), when forming the active layer (200), an acidic solvent of a strong acid, such as methanesulfonic acid, is used as a solvent to dissolve the polybenzobisimidazobenzophenanthroline (BBL). Therefore, the organic solvent of the passivation layer (300) is a hydrophobic compound, specifically a low-molecular-weight organic semiconductor, more specifically a low-molecular-weight n-type organic semiconductor, preferably the PCBM (PC 60 BM, and PC 70 Any solvent capable of dissolving (one or more selected from BM) may be used. More specifically, the organic solvent may include one or more selected from chloroform, chlorobenzene, dichlorobenzene, toluene, tetrahydrofuran, and anisole. Preferably, the organic solvent may be chloroform.

[0139] Next, the coating solution can be applied onto the active layer (200) to form a passivation coating layer. Specifically, the process of forming the passivation coating layer can be performed using one or more methods selected from spin coating, blade coating, spray coating, roll coating, and bar coating. More specifically, the passivation coating layer can be formed on the active layer (200) using spin coating, and more specifically, the spin coating can be performed at 2000 rpm for 30 to 35 seconds.

[0140] Next, the passivation coating layer can be heat-treated at a temperature of 110 to 130°C for 5 to 15 minutes to remove residual solvent contained in the passivation coating layer. Accordingly, the passivation layer (300) covering the surface of the active layer (200) can be formed.

[0141] Referring to FIG. 1, an electrolyte layer (400) formed on the passivation layer (300) can be formed. The method of forming the electrolyte layer (400) may vary depending on the type of electrolyte, and since all methods for forming the electrolyte layer of an n-type organic electrochemical transistor can be applied, it is not particularly limited. The electrolyte layer (400) is an electrolyte in the form of a hydrogel containing a compound having ionic bonds, and may include a hydrophilic polymer matrix such as polyvinyl alcohol (PVA), water, cations, and anions. Specifically, for example, the compound having ionic bonds may include sodium chloride (NaCl), potassium chloride (KCl), or calcium chloride (CaCl2), but is not limited thereto, and any material applicable to an n-type organic electrochemical transistor can be used. In one embodiment, when an electrolyte in the form of an aqueous solution containing ions is used as the electrolyte layer (400), an electrolyte receiving layer capable of accommodating such an electrolyte in the form of an aqueous solution may be prepared first, and then the electrolyte may be filled into the prepared electrolyte receiving layer. Specifically, for example, the electrolyte constituting the electrolyte layer (400) may be prepared by dissolving sodium chloride (NaCl) in water at a concentration of 0.1 M to be similar to the electrolyte concentration in the body. However, since performance may vary depending on the concentration of the electrolyte, the concentration may be adjusted from 0.05 M to 1.0 M according to the embodiment.

[0142] Referring to FIG. 1, a gate electrode (500) can be placed within the electrolyte layer (400). Specifically, for example, the gate electrode (500) may use an Ag / AgCl pellet, but is not limited thereto. The gate electrode (500) can be placed so as to be immersed within the electrolyte layer (400).

[0143] As described above, the method for manufacturing an n-type organic electrochemical transistor including a hydrophobic passivation layer according to the present invention enables the easy formation of a passivation layer through a simple solution process by utilizing the high hydrophobicity characteristic of small molecules and surface formation capabilities. Furthermore, since the method for manufacturing an n-type organic electrochemical transistor including a hydrophobic passivation layer according to the present invention does not require an additional high-temperature process, large-area coating based on a solution process is possible, making it highly applicable to devices requiring low-temperature processes and flexible substrates. In addition, the method for manufacturing an n-type organic electrochemical transistor including a hydrophobic passivation layer according to the present invention can lower process costs through a solution process, which can be of great help in commercialization and securing price competitiveness; thus, it is expected to lead the commercialization of free-form bio-devices.

[0144] Hereinafter, preferred experimental examples are presented to aid in understanding the present invention. However, the following experimental examples are intended only to aid in understanding the present invention, and the present invention is not limited by the following experimental examples.

[0145] The materials used in the following preparation examples are BBL, methanesulfonic acid (MSA, 99.5%), fullerene-C60 (99.9%), chloroform (99%, anhydrous), NaOH (97%), triethylamine (TEA, 99.5%), ethanol (99.5%), pH indicator strip (pH 6.5–10.0), and peroxide test strip (0.5–25 mg L⁻¹). -1 ) was purchased from Sigma-Aldrich. PC 60 BM and [6,6]-phenyl-C 71 - Methyl butyric acid (PC 70BM (99.9%) was purchased from Nano-C and Solenne BV, respectively. NaCl (extra-pure grade) was purchased from Daejeong Chemical. All chemicals were used as received without further purification. The spin coating and thermal annealing steps were performed in a glove box filled with dry air (relative humidity: 6–7%), while the other steps were performed in ambient air.

[0146] <Preparation Examples 1 to 5: Organic electrochemical transistors equipped with PCBM (3 to 10) / BBL layers>

[0147] FIG. 2 is a schematic diagram showing the structure of an n-type organic electrochemical transistor according to one embodiment of the present invention.

[0148] As shown in Figure 2, an n-type organic electrochemical transistor was fabricated including BBL as the active layer and PCBM as the passivation layer.

[0149] 1) Substrate: Soda-lime glass (20mm x 20mm) was sonicated in deionized water containing detergent (bath-sonication), and then cleaned by performing continuous sonication in acetone and isopropyl alcohol.

[0150] 2) Source electrode and drain electrode: Cr (4 nm) and Au (40 nm) are deposited on a cleaned glass substrate at a depth of 2.0 x 10⁻¹⁰ -6 The bottom source electrode and drain electrode were formed by continuously depositing via thermal evaporation at a vacuum level of Torr or lower. A contact electrode was patterned using a shadow mask (L: 100 µm, W: 1000–4000 µm). The substrate was treated with UV / ozone for 20 minutes using a UV / ozone cleaner (PSDP-UVT, Novascan).

[0151] 3) Active layer: Polybenzobisimidazobenzophenanthroline (BBL) was dissolved in methanesulfonic acid, a solvent, to a concentration of 9 mg / mL, and the BBL solution was prepared by stirring at 60°C for at least 12 hours. The BBL solution was spin-coated onto a glass substrate. The thickness of the BBL film was adjusted by varying the spin-coating speed, and a BBL film with a thickness of approximately 40 nm was prepared by spin-coating at 2000 rpm for 40 seconds. The appropriate spin-coating amount of BBL solution was approximately 150 µL based on a glass substrate measuring 2 cm x 2 cm. To neutralize the coated BBL film, it was immersed in an ethanol solution containing 10% trimethylamine (TEA) for 40 minutes. To remove excess TEA solution, the film was completely dried in a fume hood for 3 hours, and then annealed at 200°C for 1 hour using a hot plate to form an active layer with high crystallinity (hereinafter referred to as BBL).

[0152] 4) Hydrophobic passivation layer: PCBM (PC 60 After adding BM, a PCBM solution was prepared by stirring at 500 rpm at room temperature for at least 30 minutes. A double layer composed of BBL / PCBM was fabricated by spin-coating the prepared PCBM solution onto a BBL film cooled to room temperature in step 3) described above at 2000 rpm for at least 30 seconds. The appropriate spin-coating amount of PCBM solution was approximately 100 µl based on a glass substrate measuring 2 cm x 2 cm. The solution was then annealed on a hot plate at 120°C for 10 minutes to remove residual solvent.

[0153] As described above, when forming the hydrophobic passivation layer in Preparation Examples 1 to 5, the thickness of the hydrophobic passivation layer was controlled by varying the concentration of the PCBM solution in chloroform from 3 to 10 mg / ml. Specifically, when forming a PCBM layer with the concentrations shown in Table 1 on a BBL layer having a thickness of about 40 nm, the thickness of the PCBM layer was formed to be about 5 nm in Preparation Example 1, about 10 nm in Preparation Example 2, 25 nm in Preparation Example 3, and 40 nm in Preparation Example 4.

[0154] 5) Electrolyte layer: An electrolyte was prepared by dissolving NaCl and NaOH in deionized water. An electrolyte receiving layer was fabricated using a polymer to contain the electrolyte (0.1 M NaCl) around the lower electrode region of the film prepared in 4) above, and about 40 µl of electrolyte was added.

