A composite transparent conductive electrode, its preparation method and application

Abstract

This invention belongs to the field of conductive electrode technology, and specifically relates to a composite transparent conductive electrode, its preparation method, and its application. The composite transparent conductive electrode of this invention comprises a conductive framework layer and a polymer-filled layer stacked sequentially; the conductive framework layer includes a metal nanowire network; the polymer in the polymer-filled layer fills the voids in the metal nanowire network; the polymer is an n-type conductive polymer. The n-type conductive polymer of this invention penetrates into the interior of the metal nanowire network, filling the voids and increasing the contact area at the nanowire intersections. While maintaining light transmittance, it significantly reduces surface roughness and sheet resistance, improving the mechanical bending stability of the electrode. Simultaneously, utilizing the n-type characteristics of the n-type conductive polymer with a heavily p-doped hole injection layer, a p-n heterojunction is constructed. This heterojunction successfully bypasses the high injection barrier caused by traditional low work functions, achieving efficient hole injection in OLED devices.

Description

Technical Field

[0001] This invention belongs to the field of conductive electrode technology, and specifically relates to a composite transparent conductive electrode, its preparation method, and its application. Background Technology

[0002] In recent years, the rapid development of flexible organic light-emitting diode (OLED) technology has placed stringent requirements on transparent conductive electrodes, demanding a combination of high optical transparency, excellent mechanical flexibility, and high conductivity. Indium tin oxide (ITO) has become the primary transparent electrode material for current OLED devices due to its low sheet resistance and high transmittance (>85%). However, the inherent brittleness of ITO causes its resistance to increase by orders of magnitude after repeated bending, making it unsuitable for the needs of next-generation flexible devices.

[0003] To address these issues, researchers have proposed numerous alternatives, such as graphene, conductive polymers, carbon nanotubes, and metal nanowires. Among these, silver nanowire (Ag NWs) electrodes have attracted significant attention due to their high conductivity, high transmittance, and ease of fabrication. However, applying Ag NWs to flexible OLEDs still faces many challenges. For instance, the loose network structure of Ag NWs results in high contact resistance and hinders the formation of a uniform charge injection interface. Furthermore, exposed nanowire tips easily pierce the ultrathin organic functional layers in OLED devices, leading to short circuits and leakage. More importantly, the low work function of Ag NWs (4.0 eV) creates a significant Schottky barrier between the highest occupied molecular orbital (HOMO) energy level of conventional hole injection layers (HILs), severely limiting effective hole injection and resulting in high device turn-on voltage. In addition, environmental corrosion can affect the long-term stability of Ag NWs. To solve these problems, composite electrodes fabricated using conductive polymers have emerged as a promising solution. However, widely used p-type conductive polymers, such as poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate)PEDOT:PSS, still suffer from low conductivity. Although their conductivity can be improved through strategies such as acid treatment or solvent engineering, the high conductivity of acidic PEDOT:PSS can lead to corrosion of the underlying Ag NWs, and its hygroscopic properties can cause interfacial degradation over time.

[0004] Therefore, it is of great significance to provide a composite transparent conductive electrode with high efficiency of hole injection, good mechanical bending stability, high light transmittance, and low resistance. Summary of the Invention

[0005] The present invention aims to solve one or more technical problems existing in the prior art, and at least provide a beneficial solution. Specifically, the present invention provides a composite transparent conductive electrode, which has high efficiency in hole injection, good mechanical bending stability, high light transmittance, and low resistance.

[0006] The inventive concept of this invention: The composite transparent conductive electrode of this invention comprises a conductive framework layer and a polymer filling layer stacked sequentially; the conductive framework layer comprises a metal nanowire network; the polymer in the polymer filling layer fills the voids in the metal nanowire network; the polymer is an n-type conductive polymer.

[0007] This invention employs n-type conductive polymers (such as poly(3,7-dihydrobenzo[1,2-]) b :4,5- b' Difuran-2,6-dione: poly(2-ethyl-2-oxazoline), PBFDO:PEOx), utilizing its n-type characteristics to combine with heavily p-doped hole injection layers (such as... N,N,N',N' -Tetra(4-methoxyphenyl)benzidine:2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinone dimethyl ether (MeO-TPD:F4TCNQ) forms a pn heterojunction at the interface. This heterojunction, acting as a charge generation layer (CGL), forms an extremely narrow depletion region and a steep band bend under forward bias, enabling electrons to efficiently tunnel from the HOMO level of the p-type hole injection layer (HIL) to the lowest unoccupied molecular orbital (LUMO) level of PBFDO:PEOx (equivalent to hole injection) via interband tunneling. This successfully bypasses the high injection barrier caused by the traditional low work function, achieving a highly efficient hole injection effect. Simultaneously, the n-type conductive polymer can penetrate into the interior of the metal nanowire network, filling the voids and increasing the contact area at the nanowire intersections. This not only significantly reduces surface roughness and sheet resistance while maintaining transmittance, but also greatly improves the mechanical bending stability of the electrode.

[0008] Therefore, a first aspect of the present invention provides a composite transparent conductive electrode.

[0009] Specifically, the composite transparent conductive electrode comprises a conductive framework layer and a polymer filling layer stacked sequentially; The conductive framework layer includes a metal nanowire network; The polymer in the polymer-filled layer fills the voids in the metal nanowire network; The polymer is an n-type conductive polymer.

[0010] Preferably, the metal nanowire network includes a silver nanowire network, a copper nanowire network, a gold nanowire network, and a metal nanowire-oxide core-shell network.

[0011] Specifically, in the metal nanowire-oxide core-shell network, the metal nanowire is the core and the oxide is the shell. That is, it is composed of the metal nanowire core and the metal oxide shell covering its surface, forming a porous three-dimensional conductive framework.

[0012] Preferably, the metal oxide includes any one of ZnO, SnO2, and TiO2.

[0013] Preferably, the n-type conductive polymer comprises poly(3,7-dihydrobenzo[1,2-]) b :4,5- b' Difuran-2,6-dione): Poly(2-ethyl-2-oxazoline) (PBFDO:PEOx), Poly{[ N , N' -bis(2-octyldodecyl)naphthalene-1,4,5,8-tetracarboxylic diimide-2,6-diyl]-alternating-[5,5'-(2,2'-bithiophene)]} (P(NDI2OD-T2)), poly{[ N , N' -bis(2-hexyldecyl)perylene-3,4,9,10-tetracarboxylic diimide-1,7-diyl]-alternating-[5,5'-(2,2'-bithiophene)]} (PDI-T2), poly{[3,7-bis(4-decyltetradecyl)benzo[1,2- b :4,5- b' [Difuran-2,6-dione]-alternating-[5,5'-(2,2'-bithiophene)]} (PBDF-T2), poly{[ N , N' -bis(2-octyldodecyl)naphthalene-1,4,5,8-tetracarboxylic diimide-2,6-diyl]-alternating-[( E )-1,2-Di(thiophen-2-yl)ethylene]} (PNDI-TVT), poly{[ N , N' At least one of bis(2-(2-(2-(2-methoxyethoxy)ethoxy)ethyl)naphthalene-1,4,5,8-tetracarboxylic acid diimide-2,6-diyl]-alternating-[5,5'-(2,2'-bithiophene)]} (PTEG-NDI).

