CN109830545B

CN109830545B - Aluminum-doped zinc oxide film surface modification material, preparation method and battery

Info

Publication number: CN109830545B
Application number: CN201910116789.XA
Authority: CN
Inventors: 孟磊; 杨涛
Original assignee: Institute of Semiconductors of CAS
Current assignee: Institute of Semiconductors of CAS
Priority date: 2019-02-14
Filing date: 2019-02-14
Publication date: 2021-10-15
Anticipated expiration: 2039-02-14
Also published as: CN109830545A

Abstract

The invention provides an aluminum-doped zinc oxide film surface modification material, a preparation method and a battery. The surface modification material is ZnMoO_xFilm, wherein 3 < x < 4, and the ZnMoO_xThe surface work function of the film is 4.3 eV-4.86 eV. The surface modification material of the aluminum-doped zinc oxide transparent conductive film provided by the invention has a stable tunable surface work function in a wide range (3.83eV-4.86eV), and solves the problem that the conventional surface modification technology for increasing the work function of ZnO and Al is difficult to form a stable surface structure so as to ensure the stability of the surface work function. With this ZnMoO_xThe amorphous silicon single-junction thin-film solar cell with the surface-modified aluminum-doped zinc oxide transparent conductive thin film as the anode electrode has the open-circuit voltage of 0.89V, the filling factor of 0.61 and the photoelectric conversion efficiency of 6.54 percent.

Description

Aluminum-doped zinc oxide film surface modification material, preparation method and battery

Technical Field

The disclosure belongs to the technical field of photoelectrons, and particularly relates to an aluminum-doped zinc oxide film surface modification material, a preparation method and a battery.

Background

Transparent conductive oxide films are a very critical material in thin film optoelectronic devices, which have both good conductivity and high transmittance in the visible range. These properties make them widely used in optoelectronic devices such as liquid crystal displays, electroluminescent devices, thin film solar cells, and the like. Fluorine doped tin oxide (SnO)₂: F) and tin-doped indium oxide (In)₂O₃: sn) is a commercially available transparent conductive oxide thin film material that is currently widely used. Both have superior electrical properties, but there are still drawbacks that prevent their use in next generation optoelectronic devices. First, In₂O₃: since Sn uses indium mineral, which is rare in nature, as a raw material, there are problems that the supply of raw materials is not sustainable and the cost of raw materials is high. Second, SnO₂: f and In₂O₃: sn is easy to be reduced by hydrogen plasma, and can negatively influence the performance of the thin film silicon solar cell prepared by the plasma enhanced chemical vapor deposition process; the In or Sn ions or atoms of the metal reduced by the hydrogen plasma may diffuse into the optical absorption layer to deteriorate the device performance.

The aluminum-doped zinc oxide (ZnO: Al) transparent conductive film has the advantages of rich earth crust element content, low raw material cost, no toxicity, high stability in hydrogen plasma environment and the like, thereby being a substitute for SnO₂: f and In₂O₃: a strong candidate for Sn. However, with SnO₂: f and In₂O₃: sn, ZnO: surface on which Al existsThe work function value is low. Depending on the preparation method of the material and the measurement method of the work function, the ZnO which has been disclosed so far: the surface work function value of Al is between 3.7eV and 4.62 eV. SnO₂: f has a surface work function value of 4.50eV or higher, while In₂O₃: the surface work function value of Sn is between 4.3eV and 4.84 eV. Therefore, when ZnO: when Al is used as an anode material for optoelectronic devices such as light emitting diodes or solar cells, the ratio of ZnO: the barrier formed at the interface of Al and the p-type functional layer hinders the injection and extraction processes of hole carriers and degrades the device performance.

The prior method can improve the ZnO: there are three main methods for the surface work function of Al. One is surface cleaning, e.g. acetone and deionized water cleaning ZnO: the Al surface can increase the surface work function by about 3% by removing surface carbon contamination. And for example, argon ion sputtering cleaning can also effectively remove surface carbon pollution and improve the surface work function by about 6 percent. And secondly, ultraviolet light-assisted ozonization treatment or oxygen plasma treatment is adopted, and the surface work function is improved by about 13 percent by changing the proportion of surface component elements and forming active oxygen free radicals. However, these two methods can only convert ZnO: the Al surface work function is increased to about 4.3 eV. Thirdly, organic surface modification materials are used for forming a specific molecular structure or dipole on the surface of ZnO so as to regulate and control the work function of the surface. The method can greatly improve the ZnO: the Al surface work function is up to about 5.6 eV. Methods two and three although significantly improved ZnO: al surface work function, but the surface composition and structure after modification easily and rapidly change under ambient environment to cause the surface work function to decrease. Therefore, how to increase the ratio of ZnO: the problem that researchers in the field need to solve is that the work function of the surface of Al is ensured and the stability of the work function of the surface is ensured at the same time.