[0155] 6) Gate electrode: An 3-terminal FET measurement setup was fabricated using an Ag / AgCl pellet (EP1, World Precision Instrument) as the gate electrode.

[0156] <Manufacturing Example 6: PC 70 Organic electrochemical transistor equipped with BM(5) / BBL layer>

[0157] In the above Manufacturing Example 2, PC as the passivation layer 60 PC, not BM 70 An organic electrochemical transistor was fabricated by performing the same procedure except that BM was used.

[0158] <Preparation Example 7: C 60 (5) Organic electrochemical transistor equipped with a BBL layer

[0159] In the above Manufacturing Example 2, C, rather than PCBM, is used as the passivation layer. 60 An organic electrochemical transistor was fabricated by performing the same procedure except for using [the appropriate method].

[0160] <Comparative Example 1: Organic electrochemical transistor equipped with a BBL layer>

[0161] An organic electrochemical transistor was manufactured by performing the same procedure as in Manufacturing Example 2 above, except that the PCBM layer was not formed.

[0162] <Comparative Example 2: Organic electrochemical transistor equipped with a PCBM layer>

[0163] An organic electrochemical transistor was prepared by performing the same procedure as in Preparation Example 2 above, except that the BBL layer was not formed. At this time, the concentration of PCBM is 5 mg / mL.

[0164] <Comparative Example 3: Substrate with gold (Au) deposited having a BBL layer>

[0165] A BBL film was formed by thermal evaporation on a substrate on which gold (Au) was deposited. The method for forming the BBL film was performed in the same manner as the active layer formation process of Preparation Examples 1 to 5.

[0166] <Comparative Example 4: Substrate with deposited gold (Au)>

[0167] A substrate with gold (Au) deposited on it was prepared.

[0168] The structures of the OECTs of Manufacturing Examples 1 to 7 described above and the OECTs of Comparative Examples 1 and 2 are shown in Table 1 below.

[0169] Sample (Name) Active layer type (concentration) (Unit: mg / ml) Passivation layer type (concentration) (Unit: mg / ml) Preparation Example 1 (PCBM / BBL(3)) BBL(9) PC 60 BM(3)Manufacturing Example 2(PCBM / BBL(5))BBL(9)PC 60 BM(5)Manufacturing Example 3(PCBM / BBL(7))BBL(9)PC 60 BM(7)Manufacturing Example 4(PCBM / BBL(10))BBL(9)PC 60 BM(10)Manufacturing Example 5(PCBM / BBL(9))BBL(9)PC 60 BM(9)Manufacturing Example 6(PCBM / BBL(9))BBL(9)PC 70 BM(5)Manufacturing Example 7(PCBM / BBL(9))BBL(9)C 60(5)Comparative Example 1 (BBL(5))BBL(9)_Comparative Example 2 (PCBM(5))_PC 60 BM(5)

[0170] As shown in Table 1, the active layer / passivation layer is denoted as PCBM / BBL, and the concentration of PCBM (n) is indicated in PCBM / BBL. For example, PCBM(n) / BBL may refer to a PCBM / BBL bilayer prepared using an n mg / mL PCBM chloroform solution.

[0171] Experimental Example

[0172] 1) The thickness of the channel, which is the active layer, was measured using a surface profiler (Alpha Step IQ, KLA Tencor), and the thickness range was 40 to 60 nm for BBL and 50 to 70 nm for PCBM(5) / BBL.

[0173] 2) Transfer curve measurements on an organic electrochemical transistor (OECT) were performed at 25 mV / s V G It was performed at the sweep rate using a Keithley 4200-SCS parameter analyzer. The drain current obtained through the transfer curve is I D , the applied drain voltage V D When given that, transconductance maximum(g m ) can be obtained through the following equation (1). That is, g m It was determined as the maximum slope of the transfer curve in the forward sweep.

[0174] g m = ∂I D / ∂V D … … Equation (1)

[0175] g m,normThe transconductance maximum obtained from the above equation (1) was obtained using the following equation (2) by geometrical normalization due to the thickness (d) of the active layer and the channel size (width:W, length:L).

[0176] g m,norm = g m WdL -1 … … Equation (2)

[0177] μ OECT It was determined using the following equation (3).

[0178] μ OECT = L 2 τ e-1 V D -1 … … Equation (3)

[0179] Here, τ e I using the constant gate current method D Transient vs. I G This is the passage time extracted from the plot. Each parameter was determined as the average value measured at least five different devices.

[0180] In addition, g obtained through the above equation (1) m It can be composed of the following equation (4), and by substituting the physical quantity used in the experiment into the equation, μC * can be obtained

[0181] g m = WdL -1 ×μC * ×(|V T -V G |) … … Equation (4)

[0182] Here, C * ε is volume capacitance, μ is mobility, V T is the threshold voltage, V G is the gate voltage.

[0183] 3) For the pulse stability test, V G It was pulsed using a Keithley 2636A source meter. The switching time of the pulsed OECT is the measured I D It was determined by a bi-exponential fitting of the transient. The equation for the switching time is as follows, Equation (5) and Equation (6), depending on the case.

[0184] τ ON In the case of, I D = A1(e -t / τ1 ) + A2(1-e -t / τ2 ) … … Equation (5)

[0185] τ OFF In the case of I D = A1(e -t / τ1 ) + A2(e -t / τ2 ) … … Equation (6)

[0186] Here, τ i is the decay time constant and A i is the corresponding strength.

[0187] All electrical measurements were performed under ambient atmosphere.

[0188] 4) An active layer was prepared on an ITO (indium tin oxide) coated glass substrate using the methods and conditions mentioned above for UV-vis-NIR absorption measurements in situ.

[0189] UV-vis-NIR spectra were recorded using a spectrophotometer (V670M, JASCO) and a voltage bias was applied between the Ag / AgCl pellet and the ITO electrode using a Keithley 2400 source meter.

[0190] A three-electrode setup was used for EIS, CV, LSV, and QCM measurements using a Pt sheet (counter electrode) and an Ag / AgCl electrode (reference electrode).

[0191] C * BBL and PCBM (5) / BBL films were prepared on an Au-deposited glass substrate that serves as a working electrode for EIS measurement to determine the value (see Comparative Example 3 and Comparative Example 4).

[0192] Glassy carbon piece (disk area = 0.1989 cm²) for CV and LSV measurements 2 ) was used as the RDE (working electrode), and the scan speeds were 100 mV / s (static CV) and 5 mV / s (LSV). For LSV measurements, background correction was performed by subtracting the current density determined under the corresponding Ar purging condition from the current density determined under the O2 purging condition. In addition, voltage loss compensation was applied using the contact resistance obtained through EIS measurement at the open-circuit voltage.

[0193] 5) EIS(C *RDE (CV and LSV) measurements (for determining value and voltage loss compensation) and RDE (CV and LSV) measurements were performed using a potentiometer (PGSTAT302N, Auto Lab), whereas QCM (and corresponding CV) measurements were performed using a potentiometer (Versa STAT, AMETEK Scientific Instruments) connected to a QCM (QCM922A, AMETEK Scientific Instruments). AT-cut gold (Au) quartz (8.94 MHz ± 30 kHz) was used as the substrate and working electrode for QCM (and corresponding CV) measurements. In the Rotating Disk Electrode (RDE) and Quartz Crystal Microbalance (QCM) experiments, the BBL film was floated on water to neutralize it, and then transferred to a glassy carbon or gold-quartz electrode. The transferred film was dried overnight in a 60°C convection oven to completely remove residual solvent. To prepare a bilayer sample, a PCBM solution (20 µl, 5 mg / ml) was drop-casted and then dried in a 60°C convection oven for 30 minutes.

[0194] 6) Surface morphology was investigated using two scanning electron microscopes (Nova NanoSEM 450 and Verios G4UC, FEI), an atomic force microscope (NX 70, Park Systems), and an optical microscope (BX53M, Olympus).

[0195] 7) 2D-GIXD measurements were performed using a high-resolution synchrotron X-ray source (beam energy = 10.35 keV) with a fixed grazing angle of 0.15° at the 3C beamline of the Pohang Accelerator Laboratory.