[0014] Preferably, the diameter of the nanowires in the metal nanowire network is 20-50 nm; for example, 20 nm, 30 nm, 40 nm, 50 nm, etc.

[0015] Preferably, the aspect ratio of the nanowires in the metal nanowire network is greater than 300; more preferably, the aspect ratio of the metal nanowires in the metal nanowire network is 500-2000.

[0016] Specifically, the n-type conductive polymer penetrates into the interior of the metal nanowire network, increasing the contact area at the intersections of the metal nanowires and forming a planarized interface on the surface of the composite transparent conductive electrode.

[0017] Preferably, the root mean square (RMS) surface roughness of the composite transparent conductive electrode is ≤30nm; more preferably, the root mean square surface roughness of the composite transparent conductive electrode is ≤10nm.

[0018] Preferably, the transmittance of the composite transparent conductive electrode is ≥80% at a wavelength of 550nm; more preferably, the transmittance of the composite transparent conductive electrode is ≥90% at a wavelength of 550nm.

[0019] Preferably, the sheet resistance of the composite transparent conductive electrode is ≤100Ω / sq; more preferably, the sheet resistance of the composite transparent conductive electrode is ≤18Ω / sq.

[0020] A second aspect of the present invention provides a method for preparing the composite transparent conductive electrode described in the first aspect of the present invention.

[0021] Specifically, the preparation method of the composite transparent conductive electrode includes the following steps: (1) The metal nanowire dispersion was coated on the substrate and annealed to obtain a conductive framework layer; (2) The n-type conductive polymer dispersion is coated on the conductive skeleton layer and annealed to obtain a polymer filling layer. The conductive skeleton layer and the polymer filling layer constitute the composite transparent conductive electrode.

[0022] Preferably, in step (1), the substrate includes either a rigid substrate or a flexible substrate.

[0023] Preferably, the rigid substrate comprises glass.

[0024] Preferably, the flexible substrate comprises any one of polyimide (PI), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN).

[0025] Preferably, in step (1), the mass fraction of the metal nanowire dispersion is 4-6%; for example, 4%, 4.5%, 5%, 5.5%, 6%, etc.

[0026] Preferably, the solvent in the metal nanowire dispersion includes an alcohol; more preferably, the alcohol includes ethanol.

[0027] Preferably, in step (1), the annealing temperature is 60-100℃ and the annealing time is 10-20min; for example, the annealing temperature is 60℃, 70℃, 80℃, 90℃, 100℃, etc., and the annealing time is 10min, 15min, 20min, etc.

[0028] Preferably, in step (2), the concentration of the n-type conductive polymer dispersion is 2-30 mg / mL; more preferably, the concentration of the n-type conductive polymer dispersion is 3-20 mg / mL; for example, 3 mg / mL, 5 mg / mL, 8 mg / mL, 12 mg / mL, 20 mg / mL, etc.

[0029] Preferably, the solvent in the n-type conductive polymer dispersion includes at least one of water, alcohol solvents, chlorobenzene, xylene, and chloroform.

[0030] Preferably, in step (2), the annealing temperature is 80-150℃ and the annealing time is 10-20min; for example, the annealing temperature is 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, etc., and the annealing time is 10min, 15min, 20min, etc.

[0031] A third aspect of the present invention provides an organic light-emitting diode device.

[0032] Specifically, the organic light-emitting diode device includes a substrate, an anode, a cathode, and an organic functional layer disposed between the anode and the cathode, which are stacked in sequence; the anode is the composite transparent conductive electrode described in the first aspect of the present invention.

[0033] Preferably, the organic functional layer includes at least a hole injection layer; the hole injection layer is composed of a p-type material.

[0034] Preferably, the organic light-emitting diode device comprises a substrate, a composite transparent conductive electrode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode, which are stacked sequentially. That is, the hole injection layer, hole transport layer, electron blocking layer, light-emitting layer, electron transport layer, and electron injection layer are organic functional layers located between the anode and the cathode. The lowest unoccupied molecular orbital (LUMO) level of the n-type conductive polymer in the composite transparent conductive electrode matches the highest occupied molecular orbital (HOMO) level of the p-type material to form a pn heterojunction.

[0035] Specifically, the pn heterojunction formed at the interface between the n-type conductive polymer and the p-type material in the hole injection layer can bypass the high injection barrier caused by traditional energy level mismatch, thus achieving a highly efficient hole injection effect.

[0036] Preferably, the hole injection layer is a heavily p-doped hole injection layer.

[0037] Preferably, the p-type material comprises a p-type hole transport matrix material and a strong electron acceptor dopant; the p-type hole transport matrix material comprises N,N,N',N'-Tetra(4-methoxyphenyl)benzidine (MeO-TPD), 4,4',4''-tris( N 3-Methylphenyl-N-phenylamino)triphenylamine (m-MTDATA) N,N' -diphenyl- N,N' -Di(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB), 4,4'-cyclohexylidene bis[ N,N [-Di(4-methylphenyl)aniline] (TAPC), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), poly[ N,N' -bis(4-butylphenyl)- N,N' At least one of [-bis(phenyl)-benzidine] (Poly-TPD); the strong electron acceptor dopant includes at least one of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinone dimethyl ether (F4TCNQ), 2,2'-(perfluoronaphthalene-2,6-dimethylethylene)dimalononitrile (F6TCNNQ), and tris[1,2-bis(trifluoromethyl)ethylene-1,2-dithionene]molybdenum (Mo(tfd)3).

[0038] Preferably, the doping concentration of the hole injection layer is 3.5-4.5 wt%; for example, 3.5 wt%, 4 wt%, 4.5 wt%, etc.

[0039] Specifically, the doping concentration of the hole injection layer is the mass fraction of a strong electron acceptor material (such as F4TCNQ) to a p-type hole transport matrix material (such as MeO-TPD or m-MTDATA); the Fermi level of the material is lowered by heavy p-doping to match the energy level of the adjacent n-type conductive polymer.

[0040] Preferably, the hole transport layer comprises: N,N'- Diphenyl- N,N' -Di(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB).

[0041] Preferably, the electron blocking layer comprises 4,4',4''-tris(carbazole-9-yl)triphenylamine (TCTA).

[0042] Preferably, the composition of the light-emitting layer includes bis(2-(2-hydroxyphenyl)pyridine)beryllium and tris(2-phenylpyridine)iridium(III) (Bepp2:Ir(ppy)3). Preferably, the doping concentration of the light-emitting layer is 4.5-5.5 wt%; for example, 4.5 wt%, 5 wt%, 5.5 wt%, etc.