Disclosure of Invention

Technical problem to be solved

The existing method for increasing ZnO: the technique of Al surface work function is difficult to form stable surface components and structures to ensure the stability of the surface work function. If these techniques are applied to ZnO: when Al is applied to optoelectronic devices, the instability of the surface work function can cause the problems of the degradation of the device performance and the like.

(II) technical scheme

One aspect of the present invention provides a ZnO: the surface modification material of the Al transparent conductive film is ZnMoO_xFilm, wherein 3 < x < 4, and the ZnMoO_xThe surface work function of the film is 4.3 eV-4.86 eV. Wherein, the ZnMoO_xThe thickness of the film is 28 to 32 nm. The ZnMoO_xThe surface roughness of the film is less than 3 nm.

The ZnO provided by the invention: ZnMoO of Al_xSurface-modified materials by ZnO and MoO_xForm ZnMoO with a specific crystal structure_xThe alloy compound realizes stable tunable surface work function in a wide range (3.83eV-4.86eV), and solves the problems of increasing the ratio of ZnO: the surface modification technology of the Al work function is difficult to form stable surface components and structures so as to ensure the stability of the surface work function.

The invention also provides a preparation method of the aluminum-doped zinc oxide transparent conductive film surface modification material, which is characterized by comprising the following steps: step A: preparing an aluminum-doped zinc oxide transparent conductive film on a glass substrate, and cleaning the surface of the transparent conductive film; and B: growing a molybdenum oxide film on the cleaned aluminum-doped zinc oxide transparent conductive film by using a vacuum evaporation method to obtain ZnMoO on the surface of the aluminum-doped zinc oxide transparent conductive film_xA film.

The preparation method of the aluminum-doped zinc oxide transparent conductive film in the step A comprises the following steps: metal organic chemical vapor deposition, magnetron sputtering, sol-gel, pulsed laser deposition, and spray pyrolysis.

And B, in the preparation method of the molybdenum oxide film in the step B, the model of the vacuum evaporator is Sanvac RD-1250R, and the voltage applied to two ends of a tungsten boat of the vacuum evaporator is 14-16V.

The method further comprises the following steps: and C: carrying out atmospheric heat treatment on the product obtained in the step B to obtain ZnMoO which is positioned on the surface of the aluminum-doped zinc oxide transparent conductive film and is subjected to atmospheric heat treatment_xA film.

ZnMoO after Heat treatment by atmospheric atmosphere_xThe surface work function of the modified film can reach 4.86 eV; stable surface components are obtained due to the formation of crystalline phases, ensuring the stability of the surface work function.

The method further comprises the following steps: step D: c, carrying out nitrogen atmosphere heat treatment on the product obtained in the step C to obtain ZnMoO which is positioned on the surface of the aluminum-doped zinc oxide transparent conductive film and is subjected to atmosphere and nitrogen atmosphere heat treatment_xA film.

ZnMoO after Heat treatment by Nitrogen atmosphere_xThe surface work function of the film after modification can reach 4.85eV, and the film is stable in the ambient environment.

The vacuum degree of the vacuum evaporator adopted in the vacuum evaporation method in the step B is 4.1-4.5 multiplied by 10^-4Pa, the film growth rate of the molybdenum oxide film is 0.08-0.12 nm/s.

The step C comprises the following steps: and C, putting the product obtained in the step B into a heating furnace cavity of an infrared lamp, heating to 350-400 ℃ at a heating rate of 2.4 ℃/s in the atmosphere, preserving heat for 5min, and naturally cooling to be lower than 80 ℃ along with the furnace.

The step D comprises the following steps: and D, putting the product obtained in the step C into a heating furnace cavity of an infrared lamp, introducing nitrogen into the heating furnace at the flow rate of 0.9-1.1L/min, heating to 400 ℃ at the heating rate of 2.4 ℃/s, preserving heat for 5-60 min, and naturally cooling to below 80 ℃ along with the furnace.

The invention also provides a thin film solar cell, which comprises an amorphous silicon thin film solar cell, a perovskite thin film solar cell and an organic thin film solar cell, and is characterized in that the cell comprises the aluminum-doped zinc oxide transparent conductive thin film surface modification material.

