CN114094019A

CN114094019A - A method for improving the adsorption density of self-assembled monomolecular carrier transport layers

Info

Publication number: CN114094019A
Application number: CN202111279464.7A
Authority: CN
Inventors: 寿春晖; 孙娟娟; 杨熹; 应智琴; 贺海晏; 黄绵吉; 丁莞尔; 盛江; 孙靖淞; 闫宝杰; 叶继春
Original assignee: Ningbo Institute of Material Technology and Engineering of CAS; Zhejiang Energy Group Research Institute Co Ltd
Current assignee: Ningbo Institute of Material Technology and Engineering of CAS; Zhejiang Energy Group Research Institute Co Ltd
Priority date: 2021-10-28
Filing date: 2021-10-28
Publication date: 2022-02-25

Abstract

The invention relates to a method for improving the adsorption density of a self-assembled monomolecular carrier transport layer, which comprises the following steps: preparing NiO on clean substrate by utilizing magnetron sputtering coating equipment at normal temperature_xA hole transport layer; regulating and controlling the binding sites on the substrate, selecting the organic matter containing anchoring groups and NiO on the surface of the substrate due to the hydroxyl contained on the surface of the substrate_xThe substrate of the hole transport layer reacts. The invention has the beneficial effects that: selecting organic matter containing anchoring group and NiO as surface_xReacting the substrate of the hole transport layer, selecting proper (molecular weight, symmetry, polarity and the like) organic matters containing anchoring groups by regulating and controlling the binding sites of the substrate, and preparing the required performances of high adsorption density, strong polarity and the like by regulating the content, deposition mode, growth direction and the like of the anchoring groups; the addition of a layer containing-OR functional groups prevents direct contact of the transparent conductive oxide substrate with the active layer; is favorable for improving the adsorption density of the organic matters containing the anchoring groups.

Description

Method for improving adsorption density of self-assembled monomolecular carrier transport layer

Technical Field

The invention belongs to the field of photovoltaics, and particularly relates to a method for improving the adsorption density of a self-assembled monomolecular carrier transport layer.

Background

In recent decades, photovoltaic technologies such as organic light emitting diodes, photodetectors, dye-sensitized solar cells, quantum dot solar cells, organic solar cells, and perovskite solar cells have been rapidly developed. Among them, organic-inorganic hybrid perovskite solar cells are receiving wide attention due to the advantages of high light absorption coefficient, long diffusion length, high carrier mobility, low exciton binding energy, adjustable band gap and the like, and the photoelectric conversion efficiency of a single perovskite solar cell is improved from 3.8% to 25.5% in nearly ten years. However, with the further improvement of the quality of perovskite crystals, efficient, stable and cheap carrier transport materials are of great importance for the further development of perovskite solar cells. The photoelectric conversion efficiency of the organic solar cell is close to the predicted limit value of 20%, and in order to further improve the efficiency and stability of the organic solar cell, the carrier transport material is also important to research.

Currently, several commonly used carrier transport materials are described below:

(1) perovskite solar cell: common hole transport materials include PEDOT PSS, PTAA, NiO_X，CuO_XCuSCN, poly-TPD and SAMs, etc.; common electron transport materials include PCBM, C₆₀/BCP，TiO₂，SnO₂And SAMs, and the like.

(2) Organic solar cell: the material is usually PEDOT, PSS, which is used as a hole transport material; commonly used electron transport materials include PNDIT-F₃N, PFN-Br, PDINO, ZnO, SAMs and the like.

Wherein SAMs refers to self-assembled monolayer materials consisting essentially of a head anchoring group (including-Si (OR))₃，-P(OH)₃-COOH, etc.), a central linking group and a tail functional group. SAMs has the advantages of simple preparation (spin coating, soaking, spraying, etc.), small parasitic absorption, low material consumption, conformal substrate, adjustable substrate energy level, and passivation of functional groupsThe advantages of the layer are widely noted. Since Albrecht et al 2018, SAM V1036 is applied to perovskite solar cells as a hole transport material for the first time, and various SAMs such as MeO-2PACz, 2PACz, Me-4PACz, Br-2PACz, TPA, EADR04 and the like are widely applied to perovskite solar cells and organic solar cells. SAMs are mostly used as SnO, although in other photovoltaic fields₂And interface modification of ITO and the like (for example, 5-MePIFA, 5-DPIFA, FPA and the like are commonly used as modifiers in organic light emitting diodes), but can simultaneously function as a transport layer and an interface modifier as long as appropriate SAMs materials are selected.

