阅读说明：本技术 一种具有可调功函数的透明电极及其制备方法和应用、有机太阳能电池 (Transparent electrode with adjustable work function, preparation method and application thereof, and organic solar cell ) 是由 杨津津 李辉 唐正 马在飞 于 2021-07-09 设计创作，主要内容包括：本发明涉及太阳能电池技术领域,尤其涉及一种具有可调功函数的透明电极及其制备方法和应用。本发明提供了一种具有可调功函数的透明电极的制备方法,包括以下步骤：在ITO基底上涂覆含氨基聚合物溶液,退火,得到电极修饰层；将所述电极修饰层进行氧等离子体处理,得到所述具有可调功函数的透明电极。本发明对电极修饰层进行氧等离子体处理,可以使高能氧离子注入到电极修饰层表面并形成新的界面偶极子,达到改变整个基底的表面功函数。同时,经过氧等离子体处理后的电极功函数具有较好的稳定性。(The invention relates to the technical field of solar cells, in particular to a transparent electrode with adjustable work function and a preparation method and application thereof. The invention provides a preparation method of a transparent electrode with adjustable work function, which comprises the following steps: coating an amino-containing polymer solution on the ITO substrate, and annealing to obtain an electrode modification layer; and carrying out oxygen plasma treatment on the electrode modification layer to obtain the transparent electrode with the adjustable work function. The invention carries out oxygen plasma treatment on the electrode modification layer, so that high-energy oxygen ions can be injected into the surface of the electrode modification layer to form a new interface dipole, and the aim of changing the surface work function of the whole substrate is achieved. Meanwhile, the work function of the electrode treated by the oxygen plasma has better stability.)

1. A preparation method of a transparent electrode with adjustable work function is characterized by comprising the following steps:

coating an amino-containing polymer solution on the ITO substrate, and annealing to obtain an electrode modification layer;

and carrying out oxygen plasma treatment on the electrode modification layer to obtain the transparent electrode with the adjustable work function.

2. The method of claim 1, wherein the oxygen plasma treatment conditions are: the oxygen flow is 10-15 cm³Min; the oxygen partial pressure is 0.12mbar, the power of the plasma generator is less than or equal to 80W, the system pressure is 0.2mbar, and the processing time is 5-100 s.

3. The method of claim 1, wherein the amino-containing polymer in the amino-containing polymer solution comprises a polyethyleneimine or a polyetherimide;

the mass concentration of the amino-containing polymer solution is 0.04-0.4%.

4. The production method according to claim 1 or 3, wherein the coating is performed by spin coating;

the spin coating speed is 3000rpm, and the time is 40-60 s.

5. The method of claim 1, wherein the annealing is performed at a temperature of 100 ℃ for a period of 5 min.

6. The transparent electrode with adjustable work function prepared by the preparation method of any one of claims 1 to 5, wherein the adjustable range of the work function of the transparent electrode with adjustable work function is 4.0-5.2 eV.

7. Use of the transparent electrode with tunable work function according to claim 6 in organic solar cells, organic light emitting diodes and organic field effect transistors.

8. An organic solar cell, comprising an organic solar cell anode, an active layer and an organic solar cell cathode;

the organic solar cell anode is the transparent electrode with adjustable work function in claim 6.

9. An organic solar cell, comprising an organic solar cell anode, a first active layer, a second active layer and an organic solar cell cathode;

the organic solar cell anode is the transparent electrode with adjustable work function in claim 6.

10. The organic solar cell of claim 9, wherein the organic solar cell cathode is prepared by a process comprising the steps of: and coating an amino-containing polymer solution on the ITO substrate, and annealing to obtain the organic solar cell cathode.

Technical Field

The invention relates to the technical field of solar cells, in particular to a transparent electrode with an adjustable work function, a preparation method and application thereof, and an organic solar cell.