(III) advantageous effects

The aluminum-doped zinc oxide transparent conductive film surface modification material, the preparation method and the thin film solar cell provided by the invention have at least one or one part of the following beneficial effects:

(1) prepared ZnMoO_xThe material has a tunable surface work function in a wide range (3.83eV-6.86 eV).

(2) Prepared ZnMoO_xThe material forms a crystalline phase through atmospheric heat treatment, so that stable surface components and structures are obtained to ensure the stability of the surface work function while the surface work function is further improved.

(3) Prepared ZnMoO_xThe polycrystalline material can realize low sheet resistance by generating an oxygen vacancy donor state through nitrogen atmosphere heat treatment, thereby reducing the series resistance in the device.

(4) Prepared ZnMoO_xThe polycrystalline material can realize the regulation and control of performance parameters such as surface work function, light number constant (refractive index coefficient and extinction coefficient) and the like by accurately controlling the content of Mo.

(5) Prepared ZnMoO_xModified ZnO: the Al transparent conductive substrate can be applied to amorphous silicon, perovskite or organic thin-film solar cells and the like, and can also be applied to the field of optoelectronic devices such as a light detector, an organic photodiode and the like.

Drawings

FIG. 1(a) is a surface scanning electron microscope photograph of comparative example 1 in example 7, provided by the present invention, with a scale of 200 nm;

FIG. 1(b) is a Scanning Electron Microscope (SEM) representation of the surface of ZMO1 in example 7, shown at 200 nm;

FIG. 1(c) is a Scanning Electron Microscope (SEM) representation of the surface of ZMO2 in example 7, shown at 200 nm;

FIG. 1(d) is a Scanning Electron Microscope (SEM) of the surface of ZMO3 in example 7, shown at 200 nm;

FIG. 2(a) shows ZnO modified with several surface modification materials in example 8: distributing the Zn element, the Al element, the Mo element and the O element of the Al transparent conductive film along the depth of the material;

FIG. 2(b) shows ZnO modified with several surface modification materials in example 8: the relative change of the proportion of O element to Mo element (O/Mo element proportion) of the Al transparent conductive film is distributed along the depth of the material;

FIG. 3 is ZnO modified by several surface modification materials in example 9: x-ray diffraction patterns of the Al transparent conductive film, wherein ZMO0 is a conventional X-ray diffraction pattern, ZMO1, ZMO2 and ZMO3 are grazing X-ray diffraction patterns, and wurtzite ZnO is a standard pattern of JCPDS card No. 36-1451;

FIG. 4 shows ZnO modified by several surface modification materials in example 10: the ultraviolet-visible-near infrared transmittance curve chart of the Al transparent conductive film;

FIG. 5 shows ZnO modified with several surface modifying materials of example 11: and (3) an ultraviolet-electron energy spectrum of a second-electron cut-off region of the Al transparent conductive film.

FIG. 6(a) is a graph showing the short-circuit current density (J) of the amorphous silicon single-junction thin-film solar cell prepared in example 13_sc) A drawing;

FIG. 6(b) is an open circuit voltage (V) of an amorphous silicon single junction thin film solar cell prepared in example 13_oc) A drawing;

FIG. 6(c) is a Fill Factor (FF) diagram of an amorphous silicon single-junction thin-film solar cell prepared in example 13;

FIG. 6(d) is a graph showing the photoelectric conversion efficiency (. eta.) of the amorphous silicon single-junction thin-film solar cell prepared in example 13;

FIG. 6(e) is a graph showing the series resistance (R) of the amorphous silicon single-junction thin-film solar cell prepared in example 13_s) A drawing;

FIG. 6(f) is a graph showing the parallel resistance (R) of the amorphous silicon single-junction thin-film solar cell prepared in example 13_sh) Figure (a).

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to specific embodiments and the accompanying drawings.

The invention provides an aluminum-doped zinc oxide transparent conductive film surface modification material, which is ZnMoO_x(3 < x < 4) film and the ZnMoO_xThe work function of the film is 4.3 eV-4.86 eV. Wherein, the ZnMoO_xThe thickness of the film is 28 to 32 nm. The ZnMoO_xThe surface roughness of the film is less than 3 nm.

The surface modification material of the aluminum-doped zinc oxide transparent conductive film provided by the invention has a stable tunable surface work function in a wide range (3.83eV-4.86 eV). The problems of adding ZnO in the prior art are solved: the technique of Al surface work function has a problem that it is difficult to form a stable surface component to secure stability of the surface work function.