[0196] 8) Static contact angle measurements were performed using a contact angle analyzer (Phoenix 300, SEO) with a water droplet (0.1M NaCl).

[0197] 9) XPS measurements were performed using an X-ray photoelectron spectrometer (Kα Plus, Thermo Fisher Scientific) equipped with a monochromatic Al-Kα X-ray source (1486.6 eV, operating voltage / current: 12 keV / 6 mA).

[0198] For the aforementioned SEM, AFM, 2D-GIXD, and XPS measurements, a highly doped Si wafer covered with SiO2 (100 nm) was used as the substrate.

[0199] 10) AES measurements were performed using a scanning Auger nanoprobe (PHI 700 Xi, ULVAC-PHI) equipped with an electron gun (incident angle: 30°, operating voltage / current: 10 keV / 10 nA).

[0200] FIG. 3 is a schematic image illustrating the surface shape of the roughness of a BBL film according to the thickness of a PCBM film according to one embodiment of the present invention.

[0201] Referring to Fig. 3, the BBL film can form a rough surface due to its strong self-assembling tendency. Therefore, in order to passivate the BBL film surface so that it is not exposed, it may be necessary to increase the PCBM concentrations and increase the thickness of the PCBM film.

[0202] FIGS. 4(a) to 4(d) are graphs showing consecutive transfer curves measured over multiple cycles of the OECTs of Preparation Examples 1 to 4 of the present invention. At this time, the fixed drain voltage (V D ) is 0.7 V, and W / L = 1000 / 100 μm.

[0203] The OECT of Preparation Example 1 (PCBM(3) / BBL) in Fig. 4(a) and the OECT of Preparation Example 2 (PCBM(5) / BBL) in Fig. 4(b) were saturated in the first cycle. On the other hand, the OECT of Preparation Example 3 (PCBM(7) / BBL) in Fig. 4(c) and the OECT of Preparation Example 4 (PCBM(10) / BBL) in Fig. 4(d) required additional cycles to reach saturation. That is, it can be seen that the number of cycles required to saturate the OECT equipped with PCBM / BBL increases with the concentration of PCBM. This may mean that as the thickness of the hydrophobic PCBM layer increases, more energy is required for sufficient ions to penetrate into the BBL layer.

[0204] After the OECT reached a saturation state, the operational stability of the OECT of Comparative Example 1 (BBL) and the OECT of Manufacturing Example 2 (PCBM(5) / BBL) was investigated during repeated measurement cycles.

[0205] FIG. 5 is a graph showing the continuous transfer curve measured over multiple cycles of the OECT of Comparative Example 1 (BBL) of the present invention, and FIG. 6 is a graph showing the OECT of Manufacturing Example 2 (PCBM(5) / BBL) of the present invention. At this time, the fixed drain voltage (V D ) is 0.7 V, and W / L = 2000 / 100 μm. Specifically, FIG. 5 is the result of measuring the transfer repeatability in a 0.1 M NaCl aqueous electrolyte similar to the electrolyte concentration of a biological organism to evaluate the repeatability of the active layer coated with the passivation layer of the present invention.

[0206] When comparing the aforementioned FIGS. 4(a) to (d) with FIG. 5, the OECT equipped with the PCBM / BBL of the present invention experiences a critical voltage (V) due to the PCBM layer during consecutive sweeps. T It can be confirmed that ) has moved to a positive. However, it can be seen that these soon become similar to the OECT of Comparative Example 1 (BBL) in Fig. 5.

[0207] In addition, as shown in FIG. 5, the drain current (I) of the OECT of Comparative Example 1 (BBL) D The maximum value is compared with the initial value in the 7th cycle (7 th It can be confirmed that it decreases by approximately 83% after the cycle. On the other hand, referring to Fig. 6, the OECT of Manufacturing Example 2 (PCBM(5) / BBL) is at the 50th cycle (50 th It can be seen that it exhibits excellent operational stability by maintaining 97% of the initial on-current even after performing a cycle.

[0208] FIG. 7 shows the first (1) of the OECT of Comparative Example 1 (BBL) of the present invention and the OECT of Manufacturing Example 2 (PCBM(5) / BBL). st ) Cycle and the last(50 th g between ) cycles m,norm This is a graph showing a comparison of ratios.

[0209] Referring to Fig. 7, the normalized transconductance (g) of the OECT m, norm It can be seen that ) shows a similar trend. Specifically, g for the OECT of Comparative Example 1 (BBL). m, norm It is 3.57 mS / cm in the first cycle, and the 8th (8 th In the cycle, it showed a significant decrease to 0.56 mS / cm. In contrast, in the case of the OECT of Preparation Example 2 (PCBM(5) / BBL), it showed 2.54 mS / cm at the 50th cycle, which was slightly lower than the 1st cycle.

[0210] Figure 8(a) is a schematic cross-sectional view of the OECT measured after performing the 8th cycle of Comparative Example 1 (BBL) of the present invention and a planar SEM image observed with a scanning electron microscope (SEM), and (b) is a tilted-view SEM image of the upper part of the drain electrode, which is the red box area of ​​Figure 8(a), taken by tilting it 50° before and after the 8th cycle measurement.

[0211] Referring to Figures 8 (a) and (b), numerous white aggregates were observed on the surface of the BBL film on the drain electrode of Comparative Example 1 (BBL) OECT, to which the reduction potential was applied multiple times.

[0212] Figure 9(a) is a schematic cross-sectional view of the OECT and a planar SEM image observed with a scanning electron microscope after performing the 8th cycle of the OECT of Manufacturing Example 2 (PCBM(5) / BBL) of the present invention, and (b) is an SEM image taken by tilting the upper part of the drain electrode, which is the red box area of ​​Figure 9(a), at 50° before and after the 8th cycle measurement.

[0213] Referring to Figures 9 (a) and (b), no white aggregates were observed on the PCBM / BBL on the drain electrode of the OECT of Preparation Example 2 (PCBM(5) / BBL).

[0214] Figure 10 (a) is a planar SEM image measured after performing the 15th cycle of the OECT of Comparative Example 1 (BBL) of the present invention, and (b) is a planar SEM image of the OECT of Manufacturing Example 2 (PCBM(5) / BBL) of the present invention. The left image shows the source electrode, the center image shows the channel, and the right image shows the drain electrode area. All images have the same scale bar.

[0215] Referring to FIG. 10(a), in the OECT of Comparative Example 1 (BBL) of the present invention, as the number of sweep cycles increases to the 15th, it can be seen that the aggregates in the drain electrode region become significantly larger and some small aggregates are newly observed in the channel and source electrode regions. On the other hand, in the case of the OECT of Manufacturing Example 2 (PCBM(5) / BBL) of FIG. 10(b), no aggregates were observed even after the 15th cycle was performed.

[0216] Figure 11 (a) is an Auger electron spectroscopy (AES) image after performing the 8th cycle (period) of the OECT of Comparative Example 1 (BBL) of the present invention, and (b) is a graph showing the differential AES spectra for the white aggregate (indicated by the red box) and the dark background (indicated by the blue box) shown in (a). In (b), the x-axis represents kinetic energy and the y-axis represents intensity.

[0217] Referring to Figures 11 (a) and (b), it can be seen that the AES spectrum in the dark background region shows distinct peaks of C (approx. 268 eV), N (approx. 384 eV), and O (approx. 508 eV) corresponding to BBL. In contrast, the spectrum of the bright white aggregate showed an additional peak associated with Au (approx. 69 eV) along with the BBL-related peaks.

[0218] Figure 12(a) is a graph showing the XPS results when a voltage bias is applied (BBL-biased) and when no voltage bias is applied (BBL) to a BBL film thermally deposited on a gold (Au) substrate of Comparative Example 3 of the present invention, (b) is an enlarged graph of (a) for the analysis of Au 4f binding energy plotted together with the XPS analysis of a pristine gold (Au) substrate, and Figure 12(c) is a normalized graph of (b).

[0219] In Fig. 12(a), a voltage bias was applied back and forth from -0.2 V to +0.7 V for 30 minutes (25 mV / s) between the top (Ag / AgCl pellet) and bottom (thermally deposited Au) electrodes in a 0.1 M NaCl electrolyte, and the green circle indicated by the dashed line represents the Au-related peak. For reference, the atomic percentage of Au is 0.05% for the BBL film and 3.51% for the biased BBL film (BBL-biased). The Au peak in the BBL without voltage bias (indicated in black) may occur in the background signal due to the thermally deposited base Au layer.