Background

Organic Solar Cells (OSCs) are typically sandwich structures, i.e., they include an anode, a cathode, and an organic active layer sandwiched therebetween. The common organic solar cell has a positive structure and a reverse structure, wherein a cathode is generally attached to a transparent substrate through a transparent conductive layer, an anode is made of metal, and the positive structure is also the same, and the difference is only that an interface modification layer on the transparent conductive layer is different.

Indium Tin Oxide (ITO) conductive films have excellent conductivity and transparency characteristics and are widely used in the field of organic optoelectronics, where ITO can be placed on a cathode to collect electrons and can also be used as an anode to collect holes and also can be used as a light incidence window. For organic photovoltaic devices, however, it is desirable that the lower the cathode work function is, the better the electron transport is, the higher the anode work function is, the hole transport is, and the work function of ITO lies between the common cathode and anode work functions and cannot match the highest occupied orbital (HOMO), lowest unoccupied orbital (LUMO) of the active layer to form an ohmic contact, which means that ITO is not an excellent cathode or anode.

In view of the above problems, at present, ohmic contact is formed between an electrode and an active layer mainly by using a cathode interface modification layer, and a common cathode interface modification layer includes zinc oxide or an amino group-containing polymer. For example, in Science 2012,336(6079), 327-. However, the work function of the ITO modified by the cathode interface modification layer can only satisfy the requirement of the ITO as a cathode, and the ITO cannot be used as an anode.

Disclosure of Invention

The invention aims to provide a transparent electrode with adjustable work function, a preparation method and application thereof, and an organic solar cell.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a preparation method of a transparent electrode with adjustable work function, which comprises the following steps:

coating an amino-containing polymer solution on the ITO substrate, and annealing to obtain an electrode modification layer;

and carrying out oxygen plasma treatment on the electrode modification layer to obtain the transparent electrode with the adjustable work function.

Preferably, the oxygen plasma treatment conditions are: the oxygen flow is 10-15 cm³Min; the oxygen partial pressure is 0.12mbar, the power of the plasma generator is less than or equal to 80W, the system pressure is 0.2mbar, and the processing time is 5-100 s.

Preferably, the amino-containing polymer in the amino-containing polymer solution comprises a polyethyleneimine or a polyetherimide;

the mass concentration of the amino-containing polymer solution is 0.04-0.4%.

Preferably, the coating mode is spin coating;

the spin coating speed is 3000rpm, and the time is 40-60 s.

Preferably, the annealing temperature is 100 ℃ and the annealing time is 5 min.

The invention also provides the transparent electrode with the adjustable work function prepared by the preparation method in the technical scheme, and the adjustable range of the work function of the transparent electrode with the adjustable work function is 4.0-5.2 eV.

The invention also provides the application of the transparent electrode with the adjustable work function in an organic solar cell, an organic light-emitting diode and an organic field effect transistor.

The invention also provides an organic solar cell, which comprises an organic solar cell anode, an active layer and an organic solar cell cathode;

the organic solar cell anode is the transparent electrode with the adjustable work function in the technical scheme.

The invention also provides an organic solar cell, which comprises an organic solar cell anode, a first active layer, a second active layer and an organic solar cell cathode;

the organic solar cell anode is the transparent electrode with the adjustable work function in the technical scheme.

Preferably, the preparation process of the organic solar cell cathode comprises the following steps: and coating an amino-containing polymer solution on the ITO substrate, and annealing to obtain the organic solar cell cathode.

The invention provides a preparation method of a transparent electrode with adjustable work function, which comprises the following steps: coating an amino-containing polymer solution on the ITO substrate, and annealing to obtain an electrode modification layer; and carrying out oxygen plasma treatment on the electrode modification layer to obtain the transparent electrode with the adjustable work function. According to the invention, oxygen plasma treatment is carried out on the electrode modification layer, so that high-energy oxygen ions are injected to the surface of the electrode modification layer, and an interface dipole formed by orientation effect on a polymer polar group can regulate and control the work function of the electrode, thereby promoting the collection of charges on the electrode and the exciton separation. Meanwhile, the electrode modification layer treated by the oxygen plasma has better acid resistance and corrosion resistance, so that the stability of the electrode is improved.

