Full-spectrum transparent conductive film material and preparation method thereof
By employing a quasi-continuous homologous nanocrystalline reinforced amorphous composite structure in transparent conductive films, the problem of balancing the performance of full-spectrum transparent conductive film materials in the visible and infrared bands has been solved, achieving the integration of high transparency and high conductivity.
Patent Information
- Application Number
- CN202511719145.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-21
- Publication Date
- 2026-02-06
AI Technical Summary
Existing transparent conductive film materials struggle to achieve both high transmittance and high conductivity across the entire spectrum, especially in the visible and infrared bands.
A quasi-continuous homologous nanocrystal-reinforced amorphous composite structure is adopted, which includes CuSe1+x amorphous regions as transparent substrates and CuSe1-y nanocrystals as conductive reinforcing phases. A thin film with a thickness of 20-40 nm is formed by magnetron sputtering and thermal annealing. The nanocrystals are quasi-continuously distributed laterally in the film and separated by amorphous particles.
It achieves high transparency and high conductivity across the entire spectrum. The distribution of nanocrystals optimizes the carrier percolation channels and suppresses absorption and reflection, thus integrating full-band transparency and conductivity.
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Figure CN121483716A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of optoelectronic thin film materials technology, specifically relating to a full-spectrum transparent conductive thin film material and its preparation method. Background Technology
[0002] Transparent conductive films (TCFs) are key foundational materials for many optoelectronic systems, including displays, imaging, photovoltaics, infrared / microwave fusion sensing, and electromagnetic protection. Traditional TCF research primarily focuses on the visible-near-infrared (400–2000 nm) window, and various oxide transparent conductive materials, such as ITO (In₂O₃:Sn), AZO (ZnO:Al), and FTO (SnO₂:F), have been commercially available on a large scale. However, achieving both high transmittance and high conductivity across the broader full spectrum (400–12000 nm) remains a challenge, lacking mature materials and processing systems. This significantly limits the development of next-generation light-emitting, detection, and human therapeutic technologies. Therefore, developing a thin film material that combines full-spectrum transparency and conductivity is a pressing issue in this field. The technological bottleneck stems from the different physical mechanisms in different spectral regions.
[0003] For the visible light band (400–800 nm), it is necessary to suppress interband transition absorption, and the optical bandgap of the material should satisfy Eg ≥ 3.5 eV to achieve high transmittance. However, traditional doping methods introduce defect and ionized impurity scattering, reducing mobility; at the same time, they also introduce subbandgap absorption centers, further impairing transparency.
[0004] For the infrared band (0.8–12 μm), transmittance is mainly affected by the plasma wavelength (λ). p The limitation of plasma wavelength (λ) p The relationship between electrical conductivity (σ) and electrical conductivity (σ) can be described by the following two formulas:
[0005]
[0006]
[0007] Where C0 is the speed of light in vacuum, m* is the effective mass of a hole, ε0 is the vacuum permittivity, and ε ∞ τ is the optical frequency dielectric constant, n is the carrier concentration, e is the unit charge, and τ is the relaxation time.
[0008] To achieve infrared transparent conductivity, an ideal infrared transparent conductor should simultaneously possess a large λ. p And a large σ. Most existing transparent conductive materials achieve this by adjusting n / m*, but compared with the above formula, it is difficult to achieve a balance between transparency and conductivity.
[0009] In view of this, the inventors aim to provide a novel transparent conductive material that simultaneously possesses high full-spectrum transparency and high electrical conductivity. Summary of the Invention
[0010] The purpose of this invention is to overcome the above-mentioned problems existing in the conventional technology and to provide a full-spectrum transparent conductive thin film material and its preparation method.
[0011] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution:
[0012] This invention provides a full-spectrum transparent conductive thin film. The thin film material is a quasi-continuous homologous nanocrystalline reinforced amorphous composite structure, specifically comprising:
[0013] As an amorphous transparent matrix, the amorphous regions of the transparent matrix have a chemical composition of CuSe. 1+x , where x = 0.8 to 1; the composition of the entire amorphous region is uniform, exhibiting an amorphous structure;
[0014] As a conductive enhancement phase within the crystalline phase, the crystalline region of the conductive enhancement phase is composed of nanocrystals with space group Fm-3m, and the chemical composition of the nanocrystals is CuSe. 1-y , where y = 0.4 to 0.6.