For photovoltaic cells, the photoactive layer, the transport layer, and the electrodes are not critical to the performance of the device. With the rapid development of photovoltaic technology, the existing transport layer materials generally have the following problems, which greatly limit the further development of photovoltaic technology:

(1) conventional organic transport layer materials are expensive, have poor stability, and require complex doping processes.

(2) Conventional inorganic transport materials have interface defects and poor electrical conductivity.

(3) SAMs transport materials are adsorbed in a single layer and easily tunneled or formed into pores.

Therefore, developing a new transport layer material is a direct method to solve the above problems, but is not the fastest method to solve the above problems because the development of a new material takes a long time.

Aiming at the problem of poor conductivity of the traditional inorganic material, the problem is usually solved by adopting a doping mode at present. With NiO_XTransport Material for example, Defect from Nickel oxide equation 2Ni_Ni ^x+1/2O₂(g)→2Ni_Ni ^·+O_o ^x+V_NiThe conduction mechanism is known as follows: two in-situ Ni under oxygen atmosphere²⁺Will generate two Ni³⁺And a nickel vacancy, Ni²⁺And Ni³⁺There is charge transfer between them to make them conductive. Therefore, NiO is improved_XBesides doping, the conductivity of the material can be improved to a certain extent by changing the growth conditions.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a method for improving the adsorption density of a self-assembled monomolecular carrier transport layer.

The method for improving the adsorption density of the self-assembled monomolecular carrier transport layer comprises the following steps:

step 1, preparing NiO on a clean (TCO) substrate by utilizing magnetron sputtering coating equipment at normal temperature_xHole transport layer: when the working pressure of the magnetron sputtering coating equipment is smaller than a set value (the smaller the working pressure is, the higher the vacuum degree is, the less the residual impurity gas is, and the influence on the coating is smaller), the NiO is changed_xThe flow rates of oxygen and argon are controlled to control the growth conditions of the hole transport layer₂/(Ar+O₂) Controlling to adjust the oxygen content O in the mixed gas of argon and oxygen₂/(Ar+O₂) To within 0-50%; electrons collide with argon atoms (due to equipment problem, after the power exceeds 80W, the surface temperature of a sample is high, and the sample is easy to crack) in the process of flying to the substrate under the action of an electric field with the power of 30-80W, and the argon atoms are ionized to generate Ar⁺And a new electron, Ar⁺Bombarding the surface of the cathode target under the action of an electric field; the thickness/time is estimated, the generated neutral target atoms or molecules are deposited on the substrate at a speed of 0.01-0.05 nm/s within 200-1000 s under a set pressure, and NiO is prepared_xThe hole transport layer improves the conductivity to a certain extent; the higher the argon content is, the faster the growth rate of the film is; while an increase in oxygen content accelerates defect equation 2Ni_Ni ^x+1/2O₂(g)→2Ni_Ni ^·+O_o ^x+V_NiProceeding to the right, Ni³+ and nickel vacancies increase, i.e. carrier concentration increases, mobility increases, and Ni³⁺The black color is gray, which can reduce the transmittance;

step 2, regulating and controlling the binding sites on the substrate treated in the step 1, wherein the surface of the substrate contains hydroxyl, and organic matters containing anchoring groups and NiO on the surface are selected_xThe substrate of the hole transport layer reacts.

Preferably, the step ofThe substrate 1 includes metal oxide substrate, metal substrate, non-metal oxide substrate, and substrate containing-Si (OR)₃、-P(OR)₃、-COOR、-SO₃A substrate for an R, -COR, -SH, OR-OR group and a substrate without a linking group.

Preferably, in step 2:

when the substrate is a metal oxide substrate, the anchoring group comprises-Si (OR)₃、-P(OR)₃、-COOR、-SO₃R and-COR;

when the substrate is a metal substrate, the anchoring group comprises-Si (OR)₃、-P(OR)₃、-COOR、-SO₃R, -COR, -SH and-NH₃；

When the substrate is a non-metal oxide, the anchoring group comprises-Si (OR)₃、-P(OR)₃、-COOR、-SO₃R and-COR;

the substrate is a film containing-Si (OR)₃，-P(OR)₃、-COOR、-SO₃When the substrate for the R, -COR, -SH OR-OR group is present, the anchor group comprises-Si (OR)₃、-P(OR)₃、-COOR、-SO₃R and-COR;

when the substrate is a substrate without connecting groups, firstly, ultraviolet ozone treatment is carried out to introduce dangling bonds, and then, groups are introduced on the dangling bonds, wherein the introduced groups comprise-Si (OR)₃，-P(OR)₃、-COOR、-SO₃R and-COR.