Drawings

FIG. 1 shows that the transparent electrode with adjustable work function obtained after oxygen plasma treatment for 5s, 10s, 15s, 30s, 50s and 100s in example 1 is used as an anode, the Glass/ITO/PEIE prepared in example 1 is used as a cathode of an organic solar cell, and MoO is used as a cathode of the organic solar cell₃The illumination current-voltage curve of the organic solar cell is prepared by taking Ag as an anode and PM6: ITIC as an active layer;

FIG. 2 is an illumination current-voltage curve of the organic solar cell obtained after oxygen plasma treatment for 5s, 10s, 15s, 30s, 50s and 100s in example 2;

FIG. 3 is a graph of the work function versus time for the transparent electrode with tunable work function obtained in example 1 and for Glass/ITO/PEIE prepared in example 1;

FIG. 4 is a schematic flow chart of the preparation of an organic solar cell in example 3;

FIG. 5 is a graph of an illumination current-voltage of the organic solar cell obtained by using the organic solar cell described in comparative example 1 and the organic solar cell obtained in example 2 in which the oxygen plasma treatment time was 150 seconds;

fig. 6 is a graph showing the decay curve of the open circuit voltage of an organic solar cell further prepared by the transparent electrode with adjustable work function prepared in example 2 under different oxygen plasma treatment times (the curves are 150s, 100s, 30s, 5s and 1s from top to bottom);

FIG. 7 is a UPS graph showing the transparent electrode having an adjustable work function obtained after the oxygen plasma treatment time is 3s, 5s, 10s, 15s, 20s and 80s for ITO, ITO/PEIE and example 1, respectively, and the transparent electrode having an adjustable work function prepared in example 4;

FIG. 8 is an illumination current-voltage curve of the organic solar cells obtained in comparative examples 1 to 2 and example 3.

Detailed Description

The invention provides a preparation method of a transparent electrode with adjustable work function, which comprises the following steps:

coating an amino-containing polymer solution on the ITO substrate, and annealing to obtain an electrode modification layer;

and carrying out oxygen plasma treatment on the electrode modification layer to obtain the transparent electrode with the adjustable work function.

In the present invention, all the starting materials for the preparation are commercially available products known to those skilled in the art unless otherwise specified.

According to the invention, an ITO substrate is coated with an amino-containing polymer solution, and annealing is carried out to obtain the electrode modification layer.

In the present invention, the mass concentration of the amino group-containing polymer solution is preferably 0.04 to 0.4%, more preferably 0.05 to 0.3%, and most preferably 0.06 to 0.1%. In the present invention, the amino-containing polymer in the amino-containing polymer solution preferably comprises a polyethyleneimine or a polyetherimide, more preferably a Polyethyleneimine (PEIE).

In the present invention, the amino group-containing polymer solution is preferably prepared by diluting the amino group-containing polymer. In the present invention, the diluent used for the dilution is preferably ultrapure water.

Prior to said coating, the present invention preferably comprises pre-treating said ITO substrate; the pretreatment is preferably ultrasonic cleaning in an ultrapure water solution containing a detergent for 15min, then washing with ultrapure water until no foam exists, then sequentially ultrasonic cleaning in acetone for 15min, ultrasonic cleaning in isopropanol for 15min and ultrasonic cleaning in ethanol for 15min, and then blow-drying with nitrogen.

In the invention, the coating mode is preferably spin coating; the spin coating is preferably performed at a speed of 3000rpm for a period of 1 min.

In the present invention, the spin coating process is preferably: and placing the ITO substrate on a spin coater, vacuumizing and sucking the ITO substrate, and pumping 80 mu L of amino-containing polymer solution by a liquid-transferring gun to spin-coat the ITO substrate at the rotating speed of 3000rpm for 40-60 s.