[0220] Referring to Figures 12 (a) to (c), a clear Au peak can be observed in the XPS profile of the BBL film containing white aggregates. At this time, the binding energy was identical to that of the thermally deposited Au electrode. This can be attributed to the severe degradation of device performance resulting from the formation of a BBL / Au composite on the BBL layer, which is the OMIEC layer formed on the Au drain electrode during the repetitive doping and de-doping processes. The formation of the BBL / Au composite is due to OH - It is determined that it is related to OECT components having ORR byproducts such as and H2O2.

[0221] FIG. 13 (a) and (b) show the OH of Comparative Example 3 (BBL) OECT of the present invention in the original electrolyte (0.1M NaCl) and a degraded electrolyte (0.1M NaOH). - Images showing the results of a rapid strip test to detect H2O2, where (a) is a pH test strip and (b) is a peroxide test strip. Figures 13 (a) and (b) were taken while the test strips were wet.

[0222] Referring to FIG. 13 (a) and (b), H2O2 and OH were introduced into the electrolyte of the decomposed BBL OECT of Comparative Example 3 through a test strip. - The existence of can be confirmed.

[0223] Figures 14 (a) to (c) are optical microscopy images of Comparative Example 3 (BBL) OECT of the present invention after being immersed for one day in (a) a 0.1M NaCl aqueous solution, (b) a 0.1M NaOH aqueous solution, and (c) a 0.1M NaCl aqueous solution containing 1 mM H2O2, and Figure 14 (d) is an optical microscopy image of the Au-deposited substrate of Comparative Example 4 after being immersed for one day in a 0.1M NaCl aqueous solution containing 1 mM H2O2. All images share the same scale bar.

[0224] As shown in FIG. 14(c) and FIG. 14(d), it can be confirmed that the surface of the Au-deposited substrate of Comparative Example 4 and the BBL film on the Au-deposited substrate of Comparative Example 3 were significantly damaged when immersed in an aqueous solution (electrolyte) containing H2O2. Referring to FIG. 14(b), slight surface changes were observed on the BBL film of the Au-deposited substrate of Comparative Example 3 when immersed in a 0.1M NaOH aqueous solution. This is, OH - Rather, it may indicate that H2O2 is a major species contributing to the damage of the Au electrode covered with the BBL active layer.

[0225] FIG. 15 is the result of surface analysis using an atomic force microscope (AFM) of the BBL film of Comparative Example 1 of the present invention, the PCBM (3) / BBL film of Preparation Example 1, and the PCBM (5) / BBL film of Preparation Example 2, FIG. 16 is the result of surface analysis using an atomic force microscope (AFM) of the PCBM (7) / BBL film of Preparation Example 3 of the present invention, the PCBM (10) / BBL film of Preparation Example 4, and the PCBM (5) film of Comparative Example 2, where (a) is an image of the topography and (b) is an image of the phase. The image size is 5 x 5 μm, and all images share the same scale bar.

[0226] Looking at Figures 15 and 16, it can be seen that as the PCBM concentration increases, the surface roughness decreases and the BBL film becomes smoother. Referring to the AFM phase images, it can be seen that in the case of Preparation Example 1 (PCBM(3) / BBL), a segregated film surface was shown, whereas in the case of Preparation Example 2 (PCBM(5) / BBL), Preparation Example 3 (PCBM(7) / BBL), and Preparation Example 4 (PCBM(10) / BBL), a relatively uniform surface was shown.

[0227] FIG. 17 shows the root-mean-square surface roughness (R) for the BBL film of Comparative Example 1 of the present invention, the PCBM (5) film of Comparative Example 2, and the PCBM (3-10) / BBL films of Preparation Examples 1 to 4. q This is a graph showing the measurement results.

[0228] Referring to Fig. 17, the clean BBL film of Comparative Example 1 exhibited a high mean square surface roughness (Rq) of 7.18 nm, and it can be seen that this surface roughness gradually decreases as the PCBM concentration increases. This can be seen as a result of the pits on the surface of the BBL film being effectively filled with the PCBM coating while forming a continuous PCBM layer at high PCBM concentrations.

[0229] Through this, it can be confirmed that when a PCBM layer is coated on the BBL layer in the present invention, the contact angle gradually increases as the concentration of PCBM increases, and the surface roughness is relatively reduced.

[0230] FIG. 18 shows Comparative Example 1 (BBL) and Preparation Example 2 (PC) of the present invention. 60 BM(5) / BBL), Preparation Example 6 (PC 70 BM(5) / BBL), and Preparation Example 7 (C 60 (5) / BBL) This is a topographic image of the active layer of the OECT surface analyzed by scanning probe microscopy (AFM). Preparation Examples 2 and 6 used chloroform and chlorobenzene, respectively, as solvents, and the images share the same scale bar.

[0231] Referring to FIG. 18, Manufacturing Example 2 (PC 60 Preparation Example 6 (PC) using a passivation layer of OECT of BM(5) / BBL) and a different fullerene derivative 60 BM(5) / BBL), and Preparation Example 7 (C 60 (5) / BBL) The OECT has a slightly higher roughness compared to the OECT of Example 2, but the surface roughness is much lower compared to the OECT of Comparative Example 1, and a smooth surface can be shown.

[0232] FIG. 19 shows Comparative Example 1 (BBL) and Manufacturing Example 2 (PC) of the present invention. 60 BM(5) / BBL), Preparation Example 6 (PC 60 BM(5) / BBL), and Preparation Example 7 (C 60 (5) This is a graph showing the relative on-currents according to the number of cycles in 0.1M NaCl of the OECT of BBL. That is, Figure 19 shows the initial on-current ratio according to the type of fullerene unit coated on BBL, and consecutive transfer curves measured over several cycles.

[0233] Referring to FIG. 19, the PC of Manufacturing Example 2 60 The OECTs of Preparation Examples 6 and 7, in which a passivation layer was formed with BM and other fullerene derivatives, exhibited improved stability compared to Comparative Example 1, and in particular, the PC of Preparation Example 6 70 When BM was used, OECT stability similar to that of Preparation Example 2 was exhibited. That is, PC with different fullerene sizes 70 BM and PC 60 While all BMs show stable results during the repetitive driving process as shown in Fig. 19 above, C without side chains 60 In the case of [the product], it can be seen that performance decreases rapidly because a passivation layer of sufficient thickness cannot be formed on the BBL film due to low solubility.

[0234] Figures 20 (a) to (c) are images showing the water contact angle of the active layer of Comparative Example 1 (BBL), Comparative Example 2 (PCBM(5)), and Preparation Example 2 (PCBM(5) / BBL) OECTs of the present invention, and Figure 21 is a graph showing the measurement results of the water contact angle of the active layer of Comparative Example 1 (BBL), Comparative Example 2 (PCBM(5)), and Preparation Examples 1 to 4 (PCBM(3~10) / BBL) OECTs of the present invention. The water contact angles presented in Figure 21 are average values ​​based on multiple measurements.

[0235] Referring to FIGS. 20 and 21, the contact angle with water of the OECTs of Preparation Examples 1 to 4 (PCBM (3-10) / BBL) showed a similar trend as the concentration of the passivation layer, PCBM, increased. Specifically, the contact angle with water of the PCBM (3) / BBL film of Preparation Example 1 was 62.71°, and the contact angle with water of the BBL film of Comparative Example 1 was 58.9°, so it can be confirmed that the contact angle of Preparation Example 1 was slightly higher than that of Comparative Example 1.

[0236] On the other hand, the contact angle of the PCBM (5-10) / BBL films of Preparation Examples 2 to 4 gradually increased as the PCBM concentration increased, becoming similar to the contact angle of the original PCBM (5) film of Comparative Example 2. Through the above-described AFM and contact angle measurements with respect to water, it can be seen that a smoother surface with lower surface energy can be produced by coating the active layer, the BBL layer, with PCBM.

[0237] Next, the effect of PCBM coating on the crystallinity of BBL films was investigated using two-dimensional grazing incidence X-ray diffraction (2D-GIXD).