ZnMoO prepared by the preparation methods A and B of the invention_xThe film is stable in the surrounding environment because the surface component is an inorganic modified material.

ZnMoO after Heat treatment by atmospheric atmosphere_xThe surface work function of the film can reach 4.86eV, and the film is stable under the ambient environment.

Here, ZnMoO after heat treatment in the atmosphere and in the nitrogen atmosphere_xThe film means obtained by the above step BZnMoO of_xAfter the film is subjected to two heat treatments, namely, the film is subjected to a first atmospheric heat treatment, and then the product subjected to the first atmospheric heat treatment is subjected to a second nitrogen atmosphere heat treatment to obtain the ZnMoO subjected to the atmospheric and nitrogen atmosphere heat treatments_xA film.

ZnMoO after heat treatment in nitrogen atmosphere_xThe surface work function of the film can reach 4.85eV, and lower film resistance is realized.

The invention also provides a thin film solar cell, which comprises an amorphous silicon thin film solar cell, a perovskite thin film solar cell and an organic thin film solar cell, and is characterized by comprising the aluminum-doped zinc oxide transparent conductive thin film surface modification material.

In order to further illustrate the technical solution of the present invention, the following specific examples are given by way of example:

example 1:

this example provides an amorphous ZnMoO_x(3 < x < 4) filmThe surface modification material is used as the surface modification material of the aluminum-doped zinc oxide transparent conductive film. The ZnMoO_xThe surface work function of the film was 4.3 eV. The ZnMoO_xThe thickness of the film is 28-32 nm. The ZnMoO_xThe surface roughness of the film was 1.9 nm.

Example 2:

this example provides a polycrystalline ZnMoO_xAnd (x is more than 3 and less than 4) the film is used as a surface modification material of the aluminum-doped zinc oxide transparent conductive film. The ZnMoO_xThe surface work function of the film was 4.86 eV. The ZnMoO_xThe thickness of the film is 28-32 nm. The ZnMoO_xThe surface roughness of the film was 1.5 nm.

Example 3:

the present example provides a low resistance polycrystalline ZnMoO_xAnd (x is more than 3 and less than 4) the film is used as a surface modification material of the aluminum-doped zinc oxide transparent conductive film. The ZnMoO_xThe surface work function of the film was 4.85 eV. The ZnMoO_xThe thickness of the film was 32 nm. The ZnMoO_xThe surface roughness of the film was 2.6 nm.

Example 4:

the embodiment provides a preparation method of an aluminum-doped zinc oxide transparent conductive film surface modification material, which is obtained through the following steps A and B:

step A: preparing aluminum-doped zinc oxide ZnO on a glass substrate by a sol-gel method: al transparent conductive film, ZnO prepared: the performance parameters of the Al transparent conductive film are shown in table 1, wherein the film resistance is the average value measured by a four-probe resistance measuring instrument at 6 different positions on the surface of the sample. Sigma_rmsRoughness is the root mean square value of the surface roughness profile of the film as measured by Atomic Force microscopy (Atomic Force microscopy). Then cleaning the surface of the transparent conductive film, respectively ultrasonically cleaning the transparent conductive film in alcohol, acetone and alcohol for 10 minutes, and finally drying the transparent conductive film by dry nitrogen.

TABLE 1 Property parameter Table for transparent conductive film of aluminum-doped zinc oxide

Transparent conductive film	Thickness (nm)	Resistivity (omega cm)	Film resistance (omega/sq)	Roughness sigma_rms(nm)
					ZnO：Al	1500	2.34×10^-3	15.6	2.6

And B: growing molybdenum oxide (MoO) on the cleaned aluminum-doped zinc oxide transparent conductive film by using a vacuum evaporation method_3-δWherein 0 is less than 6 and less than 1) to obtain ZnMoO on the surface of the aluminum-doped zinc oxide transparent conductive film_xA film. Specifically, the ZnO after washing: the Al transparent conductive film was placed in a high vacuum evaporation apparatus (model No. Sanvac RD-1250R). Vacuum-pumping to 4.1-4.5X 10^-4Pa; slowly increasing the voltage at two ends of the tungsten boat to about 14-16V, opening the shielding plate when the tungsten boat turns red, and simultaneously starting timing to deposit a film at a growth rate of 0.08-0.12nm/s, wherein the weight of the raw material molybdenum oxide powder is 0.0060-0.0080 g; when the film reaches 28-32nm, closing the shutter, and slowly reducing the voltage to 0V; when the temperature is reduced to be near the room temperature, taking out the sample to obtain ZnMoO on the surface of the aluminum-doped zinc oxide transparent conductive film_xA film.