In the present invention, the temperature of the annealing is preferably 100 ℃ and the time is preferably 5 min.

In the invention, the thickness of the electrode modification layer is preferably 1-10 nm, more preferably 1-5 nm, and most preferably 2 nm.

After the electrode modification layer is obtained, the electrode modification layer is subjected to oxygen plasma treatment to obtain the transparent electrode with the adjustable work function.

In the present invention, the conditions of the oxygen plasma treatment are preferably: the oxygen flow is preferably 10-15 cm³A/min, more preferably 10 to 12cm³Min; the oxygen partial pressure is preferably 0.12 mbar; the power of the plasma generator is preferably less than or equal to 80W; the system pressure is preferably 0.2 mbar; the treatment time is preferably 5 to 100 seconds, more preferably 20 to 80 seconds, and most preferably 40 to 60 seconds.

In a specific embodiment of the present invention, the oxygen plasma treatment process specifically includes: and placing the substrate containing the electrode modification layer on a substrate table of a plasma chamber, wherein the electrode modification layer faces towards the plasma, and introducing oxygen to perform oxygen plasma treatment.

The invention also provides the transparent electrode with the adjustable work function prepared by the preparation method in the technical scheme, and the adjustable range of the work function of the transparent electrode with the adjustable work function is 4.0-5.2 eV.

The invention also provides the application of the transparent electrode with the adjustable work function in an organic solar cell, an organic light-emitting diode and an organic field effect transistor.

The invention also provides an organic solar cell, which comprises an organic solar cell anode, an active layer and an organic solar cell cathode;

the organic solar cell anode is a transparent electrode with adjustable work function in the technical scheme.

In the present invention, the thickness of the active layer is preferably 100 nm. The material of the active layer is preferably non-fullerene material or fullerene material; the non-fullerene material is preferably PM6: ITIC or PM6: y7; the PM6: the mass ratio of PM6 to ITIC in ITIC is preferably 1: (1-2), more preferably 1: (1-1.5); the PM6: the mass ratio of PM6 and Y7 in Y7 is preferably 1: (1-2), more preferably 1: (1-1.5); the fullerene material is preferably P3HT: PCBM; the mass ratio of P3HT to PCBM in the P3 HT-PCBM is preferably as follows: (1-2), more preferably 1: (1-1.5).

In the invention, the thickness of the organic solar cell cathode is preferably 1-10 nm, more preferably 1-5 nm, and most preferably 2 nm. In the invention, the material of the cathode of the organic solar cell is preferably LiF/Al or PDNIO/Al, and is also preferably an ITO substrate containing an electrode modification layer; the electrode modification layer is preferably PEIE; the thickness of the electrode modification layer is preferably 1-10 nm, more preferably 1-5 nm, and most preferably 2 nm.

In the present invention, the method for manufacturing an organic solar cell preferably includes the steps of:

coating an active layer material on the surface of the modification layer of the organic solar cell anode to obtain an active layer;

and evaporating a cathode material on the surface of the active layer to obtain an organic solar cell cathode, and further obtaining the organic solar cell.

The coating and evaporation process is not particularly limited, and may be performed by a process known to those skilled in the art.

The invention also provides an organic solar cell, which comprises an organic solar cell anode, a first active layer, a second active layer and an organic solar cell cathode;

the organic solar cell anode is the transparent electrode with the adjustable work function in the technical scheme.

In the present invention, it is preferable that the materials of the thicknesses of the first active layer and the second active layer are independent, refer to the definition of the active layer in the above technical solution, and are not described herein again.

In the present invention, the process for preparing the cathode of the organic solar cell preferably includes the steps of: and coating an amino-containing polymer solution on the ITO substrate, and annealing to obtain the organic solar cell cathode. In the present invention, the process of coating preferably refers to the process of preparing the electrode modification layer in the above technical scheme, and is not described herein again.