Preferably, the NiO prepared in step 1_xThe thickness of the hole transport layer is 1-10 nm; the electric field power during sputtering in step 1 was 80W, and the pressure during deposition was 0.4 Pa.

Preferably, the working pressure set value of the magnetron sputtering coating equipment in the step 1 is 4 multiplied by 10^-4Pa。

Preferably, when the working pressure of the magnetron sputtering coating equipment in the step 1 is less than 4 multiplied by 10^-4At Pa, adjusting O₂/(Ar+O₂) The ratio of (A) to (B) is 5 to 25 percent.

The method for improving the adsorption density of the self-assembled monomolecular carrier transport layer is applied to the preparation of the solar cell and comprises the following steps:

step 1, dissolving a self-assembly monomolecular layer material in an absolute ethyl alcohol solution to prepare a hole transport layer precursor solution;

step 2, after stirring the precursor solution of the hole transport layer at room temperature for a set time, dripping the precursor solution of the hole transport layer in NiO_xThe surface of the substrate of the hole transport layer rotates at a set rotating speed for a set time length to form NiO_xA substrate for a hole transport layer;

step 3, the surface is fully distributed with the NiO of the hole transport layer precursor solution_xAfter stopping the substrate of the hole transport layer, putting the substrate on a heating table for annealing; after cooling, washing the material by using a solution of the self-assembled monomolecular layer material at a set rotating speed to obtain a self-assembled monomolecular carrier transmission layer, and removing the unadsorbed material self-assembled monomolecular layer material;

step 4, preparing a perovskite thin film on the surface of the self-assembly monomolecular carrier transmission layer;

step 5, preparing a hole transport layer C on the surface of the perovskite thin film in the step 4 by adopting a thermal evaporation method₆₀a/BCP and Ag electrode.

Preferably, the degree of vacuum in the vapor deposition in step 5 is less than 8 × 10^-6Pa, evaporation rate of

The method for improving the adsorption density of the self-assembled monomolecular carrier transport layer is applied to the preparation of the organic light-emitting diode, and specifically comprises the following steps:

step 1, selecting F₅BnPA as the self-assembled monomolecular layer material with NiO_xPreparing a self-assembled monomolecular carrier transport layer on the substrate surface of the hole transport layer: the interface is different from the bulk phase, because the surface has a dangling bond with strong activity, the-OH and the adsorbed water molecules generally exist on the interface of the metal oxide, and NiO is formed at the set temperature_xSubstrate for hole transport layer in F₅Soaking in a BnPA toluene solution; then NiO_xRotating the substrate of the hole transport layer at a set rotation speed, washing with anhydrous ethanol, and removing unadsorbed self-assembled sheetsA molecular layer material;

step 2, preparing Ir (mppy) by spin coating method₃TCTA film, preparing LiF and MoO in turn by thermal evaporation method₃And an Al electrode to obtain the organic light emitting diode.

The invention has the beneficial effects that:

mainly researches magnetron sputtering NiO_XAt different O₂/(Ar+O₂) In the atmosphere, Ni²⁺And Ni³⁺The NiO with better performance is prepared by the content change and the regulation and control of the power, the temperature and the deposition pressure during the magnetron sputtering_XThe material provides a modification layer to improve the adsorption density of the monomolecular layer. In addition, the invention combines the defect problem of the traditional inorganic material and the adsorption density problem of the self-assembled monolayer, and experiments show that the adsorption mode and the adsorption density of the SAM can be changed by selecting different oxide substrates, and the SAM can adjust the substrate energy level and passivate the active layer.

The invention selects organic matter containing anchoring group and NiO on the surface_xReacting the substrate of the hole transport layer, selecting proper (molecular weight, symmetry, polarity and the like) organic matters containing anchoring groups by regulating and controlling the binding sites of the substrate, and preparing the required performances of high adsorption density, strong polarity and the like by regulating the content, deposition mode, growth direction and the like of the anchoring groups;

the addition of the layer containing the-OR functional group in the invention can prevent the Transparent Conductive Oxide (TCO) substrate from directly contacting with the active layer; the adsorption density of the organic matter containing the anchoring group is improved; the increase of the adsorption density of the organic matter containing the anchoring group can improve the passivation capability of the interface; and the organic matter with proper functional groups is selected, so that the energy level alignment of the carrier transport layer and the active layer can be adjusted.