Example 5:

this embodiment provides aA preparation method of an aluminum-doped zinc oxide transparent conductive film surface modification material, which is to be used for preparing the ZnMoO on the surface of the aluminum-doped zinc oxide transparent conductive film obtained by the preparation method in the embodiment 4_xA film as a starting sample, to which the process of step C: for the ZnMoO_xSubjecting the film to an atmospheric heat treatment, in particular, to a ZnMoO treatment_xThe film is put into a heating furnace cavity of an infrared lamp, heated to 350-400 ℃ at the heating rate of 2.4 ℃/s in the surrounding atmosphere, and kept for 5min, and then naturally cooled to be lower than 80 ℃ along with the furnace. Obtaining ZnMoO which is positioned on the surface of the aluminum-doped zinc oxide transparent conductive film and is subjected to atmospheric heat treatment_xA film.

Example 6:

this example provides a method for preparing a surface modification material for an aluminum-doped zinc oxide transparent conductive film, which is to dispose the ZnMoO obtained by the preparation method of example 5 on the surface of the aluminum-doped zinc oxide transparent conductive film after being subjected to an atmospheric heat treatment_xA film as a starting sample, to which the step D: for the ZnMoO_xSubjecting the film to an atmospheric heat treatment, in particular, to a ZnMoO treatment_xPlacing the film in a heating chamber of an infrared lamp, and introducing N into the heating chamber at a flow rate of 0.9-1.1L/min₂Heating to 400 ℃ at a heating rate of about 2.4 ℃/s, then preserving the heat for 5-60 min, and then naturally cooling to be lower than 80 ℃ along with the furnace. Obtaining ZnMoO which is positioned on the surface of the aluminum-doped zinc oxide transparent conductive film and is subjected to heat treatment in atmosphere and nitrogen atmosphere_xA film.

Example 7:

this example compares the ZnO after cleaning obtained by step a in example 4: an Al transparent conductive film was designated ZMO0 as comparative example 1, and ZnMoO on the surface of the aluminum-doped zinc oxide transparent conductive film obtained by step B in example 4 was used_xThe film was designated as ZMO1, and the ZnMoO obtained in example 5 and subjected to a heat treatment in an atmospheric atmosphere_xThe film was designated as ZMO2, and the ZnMoO obtained in example 6 and heat-treated in air or nitrogen atmosphere_xThe film is designated ZMO 3.

Surface SEM pictures were obtained by Scanning Electron Microscopy (SEM) for ZMO0, ZMO1, ZMO2, and ZMO3, respectively, and the results are shown in fig. 1. FIG. 1(a) is a surface SEM of ZMO0 provided in comparative example 1, FIG. 1(b) is a surface SEM of ZMO1, FIG. 1(c) is a surface SEM of ZMO2, and FIG. 1(d) is a surface SEM of ZMO 3.

Referring to FIG. 1, several ZnMoO's can be seen_xThe film samples all had very flat surfaces, and the surfaces of these samples consisted of nano-sized grains. The ZMO1, ZMO2, ZMO3 have finer and more uniform grains than ZMO 0. Surface sigma of ZMO1 and ZMO2_rmsRoughness lower than ZMO0, and surface sigma of ZMO3_rmsThe roughness was slightly higher than ZMO 0.

Example 8:

in this example, the ZnMoO on the surface of the aluminum-doped zinc oxide transparent conductive film obtained in the step B of the example 4 is_xThe film was designated as ZMO1, and the ZnMoO obtained in example 5 and subjected to a heat treatment in an atmospheric atmosphere_xThe film was designated as ZMO2, and the ZnMoO obtained in example 6 and heat-treated in air or nitrogen atmosphere_xThe film is designated ZMO 3.

The measurements of the elemental distribution along the depth of the material were performed on ZMOs 1, ZMOs 2, ZMOs 3, respectively, and the results are shown in fig. 2, where fig. 2(a) is ZnO modified by several surface modifying materials of example 8: the Zn element, the Al element, the Mo element and the O element of the Al transparent conductive film are distributed along the depth element of the material. FIG. 2(b) shows ZnO modified with several surface modification materials in example 8: the relative change of the ratio of the O element to the Mo element (O/Mo element ratio) of the Al transparent conductive film is distributed along the depth of the material. Wherein the O/Mo element ratio in ZMO1 has been set to 1.