[0043] Specifically, the doping concentration of the light-emitting layer is the mass fraction of Ir(ppy)3 to Bepp2.

[0044] Preferably, the electron transport layer comprises bis(2-(2-hydroxyphenyl)pyridine)beryllium (Bepp2).

[0045] Preferably, the composition of the electron injection layer includes lithium fluoride (LiF).

[0046] Preferably, the cathode comprises an aluminum cathode.

[0047] Compared with the prior art, the beneficial effects of the technical solution provided by the present invention are as follows: This invention utilizes an n-type conductive polymer to form a pn heterojunction with a heavily p-doped hole injection layer. This heterojunction, acting as a charge generation layer, forms an extremely narrow depletion region and a steep bandgap under forward bias. Through interband tunneling, it successfully bypasses the injection barrier caused by the low work function, thus overcoming the high injection barrier associated with traditional low work functions and achieving highly efficient hole injection. Simultaneously, the n-type conductive polymer can penetrate into the metal nanowire network, filling the gaps and increasing the contact area at nanowire intersections. This significantly reduces surface roughness and sheet resistance while maintaining transmittance, greatly improving the mechanical bending stability of the electrode.

[0048] The specific beneficial effects are as follows: (1) Excellent interface smoothing: n-type conductive polymer effectively fills the gaps in the Ag NWs network, and the roughness of the composite transparent conductive electrode is significantly reduced from 30nm in pure Ag NWs to a minimum of 6nm, which greatly reduces the risk of device leakage and short circuit.

[0049] (2) Significantly reduced sheet resistance and quality factor (FoM): The n-type conductive polymer can penetrate into the Ag NWs network, filling the voids and increasing the contact area at the nanowire intersections, thereby effectively reducing contact resistance. At low concentrations (3 mg / mL), the transmittance of the composite transparent conductive electrode remains at 94%, the sheet resistance drops to 18 Ω / sq, and the FoM value reaches as high as 338, far superior to pure Ag NWs (FoM=113). At the highest concentration, the composite film achieves a minimum sheet resistance of 12 Ω / sq.

[0050] (3) Excellent mechanical bending stability: The composite transparent conductive electrode of this invention maintains its resistance unchanged after 10,000 bends with a bending radius of 2.5 mm. In contrast, the resistance of pure Ag NWs increases by a factor of two, while the resistance of ITO increases by more than an order of magnitude.

[0051] (4) Unique injection mechanism: Utilizing the n-type characteristics of the n-type conductive polymer, a unique pn heterojunction is achieved with the p-type doped hole injection layer, which can achieve a similar function to the charge generation layer and achieve a highly efficient hole injection effect that ignores the high energy difference.

[0052] (5) High-efficiency device performance: The OLED device based on the composite transparent conductive electrode of this invention has a turn-on voltage as low as 2.4V (comparable to ITO devices) and the highest current efficiency (CE) max It reaches 61.5 cd / A, and the light emission is uniform with no dark spots. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the preparation process of the composite transparent conductive electrode in Embodiment 1 of the present invention; Figure 2 These are scanning electron microscope (SEM) images of the composite transparent conductive electrodes of Examples 1-4 and the electrode of Comparative Example 1 of the present invention. Figure 3 Atomic force microscopy images of the composite transparent conductive electrodes of Examples 1-4, Comparative Example 1, and Comparative Example 3 of the present invention; Figure 4 Transmittance diagrams of the composite transparent conductive electrodes of Examples 1-4 and Comparative Examples 1-2 of the present invention; Figure 5 The sheet resistance and transmittance diagrams of the composite transparent conductive electrodes of Examples 1-4, Comparative Examples 1-2, and Comparative Example 4 are shown below. Figure 6 The Raman spectra of the electrodes of Embodiment 1, Comparative Example 1, and Comparative Example 4 of the present invention are shown below. Figure 7 The ultraviolet photoelectron spectra of the electrodes of Embodiment 1, Comparative Example 1, and Comparative Example 4 of the present invention are shown below. Figure 8 The X-ray photoelectron spectra of the electrodes in Embodiment 1 and Comparative Example 1 of this invention are shown below. Figure 9 This is a schematic diagram of the HOD device structure of the present invention; Figure 10 The graphs show the electrical characteristics of HOD devices with different anode materials according to the present invention. Figure 11 This is a schematic diagram showing the energy level alignment of HOD devices with different anode materials according to the present invention; Figure 12 This is a schematic diagram of the metal-insulator-semiconductor capacitor structure of the present invention; Figure 13 This is a capacitance-voltage characteristic curve of the capacitor of the present invention; Figure 14 This is a schematic diagram of the OLED device structure using glass as a substrate according to the present invention; Figure 15This is a current density-voltage-brightness curve of the OLED device with electrodes in Embodiment 3, Comparative Example 1, and 3 of the present invention; Figure 16 The current density-voltage-brightness curves of the OLED devices with electrodes in Embodiments 1-4 and Comparative Examples 1-2 of this invention are shown. Figure 17 This is a luminous efficiency-brightness curve of the OLED device composed of three electrodes in Embodiment 3, Comparative Example 1, and Example 2 of the present invention. Figure 18 The luminous efficiency-brightness curves are shown for the OLED devices composed of electrodes in Embodiments 1-4 and Comparative Examples 1-2 of this invention. Figure 19 This is an optical electroluminescence diagram of the OLED light-emitting region using glass as a substrate in this invention. Figure 20 The current density-voltage-brightness curves are shown for the flexible OLED devices composed of electrodes in Embodiments 1-4 and Comparative Examples 1-2 of this invention. Figure 21 The graphs show the luminous efficiency-brightness curves of the flexible OLED devices with electrodes from Embodiments 1-4 and Comparative Examples 1-2 of this invention. Figure 22 The images show the optical and electroluminescence properties of the flexible OLED device before and after 30 bending cycles in Embodiment 3 and Comparative Example 1 of this invention. Figure 23 This is a graph showing the resistance change of different electrodes in the flexible OLED device of the present invention after 10,000 bending cycles. Figure 24 The images show scanning electron microscope (SEM) images of the electrodes of Example 4 and Comparative Example 2 after the flexible OLED device of the present invention has been bent 10,000 times. Detailed Implementation

[0054] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0055] Unless otherwise specified, the raw materials, reagents or devices used in the following examples are available from conventional commercial sources or can be obtained by existing known methods.