[0238] FIG. 22 is a graph showing the results of two-dimensional grazing incident X-ray diffraction (2D-GIXD) analysis of the active layers of the OECTs of Comparative Example 1 (BBL), Comparative Example 2 (PCBM(5)), and Preparation Examples 1 to 4 (PCBM(3~10) / BBL) of the present invention, FIG. 23 is a line-scan profile of the 2D-GIXD of FIG. 22, where (a) is out-of-plane (q z ), (b) is in the plane (in-plane, q xy These are images according to the direction. Table 2 below summarizes the d-spacing values ​​of the 2D-GIXD peaks extracted from Fig. 23. In Table 2, FWHM stands for Full-width-at-half-maximum.

[0239] Classification q z [A -1 ]q xy [A -1 ]d-spacing[A]FWHM[A -1]BBL(100)BBL0.77_8.170.19PCBM(3) / BBL0.77_8.210.18PCBM(5) / BBL0.77_8.170.18PCBM(7) / BBL0.76_8 .290.18PCBM(10) / BBL0.76_8.240.19BBL(010)BBL_1.803.500.16PCBM(3) / BBL_1.813.480.15PCBM(5) / BB L_1.813.470.15PCBM(7) / BBL_1.813.470.15PCBM(10) / BBL_1.823.450.14PCBMBBL_1.354.650.26PCBM(3) / BBL_1.384.540.38PCBM(5) / BBL_1.344.700.17PCBM(7) / BBL_1.344.690.19PCBM(10) / BBL_1.354.650.15

[0240] Referring to Figures 22 and 23 and Table 2, it can be seen that the PCBM coating hardly changes the d-spacing corresponding to the BBL (100) and BBL (010) peaks. This indicates that the crystallinity of the BBL layer is not affected by the PCBM coating. This may be because chloroform hardly interacts with the BBL chains. In other words, at all concentrations of PCBM, the underlying BBL remained intact and did not undergo any change in crystallinity.

[0241] In addition, the signal of the PCBM amorphous ring in the PCBM (5-10) / BBL films of Preparation Examples 2 to 4 is q xy =1.33~1.34Å -1 It was observed at (d-spacing: 9.38–9.46 Å). This value is almost identical to that of the PCBM reference sample.

[0242] On the other hand, in the profile of the PCBM (3) / BBL film of Preparation Example 1, the PCBM peak is at a slightly different position (q xy =1.38Å -1It was observed at a low intensity. This may mean that the PCBM layer of Preparation Example 1 was formed insufficiently to completely cover the BBL surface. This result is consistent with the AFM and contact angle measurement results for water described above.

[0243] As described above, when combining the increased thickness, contact angle, and the grazing incidence wide angle X-ray spectrum (GIWAXS) results of the entire film, it can be confirmed that the formation of the PCBM layer using the solution process does not compromise the crystallinity of the underlying BBL layer.

[0244] Therefore, based on 2D-GIXD data and transport characteristics, 5 mg / mL was selected as the optimal concentration of the PCBM solution for passivation of BBL films. The potential influence of the top PCBM layer on the redox behavior of BBL was investigated using cyclic voltammetry (CV) measurements with 0.1 M NaCl electrolyte under various purging conditions (Ar or O2 purging).

[0245] Figure 24 (a) shows the CV curves of the OECTs of Comparative Example 1 (BBL) and Preparation Example 2 (PCBM(5) / BBL) of the present invention, measured using 0.1M NaCl electrolyte under Ar-purged conditions (Ar-purged) and O2-purged conditions (O2-purged). Through Figure 24, the effect of the oxygen concentration in the electrolyte, confirmed by cyclic voltammetry, on the reduction current of the film can be confirmed.

[0246] Referring to FIG. 24(a), the BBL film of Comparative Example 1 and the PCBM (5) / BBL film of Preparation Example 2 were tested 10 times (10 th) exhibited similar CV curves during repeated cycles. In contrast, in the O2-purged electrolyte, the CV curve of the BBL film of Comparative Example 1 shifted significantly downward, whereas the CV curve of the PCBM (5) / BBL film of Preparation Example 2 did not change significantly, similar to the Ar-purged electrolyte. That is, the OECT equipped with the PCBM (5) / BBL of Preparation Example 2 exhibits similar reduction potential in both oxygen-saturated solutions and argon (Ar)-saturated aqueous electrolytes, but in Comparative Example 1, when the active layer exists only as a single BBL layer, it exhibits a very large reduction potential in the oxygen-saturated solution.

[0247] Next, to quantitatively compare the amount of charge transferred during repeated redox cycles, a cumulative charge versus time plot was obtained for the 10th CV cycle.

[0248] Figure 25 (a) is a graph showing the accumulated charge (top), current (middle), and voltage (bottom) profiles in an Ar-purged 0.1M NaCl electrolyte of the BBL film of Comparative Example 1 and the PCBM (5) / BBL film of Preparation Example 2, which underwent the 10th CV cycle in Figure 24, and Figure 26 is a graph showing these measured in an O2-purged 0.1M NaCl electrolyte.

[0249] Referring to FIG. 25, when using an electrolyte from which Ar was removed (i.e., lacking O2), a reversible redox process was observed in both the BBL of Comparative Example 1 and the PCBM (5) / BBL film of Preparation Example 2. In contrast, under the O2-purged (i.e., O2-rich) conditions in FIG. 26, both films exhibited charge asymmetry indicating non-capacitated Faraday charge transfer during the CV cycle. However, charge hysteresis was much smaller in the PCBM (5) / BBL film of Preparation Example 2 than in the BBL film of Comparative Example 1. This can be attributed to the PCBM layer hindering the interaction between the BBL and the O2 dissolved in the electrolyte.

[0250] Next, in addition to static CV measurements, LSV (linear sweep voltammetry) measurements were performed using an O2 purge electrolyte (0.1 M NaCl) and various rotor speeds, with the RDE as the working electrode. Since ORR products are removed by rotation-induced convection, changes in current density with changes in rotation speed can provide evidence of ORR occurrence.

[0251] FIG. 27 is a graph showing the LSV curves of Comparative Example 1 (BBL) and Manufacturing Example 2 (PCBM(5) / BBL) of the present invention measured at various rotor speeds. Specifically, FIG. 27 is an oxygen reduction reaction (RDE) experiment using linear scanning potentiometry (LSV) with a rotating disc electrode (RDE).

[0252] Referring to FIG. 27, it can be seen that in the case of the RDE's BBL film, the current density changed significantly with the rotor speed, whereas the current density of the RDE's PCBM (5) / BBL film remained almost unchanged at all speeds. Specifically, this indicates the effect of the PCBM layer, which can block contact with the charged BBL layer even in the presence of oxygen. In addition, in an additional rotating disc electrode linear scanning potentiometry experiment to evaluate reactivity with oxygen, the BBL layer with the PCBM layer did not show an effect due to Faraday electron transfer, which is consistent with the result that the PCBM inhibits the oxygen reduction reaction.

[0253] FIG. 28 is a Koutecky-Levich plot derived from the results of FIG. 27 for the OECT of (a) Comparative Example 1 (BBL) and (b) Preparation Example 2 (PCBM(5) / BBL) of the present invention, and (c) is a graph showing the number of electron transfers (n) of the BBL film at each potential (vs. Ag / AgCl) extracted from the slope of the Koutecky-Levich plot.

[0254] At this time, the current density (J) is the value obtained by dividing the measured current by the working electrode area, and ω is the rotor speed of the working electrode. The above Koutecky-Levich plot was used to compare the number of electrons transferred in the BBL layer (electron transfer number (n)) at each potential (relative to Ag / AgCl) from -0.4V to -0.7V.

[0255] Referring to FIG. 28, the BBL film of Comparative Example 1 consumed one or more electrons during the reduction process, whereas the plot of the PCBM (5) / BBL film of Preparation Example 2 was nearly flat at all potentials, indicating no irreversible electron consumption. These results can be seen as clearly indicating that the ORR activity of BBL in the presence of dissolved O2 can be effectively suppressed by introducing a single PCBM protective layer.