As shown in fig. 2(a), in ZnO: a new substance consisting of Zn, Mo and O elements exists in the range of about 30nm thick on the surface of Al. This demonstrates ZnMoO_xThe modified layer is formed by ZnO: the surface of Al is formed. As shown in FIG. 2(b), ZnMoO_xThe ratio of O/Mo elements in the layer is obviously changed; the O/Mo element ratio of ZMO2 is significantly greater than that of ZMO 1; this demonstrates that oxidation reactions occur during the first atmospheric heat treatment to increase ZnMoO_xThe oxygen content within the layer. The O/Mo element ratio of ZMO3 being slightly less than that of ZMO2But still greater than ZMO 1; this indicates that the second nitrogen atmosphere heat treatment process slightly reduced ZnMoO_xThe oxygen content within the layer.

Example 9:

this example compares the ZnO after cleaning obtained by step a in example 4: an Al transparent conductive film was designated ZMO0 as comparative example 1, and ZnMoO on the surface of the aluminum-doped zinc oxide transparent conductive film obtained by step B in example 4 was used_xThe film was designated as ZMO1, and the ZnMoO obtained in example 5 and subjected to a heat treatment in an atmospheric atmosphere_xThe film was designated as ZMO2, and the ZnMoO obtained in example 6 and heat-treated in air or nitrogen atmosphere_xThe films were designated as ZMO3, and X-ray diffraction measurements were performed on ZMO0, ZMO1, ZMO2, and ZMO3, respectively, and the results are shown in FIG. 3.

As shown in fig. 3, ZMO0 exhibits a pronounced (002) direction preferred orientation. ZMO1 exhibits a pattern similar to standard wurtzite-type ZnO. This indicates that ZMO1 should be amorphous. After the first atmospheric heat treatment, two positions of about 27 degrees on the ZMO2 spectrum appear, marked as X respectively₁And X₂New diffraction peak of (2). This demonstrates that the atmospheric heat treatment causes crystallization and the formation of a new phase. After the second nitrogen atmosphere heat treatment, ZMO3 exhibits nearly the same X as ZMO2₁And X₂The diffraction peak of (2) is strong. This indicates that the nitrogen atmosphere heat treatment did not have a significant effect on the new phase formed. From the elemental composition shown in FIG. 2, X can be inferred₁And X₂Should be related to ZnMoO_xWith respect to a certain crystalline phase.

Example 10:

this example compares the ZnO after cleaning obtained by step a in example 4: an Al transparent conductive film was designated ZMO0 as comparative example 1, and ZnMoO on the surface of the aluminum-doped zinc oxide transparent conductive film obtained by step B in example 4 was used_xThe film was designated as ZMO1, and the ZnMoO obtained in example 5 and subjected to a heat treatment in an atmospheric atmosphere_xThe film was designated as ZMO2, and the ZnMoO obtained in example 6 and heat-treated in air or nitrogen atmosphere_xFilm(s)Ultraviolet-visible-near infrared transmittance measurements were made for ZMO0, ZMO1, ZMO2, and ZMO3, respectively, as ZMO3, and the results are shown in fig. 4.

As shown in FIG. 4, all the films exhibited a transmittance of more than 85% in the wavelength range of 400-1500 nm; in the presence of ZnO: ZnMoO formed on Al surface_xThe modified layer hardly reduced ZnO: transmittance of Al substrate. However, in the short wavelength region of 350-400nm, ZMO2 and ZMO3 exhibit lower transmittances than ZMO0 and ZMO 1. This indicates ZnMoO_xThe optical forbidden bandwidth of the material becomes slightly smaller after the heat treatment in the atmospheric atmosphere. This is probably due to the generation of X in FIG. 3 during the atmospheric heat treatment₁And X₂ZnMoO corresponding to diffraction peak of (1)_xA crystalline phase. In general, a crystalline phase of a material exhibits a smaller optical forbidden bandwidth than an amorphous phase. In addition, the transmission spectra of all films appear wavy with increasing wavelength. This is caused by the Fabry-Perot interference effect between the beams of different phases. The flat surfaces of these films result in the formation of many light rays at the exit end that are in the same direction but in different phases.