Drawings

FIG. 1 shows ITO/HTL/C₆₀A semi-logarithmic current density-voltage plot for the/BCP/Ag hole-electron structure;

FIG. 2 is a graph of half-log current density versus voltage for ITO/HTL/PVK/spiro-OMeTAD/Ag with hole-only structures;

FIG. 3 is MeO-2PACz and NiO_XUltraviolet electron spectrum curve diagram of the secondary cut-off edge of the/MeO-2 PAC after differential processing.

Detailed Description

The present invention will be further described with reference to the following examples. The following examples are set forth merely to aid in the understanding of the invention. It should be noted that, for a person skilled in the art, several modifications can be made to the invention without departing from the principle of the invention, and these modifications and modifications also fall within the protection scope of the claims of the present invention.

Example one

The embodiment of the application provides an application of a method for improving the adsorption density of a self-assembled monomolecular carrier transport layer in the preparation of a perovskite solar cell, which comprises the following steps:

preparation of NiO on clean Transparent Conductive Oxide (TCO) substrate using magnetron sputtering coating equipment_XA hole transport layer. When the working pressure is less than 4 x 10^-4At Pa, adjusting O₂/(Ar+O₂) The ratio of (A) to (B) is 0-50%. The mechanism of magnetron sputtering is that electrons collide with argon atoms in the process of flying to a substrate under the action of an electric field so as to ionize the argon atoms to generate Ar⁺And new electrons. Ar (Ar)⁺Bombarding the surface of the cathode target under the action of an electric field, and depositing the generated neutral target atoms or molecules on a substrate to form a film. The higher the argon content, the faster the growth rate of the film. The increase of the oxygen content accelerates the rightward progress of the defect equation to generate high-valence nickel and nickel vacancies, and causes the change of the properties such as carrier concentration, mobility, transmittance and the like. When the film is deposited, the sputtering power is set to be 80W, the deposition pressure is 0.4Pa, and NiO with better performance is prepared at normal temperature_XA film material.

In NiO_XAnd preparing a self-assembly monomolecular layer material MeO-2PACz on the surface. The interface is different from the bulk phase, and because the surface has a dangling bond with strong activity, the-OH and adsorbed water molecules generally exist on the interface of the metal oxide. MeO-2PACz was dissolved in an anhydrous ethanol solution to prepare a hole transport layer precursor solution having a concentration of 2 mmol/l. After stirring at room temperature for 15min, the above liquid was dropped on NiO_XSurface ofThe upper rotation is 30s, and the rotation speed is 4000 rpm. After the run was stopped, it was annealed for 10min on a heating stage at a temperature of 100 ℃. After cooling, the non-adsorbed material was removed by dynamic rinsing twice with anhydrous ethanol at 4000 rpm. ITO glass substrate and ITO glass substrate/NiO before and after spin coating of MeO-2PACz_XThe atomic contents of the main elements in the film are shown in table 1 below:

TABLE 1 ITO glass substrate and ITO glass substrate/NiO before and after spin coating with MeO-2PACz_XAtomic content table of main element in thin film

In the above table, N/A indicates that the element is not present in the sample, and the unit of each parameter is% indicates the atomic concentration percentage. From the above table, it can be seen that the addition of the layer containing an-OR functional group is advantageous for increasing the adsorption density of the organic substance containing an anchor group.

Perovskite thin films were prepared by spin coating: dissolving perovskite powder in a solvent with a DMF/DMSO ratio of 4:1, and stirring for 2h for use; dropwise adding the filtered perovskite precursor solution into ITO/NiO covered by MeO-2PACz_XThe surface of the film is rotated for 35s at 3500 rmp; dripping 330 μ l chlorobenzene continuously 25s before the program is finished, and annealing for 20min on a heating table at 100 deg.C; and finishing the preparation of the perovskite solar cell.