[0256] FIG. 29 shows (a) a schematic diagram and (b) an image from the field showing a UV-vis-NIR measurement setup according to one embodiment of the present invention, and FIG. 30 is a graph showing the UV-vis-NIR absorption spectra of OECTs of Comparative Example 1 (BBL), Comparative Example 2 (PCBM(5)), and Preparation Example 2 (PCBM(5) / BBL) of the present invention. In this case, the solid line represents the undoped case measured at 0V vs. Ag / AgCl, and the dashed line represents the doped case measured at -0.7V vs. Ag / AgCl.

[0257] As shown in FIG. 29(a), a 0.1M NaCl (sodium chloride) electrolyte was filled into a cuvette, and an ITO substrate equipped with a g / AgCl pellet and a semiconductor film was immersed in it, and the Ag / AgCl pellet and the ITO substrate were connected to a voltage source (Keithley 2400). As shown in FIG. 29(b), the effect of the PCBM layer on polaron formation by BBL using ion implantation in the 0.1M NaCl electrolyte was investigated using in situ UV-vis-NIR spectroscopy.

[0258] Referring to FIG. 30, it can be seen that the absorbance spectrum of the PCBM (5) film of Comparative Example 2 does not change regardless of the applied voltage. This can be seen as indicating that there is no OMIEC activity. On the other hand, compared to the BBL film of Comparative Example 1, it can be seen that the absorption of the PCBM (5) / BBL double layer film of Preparation Example 2 increased to less than 550 nm due to the PCBM layer.

[0259] FIG. 31 is a graph showing the UV-vis-NIR absorption spectra in situ of (a) Comparative Example 2 (PCBM(5)), (b) Comparative Example 1 (BBL), and Preparation Example 2 (PCBM(5) / BBL) OECTs of the present invention. At this time, the OECTs were subjected to electrolyte gating in the 0.1V step from the undoped state measured at 0V vs. Ag / AgCl to the doped state measured at -0.7V vs. Ag / AgCl.

[0260] Referring to Fig. 31, when a voltage bias is applied, π-π *It can be confirmed that the absorbance of the BBL film gradually decreased at the neutral peak of the BBL in the transition region of 480 to 700 nm, and that polaron absorption increased in the doped BBL layer at 700 to 950 nm. On the other hand, the absorption intensity of the PCBM (5) / BBL film of Preparation Example 2, particularly the π-π of the BBL * In the region of 480 nm or higher, which includes both transition and polaron absorption, an overall increase was observed depending on the applied voltage. Additionally, in the neutral peak region of BBL, it was observed that the BBL film of Comparative Example 1 decreased, while the PCBM (5) / BBL film of Preparation Example 2 increased.

[0261] Next, to further verify this, additional experiments were performed on doped (-0.7V vs. Ag / AgCl) and undoped (0V vs. Ag / AgCl) PCBM / BBL bilayer films with various PCBM thicknesses.

[0262] FIG. 32 is a graph showing the UV-vis-NIR absorption spectra in situ of (a) Comparative Example 1 (BBL), (b) Preparation Example 1 (PCBM(3) / BBL), (c) Preparation Example 2 (PCBM(5) / BBL), (d) Preparation Example 3 (PCBM(7) / BBL), (e) Preparation Example 5 (PCBM(9) / BBL) OECT, and (f) Comparative Example 2 (PCBM(5)) OECT of the present invention. At this time, electrolyte gating was performed on the OECT from an undoped state measured at 0V vs. Ag / AgCl to a doped state measured at -0.7V vs. Ag / AgCl.

[0263] Referring to Fig. 32, the absorbance of all PCBM(n) / BBL films with n > 3 increased in the neutral peak region of BBL between 480 and 700 nm, which overlaps with the anionic peak of PCBM. The increased absorbance may indicate that ions absorbed by the BBL layer contribute to the electrochemical reduction of PCBM, inducing the formation of an anionic state of fullerene units. In particular, it can be confirmed that this spectral response appears similar to the response of other fullerene derivatives observed through electrochemical doping. This suggests that when the PCBM layer forms a double layer on an ion-absorbing material such as BBL, it can promote electron transport in OECT operations.

[0264] FIG. 33 is a graph showing the mass change (top), current density (middle), and voltage (bottom) profiles obtained from QCM measurements coupled with CV cycles for the OECTs of Comparative Example 1 (BBL), Comparative Example 2 (PCBM(5)), and Preparation Example 2 (PCBM(5) / BBL) of the present invention. In this case, the light blue and gray areas represent ion doping, which is a forward sweep, and the white areas represent de-doping, which is a reverse sweep. As shown in FIG. 33, information regarding the ion expansion of the OMIEC layer during electrochemical doping can be confirmed through Quartz crystal microbalance (QCM) measurements. Accordingly, the films of Comparative Example 1 (BBL), Preparation Example 2 (PCBM(5) / BBL), and Comparative Example 2 (PCBM(5)) underwent QCM measurements along with CV, and the mass change was monitored while applying a voltage bias.

[0265] In addition, FIG. 34 is a graph of QCM corrected by galvanostatic deposition of silver (Ag) on ​​a quartz crystal according to one embodiment of the present invention. At this time, the linear sensitivity coefficient (C) was determined from a plot of mass change (Δm) against the slope of the recorded frequency change (Δf). That is, Δf = -CΔm. Specifically, the electrolyte consisted of N2-purged 0.1M NaCl, and the QCM was corrected by determining the linear sensitivity coefficient using the Sauerbrey equation along with galvanostatic deposition of silver (Ag).

[0266] In Fig. 33, the CV scan rate was set to 20 mV / s, which is similar to the sweep rate used to acquire the transfer curve to achieve similar diffusion layer conditions in the electrolyte. Additionally, the current and mass of the PCBM sample in Fig. 33 remained unchanged. This indicates that the sample is nearly ion-impermeable, a result consistent with the in situ UV-vis-NIR spectroscopy results presented in Fig. 30 above.

[0267] Meanwhile, it is known that during the BBL doping process of OECT, a certain amount of bulk water enters the BBL layer along with hydrated ions. The introduced bulk water remains in the BBL film even after the ions leave the film during dedoping, which can lead to irreversible mass changes after doping.

[0268] Looking at the first gray box in Fig. 33, the aforementioned irreversible mass change was observed in the system with the BBL of Comparative Example 1 and the PCBM (5) / BBL film of Manufacturing Example 2 after the first CV cycle. However, it can be seen that the mass change of the BBL was much greater than that of the other two samples, even though the current densities were similar.

[0269] The fact that the mass change differs at the maximum voltage drop (-0.7V vs. Ag / AgCl, red asterisk in Fig. 33) despite similar current values ​​suggests that the PCBM layer plays an important role in the penetration of bulk water into the BBL layer. In other words, considering similar current values, it is determined that the PCBM layer has minimal effect on the BBL doping level while hindering the inflow of large amounts of water due to the low surface energy of PCBM.

[0270] When comparing the onset voltage of the current density and mass change for PCBM (5) / BBL of Preparation Example 2 in the first doping method, which is the blue box in Fig. 33, it can be seen that the value has shifted to a more negative region (i.e., a more reductive region). At this time, for BBL of Comparative Example 1, it is about -0.2V (vs. Ag / AgCl), and for PCBM (5) / BBL of Preparation Example 2, it is about -0.3V (vs. Ag / AgCl).

[0271] These results are consistent with the VT shift of the first cycle for the PCBM (5) / BBL OECT presented in Figure 4 (b) above, which may mean that the PCBM layer above increases the voltage required for the ion expansion of the BBL.

[0272] As OECT operation is based on mixed ion-electron coupling, both the electron charge carrier mobility (μ) and volumetric capacitance (C*) are g m It can contribute to. Accordingly, the PCBM layer g m , μ and C * To determine what effect it has on the OMIEC layer, a set of BBL and PCBM (5) / BBL OECT devices with various OMIEC layer volumes was fabricated by controlling the OMIEC layer thickness (d), channel width (W), and channel length (L).

[0273] FIG. 35 shows the μC of Comparative Example 1 (BBL) and Preparation Example 2 (PCBM(5) / BBL) OECT of the present invention.* g for extracting m vs. This is a plot showing channel geometry and operating conditions. In this case, R 2 is the fitting coefficient. That is, Fig. 35 shows the g of the OECT device in the saturated state. m Shows the value, and g from this value m, norm and μC * was extracted.