[0056] Example 1 This embodiment provides a method for preparing a composite transparent conductive electrode, the specific steps of which are as follows: (1) A 5% (w / w) Ag NWs ethanol dispersion was spin-coated onto a clean glass substrate. The Ag NWs had a diameter of 20 nm and an aspect ratio of 500-2000. The coating amount of the Ag NWs ethanol dispersion was 25 μL / cm. 2This results in the Ag NWs film having an areal density of 0.1 g / m³. 2 Subsequently, it was heat-annealed at 60°C for 15 minutes to form a pure Ag NWs network film with voids, namely a conductive framework layer. (2) A 3 mg / mL n-type conductive polymer (PBFDO:PEOx) ethanol solution was spin-coated onto the Ag NWs network film obtained in step (1), with a coating amount of 25 μL / cm. 2 The polymer was heat-annealed at 100℃ for 15 minutes to penetrate and fill the gaps, and then cured to obtain a polymer-filled layer. The conductive skeleton layer and the polymer-filled layer constitute a composite transparent conductive electrode (Ag NWs / PBFDO:PEOx composite electrode) with a thickness of 37nm.

[0057] Example 1: A schematic diagram of the fabrication process of the composite transparent conductive electrode is shown below. Figure 1 As shown.

[0058] Example 2 The only difference between Example 2 and Example 1 is that the concentration of the n-type conductive polymer solution in Example 2 is 5 mg / mL, while the rest is the same as in Example 1, and the thickness of the composite transparent conductive electrode is 37 nm.

[0059] Example 3 The only difference between Example 3 and Example 1 is that the concentration of the n-type conductive polymer solution in Example 3 is 8 mg / mL and the thickness is 46 nm. The rest is the same as in Example 1, and the thickness of the composite transparent conductive electrode is 46 nm.

[0060] Example 4 The only difference between Example 4 and Example 1 is that the concentration of the n-type conductive polymer solution in Example 4 is 12 mg / mL and the thickness is 61 nm. Everything else is the same as in Example 1, and the thickness of the composite transparent conductive electrode is 61 nm.

[0061] Examples 5-9 The only difference between Examples 5-9 and Example 1 is that Examples 5-9 respectively use n-type conductive polymers. N , N' -bis(2-octyldodecyl)naphthalene-1,4,5,8-tetracarboxylic diimide-2,6-diyl]-alternating-[5,5'-(2,2'-bithiophene)]}, poly{[ N , N' -bis(2-hexyldecyl)perylene-3,4,9,10-tetracarboxylic diimide-1,7-diyl]-alternating-[5,5'-(2,2'-bithiophene)]}, poly{[3,7-bis(4-decyltetradecyl)benzo[1,2- b :4,5- b'[difuran-2,6-dione]-alternating-[5,5'-(2,2'-bithiophene)]}, poly{[ N , N' -bis(2-octyldodecyl)naphthalene-1,4,5,8-tetracarboxylic diimide-2,6-diyl]-alternating-[( E )-1,2-Di(thiophen-2-yl)ethylene]}, poly{[ N , N' -Bis(2-(2-(2-(2-methoxyethoxy)ethoxy)ethyl)naphthalene-1,4,5,8-tetracarboxylic acid diimide-2,6-diyl]-alternating-[5,5'-(2,2'-bithiophene)]} replaces PBFDO:PEOx in Example 1, and the concentration of the n-type conductive polymer ethanol solution is 4 mg / mL, otherwise the same as in Example 1.

[0062] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not perform step (2) to prepare a pure Ag NWs electrode, while the rest is the same as Example 1.

[0063] Comparative Example 2 Comparative Example 2 uses a traditional ITO electrode.

[0064] Comparative Example 3 The only difference between Comparative Example 3 and Example 1 is that PEDOT:PSS is used as the conductive polymer in step (2) of Comparative Example 3, and the concentration of PEDOT:PSS solution is 1.7wt%. The rest is the same as in Example 1.

[0065] Comparative Example 4 The only difference between Comparative Example 4 and Example 4 is that Comparative Example 4 does not perform step (1), but directly spin-coates a 12 mg / mL n-type conductive polymer (PBFDO:PEOx) ethanol solution onto the substrate. In order to further illustrate the advantages of the composite electrode, the pure film is heated at 300°C for 15 minutes to promote the improvement of conductivity. Other preparation steps are the same as in Example 4, and finally a pure PBFDO:PEOx electrode is obtained.

[0066] Performance testing 1. Observation using scanning electron microscopy and atomic force microscopy Scanning electron microscopy was performed on the composite transparent conductive electrodes of Examples 1-4 and the electrode of Comparative Example 1. The results are as follows: Figure 2 As shown. Atomic force microscopy was used to observe the composite transparent conductive electrodes of Examples 1-4, Comparative Example 1, and Comparative Example 3. The results are as follows. Figure 3 As shown. Among them, Figure 2 , Figure 3In the figure, Ag NWs, thin film I, thin film II, thin film III, and thin film IV represent the electrode of Comparative Example 1 and the composite transparent conductive electrode of Examples 1-4, respectively.

[0067] Depend on Figure 2 As can be seen, the pure Ag NWs network in Comparative Example 1 exhibits a loosely stacked structure, and the exposed Ag NWs tips may pierce the thin organic layer in the OLED device, leading to a short circuit. After coating with PBFDO:PEOx, the voids inside the Ag NWs network gradually fill with increasing PBFDO:PEOx concentration. When the concentration reaches 8 mg / mL, the voids in the film are completely filled (film III), which effectively enhances mechanical stability and photoelectric performance.

[0068] Figure 3 Atomic force microscopy (AFM) images further confirmed the transformation of the surface morphology of the composite transparent conductive electrode. The root mean square roughness (RMS) of the conductive electrode gradually decreased from 30 nm in the uncoated PBFDO:PEOx Ag NWs network to 6 nm in the IV layer of the film when the PBFDO:PEOx concentration was 12 mg / mL, indicating that the interface became smoother. This demonstrates that the coating of the conductive polymer can fill the voids within the Ag NWs network, resulting in a smoother interface. Furthermore, in Comparative Example 3, the RMS roughness of the composite transparent conductive electrode using other types of conductive polymers was 13 nm.

[0069] 2. Transmittance and sheet resistance tests The transmittance of the composite transparent conductive electrodes of Examples 1-4, Comparative Examples 1-2, and Comparative Example 4 was tested using a UV-Vis spectrophotometer (Shimadzu, UV-1900); the sheet resistance of the composite transparent conductive electrodes of Examples 1-4, Comparative Examples 1-2, and Comparative Example 4 was tested using a four-probe sheet resistance meter.

[0070] The transmittance spectra of the composite transparent conductive electrodes of Examples 1-4 and the electrodes of Comparative Examples 1-2 are shown below. Figure 4 As shown. The sheet resistance and transmittance of the composite transparent conductive electrodes of Examples 1-4, Comparative Examples 1-2, and Comparative Example 4 are as follows. Figure 5 As shown. Among them, ITO, Ag NWs, pure PBFDO:PEOx, thin film I, thin film II, thin film III, and thin film IV represent the electrodes of comparative example 2, comparative example 1, comparative example 4, and the composite transparent conductive electrodes of examples 1-4, respectively.