Example 11:

this example compares the ZnO after cleaning obtained by step a in example 4: an Al transparent conductive film was designated ZMO0 as comparative example 1, and ZnMoO on the surface of the aluminum-doped zinc oxide transparent conductive film obtained by step B in example 4 was used_xThe film was designated as ZMO1, and the ZnMoO obtained in example 5 and subjected to a heat treatment in an atmospheric atmosphere_xThe film was designated as ZMO2, and the ZnMoO obtained in example 6 and heat-treated in air or nitrogen atmosphere_xThe films were designated as ZMO3, and Secondary-electron cut-off region UV photoelectron measurements were made on ZMO0, ZMO1, ZMO2, and ZMO3, respectively, and the results are shown in FIG. 5. FIG. 5 shows the ZnO modified by ZMO0, ZMO1, ZMO2 and ZMO 3: and (3) an ultraviolet-electron energy spectrum of a second-electron cut-off region of the Al transparent conductive film.

As shown in fig. 5, in ZnO: ZnMoO formed on Al surface_xAfter the modification layer, the second-electron cut-off edge was significantly shifted to the high energy direction, indicating that the surface work function was significantly increasedAnd (5) rising.

Example 12:

this example compares the ZnO after cleaning obtained by step a in example 4: an Al transparent conductive film was designated ZMO0 as comparative example 1, and ZnMoO on the surface of the aluminum-doped zinc oxide transparent conductive film obtained by step B in example 4 was used_xThe film was designated as ZMO1, and the ZnMoO obtained in example 5 and subjected to a heat treatment in an atmospheric atmosphere_xThe film was designated as ZMO2, and the ZnMoO obtained in example 6 and heat-treated in air or nitrogen atmosphere_xThe film is designated ZMO 3. Work function value measurements were performed on ZMO0, ZMO1, ZMO2, and ZMO3, respectively, and the results of the measurements are shown in table 2.

TABLE 2 work function values for ZMO0, ZMO1, ZMO2 and ZMO3

Sample (I)	ZMO0	ZMO1	ZMO2	ZMO3
					Work function (eV)	3.83	4.30	4.86	4.85

From the results in Table 2, ZMO0 has a surface work function value of 3.83 eV. This is in contrast to ZnO prepared by rf magnetron sputtering: the surface work function of the Al transparent conductive film is very highAnd (4) approaching. The surface work function of amorphous ZMO1 is increased by 12% relative to ZMO 0. During step B in example 4 of the present disclosure, MoO was deposited under vacuum_3-δIn the thin film process, MoO_3-δReact with ZnO on the surface to form amorphous ZnMoO_x。MoO_3-δHaving a work function of up to 6.86 eV. MoO due to high work function_3-δThe incorporation of (b) allows ZMO1 to achieve a higher work function than ZMO 0. The surface work function of ZMO2 crystallized by atmospheric heat treatment increased 27% relative to ZMO0, achieving a high work function value of 4.86 eV. This reflects the formation of certain ZnMoO during atmospheric heat treatment_xThe crystalline phase leads to a further increase in the surface work function. In addition, the surface work function of ZMO3 was almost unchanged from that of ZMO2 by the heat treatment in a nitrogen atmosphere. This demonstrates the better stability of the surface work function enhanced by the atmospheric heat treatment. This is probably due to the fact that the crystallized ZMO2 has a robust surface structure, i.e., ordered atomic arrangement and relatively strong bonding to ensure a stable surface composition to improve the stability of the surface work function. Further, referring to fig. 3, the nitrogen atmosphere heat treatment according to example 9 does not significantly affect the new phase formed during the atmospheric heat treatment, and it can be concluded that ZMO3 still has a robust surface crystal structure similar to ZMO2 while ensuring a stable surface composition. Therefore, it can be concluded that the surface work function of ZMO3 also has better stability. In addition, the surface work function values of ZMO2 and ZMO3 have reached or even exceeded SnO₂: f and In₂O₃: surface work function level of Sn.

Example 13:

this example compares the ZnO after cleaning obtained by step a in example 4: an Al transparent conductive film was designated ZMO0 as comparative example 1, and ZnMoO on the surface of the aluminum-doped zinc oxide transparent conductive film obtained by step B in example 4 was used_xThe film was designated as ZMO1, and the ZnMoO obtained in example 5 and subjected to a heat treatment in an atmospheric atmosphere_xThe film was designated as ZMO2, and the ZnMoO obtained in example 6 and heat-treated in air or nitrogen atmosphere_xThe film is designated ZMO 3. ZnO modified with ZMO0, ZMO1, ZMO2, ZMO3, respectively: al transparent conductive liningThe bottom is used as an anode electrode to manufacture an amorphous silicon (a-Si: H) single-junction thin-film solar cell. This amorphous silicon unijunction thin-film solar cell from the bottom up includes in proper order: ZnO: al transparent conductive substrate, ZnMoO_xSurface modification layer, p-i-na-Si: h absorption layer, boron-doped zinc oxide (ZnO: B) back scattering layer, and aluminum metal electrode. Wherein p-i-n a-Si: the H absorption layer is prepared by adopting a plasma enhanced chemical vapor deposition method; ZnO: the B back scattering layer (thickness 1500nm) is prepared by metal organic chemical vapor deposition.