[0274] Table 3 below shows the parameters of Comparative Example 1 (BBL) and Manufacturing Example 2 (PCBM(5) / BBL) OECTs. At this time, V T The OECT of Preparation Example 2 (PCBM(5) / BBL) was extracted from the transmission curve of the second forward sweep. μ OECT is the mobility obtained using the constant gate current method.

[0275] Thickness [nm]g m,norm [S cm -1 ]VT[V]μC*[F cm -1 V -1 s -1 ]C*[F ㎝ -3 ]μ OECT [㎝ 2 V -1 s -1 ]BBL48.4±2.93.27±0.290.139±0.0345.408563.81X10 -4 PCBM(5) / BBL59.1±2.73.38±0.330.156±0.0395.555226.40X10 -4

[0276] Referring to FIG. 35 and Table 3, despite the larger d value, the OECT of Manufacturing Example 2 (PCBM(5) / BBL) has a slightly higher g than the OECT of Comparative Example 1 (BBL). m, norm and, μC * It represented the value. That is, μC, which is used as a performance indicator for organic electrochemical transistors. *When evaluating the product of electron mobility and ion capacitance at various thicknesses and channel sizes, μC despite the overall thickness increase due to PCBM * It was found to be 5.40 in Comparative Example 1 and 5.55 in Manufacturing Example 2, confirming that the performance of the PCBM-coated device increased slightly.

[0277] FIG. 36 shows the C of Comparative Example 1 (BBL) and Manufacturing Example 2 (PCBM(5) / BBL) OECT of the present invention. * This is a plot showing capacitance vs. layer volume for extracting. Figure 36 shows capacitance as a function of layer volume, through which μ and C * It can be decided separately.

[0278] Electrochemical impedance spectroscopy (EIS) was used to measure the capacitance of BBL and PCBM (5) / BBL films with various OMIEC volumes, and the results were applied to Randles circuits.

[0279] Figure 37 (a) is a Nyquist plot of Comparative Example 1 (BBL) and Preparation Example 2 (PCBM(5) / BBL) OECTs of the present invention measured by electrochemical impedance spectroscopy (EIS); (b) is an enlarged graph of (a) for determining charge transfer resistance; and (c) and (d) are Bode plots of Comparative Example 1 (BBL) and Preparation Example 2 (PCBM(5) / BBL) OECTs of the present invention applied to Randles equivalent circuits, respectively. Here, R1 is the solution resistance, R2 is the charge transfer resistance, and CPE is the constant phase element. All measurements were performed at -0.5V (relative to Ag / AgCl) in 0.1M NaCl with an amplitude of 10mV.

[0280] Referring to FIG. 37, C determined by plotting the capacitance against the layer volume * The value is 856 F cm for the BBL of Comparative Example 1. -3 and, in the case of PCBM(5) / BBL of Manufacturing Example 2, 522 F cm -3 (In the case of PCBM(5) / BBL) In particular, C of PCBM(5) / BBL of Manufacturing Example 2 * The value is C of BBL in Comparative Example 1. * It was much smaller than the value, which was consistent with previously reported values ​​for single-layer BBL films. μC * Considering that the value is similar for BBL of Comparative Example 1 and PCBM (5) / BBL of Manufacturing Example 2, the calculated μ was expected to be much larger for PCBM (5) / BBL of Manufacturing Example 2 than for BBL of Comparative Example 1.

[0281] FIG. 38 shows the extracted τ of Comparative Example 1 (BBL) and Preparation Example 2 (PCBM(5) / BBL) OECT of the present invention. e I with a value D transient vs. I G This is a plot. In this case, W / L = 1000 / 100 μm.

[0282] The Nyquist plot in Fig. 38 shows a lower charge transfer resistance for the PCBM (5) / BBL of Preparation Example 2, which can support the analysis in Fig. 37.

[0283] Charge carrier mobility (μ OECT To directly measure ), a constant gate current (IG) method was applied to the BBL of Comparative Example 1 and the OECT of Manufacturing Example 2 (PCBM(5) / BBL). Several I G Fixed V for the value D and I G In I D By analyzing transients, the μ of each device OECT obtained.

[0284] Referring to FIG. 38 and Table 3 above together, in the case of BBL of Comparative Example 1, 3.81X10 -4 cm 2 V -1 s -1 and, in the case of PCBM(5) / BBL of Manufacturing Example 2, 6.40X10 -4 cm 2 V -1 s -1 It appeared as.

[0285] FIG. 39 shows the I of Comparative Example 1 (BBL) and Manufacturing Example 2 (PCBM(5) / BBL) OECT of the present invention. D This is a graph showing the transient response of. In this case, V D = 0.7V, V G It was measured at = 0 V~0.7 V, a pulse width of 1 second, and W / L = 1000 / 100 μm.

[0286] In Fig. 39, turning on (τ on ) and turn off(τ off V to extract switching time for the ) state G A fixed V of 0.7V while pulses (0V to 0.7V, 1-second pulse width) D In I D The transient response of was monitored. As expected, the OECT of Manufacturing Example 2 (PCBM(5) / BBL) was compared to the OECT (τ) of Comparative Example 1 (BBL). on :171.8ms and τ off A switching time shorter than :139.9ms (τ) on : 103.2ms and τ off : 82.9ms). In other words, it can be confirmed that the on / off time of the OECT equipped with the PCBM layer has been shortened. Through this, it can be seen that the PCBM layer, which is the passivation layer of the present invention, improves electron transport in the OECT, increases carrier mobility, and reduces the switching time.

[0287] Next, in addition to the improved electron transport described above, experiments were also conducted on the improved operational stability of the OECT of Manufacturing Example 2 (PCBM(5) / BBL).

[0288] FIG. 40 is a schematic diagram showing the role of the PCBM layer in the ion doping of Comparative Example 1 (BBL) and Preparation Example 2 (PCBM(5) / BBL) OECTs of the present invention.

[0289] As shown in the schematic diagram schematically described in FIG. 40, it was confirmed in FIG. 24 and FIG. 27 above that the PCBM passivation layer effectively suppresses the ORR of the BBL layer.

[0290] Next, to investigate dynamic operational stability, a pulse cycle test was performed using Comparative Example 1 (BBL) and Manufacturing Example 2 (PCBM(5) / BBL) OECTs.

[0291] FIG. 41 shows the I of Comparative Example 1 (BBL) and Manufacturing Example 2 (PCBM(5) / BBL) OECT of the present invention. D This is a graph showing the pulse responses of. This is V, the reported reductive bias-only condition. D = 0.6 V, V G = 0 V to 0.7 V, with a pulse width of 5 seconds, and W / L = 2000 / 100 μm.

[0292] Referring to FIG. 41, in reductive bias-only switching (VG switching from 0V to 0.7V), both BBL and PCBM (5) / BBL OECT operated stably over a full pulse period of 4,000 seconds, consistent with data for previously reported BBL OECTs.

[0293] FIG. 42 shows the I of Comparative Example 1 (BBL) and Manufacturing Example 2 (PCBM(5) / BBL) OECT of the present invention. D This is a graph showing the pulse responses of. This is the reducing and oxidizing VG It was performed at bias (VD = 0.7V, VG = 0.2V ~ 0.7V, 5-second pulse width).

[0294] In Fig. 42, the maximum V in the ON state G V in the off state while maintaining G When extended to -0.2V (i.e., oxidation bias), the OECTs of Comparative Example 1 and Preparation Example 2 exhibited different behaviors. Specifically, the OECT of Comparative Example 1 (BBL) showed a rapid I immediately after 8 pulse cycles. D While it showed a decline, the performance of the OECT of Preparation Example 2 (PCBM(5) / BBL) was maintained throughout the entire measurement cycle. This indicates that the OECT of Preparation Example 2 (PCBM(5) / BBL) can operate stably even under mixed voltage conditions including both oxidation and reduction biases.

[0295] FIG. 43 is a graph showing the continuous transfer curves measured over multiple cycles under basic electrolyte (0.1 M NaOH) conditions of Comparative Example 1 (BBL) and Preparation Example 2 (PCBM(5) / BBL) OECTs of the present invention (V D = 0.7V).