[0071] Depend on Figure 4 and 5It can be seen that, regarding sheet resistance, the sheet resistance of the pure Ag NWs network in Comparative Example 1 is 65 Ω / sq, and the sheet resistance of the pure PBFDO:PEOx electrode in Comparative Example 4 is 94 Ω / sq. When the highest concentration of PBFDO:PEOx is used, the film IV exhibits the lowest sheet resistance value (12 Ω / sq). That is, the sheet resistance of the pure Ag NWs electrode in Comparative Example 1 and the pure PBFDO:PEOx electrode in Comparative Example 4 is significantly higher than that of the composite transparent conductive electrode of this invention. This indicates that the synergistic effect between the conductive polymer and Ag NWs in the composite transparent conductive electrode can significantly reduce the sheet resistance. Because the Ag NWs network in the composite transparent conductive electrode provides high-mobility electron transport channels, the addition of PBFDO:PEOx can fill its gaps, making the Ag NWs more tightly bound, thereby increasing the contact area at the Ag NWs interface and reducing the contact resistance. At the same time, the ordered rigid conjugated backbone of PBFDO:PEOx provides an additional conductive path for the electrode through intramolecular π-π stacking.

[0072] Regarding transmittance, as the concentration of PBFDO:PEOx increases, the transmittance of the composite transparent conductive electrode in Examples 1-4 at a wavelength of 550nm decreases from 94% to 86%, but it is still higher than the transmittance of the pure PBFDO:PEOx electrode in Comparative Example 4 (64%).

[0073] To further evaluate the performance of the composite transparent conductive electrode through the factor of quality (FoM), which is defined as the DC conductivity (σ) dc ) and optical conductivity (σ opt The ratio of ) can be calculated using the following equation: FoM = ; Where T is the optical transmittance at a wavelength of 550 nm (T 550nm ), R s Z0 is the sheet resistance of the electrode, and Z0 is the free space impedance. ).

[0074] The transmittance, sheet resistance, and quality factor of the composite transparent conductive electrodes of Examples 1-4, Comparative Examples 1-2, and Comparative Example 4 are shown in Table 1.

[0075] Table 1: Transmittance, Sheet Resistance, and Quality Factor of Composite Transparent Conductive Electrodes in Examples 1-4, Comparative Examples 1-2, and Comparative Example 4

[0076] As shown in Table 1, the optical performance of Ag NWs is significantly improved by combining PBFDO:PEOx. The low concentration of PBFDO:PEOx solution (3 mg / mL) has little effect on transmittance (only decreasing from 95% to 94%), while effectively increasing the contact area between silver nanowires, reducing the sheet resistance from 65 Ω / sq in Comparative Example 1 to 18 Ω / sq in Example 1, thereby increasing its quality factor from 113 for pure Ag NWs to 338 for film I in Example 1. With increasing PBFDO:PEOx concentration, the sheet resistance of the composite transparent conductive electrode continues to decrease. However, the increased thickness of the composite transparent conductive electrode during this process enhances light absorption, leading to a decrease in the quality factor. Although the FoM value of film IV in Example 4 decreases to 199, it is still significantly better than that of pure Ag NWs (113). It is noteworthy that the performance of film I in Example 1 and film II in Example 2 is comparable to that of state-of-the-art multilayer silver nanowire electrodes. These results demonstrate that by striking a balance between high electrical conductivity and optical transparency, the silver nanowire / PBFDO:PEOx composite film meets the stringent requirements of flexible OLED electrodes.

[0077] 3. Raman spectroscopy, ultraviolet photoelectron spectroscopy (UPS spectroscopy), and X-ray photoelectron spectroscopy (XPS) tests Raman spectra of the samples were acquired using a Raman microscope (Horiba Jobin Yvon, LabRAM Odyssey); elemental composition and valence band information of the samples were analyzed using X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) on a Kratos Axis Supra+ instrument. The interaction mechanism and electronic properties of the AgNWs / PBFDO:PEOx composite transparent conductive electrode were investigated using Raman spectroscopy, XPS, and UPS.

[0078] The Raman spectra and ultraviolet photoelectron spectra of the electrodes of Example 1, Comparative Example 1, and Comparative Example 4 are as follows: Figure 6 , Figure 7 As shown, the X-ray photoelectron spectra of the electrodes in Example 1 and Comparative Example 1 are as follows. Figure 8 As shown. Figure 6 , 7 In Example 1, Comparative Example 1, and Comparative Example 4, Ag NWs / PBFDO:PEOx, Ag NWs, and PBFDO:PEOx respectively represent Example 1, Comparative Example 1, and Comparative Example 4.

[0079] Figure 6 Raman spectroscopy measured at a 785 nm excitation laser wavelength showed that the pure PBFDO:PEOx electrode and the Ag NWs / PBFDO:PEOx composite transparent conductive electrode had the same characteristic vibrational peaks, indicating that the molecular backbone of PBFDO:PEOx remained intact and no new covalent bonds were formed.

[0080] Figure 7 UPS spectroscopy shows that the operating function (4.44 eV) of the Ag NWs / PBFDO:PEOx composite transparent conductive electrode is comparable to that of the pure PBFDO:PEOx electrode (4.42 eV) and is 0.48 eV higher than that of pure Ag NWs (3.98 eV). However, a significant energy barrier still exists relative to the highest unoccupied molecular orbital energy level of the high charge injection layer (HIL), limiting efficient hole injection. To address this, based on the n-type characteristics of PBFDO:PEOx, we introduce a p-type doped hole injection layer to construct a unique pn heterojunction, generating a charge generation layer-like effect, thereby bypassing the high energy level barrier and achieving efficient hole injection.

[0081] Figure 8 XPS spectroscopy revealed that the Ag 3d binding energy on Ag NWs shifted by about 0.6 eV towards higher binding energy after mixing with PBFDO:PEOx. This is because the Fermi level equilibrium process promotes electron transfer from Ag NWs to PBFDO:PEOx, which effectively reduces the interfacial contact resistance and promotes charge transfer.

[0082] 4. Research on the mechanism of hole injection The hole injection mechanism was verified by constructing a hole-only device (HOD). Its structure is an anode / P-type doped hole injection layer / cathode (i.e., anode / MeO-TPD:F4TCNQ / Al). A schematic diagram of the HOD device structure is shown below. Figure 9 As shown. The electrodes of Comparative Example 1, Comparative Example 2, and Example 3 were used as anodes to form HOD devices, and then the electrical characteristics and the highest occupied molecular orbital (HOMO) energy levels of MeO-TPD were measured.