Preparing the hole transport layer C by thermal evaporation₆₀BCP, and Ag electrode: 24nm C60 and 6nm BCP were prepared in sequence by thermal evaporation at a rate of 0.1A/s to 3A/s. 100nm Ag electrode is prepared by thermal evaporation method, and the evaporation rate is 0.1-5A DEG/s. Vacuum degree during vapor deposition is lower than 8 x 10^-6Pa, evaporation rate of

Example two

The second embodiment of the present application provides an application of the method for improving the adsorption density of the self-assembled monomolecular carrier transport layer in the preparation of an organic solar cell:

In NiO_XPreparing self-assembly monomolecular layer material Br-2PACz on the surface. The interface is different from the bulk phase, and because the surface has a dangling bond with strong activity, the-OH and adsorbed water molecules generally exist on the interface of the metal oxide. Br-2PACz was dissolved in an anhydrous ethanol solution to prepare a hole transport layer precursor solution having a concentration of 0.3 mg/mL. After stirring at room temperature for 1h, the above liquid was dropped on NiO_XThe surface was spun for 30s at 3000 rpm. After the run was stopped, it was annealed for 5min on a heating stage at a temperature of 50 ℃. After cooling, the unadsorbed material was removed by dynamic washing twice with 0.3mg/mL Br-2PACz solution at 4000 rpm.

And finishing the preparation of the organic solar cell. PEDOT PSS film, PM6 BTP-eC9 PC was prepared in this order by spin-coating₇₁BM film and PFN-Br film, and Ag electrode is prepared through thermal evaporation process. Vacuum degree during vapor deposition is lower than 8 x 10^-6Pa, evaporation rate of

EXAMPLE III

The third embodiment of the present application provides an application of the method for improving the adsorption density of the self-assembled monomolecular carrier transport layer in the preparation of an organic light emitting diode:

preparation of NiO on clean Transparent Conductive Oxide (TCO) substrate using magnetron sputtering coating equipment_XA hole transport layer. When the working pressure is less than 4 x 10-⁴At Pa, adjusting O₂/(Ar+O₂) The ratio of (A) to (B) is 0-50%. The mechanism of magnetron sputtering is that electrons collide with argon atoms in the process of flying to a substrate under the action of an electric field so as to ionize the argon atoms to generate Ar⁺And new electrons. Ar (Ar)⁺Bombarding the surface of the cathode target under the action of an electric field, and depositing the generated neutral target atoms or molecules on a substrate to form a film. The higher the argon content, the faster the growth rate of the film. The increase of the oxygen content accelerates the rightward progress of the defect equation to generate high-valence nickel and nickel vacancies, and causes the change of the properties such as carrier concentration, mobility, transmittance and the like. When the film is deposited, the sputtering power is set to be 80W, the deposition pressure is 0.4Pa, and NiO with better performance is prepared at normal temperature_XA film material.

In NiO_XSurface preparation of self-assembled monolayer Material F₅BnPA. The interface is different from the bulk phase, and because the surface has a dangling bond with strong activity, the-OH and adsorbed water molecules generally exist on the interface of the metal oxide. The substrate was immersed in F at a concentration of 1mmol/l₅BnPA in toluene. Soaking at 50 deg.C for 8 hr. The non-adsorbed material was then removed by dynamic washing twice with absolute ethanol at 4000 rpm.

And finishing the preparation of the organic light emitting diode. Preparation of Ir (mppy) by spin coating₃TCTA film, sequentially preparing LiF and MoO by thermal evaporation₃And an Al electrode. Vacuum degree during vapor deposition is lower than 8 x 10^-6Pa, evaporation rate of

Experiments prove that:

as shown in FIG. 1, the addition of a layer containing-OR functionality may prevent direct contact of the TCO with the active layer;

as shown in fig. 2, the increase in adsorption density of the organic substance containing an anchor group can improve the interfacial passivation ability.

As shown in fig. 3, the selection of organic materials with appropriate functional groups is beneficial to adjusting the energy level alignment of the carrier transport layer and the active layer.

By the gain of the effect, the performance of the finally prepared device is obviously improved.

Claims

1. a method for improving the adsorption density of self-assembled monomolecular carrier transport layer, is characterized in that, comprises the following steps:

Step 1. Use magnetron sputtering coating equipment to prepare a NiO _x hole transport layer on a clean substrate: when the working pressure of the magnetron sputtering coating equipment is less than the set value, the flow rate of oxygen and argon is controlled to adjust the flow rate of O2. ₂ /(Ar+O ₂ ) is controlled to adjust the proportion of oxygen in the mixed gas of argon and oxygen O ₂ /(Ar+O ₂ ) to within 0-50%; NiO _x hole transport layer is prepared;

Step 2: Regulate the binding sites on the substrate treated in step 1, and select an organic substance containing an anchor group to react with the substrate whose surface is a NiO _x hole transport layer.

2. The method for improving the adsorption density of self-assembled monomolecular carrier transport layer according to claim 1, characterized in that: in step 1, the substrate comprises a metal oxide substrate, a metal substrate, a non-metal oxide substrate, a substrate containing -Si ( OR) ₃ , -P(OR) ₃ , -COOR, -SO ₃ R, -COR, -SH, or -OR groups and substrates without linking groups.