In the present invention, the method for manufacturing an organic solar cell preferably includes the steps of:

coating a first active layer material on the surface of a modification layer of an organic solar cell anode to obtain a first active layer and further obtain an anode side;

coating a second active layer material on the surface of the modification layer of the cathode of the organic solar cell to obtain a second active layer and further obtain a cathode side;

and contacting the first active layer on the anode side and the second active layer on the cathode side, and pressing to obtain the organic solar cell.

The coating and pressing process of the present invention is not particularly limited, and may be performed by a process known to those skilled in the art.

The transparent electrode with adjustable work function, the preparation method and the application thereof, and the organic solar cell provided by the present invention are described in detail with reference to the following examples, but they should not be construed as limiting the scope of the present invention.

Example 1

Ultrasonically cleaning an ITO glass substrate in an ultrapure water solution containing a detergent for 15min, then washing the ITO glass substrate with ultrapure water until no foam exists, then sequentially ultrasonically cleaning the ITO glass substrate in acetone for 15min, ultrasonically cleaning the ITO glass substrate in isopropanol for 15min and ultrasonically cleaning the ITO glass substrate in ethanol for 15min, and blow-drying the ITO glass substrate with nitrogen to obtain a pretreated ITO glass substrate;

diluting PEIE to PEIE solution with mass concentration of 0.04% by adopting ultrapure water;

placing the pretreated ITO Glass substrate on a spin coater, vacuumizing and sucking the pretreated ITO Glass substrate, extracting 80 mu L of PEIE solution by a liquid transfer gun, spin-coating the PEIE solution on the surface of the pretreated ITO Glass substrate at the rotating speed of 3000rpm, and annealing at the temperature of 100 ℃ for 5min to obtain an electrode modification layer (the thickness is 2nm and is marked as Glass/ITO/PEIE);

placing the Glass/ITO/PEIE in a horizontal table of a plasma processor chamber, wherein the PEIE is faced upwards, closing a vacuum chamber, and vacuumizing, wherein the vacuumizing rate of the vacuumizing is 5m³Introducing oxygen into the chamber for oxygen plasma treatment, wherein the flow rate of the oxygen is 10cm³The method comprises the following steps of (1) min, partial pressure value of 0.12mpa, power of a plasma generator of 16W (the maximum power of the plasma generator is 20%), system pressure of 0.2mbar, and processing time of 1s, 3s, 5s, 10s, 15s, 20s, 30s, 50s, 60s, 80s, 100s and 150s respectively, so that the transparent electrode with the adjustable work function is obtained.

Example 2

Ultrasonically cleaning an ITO glass substrate in an ultrapure water solution containing a detergent for 15min, then washing the ITO glass substrate with ultrapure water until no foam exists, then sequentially ultrasonically cleaning the ITO glass substrate in acetone for 15min, ultrasonically cleaning the ITO glass substrate in isopropanol for 15min and ultrasonically cleaning the ITO glass substrate in ethanol for 15min, and blow-drying the ITO glass substrate with nitrogen to obtain a pretreated ITO glass substrate;

diluting PEIE to PEIE solution with mass concentration of 0.04% by adopting ultrapure water;

placing the pretreated ITO Glass substrate on a spin coater, vacuumizing and sucking the pretreated ITO Glass substrate, extracting 80 mu L of PEIE solution by a liquid transfer gun, spin-coating the PEIE solution on the surface of the pretreated ITO Glass substrate at the rotating speed of 3000rpm, and annealing at the temperature of 100 ℃ for 5min to obtain an electrode modification layer (the thickness is 2nm and is marked as Glass/ITO/PEIE);

placing the Glass/ITO/PEIE in a horizontal table of a plasma processor chamber, wherein the PEIE is faced upwards, closing a vacuum chamber, and vacuumizing, wherein the vacuumizing rate of the vacuumizing is 5m³Introducing oxygen into the chamber for oxygen plasma treatment, wherein the flow rate of the oxygen is 10cm³The method comprises the following steps of (1)/min, partial pressure value of 0.12mpa, power of a plasma generator of 16W (the maximum power of the plasma generator is 20%), system pressure of 0.2mbar, processing time of 1s, 5s, 10s, 15s, 20s, 30s, 50s, 60s, 100s and 150s, and obtaining the transparent electrode with adjustable work function;