[0083] Electrical characteristics testing: The electrical characteristics were tested using a system consisting of a Keithley 2400 digital source meter, a silicon photodiode, and a preamplifier (HB-831B), and the electrical characteristic curves were obtained. JV Characteristic curves); MeO-TPD HOMO level determination: The highest occupied molecular orbital (HOMO) energy levels of organic materials were characterized by cyclic voltammetry (CV) using an electrochemical workstation (CHI 610E). Test conditions: dichloromethane was used as the solvent, with 0.1 M tetrabutylammonium hexafluorophosphate (Bu4NPF6) as the supporting electrolyte; the scan rate was 50 mV / s. -1 Electrode system: platinum wire as auxiliary electrode, glassy carbon electrode as working electrode, Ag / Ag + This is the reference electrode. Energy level calculation: The HOMO energy level is calculated using the following formula: HOMO = [E ox -E 1 / 2(Fc / Fc + )+4.8]eV, where E ox The initial oxidation potential is Fc / Fc. + (4.8eV) is the calibration value for ferrocene.

[0084] HOD devices with different anode materials JV Characteristic curves as follows Figure 10 As shown. Among them, Ag NWs / PBFDO:PEOx, Ag NWs, and ITO represent the HOD devices composed of electrodes in Example 3 and Comparative Examples 1-2, respectively.

[0085] A schematic diagram of energy level alignment for HOD devices with different anode materials is shown below. Figure 11 As shown.

[0086] Depend on Figure 10 It can be seen that the HOD based on pure Ag NWs exhibits a high on-state voltage and significantly suppressed current under low bias voltage. This is because its low work function leads to a large Schottky barrier at the interface, thus limiting carrier injection. However, the HOD based on the Ag NWs / PBFDO:PEOx composite transparent conductive electrode exhibits conductivity comparable to that of the ITO reference device. Unlike ITO, which relies on heavily doped p-type materials to thin the Schottky barrier and achieve surface tunneling, the composite transparent conductive electrode of this invention utilizes the pn heterojunction as a charge-generating layer to achieve hole injection, effectively avoiding the significant energy level mismatch problem. Under forward device bias, this interface is in an effective reverse bias state. Theoretically, the relatively low work function of n-type conductive polymers is not suitable as an anode, but this invention, through the Ag NWs / PBFDO:PEOx composite and the pn heterojunction, achieves efficient injection while promoting surface flatness.

[0087] like Figure 11 As shown, high doping levels induce narrow depletion regions and steep band bends, prompting electrons to tunnel from the highest occupied molecular orbital of p-type HIL to the lowest unoccupied molecular orbital of PBFDO:PEOx. The resulting holes are then further injected into the hole transport layer, thereby achieving efficient hole injection.

[0088] To further clarify the interface quality, this invention fabricated a metal-insulator-semiconductor (MIS) capacitor with an anode / MeO-TPD:F4TCNQ / LiF (50nm) / Al structure. A 50nm thick LiF layer acts as an insulating barrier to suppress DC leakage. A schematic diagram of the structure is shown below. Figure 12As shown, the electrodes of Comparative Example 1 and Example 3 were used as anodes to form capacitors, and then capacitance-voltage (CV) tests were performed. Specifically, the CV characteristics of the metal-insulator-semiconductor capacitors were measured at a frequency of 1 kHz using a semiconductor parameter analyzer (Agilent B1500A).

[0089] The capacitance-voltage characteristic curve of a metal-insulator-semiconductor capacitor is as follows: Figure 13 As shown. Wherein, Ag NWs / PBFDO:PEOx and Ag NWs represent capacitors composed with electrodes of Example 3 and Comparative Example 1 as anodes, respectively.

[0090] Depend on Figure 13 As can be seen, the composite transparent conductive electrode exhibits a higher capacitance value across the entire voltage range, confirming that the conductive polymer effectively fills the voids within the Ag NWs network, thereby maximizing the effective electrical contact area. Furthermore, in the transition region (2.0–5.5 V), the capacitance rise curve of the composite transparent conductive electrode appears earlier and is more significant than that of the pure Ag NWs electrode. This behavior indicates a reduced interface defect density and enhanced carrier accumulation, confirming the excellent injection capability observed in the electrochemical discharge experiments.

[0091] In summary, by optimizing the interface with an n-type polymer and eliminating the injection barrier, the composite transparent conductive electrode of this invention achieves efficient hole injection, making it an ideal anode material for OLED devices.

[0092] 5. Performance testing of OLED devices using transparent glass as a substrate An OLED device is obtained by sequentially stacking a transparent glass, a composite transparent conductive electrode, a hole injection layer (4wt% MeO-TPD:F4TCNQ, 100nm thick), a thick hole transport layer (NPB, 15nm thick), an electron blocking layer (TCTA, 5nm thick), a light-emitting layer (5wt% Bepp2:Ir(ppy)3, 30nm thick), an electron transport layer (Bepp2, 30nm thick), an electron injection layer (LiF, 1nm thick), and a cathode (Al cathode, 200nm thick). A schematic diagram of the OLED device structure is shown below. Figure 14 As shown. The OLED device structure is the same when different electrodes are used as the anode. Figure 14 .

[0093] A system consisting of a Keithley 2400 digital source meter, silicon photodiodes, and a preamplifier (HB-831B) was used to measure the current density, voltage, and brightness of OLED devices with different electrodes as anodes. JVL The characteristics were tested. Examples 3, 1, and 3 show the characteristics of OLED devices composed of electrodes. JVL Characteristic curves as follows Figure 15 As shown, the OLED devices composed of electrodes in Examples 1-4 and Comparative Examples 1-2... JVL Characteristic curves as follows Figure 16 As shown. Among them, Figure 15 In the text, OLED device-AgNWs / PBFDO:PEOx, OLED device-Ag NWs, and OLED device-Ag NWs / PEDOT represent the OLED devices composed of electrodes in Example 3, Comparative Example 1, and Comparative Example 3, respectively. Figure 16 In the text, OLED device I, OLED device II, OLED device III, OLED device IV, OLED device-Ag NWs, and OLED device-ITO represent OLED devices composed of electrodes from Examples 1-4 and Comparative Examples 1-2, respectively.

[0094] The brightness and electroluminescence spectrum of the device were acquired using a spectroradiometer (Konica Minolta, CS-2000), and the luminous efficiency-brightness ratio was obtained. CE-L Characteristic curves. OLED devices composed of electrodes from Examples 3, 1, and 3. CE-L Characteristic curves as follows Figure 17 As shown, OLED device-Ag NWs / PBFDO:PEOx, OLED device-Ag NWs, and OLED device-Ag NWs / PEDOT represent the OLED devices composed of electrodes from Example 3, Comparative Example 1, and Comparative Example 3, respectively. The OLED devices composed of electrodes from Examples 1-4 and Comparative Examples 1-2... CE-L Characteristic curves as follows Figure 18 As shown, the optical electroluminescence image of the OLED light-emitting region is as follows: Figure 19 As shown, OLED device I, OLED device II, OLED device III, OLED device IV, OLED device-AgNWs, and OLED device-ITO represent OLED devices composed of electrodes in Examples 1-4 and Comparative Examples 1-2, respectively; and Figure 19 In the OLED off state, from left to right, are OLED devices composed of electrodes from Examples 1-4 and Comparative Examples 1-2.