[0015] Furthermore, in the aforementioned full-spectrum transparent conductive film, the amorphous region in the transparent substrate is composed of amorphous regions with a Cu:Se ratio of 1:2.
[0016] Furthermore, in the aforementioned full-spectrum transparent conductive film, the conductive and conductivity-enhancing phase is composed of p-type conductive Cu2Se nanocrystals arranged in a standard stoichiometric ratio.
[0017] Furthermore, in the above-mentioned full-spectrum transparent conductive film, the transparent substrate and the conductivity enhancer are homologous compounds.
[0018] Furthermore, in the aforementioned full-spectrum transparent conductive thin film, the total thickness of the composite structure is 20–40 nm, CuSe 1-y Nanocrystals in amorphous CuSe 1+x The nanocrystals are quasi-continuously distributed along the transverse direction of the thin film in the amorphous matrix, and are separated by amorphous CuSe with a particle size of 1-3 nm. 1+x The spacing is neither a completely continuous conductive layer nor a highly discrete large spacing.
[0019] This invention also provides a method for preparing a full-spectrum transparent conductive thin film, comprising the following steps:
[0020] 1) In the magnetron sputtering coating system, a pure CuSe target is installed in a magnetron RF sputtering target, and a high-purity intrinsic silicon wafer or zinc sulfide wafer is used as the substrate; the substrate is ultrasonically cleaned in acetone, ethanol and deionized water in sequence.
[0021] 2) Evacuate the sputtering chamber of the magnetron sputtering coating system until the vacuum level inside the chamber reaches the required vacuum level, and then introduce high-purity Ar gas into the sputtering chamber until the gas pressure inside the sputtering chamber reaches the ignition gas pressure required for sputtering.
[0022] 3) Control the sputtering power of the pure CuSe target, and the thin film material deposited on the substrate is the CuSe material.
[0023] Furthermore, in step 2), the required vacuum level is 4 × 10⁻⁶. -4 ~6×10 -4 The required ignition pressure is 0.5-1.0 Pa.
[0024] Furthermore, in step 3), the pure CuSe target uses an RF power supply with a sputtering power of 30–70 W.
[0025] Further, in step 3), the sputtering conditions are: target-substrate distance 21.5 cm, substrate temperature RT, working pressure 0.45-0.55 Pa, Ar gas flow rate 40-60 sccm, and sputtering time 1-2 min.
[0026] Furthermore, after depositing the thin film material on the substrate, a high-temperature annealing station is used, with an annealing temperature of 150–250°C and an annealing time of 1–3 min.
[0027] The beneficial effects of this invention are:
[0028] 1. Utilizing copper selenide (CuSe) as a conductive material, which exhibits excellent transmittance across the entire spectrum and high conductivity, a quasi-continuous homogeneous nanocrystalline CuSe was formed by magnetron sputtering and post-processing methods such as thermal annealing on a copper selenide (CuSe) target. 1-y (y=0.4~0.6) / Amorphous CuSe 1+x (x=0.8~1.2) Composite thin film, with amorphous regions serving as the transparent matrix and crystalline regions serving as the conductivity-enhancing phase of the crystalline phase, CuSe. 1-y The nanocrystals, approximately 10 nm in size, are distributed laterally in a quasi-continuous manner within the film, with adjacent nanocrystals separated by 1–3 nm amorphous CuSe. 1+x The spaces are separated to avoid the formation of a completely continuous CuSe. 1-y Conductive layer.
[0029] 2. The quasi-continuous arrangement of nanocrystals provides an effective hole percolation channel by strengthening the short-range coupling of the wave function, thereby achieving high conductivity. On the other hand, by limiting the free carrier volume fraction of Cu2Se below the critical value, the Drude and plasma response are broadened and weakened by geometric dilution and uneven distribution, thus effectively suppressing absorption and reflection in the 3-12μm band.