and (3) spin-coating PM6 with the concentration of 20mg/mL on the surface of the transparent electrode (as an anode): after an ITIC (PM6 and ITIC are in a mass ratio of 1: 1) solution, annealing at 100 ℃ for 5min to obtain an active layer with the thickness of about 100 nm; and then transferring the solar cell to an evaporation bin mask plate, and evaporating LiF and Al to obtain an electrode layer with the thickness of about 100 (firstly evaporating 0.6nm LiF and then evaporating 100nm Al), and finally obtaining the solar cell.

Example 3

Ultrasonically cleaning an ITO glass substrate in an ultrapure water solution containing a detergent for 15min, then washing the ITO glass substrate with ultrapure water until no foam exists, then sequentially ultrasonically cleaning the ITO glass substrate in acetone for 15min, ultrasonically cleaning the ITO glass substrate in isopropanol for 15min and ultrasonically cleaning the ITO glass substrate in ethanol for 15min, and blow-drying the ITO glass substrate with nitrogen to obtain a pretreated ITO glass substrate;

diluting PEIE to PEIE solution with mass concentration of 0.04% by adopting ultrapure water;

placing the pretreated ITO Glass substrate on a spin coater, vacuumizing and sucking the pretreated ITO Glass substrate, extracting 80 mu L of PEIE solution by a liquid transfer gun, spin-coating the PEIE solution on the surface of the pretreated ITO Glass substrate at the rotating speed of 3000rpm, and annealing at the temperature of 100 ℃ for 5min to obtain an electrode modification layer (the thickness is 2nm and is marked as Glass/ITO/PEIE);

placing the Glass/ITO/PEIE in a horizontal stage of a plasma processor chamberThe PEIE is faced upwards, the vacuum chamber is closed, and vacuum pumping is performed, wherein the vacuum pumping rate is 5m³Introducing oxygen into the chamber for oxygen plasma treatment, wherein the flow rate of the oxygen is 10cm³Min, the partial pressure value is 0.12mpa, the power of the plasma generator is 16W (the maximum power of the plasma generator is 20%), the system pressure is 0.2mbar, and the processing time is 150s, so that the transparent electrode with the adjustable work function is obtained;

and (3) spin-coating PM6 with the concentration of 20mg/mL on the surface of the transparent electrode (as an anode): obtaining an active layer with the thickness of 50nm after dissolving the ITIC (the mass ratio of PM6 to ITIC is 1: 1);

ultrasonically cleaning an ITO glass substrate in an ultrapure water solution containing a detergent for 15min, then washing the ITO glass substrate with ultrapure water until no foam exists, then sequentially ultrasonically cleaning the ITO glass substrate in acetone for 15min, ultrasonically cleaning the ITO glass substrate in isopropanol for 15min and ultrasonically cleaning the ITO glass substrate in ethanol for 15min, and blow-drying the ITO glass substrate with nitrogen to obtain a pretreated ITO glass substrate;

diluting PEIE to PEIE solution with mass concentration of 0.04% by adopting ultrapure water;

placing the pretreated ITO glass substrate on a spin coater, vacuumizing and sucking the pretreated ITO glass substrate, extracting 80 mu L of PEIE solution by a liquid transfer gun, spin-coating the PEIE solution on the surface of the pretreated ITO glass substrate at the rotating speed of 3000rpm, and annealing at the temperature of 100 ℃ for 5min to obtain an electrode modification layer (the thickness is 2nm) and obtain an organic solar cell cathode;

spin-coating the surface of the organic solar cell cathode with PM6 with a concentration of 20 mg/mL: the mass ratio of ITIC PM6 to ITIC is 1: 1) after the solution, an active layer with a thickness of 50nm is obtained;

after the active layers in the anode and the cathode respectively provided with the active layers were brought into contact and stacked together, annealing was performed at 100 ℃ for 5min to obtain an organic solar cell (see fig. 4 for a flowchart of the production process).