[0095] The relevant performance of OLED devices composed of electrodes as anodes in Examples 1-4 and Comparative Examples 1-3 is shown in Table 2.

[0096] Table 2: Relevant performance of OLED devices composed of electrodes in Examples 1-4 and Comparative Examples 1-3

[0097] Depend on Figure 15-18Table 2 shows that the turn-on voltage of the OLED device using the Ag NWs / PBFDO:PEOx composite transparent conductive electrode as the anode is 2.4V, which is exactly the same as the turn-on voltage of the ITO device, but 0.2V lower than that of the Ag NWs device. Consistent with the analysis results of the pure hole HOD device, the reduction in turn-on voltage strongly demonstrates the existence of a tunneling mechanism at the pn heterojunction. By bypassing the injection barrier through efficient electron tunneling, the composite transparent conductive electrode of this invention achieves hole injection capability comparable to that of the high work function ITO. Simultaneously, in terms of device performance such as current efficiency, thanks to the effective filling of the silver nanowire network and reduction of surface roughness by PBFDO:PEOx and the ingenious pn heterojunction structure, the performance of the OLED devices using the Ag NWs / PBFDO:PEOx composite transparent conductive electrode as the anode in Examples 1-4 is significantly improved. Among them, OLED device III achieves an CE of 61.5 cd / A. max This is comparable to (or even surpasses) the 60.1 cd / A of ITO in devices. However, further increasing the concentration of PBFDO:PEOx (as in Example 4) will reduce CE. max The efficiency decline is attributed to the loss of electrode transmittance caused by the increase in PBFDO:PEOx concentration.

[0098] Depend on Figure 19 As can be seen, the optical images of the Ag NWs OLED devices exhibit numerous dark spots in terms of luminescence uniformity. These dark spots are caused by irregular protrusions formed by the aggregation of silver nanowires. These dark spots disrupt the uniform injection and transport of charge carriers, resulting in non-uniform light emission across the entire luminescent region. With increasing PBFDO:PEOx concentration, the luminescence gradually becomes more uniform. The luminescence uniformity of OLED devices III and IV reaches a level comparable to that of device ITO.

[0099] To further verify the universality of the present invention, OLED devices were fabricated using the composite transparent electrodes of Examples 5-9, and the fabrication methods and structures of the OLED devices were the same as above.

[0100] The relevant performance of the OLED devices composed of composite transparent electrodes in Examples 5-9 is shown in Table 3.

[0101] Table 3: Relevant performance of OLED devices composed of composite transparent electrodes in Examples 5-9

[0102] Since an ideal pn heterojunction can also be formed between the aforementioned n-type conductive polymer and the p-type doped hole injection layer, the interface barrier is effectively reduced, thereby achieving efficient hole injection. Table 3 shows that the OLED devices prepared in Examples 5-9 not only have low turn-on voltages, but also achieve high efficiency at 1000 cd / m². 2 It exhibits excellent operating voltage and current efficiency at low brightness, achieving excellent photoelectric performance comparable to that of Examples 1-4 above, and significantly superior to the devices in the comparative examples.

[0103] 6. Performance testing of OLED devices using flexible PI as a substrate The structure of OLED devices using flexible PI as a substrate is the same as that of OLED devices using transparent glass as a substrate, except for the different substrate.

[0104] The same method as described above was used to test flexible OLED devices composed of different electrodes as anodes. JVL The characteristics were tested in the flexible OLED devices composed of electrodes in Examples 1-4 and Comparative Examples 1-2. JVL Characteristic curves as follows Figure 20 As shown. The brightness and electroluminescence spectra of flexible OLED devices with different electrode compositions were tested using the same method as described above. Examples 1-4 and Comparative Examples 1-2 show the results of testing the flexible OLED devices with electrode compositions. CE-L Characteristic curves as follows Figure 21 As shown. Example 3, Comparative Example 1: Optical and electroluminescent images of the flexible device before and after 30 bending cycles. Figure 22 As shown. Figure 20 , 21 In the text, flexible OLED I, flexible OLED II, flexible OLED III, flexible OLED IV, flexible OLED-Ag NWs, and flexible OLED-ITO represent flexible OLED devices composed of electrodes as anodes in Examples 1-4 and Comparative Examples 1-2, respectively. Figure 22 In the text, Flexible OLED III and Flexible OLED-AgNWs represent flexible OLED devices composed of electrodes as anodes in Example 3 and Comparative Example 1, respectively.

[0105] The resistance change of different electrodes in a flexible OLED device after 10,000 bends (the ratio of the sheet resistance measured after 10,000 bends to the original sheet resistance) is shown in the curve. Figure 23 As shown, thin film I, thin film II, thin film III, thin film IV, thin film-Ag NWs, and thin film-ITO represent electrodes of Examples 1-4 and Comparative Examples 1-2, respectively. Scanning electron microscope (SEM) images of the electrodes of Example 4 and Comparative Example 2 after the flexible OLED device has undergone 10,000 bending cycles are shown below. Figure 24 As shown, thin film IV and ITO represent electrodes of Example 4 and Comparative Example 2, respectively.

[0106] The relevant performance of flexible OLED devices composed of electrodes as anodes in Examples 1-4 and Comparative Examples 1-2 is shown in Table 4.

[0107] Table 4: Relevant performance of flexible OLED devices composed of electrodes from Examples 1-4 and Comparative Examples 1-2

[0108] Figure 20 , 21 Table 4 compares the performance of flexible OLEDs with different anode compositions. JVL Characteristic curves and the relationship between luminous efficiency and brightness. Due to the absorption of green light by the yellow PI substrate, the light intensity of the flexible device is lower than that of the rigid device, resulting in a decrease in its luminous efficiency. Among flexible devices, the performance of flexible OLED IV is comparable to that of flexible OLED-ITO, and significantly better than that of flexible OLED-Ag NWs. The maximum luminous efficiency of the device using composite electrodes in this invention is comparable to that of flexible OLED-ITO (CE). max =39.5%), which is comparable to the highest luminous efficiency of OLED III, which is 42%.

[0109] Figure 22 It can be seen that the flexible OLED III using Ag NWs / PBFDO:PEOx composite transparent conductive electrode still maintains uniform light emission after 30 bending cycles, while the flexible OLED with pure Ag NWs anode shows obvious black spots due to electrode breakage or local current leakage during bending.