[0030] 3. Nanocrystals and amorphous substrates are homologous, and the band arrangement and chemical bond characteristics of copper chalcogenides in the same group are more similar, thus achieving a conductive path with a smaller nanocrystal integral number. The inventors have prepared copper selenide (CuSe) thin films, achieving for the first time the integration of full-band transparency and conductivity.
[0031] Of course, any product implementing this invention does not necessarily need to achieve all of the above advantages at the same time. Attached Figure Description
[0032] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0033] Figure 1 The transparent conductivity of CuSe thin films prepared at different annealing temperatures according to the present invention;
[0034] Figure 2 The transparent conductivity of CuSe thin films of different thicknesses prepared in this invention;
[0035] Figure 3 The HTEM and EDS spectra of the CuSe thin film prepared in this invention are shown.
[0036] Figure 4 This is a transmittance diagram of the CuSe thin film prepared according to the present invention. Detailed Implementation
[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0038] Existing paths and limitations:
[0039] 1) Doped wide-bandgap oxides (ITO, IZO, IGZO, etc.): Introducing cation orbital valence bands hybridizes the O 2p orbitals with the transition metal 3d orbitals, enhancing VB dispersion and reducing the effective hole mass. While the introduction of cation orbital valence band modulation improves the conductivity of the thin film and maintains high transmittance, its performance is significantly lower than that of N-type doped oxide semiconductors. Furthermore, the introduction of impurity energy levels reduces transparency in the visible band.
[0040] 2) Two-dimensional materials and ultrathin metals: Graphene / transition metal chalcogenides / ultrathin Au, Ag can achieve transparency in the visible light band, but their extremely high carrier mobility causes strong surface plasmon reflection in the mid-infrared.
[0041] 3) Metal mesh / porous nanonetwork: It can achieve extremely high electrical conductivity, but it introduces scattering and diffraction at the short-wavelength end, and is prone to grating order, phase distortion and aberration at the mid-infrared end, making it difficult to meet the requirements of "imaging-grade" transmission quality and uniform transmission across the entire spectrum.
[0042] 4) Employing high optical frequency dielectric constant ε ∞ Heavy metal chalcogenides: For polycrystalline octahedral coordinated heavy metal chalcogenides (r-Bi2Se) rich in anion vacancies 2.4 r-Bi2Te 2.4 (etc.) possess electron-deficient multicenter bonds and high ε ∞ To achieve high conductivity and a larger λ p It is compatible with optical band gap, but due to its small optical band gap and large interband absorption, it is not transparent to visible light.
[0043] 5) Composite of amorphous matrix and conductive reinforcing phase: Conductive units such as metal nanoparticles, doped semiconductor nanocrystals, MXene or carbon nanotubes are dispersed in a transparent amorphous matrix (oxide, chalcogenide glass or polymer) to achieve compatibility between transparency and conductivity. However, due to the difference in dielectric constant between the transparent phase and the conductive phase, dielectric mismatch and scattering caused by the interface barrier reduce the optical transparency. The completely continuous conductive phase achieves high conductivity, but causes severe Drude absorption and infrared reflection. The completely discrete distribution state leads to low conductivity and performance that is difficult to meet the requirements.
[0044] In summary, the core challenges of achieving full-spectrum transparent conductivity lie in the multi-objective synergy of low optical bandgap interband absorption, low plasmonic reflection and absorption, and high conductivity: increasing the optical bandgap and reducing defect states in the visible light band, while suppressing plasmonic reflection and inhibiting Drude band absorption in the infrared band. Existing material systems struggle to achieve a unified breakthrough in high transmittance and high conductivity across the entire 0.4 μm–12 μm range.