Example 4

Ultrasonically cleaning an ITO glass substrate in an ultrapure water solution containing a detergent for 15min, then washing the ITO glass substrate with ultrapure water until no foam exists, then sequentially ultrasonically cleaning the ITO glass substrate in acetone for 15min, ultrasonically cleaning the ITO glass substrate in isopropanol for 15min and ultrasonically cleaning the ITO glass substrate in ethanol for 15min, and blow-drying the ITO glass substrate with nitrogen to obtain a pretreated ITO glass substrate;

diluting PEIE to PEIE solution with mass concentration of 0.04% by adopting ultrapure water;

placing the pretreated ITO Glass substrate on a spin coater, vacuumizing and sucking the pretreated ITO Glass substrate, extracting 80 mu L of PEIE solution by a liquid transfer gun, spin-coating the PEIE solution on the surface of the pretreated ITO Glass substrate at the rotating speed of 3000rpm, and annealing at the temperature of 100 ℃ for 5min to obtain an electrode modification layer (the thickness is 2nm and is marked as Glass/ITO/PEIE);

placing the Glass/ITO/PEIE in a horizontal table of a plasma processor chamber, wherein the PEIE is faced upwards, closing a vacuum chamber, and vacuumizing, wherein the vacuumizing rate of the vacuumizing is 5m³Introducing oxygen into the chamber for oxygen plasma treatment, wherein the flow rate of the oxygen is 10cm³And/min, the partial pressure value is 0.12mpa, the power of the plasma generator is 16W (the maximum power of the plasma generator is 20%), the system pressure is 0.2mbar, and the processing time is 150s, so that the transparent electrode with the adjustable work function is obtained.

Comparative example 1

Ultrasonically cleaning an ITO glass substrate in an ultrapure water solution containing a detergent for 15min, then washing the ITO glass substrate with ultrapure water until no foam exists, then sequentially ultrasonically cleaning the ITO glass substrate in acetone for 15min, ultrasonically cleaning the ITO glass substrate in isopropanol for 15min and ultrasonically cleaning the ITO glass substrate in ethanol for 15min, and blow-drying the ITO glass substrate with nitrogen to obtain a pretreated ITO glass substrate;

spin-coating the original solution of PEDOT (PSS (4083)) purchased;

placing the pretreated ITO glass substrate on a spin coater, vacuumizing and sucking the pretreated ITO glass substrate, extracting 120 mu L of PEDOT solution by a liquid transfer gun, spin-coating the PEDOT solution on the surface of the pretreated ITO glass substrate at the rotating speed of 5000rpm, and annealing at the temperature of 150 ℃ for 20min to obtain an electrode modification layer (the thickness is 33nm, recorded as ITO/PEDOT: PSS), so as to obtain an organic solar cell electrode;

spin coating the surface of the organic solar cell anode with PM6 at a concentration of 20mg/mL (total concentration of mixture): after an ITIC (PM6 and ITIC are in a mass ratio of 1: 1) solution, annealing at 100 ℃ for 5min to obtain an active layer with the thickness of 100 nm; and then transferring the solar cell to an evaporation bin mask plate, and evaporating LiF and Al, (firstly evaporating 0.6nm LiF, and then evaporating 100nm Al), thereby finally obtaining the solar cell.

Comparative example 2

With reference to comparative example 1, the only difference is that PEDOT: PSS was replaced by PEIE, noted as ITO/PEIE.