[0110] Figure 23 The bending stability of different electrodes on a flexible PI substrate was evaluated by the resistance ratio (R / R0) before and after bending (bending radius of 2.5 mm). The pure Ag NWs electrode exhibited a significant degradation, with its resistance doubling after 10,000 bending cycles. The stability of the composite electrode was significantly improved thanks to the synergistic effect of the aforementioned conductive polymer PBFDO:PEOx. After 10,000 bending cycles, the resistance of the composite transparent conductive electrode in Example 1 increased by 30%, attributed to insufficient PBFDO:PEOx content to completely immobilize the silver nanowires, leading to localized deformation of the composite electrode during bending. With increasing PBFDO:PEOx concentration, the composite transparent conductive electrodes in Examples 2-4 exhibited excellent stability, maintaining a constant resistance after 10,000 bending cycles. In contrast, due to the brittle nature of ITO, the resistance of the ITO electrode increased by more than 11 times after 10,000 bending cycles. Furthermore, due to… Figure 24Scanning electron microscopy (SEM) analysis following the bending test revealed that the composite transparent conductive electrode surface remained intact, while cracks appeared on the ITO electrode surface. This indicates that the Ag NWs / PBFDO:PEOx composite film is more suitable for next-generation flexible OLED applications than the brittle ITO.

[0111] In summary, this invention utilizes an n-type conductive polymer to infiltrate the interior of a metal nanowire network, filling the voids and increasing the contact area at nanowire intersections. While maintaining transmittance, it significantly reduces surface roughness and sheet resistance, and greatly improves the mechanical bending stability of the electrode. Furthermore, when used as the anode in OLED devices, it leverages the n-type properties of the n-type conductive polymer in the composite transparent electrode to construct a pn heterojunction with a heavily p-doped hole injection layer. This heterojunction, acting as a charge generation layer, forms an extremely narrow depletion region and a steep bandgap under forward bias. Through interband tunneling, it successfully bypasses the injection barrier caused by the low work function, thus overcoming the traditional high injection barrier associated with low work functions. This achieves highly efficient hole injection in OLED devices, making it an ideal anode material for OLED devices.

[0112] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A composite transparent conductive electrode, characterized in that, The composite transparent conductive electrode comprises a conductive framework layer and a polymer filling layer stacked sequentially. The conductive framework layer includes a metal nanowire network; The polymer in the polymer-filled layer fills the voids in the metal nanowire network; The polymer is an n-type conductive polymer.

2. The composite transparent conductive electrode according to claim 1, characterized in that, The metal nanowire network includes silver nanowire network, copper nanowire network, gold nanowire network, and metal nanowire-oxide core-shell network; And / or, the n-type conductive polymer comprises poly(3,7-dihydrobenzo[1,2-]) b :4,5- b' Difuran-2,6-dione): Poly(2-ethyl-2-oxazoline), Poly{[ N , N' -bis(2-octyldodecyl)naphthalene-1,4,5,8-tetracarboxylic diimide-2,6-diyl]-alternating-[5,5'-(2,2'-bithiophene)]}, poly{[ N , N' -bis(2-hexyldecyl)perylene-3,4,9,10-tetracarboxylic diimide-1,7-diyl]-alternating-[5,5'-(2,2'-bithiophene)]}, poly{[3,7-bis(4-decyltetradecyl)benzo[1,2- b :4,5- b' [difuran-2,6-dione]-alternating-[5,5'-(2,2'-bithiophene)]}, poly{[ N , N' -bis(2-octyldodecyl)naphthalene-1,4,5,8-tetracarboxylic diimide-2,6-diyl]-alternating-[( E )-1,2-Di(thiophen-2-yl)ethylene]}, poly{[ N , N' At least one of bis(2-(2-(2-(2-methoxyethoxy)ethoxy)ethyl)naphthalene-1,4,5,8-tetracarboxylic acid diimide-2,6-diyl]-alternating-[5,5'-(2,2'-bithiophene)]}.

3. The composite transparent conductive electrode according to claim 1, characterized in that, The diameter of the nanowires in the metal nanowire network is 10-30 nm; and / or, the aspect ratio of the nanowires in the metal nanowire network is greater than 300.

4. The composite transparent conductive electrode according to any one of claims 1-3, characterized in that, The root mean square surface roughness of the composite transparent conductive electrode is ≤30nm; And / or, at a wavelength of 550 nm, the transmittance of the composite transparent conductive electrode is ≥80%; And / or, the sheet resistance of the composite transparent conductive electrode is ≤100Ω / sq.

5. The method for preparing the composite transparent conductive electrode according to any one of claims 1-4, characterized in that, The preparation method includes the following steps: (1) The metal nanowire dispersion was coated on the substrate and annealed to obtain a conductive framework layer; (2) The n-type conductive polymer dispersion is coated on the conductive skeleton layer and annealed to obtain a polymer filling layer. The conductive skeleton layer and the polymer filling layer constitute the composite transparent conductive electrode.

6. The preparation method according to claim 5, characterized in that, In step (1), the mass fraction of the metal nanowire dispersion is 4-6%; and / or, the annealing temperature is 60-100℃ and the annealing time is 10-20min.

7. The preparation method according to claim 5, characterized in that, In step (2), the concentration of the n-type conductive polymer dispersion is 2-30 mg / mL; and / or, the solvent in the n-type conductive polymer dispersion includes at least one of water, alcohol solvents, chlorobenzene, xylene, and chloroform; and / or, the annealing temperature is 80-150℃ and the annealing time is 10-20 min.

8. An organic light-emitting diode device, characterized in that, The organic light-emitting diode device includes a substrate, an anode, a cathode, and an organic functional layer disposed between the anode and the cathode, which are stacked in sequence; the anode is the composite transparent conductive electrode as described in any one of claims 1-4.

9. The organic light-emitting diode device according to claim 8, characterized in that, The organic functional layer includes at least a hole injection layer; the hole injection layer includes a p-type material.

10. The organic light-emitting diode device according to claim 9, characterized in that, The organic light-emitting diode device includes a substrate, a composite transparent conductive electrode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode, which are stacked sequentially. The lowest unoccupied molecular orbital energy level of the n-type conductive polymer in the composite transparent conductive electrode matches the highest occupied molecular orbital energy level of the p-type material to form a pn heterojunction. And / or, the p-type material comprises a p-type hole transport matrix material and a strong electron acceptor dopant; the p-type hole transport matrix material comprises N,N,N',N'- Tetra(4-methoxyphenyl)benzidine, 4,4',4''-tris( N -3-Methylphenyl- N -Phenylan)triphenylamine, N,N' -diphenyl- N,N' -Di(1-naphthyl)-1,1'-biphenyl-4,4'-diamine, 4,4'-cyclohexylidene bis[ N,N [-Di(4-methylphenyl)aniline], poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], poly[ N,N' -bis(4-butylphenyl)- N,N' At least one of [-bis(phenyl)-benzidine]; the strong electron acceptor dopant includes at least one of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinone dimethyl ether, 2,2'-(perfluoronaphthalene-2,6-dimethylethylene)dimalonitrile, and tris[1,2-bis(trifluoromethyl)ethylene-1,2-dithione]molybdenum.

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