3. the method for improving the adsorption density of self-assembled monomolecular carrier transport layer according to claim 2, is characterized in that, in step 2:

When the substrate is a metal oxide substrate, the anchoring groups include -Si(OR) ₃ , -P(OR) ₃ , -COOR, -SO ₃ R and -COR;

When the substrate is a metal substrate, the anchoring groups include -Si(OR) ₃ , -P(OR) ₃ , -COOR, -SO ₃ R, -COR, -SH and -NH ₃ ;

When the substrate is a non-metal oxide, the anchoring groups include -Si(OR) ₃ , -P(OR) ₃ , -COOR, -SO ₃ R and -COR;

When the substrate is a substrate containing -Si(OR) ₃ , -P(OR) ₃ , -COOR, -SO ₃ R, -COR, -SH or -OR group, the anchoring group includes -Si(OR) ₃ , -P(OR) ₃ , -COOR, -SO ₃ R and -COR;

When the substrate is a substrate without a linking group, dangling bonds are first introduced into the dangling bonds by UV ozone treatment, and then groups are introduced on the dangling bonds. The introduced groups include -Si(OR) ₃ , -P(OR) ₃ , - COOR, -SO ₃ R and -COR.

4. The method for improving the adsorption density of self-assembled monomolecular carrier transport layer according to claim 1, characterized in that: the thickness of the NiO _x hole transport layer prepared in step 1 is 1-10 nm; during sputtering in step 1 The electric field power was 80W, and the pressure during deposition was 0.4Pa.

5 . The method for improving the adsorption density of a self-assembled monomolecular carrier transport layer according to claim 1 , wherein the set value of the working pressure of the magnetron sputtering coating equipment in step 1 is 4×10 ^-4 Pa. 6 .

6. The method for improving the adsorption density of the self-assembled monomolecular carrier transport layer according to claim 1, wherein in step 1, when the working pressure of the magnetron sputtering coating equipment is less than 4 × 10 ^-4 Pa, adjusting The ratio of O ₂ /(Ar+O ₂ ) ranges from 5% to 25%.

7. The application of the method for improving the adsorption density of self-assembled monomolecular carrier transport layer in the preparation of solar cells as claimed in claim 1, characterized in that, comprising the steps of:

Step 1, dissolving the self-assembled monolayer material in anhydrous ethanol solution to prepare a hole transport layer precursor solution;

Step 2. After stirring the hole transport layer precursor solution at room temperature for a set period of time, drop the hole transport layer precursor solution on the surface of the substrate with the NiO _x hole transport layer, and set the rotation speed for the set period of time. Internal rotation of the substrate with the NiO _x hole transport layer;

Step 3. After the substrate with the NiO _x hole transport layer covered with the hole transport layer precursor solution is stopped, it is placed on a heating table for annealing; after cooling, the solution of the self-assembled monolayer material is used in the setting. Washing at a fixed rotational speed to obtain a self-assembled single-molecule carrier transport layer;

Step 4, preparing a perovskite film on the surface of the self-assembled single-molecule carrier transport layer;

Step 5: A hole transport layer C ₆₀ /BCP and an Ag electrode are successively prepared on the surface of the perovskite thin film in step 4 by thermal evaporation.

8 . The application of the method for improving the adsorption density of self-assembled monomolecular carrier transport layer according to claim 7 in the preparation of solar cells, wherein the vacuum degree during evaporation in step 5 is lower than 8×10 ^-6 Pa, the evaporation rate is

9. The application of the method for improving the adsorption density of self-assembled monomolecular carrier transport layer in the preparation of organic light-emitting diodes as claimed in claim 1, characterized in that, the method specifically comprises the following steps:

Step 1. Select F ₅ BnPA as the self-assembled monolayer material, and prepare a self-assembled monomolecular carrier transport layer on the surface of the substrate with the NiO _x hole transport layer: at the set temperature, the NiO _x hole transport layer is The substrate of the layer was soaked in F ₅ BnPA toluene solution; then the substrate of the NiO _x hole transport layer was rotated at a set speed and washed with absolute ethanol to remove the unadsorbed self-assembled monolayer material;

In step 2, an Ir(mppy) ₃ : TCTA film is prepared by spin coating, and LiF, MoO ₃ and Al electrodes are sequentially prepared by thermal evaporation to obtain an organic light emitting diode.