Test example

The transparent electrode with adjustable work function obtained after the oxygen plasma treatment time of 0s, 5s, 10s, 15s, 30s, 50s and 100s in example 1 and the Glass/ITO/PEIE prepared in example 1 are respectively used as the cathode of an organic solar cell, and MoO is used₃Ag as anode, PM6: the ITIC is an active layer, an organic solar cell is prepared, and an illumination current-voltage curve of the organic solar cell is tested, the test result is shown in fig. 1, as can be seen from fig. 1, as the processing time increases, the open circuit voltage value gradually decreases (0.99V, 0.84V, 0.63V, 0.42V, 0.30V, 0.01V, respectively), which indicates that the electrode potential levels are more and more mismatched, and the change of the open circuit further proves that the cathode work function after oxygen plasma processing gradually increases;

fig. 2 is an illumination current-voltage curve of the organic solar cell prepared in example 2 after the oxygen plasma treatment time is 5s, 10s, 15s, 30s, 50s and 100s, respectively, and it can be seen from fig. 2 that as the treatment time increases, the open circuit voltage gradually increases (0.15V, 0.31V, 0.41V, 0.54V, 0.65V, 0.75V, 0.88V and 0.98V, respectively), which indicates that the electrode potential levels are more and more matched, and the change of the open circuit further proves that the anode work function after the oxygen plasma treatment gradually increases;

FIG. 3 is a graph showing the change of work function with time of the transparent electrode with adjustable work function obtained in example 1 and the Glass/ITO/PEIE prepared in example 1, and it can be seen from FIG. 3 that the work functions of the cathode of the organic solar cell obtained after the oxygen plasma treatment time of example 1 is respectively 0s, 5s, 10s, 15s, 30s, 50s and 100s and the work functions of the Glass/ITO/PEIE prepared in example 1 are sequentially 4.02eV, 4.11eV, 4.36V, 4.41eV, 4.68eV, 5.0eV and 5.1 eV;

FIG. 5 is a graph of an illumination current-voltage of the organic solar cell obtained by using the organic solar cell described in comparative example 1 and the organic solar cell obtained in example 2 in which the oxygen plasma treatment time was 150 seconds; as can be seen from FIG. 5, the ITO/PEIE anode obtained by the oxygen plasma treatment achieves the same work function value as the ITO/PEDOT: PSS anode, and the performance of the prepared device can be compared with that of a device using the ITO/PEDOT: PSS anode;

fig. 6 is a decay curve of the open-circuit voltage of the organic solar cell further prepared by the transparent electrode with adjustable work function prepared in example 2 under different oxygen plasma treatment times (the curve is 150s, 100s, 30s, 5s, 1s from top to bottom in sequence), and it can be seen from fig. 6 that the prepared device has a relatively stable open-circuit voltage value, that is, the processed work function value is relatively stable;

fig. 7 is a graph of UPS showing the transparent electrode having an adjustable work function obtained after ITO, ITO/PEIE, and oxygen plasma treatment times in example 1 are respectively 3s, 5s, 10s, 15s, 20s, 80s, 100s, and 150s, and the transparent electrode having an adjustable work function prepared in example 4, and as can be seen from fig. 7, UPS is a work function measuring method, and a specific value of the work function can be visually read from the graph.

FIG. 8 is an illumination current-voltage curve of the organic solar cells obtained in comparative examples 1-2 and example 3, and it can be seen from FIG. 8 that the open-circuit voltage value of the organic solar cell prepared by the method in example 3 is substantially the same as that in comparative examples 1-2, and the short-circuit current value is reduced by about 30% compared with that in comparative examples 1-2. The open-circuit voltage value is determined by the work functions of the cathode and the anode, the work functions of the cathode and the anode are basically consistent in the embodiment 3 and the comparative examples 1-2, the short-circuit current value is greatly influenced by the transparency of the electrode, the cathode and the anode are transparent electrodes in the embodiment 3, and one side of the comparative examples 1-2 is a transparent electrode, and the other side of the comparative examples 1-2 is an opaque electrode. Meanwhile, since the cathode and the anode of the device prepared in example 3 are transparent, light irradiation from the anode side and the cathode side is selected respectively when the light irradiation current-voltage test is performed, and the obtained current-voltage curves are substantially consistent.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.