[0045] The innovative ideas of this invention are reflected in the following:
[0046] In the quasi-continuous homologous nanocrystalline CuSe 1-y (x=0.4-0.6) / Amorphous CuSe 1+x In composite films (x = 0.8–1.2), CuSe 1-y The nanocrystals, approximately 10 nm in size, are distributed laterally in a quasi-continuous manner within the film, with adjacent nanocrystals separated by 1–3 nm amorphous CuSe. 1+x The spaces are separated to avoid the formation of a completely continuous CuSe. 1-y Conductive layer. The quasi-continuous arrangement of nanocrystals provides effective hole permeation channels by enhancing the short-range coupling of wave functions, achieving high conductivity. Furthermore, the amorphous spacing confines the free carrier volume fraction of Cu₂Se below the critical value, causing Drude and plasma response to be broadened and weakened by geometric dilution and uneven distribution, thus effectively suppressing absorption and reflection in the 3–12 μm wavelength band. In addition, the nanocrystals and the amorphous matrix are homologous, and the band arrangement and chemical bond characteristics of copper chalcogenides in the same group are more similar, allowing for conductive pathways to be achieved with a smaller nanocrystal integral number. The inventors have prepared a full-wavelength transparent conductive film, achieving for the first time the integration of full-wavelength transparency and conductivity.
[0047] This invention provides a full-spectrum transparent conductive thin film containing cation vacancies. This thin film material is a quasi-continuous homologous nanocrystalline reinforced amorphous composite structure, specifically comprising: a transparent matrix as the amorphous phase and a conductive reinforcing phase as the crystalline phase. The chemical composition of the transparent matrix is CuSe. 1+x (x = 0.8–1.2), the composition of the entire amorphous region is uniform, exhibiting an amorphous structure. The chemical composition of the conductive enhancement phase is CuSe. 1-y (y=0.4~0.6), space group Fm-3m, composed of nanocrystals with an average size of 10nm, CuSe 1-y (x=0.4~0.6) Nanocrystals in amorphous CuSe 1+x The nanocrystals are quasi-continuously distributed along the transverse direction of the thin film in the amorphous matrix, with amorphous CuSe of about 1-3 nm separating them. 1+x The total thickness of the composite structure is 20–40 nm.
[0048] The above-mentioned method for preparing a full-spectrum transparent conductive thin film includes the following steps:
[0049] Using high-purity CuSe as the target source and argon as the discharge gas, the sputtering power of the pure CuSe target was controlled. A zinc sulfide sheet was used as the substrate, and a CuSe film was deposited on the substrate under the set sputtering conditions. The sputtering conditions were: a base vacuum of 4 × 10⁻⁶. -4 -6×10 -4Pa, target-substrate distance 21.5 cm, substrate temperature RT, working pressure 0.45–0.55 Pa, Ar gas flow rate 40–60 sccm, sputtering time 1–2 min.
[0050] Specific embodiments of the present invention are as follows:
[0051] Example 1
[0052] A full-spectrum transparent conductive film:
[0053] This thin film material is a quasi-continuous homologous nanocrystalline reinforced amorphous composite structure, specifically comprising: a transparent matrix as the amorphous phase, the amorphous region consisting of amorphous regions with a Cu:Se ratio of 1:2; and a conductive reinforcing phase as the crystalline phase, the crystalline region consisting of p-type conductive Cu₂Se nanocrystals arranged in a standard stoichiometric ratio. The film thickness is 30 nm.
[0054] The preparation method of the above-mentioned full-band transparent conductive film includes the following steps:
[0055] 1) Set the target-substrate distance to 21.5 cm and the background vacuum to 5 × 10⁻⁶. -4 Pa, sputtering pressure 0.5 Pa, substrate temperature 25℃. Substrate pretreatment before sputtering experiment: Before placing the substrate into the vacuum chamber, it was ultrasonically cleaned with acetone, anhydrous ethanol, and distilled water in sequence, and then dried. Substrate preheating and pre-sputtering: After the vacuum chamber reached the background vacuum level, in order to remove the oxide layer and adsorbed impurities on the target surface, the target was pre-sputtered for 10 min under an argon flow rate of 50.0 sccm.