The performance parameters of the prepared amorphous silicon single-junction thin-film solar cells were measured, and the results are shown in fig. 6(a) to 6 (f). FIG. 6(a) is a graph showing the short-circuit current density (J) of the amorphous silicon single-junction thin-film solar cell prepared_sc) FIG. 6(b) is the open circuit voltage (V) of the amorphous silicon single junction thin film solar cell prepared_oc) FIG. 6(c) is a Fill Factor (FF) of the prepared amorphous silicon single-junction thin-film solar cell, FIG. 6(d) is a photoelectric conversion efficiency (η) of the prepared amorphous silicon single-junction thin-film solar cell, and FIG. 6(e) is a series resistance (R) of the prepared amorphous silicon single-junction thin-film solar cell_s) FIG. 6(f) is a graph showing the parallel resistance (R) of the amorphous silicon single-junction thin-film solar cell prepared_sh)。

From the results, it was found that using ZMO2 and ZMO3 achieves a larger J than ZMO0 and ZMO1_sc. This is probably due to ZnMoO increased by crystallization generated by heat treatment in atmospheric atmosphere_xModifying the refractive index of the layer such that the refractive index of the transparent conductive substrate with p-type a-Si: better index matching at the H-layer interface, increased light absorption and increased J_sc. Maximum J with ZMO2_scBut the highest series resistance (R) is formed_s) Resulting in the lowest Fill Factor (FF) so that the cell's photoelectric conversion efficiency is not significantly improved compared to ZMO0 and ZMO 1. Substantial reduction of R with ZMO3_sTo achieve the highest open circuit voltage (V) of 0.89V_oc) And FF of 0.61, thereby achieving the highest η (6.54%). R_sThe decrease in ZMO3 resistivity is due to the nitrogen atmosphere heat treatment. The reduction in the resistivity of ZMO3 is due to the creation of ionized oxygen vacancy donor states during heat treatment in a nitrogen atmosphere to promote ZnMoO_xCarrier concentration within the modified layer. Thus, the ZMO3 surface modification layer not only increases V_ocThat is, the carrier extraction process is effectively facilitated and FF is improved, thereby obtaining the highest photoelectric conversion efficiency. Furthermore, ZnMoO is used_xParallel resistance (R) of surface modification layer to device_sh) With little effect.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A preparation method of an aluminum-doped zinc oxide transparent conductive film surface modification material is characterized by comprising the following steps:

step A: preparing an aluminum-doped zinc oxide transparent conductive film on a glass substrate, and cleaning the surface of the transparent conductive film;

and B: growing a molybdenum oxide film on the cleaned aluminum-doped zinc oxide transparent conductive film by using a vacuum evaporation method to obtain an amorphous phase ZnMoO positioned on the surface of the aluminum-doped zinc oxide transparent conductive film_XA film;

and C: carrying out atmospheric heat treatment on the product obtained in the step B to obtain a polycrystalline phase ZnMoO positioned on the surface of the aluminum-doped zinc oxide transparent conductive film_XA film;

step D: c, carrying out nitrogen atmosphere heat treatment on the product obtained in the step C to obtain a low-resistance polycrystalline phase ZnMoO positioned on the surface of the aluminum-doped zinc oxide transparent conductive film_XA film.

2. The method according to claim 1, wherein the vacuum degree of the vacuum evaporator used in the vacuum evaporation method in the step B is 4.1 to 4.5X 10^-4Pa, the film growth rate of the molybdenum oxide film is 0.08-0.12 nm/s.

3. The method of claim 1, wherein step C comprises: and C, putting the product obtained in the step B into a heating furnace cavity of an infrared lamp, heating to 350-400 ℃ at the heating rate of 2-4 ℃/s in the atmosphere, preserving the heat for 5min, and naturally cooling to be lower than 80 ℃ along with the furnace.

4. The method of claim 1, wherein step D comprises: and D, putting the product obtained in the step C into a heating furnace cavity of an infrared lamp, introducing nitrogen into the heating furnace at the flow rate of 0.9-1.1L/min, heating to 400 ℃ at the heating rate of 2.4 ℃/s, preserving heat for 5-60 min, and naturally cooling to below 80 ℃ along with the furnace.