[0296] Referring to Fig. 43, H2O2 production by ORR of BBL of Comparative Example 1 increased significantly under basic electrolyte conditions. This indicates more OH - Ions have negative V G It can be seen as interacting with the BBL chain in the value. The I of the OECT of Comparative Example 1 (BBL). D While decreased significantly immediately after the first cycle (V G is from -0.2V to 0.7V, then to -0.2V), the OECT of Manufacturing Example 2 (PCBM(5) / BBL) is 15 times (15 thIt exhibited a relatively stable drain current during the continuous cycle of ). That is, the OECT equipped with an active layer coated with the PCBM passivation layer of Preparation Example 2 of the present invention showed stability over a wide voltage range and operational stability in various electrolytes. Through this, it can be confirmed that PCBM passivation can effectively protect the BBL even when using a strong basic electrolyte and enables stable electrochemical doping without significant degradation.

[0297] FIG. 44 shows the conventional electrolyte (0.1 M NaCl) and the extended V range of -0.7V to 0.7V of Comparative Example 1 (BBL) and Preparation Example 2 (PCBM(5) / BBL) OECTs of the present invention. G This is a graph showing the continuous transfer curve measured over multiple cycles under sweep conditions (V D = 0.7V).

[0298] As shown in FIG. 44, the I of the OECT of Comparative Example 1 (BBL) D It can be observed that it drops sharply immediately after the first cycle, similar to the results obtained with the basic electrolyte. In contrast, the I of the OECT of Preparation Example 2 (PCBM(5) / BBL) D is 10 times (10 th It was maintained stably during continuous cycles. This confirms that optimized PCBM passivation can effectively suppress the ORR of BBL while allowing stable ion doping during OECT operation under various electrolyte and voltage conditions.

[0299] As described above, the present invention can significantly improve the stability of an n-type organic electrochemical transistor by forming a highly hydrophobic passivation layer on an active layer through a simple spin coating process. At this time, since the degree of passivation on the surface of the active layer can be controlled by adjusting the concentration of the passivation solution, the present invention can uniformly cover the surface of the active layer without damaging the crystallinity of the film or impairing the ion permeability of the aqueous electrolyte by optimizing the thickness of the passivation layer.

[0300] In addition, through CV and LSV measurements using RDE depending on changes in O2 purging conditions and rotor speed, it was confirmed that the passivation layer effectively suppresses the ORR of the BBL layer by minimizing contact between O2 molecules and the electrolyte. In situ UV-vis-NIR and QCM measurements, it was found that the passivation layer does not interfere with the electrochemical doping of the active layer but rather contributes to an increase in polaron formation.

[0301] The OECT equipped with the optimized PCBM / BBL layer of the present invention exhibited significantly improved operational stability for neutral and basic electrolytes (0.1M NaCl and NaOH) and for multiple VG switching (pulses from -0.2V to 0.7V) and sweeps (from -0.7V to 0.7V) including both oxidation and reduction biases. In addition, the OECT equipped with the PCBM / BBL layer of the present invention exhibited improved electron mobility and reduced switching time compared to an OECT equipped with a single BBL layer.

[0302] Accordingly, the n-type organic electrochemical transistor of the present invention can effectively achieve high performance and stable operation under various conditions in various application fields by expanding the potential of n-type OMIEC and n-type OECT by providing a passivation layer on the active layer.

[0303] Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to the above embodiments, and various modifications and changes are possible by those skilled in the art within the technical spirit and scope of the present invention.

Claims

1. An active layer comprising an n-type organic mixed ion-electron conductor electrically connected to a source electrode and a drain electrode; A passivation layer formed on the above active layer and having hydrophobicity; An electrolyte layer formed on the above passivation layer; and An n-type organic electrochemical transistor comprising a gate electrode disposed on the electrolyte layer.

2. In claim 1, the n-type organic mixed ion-electron conductor is, An n-type organic electrochemical transistor comprising one or more selected from a monomer having a polycyclic aromatic diimide or benzodithiophene unit and a polymer having a polycyclic aromatic diimide or benzodithiophene unit.

3. In paragraph 2, the n-type organic mixed ion-electron conductor is, n-type organic electrochemical transistor comprising polybenzobisimidazobenzophenanthroline (BBL).

4. In Paragraph 3, The above active layer is an n-type organic electrochemical transistor having peaks for the (100) crystal plane and the (010) crystal plane in the XRD spectrum.

5. In paragraph 1, the passivation layer is, n-type organic electrochemical transistor comprising a small molecule organic semiconductor.

6. In paragraph 5, the passivation layer is, n-type organic electrochemical transistor comprising a small molecule n-type organic semiconductor.

7. In paragraph 5, the low-molecular-weight organic semiconductor is, n-type organic electrochemical transistor having a fullerene group.

8. In claim 7, the low-molecular-weight organic semiconductor is, An n-type organic electrochemical transistor comprising a side chain having high solubility in an organic solvent relative to the fullerene group.

9. In paragraph 8, the above side chain is, An n-type organic electrochemical transistor comprising one or more selected from methyl ester, an alkyl chain having 1 to 30 carbon atoms, ethylene glycol, and a carboxylic acid.

10. In claim 1, the passivation layer is, C 60 Fullerene, C 70 Fullerene, C 76 Fullerene, C 84 Fullerene, PC 60 BM([6,6]-phenyl-C 61 butyric acid methyl ester), and PC 70 BM([6,6]-phenyl-C 71 An n-type organic electrochemical transistor comprising one or more selected from -butyric acid methyl ester.

11. In Paragraph 1, The thickness of the active layer is 40 to 60 nm, and An n-type organic electrochemical transistor having a passivation layer thickness of 5 to 40 nm.

12. In Paragraph 1, An n-type organic electrochemical transistor in which the passivation layer is formed so as not to expose the active layer on the surface.

13. In Paragraph 1, An n-type organic electrochemical transistor having a surface roughness of 1.5 nm or less of the passivation layer.

14. In Paragraph 1, An n-type organic electrochemical transistor having a contact angle of the passivation layer with respect to water of 70° or more.

15. A step of forming a source electrode and a drain electrode on a substrate; A step of forming an active layer formed on the substrate, electrically connected to the source electrode and drain electrode, and comprising an n-type organic mixed ion-electron conductor; A step of forming a passivation layer having hydrophobicity that is formed on the active layer; A step of forming an electrolyte layer formed on the above passivation layer; and A method for manufacturing an n-type organic electrochemical transistor, comprising the step of placing a gate electrode on the electrolyte layer.

16. In paragraph 15, the above n-type organic mixed ion-electron conductor is, A method for manufacturing an n-type organic electrochemical transistor comprising polybenzobisimidazobenzophenanthroline (BBL).

17. In Clause 15, the passivation layer is, A method for manufacturing an n-type organic electrochemical transistor comprising a small molecule organic semiconductor.

18. In Paragraph 17, A method for manufacturing an n-type organic electrochemical transistor, wherein the concentration of the low-molecular-weight organic semiconductor is 3 to 10 mg / mL.

19. In Clause 15, the passivation layer is, C 60 Fullerene, C 70 Fullerene, C 76 Fullerene, C 84 Fullerene, PC 60 BM([6,6]-phenyl-C 61 butyric acid methyl ester), and PC 70 BM([6,6]-phenyl-C 71 A method for manufacturing an n-type organic electrochemical transistor comprising one or more selected from -butyric acid methyl ester.

20. In claim 15, the step of forming the passivation layer is, A process of dissolving a hydrophobic compound in an organic solvent to form a coating solution, and A process of forming a passivation coating layer by applying the coating solution onto the active layer, and A method for manufacturing an n-type organic electrochemical transistor comprising a process of heat-treating the passivation coating layer.

21. In Paragraph 20, A method for manufacturing an n-type organic electrochemical transistor, wherein the organic solvent comprises one or more selected from chloroform, chlorobenzene, dichlorobenzene, toluene, tetrahydrofuran, and anisole.

22. In Clause 20, the process of forming the passivation coating layer is, A method for manufacturing an n-type organic electrochemical transistor, performed by one or more methods selected from spin coating, blade coating, spray coating, roll coating, and bar coating.

23. In Paragraph 15, The above active layer is formed with a thickness of 40 to 60 nm, and A method for manufacturing an n-type organic electrochemical transistor, wherein the passivation layer is formed to a thickness of 5 to 40 nm.

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