[0056] 2) Using high-purity CuSe as the target source and argon as the discharge gas, a CuSe film was deposited on a 1.5cm×1.5cm single-crystal silicon (001) substrate. The argon flow rate was 50 sccm. The pure CuSe target was powered by an RF power supply with a sputtering power of 50W. The deposition time was 1.5 min, after which the target sputtering was stopped.
[0057] The composition of the full-band transparent conductive film was determined by EDS spectroscopy (e.g., Figure 3 Through a combination of experimental fabrication, optical simulation, and theoretical calculations, the microscopic mechanism integrating high optical transparency and high conductivity was revealed. The invented infrared transparent conductive film exhibits a conductivity as high as 1158 S / cm, and an average transmittance of approximately 70% in the 0.4-12 μm range (e.g., ...). Figure 4 This is the first time that full-band transparency and conductivity have been compatible, a level of compatibility that no other conductive or transparent film reported to date has achieved.
[0058] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims
1. A full-spectrum transparent conductive thin film, characterized in that, This thin film material is a quasi-continuous homologous nanocrystalline reinforced amorphous composite structure, specifically comprising: As an amorphous transparent matrix, the amorphous regions of the transparent matrix have a chemical composition of CuSe. 1+x , where x = 0.8 to 1; the composition of the entire amorphous region is uniform, exhibiting an amorphous structure; As a conductive enhancement phase within the crystalline phase, the crystalline region of the conductive enhancement phase is composed of nanocrystals with space group Fm-3m, and the chemical composition of the nanocrystals is CuSe. 1-y , where y = 0.4 to 0.
6.
2. The full-spectrum transparent conductive film according to claim 1, characterized in that, The amorphous region in the transparent matrix consists of amorphous regions with a Cu:Se ratio of 1:
2.
3. The full-spectrum transparent conductive film according to claim 1, characterized in that, The conductive enhancement phase is composed of p-type conductive Cu2Se nanocrystals arranged in a standard stoichiometric ratio.
4. The full-spectrum transparent conductive film according to claim 1, characterized in that, The transparent matrix and the conductivity enhancer are homologous compounds.
5. The full-spectrum transparent conductive film according to claim 1, characterized in that, The total thickness of this composite structure is 20–40 nm, CuSe 1-y Nanocrystals in amorphous CuSe 1+x The nanocrystals are quasi-continuously distributed along the transverse direction of the thin film in the amorphous matrix, and are separated by amorphous CuSe with a particle size of 1-3 nm. 1+x interval.
6. The method for preparing a full-spectrum transparent conductive thin film according to claims 1-5, characterized in that, Includes the following steps: 1) In the magnetron sputtering coating system, a pure CuSe target is installed in a magnetron RF sputtering target, and a high-purity intrinsic silicon wafer or zinc sulfide wafer is used as the substrate. 2) Evacuate the sputtering chamber of the magnetron sputtering coating system until the vacuum level inside the chamber reaches the required vacuum level, and then introduce high-purity Ar gas into the sputtering chamber until the gas pressure inside the sputtering chamber reaches the ignition gas pressure required for sputtering. 3) Control the sputtering power of the pure CuSe target, and the thin film material deposited on the substrate is the CuSe material.
7. The preparation method according to claim 6, characterized in that, In step 2), the required vacuum level is 4 × 10⁻⁶. -4 ~6×10 -4 The required ignition pressure is 0.5-1.0 Pa.
8. The preparation method according to claim 6, characterized in that, In step 3), the pure CuSe target uses an RF power supply with a sputtering power of 30–70W.
9. The preparation method according to claim 6, characterized in that, In step 3), the sputtering conditions are as follows: target-substrate distance 21.5 cm, substrate temperature RT, working pressure 0.45-0.55 Pa, Ar gas flow rate 40-60 sccm, and sputtering time 1-2 min.
10. The preparation method according to claim 6, characterized in that, After depositing the thin film material on the substrate, a high-temperature annealing station is used, with an annealing temperature of 150-250℃ and an annealing time of 1-3 minutes.