CN105552233A - Bulk heterojunction organic solar cell with dual-anode buffer layer and preparation method of bulk heterojunction organic solar cell - Google Patents

Abstract

The invention relates to a heterojunction organic solar cell with a double anode buffer layer. The battery adopts a positive structure, and the sequence from bottom to top is: transparent substrate, transparent conductive anode, anode buffer layer, organic active layer, and cathode buffer layer. , metal cathode; wherein the anode buffer layer is a double anode buffer layer composed of PTFE anode buffer layer and MoO ₃ anode buffer layer; the PTFE anode buffer layer is prepared on a transparent conductive anode with a thickness of 0.3-2nm _; Between the PTFE anode buffer layer and the organic active layer, the thickness is 4-10nm. The present invention improves the surface work function of the anode by introducing a double anode buffer layer between the anode and the active layer, and excellently modifies the interface energy level difference; while ensuring the transmission of holes, it improves the ability to block electrons, which is extremely The recombination of electrons and holes is greatly reduced, thereby improving the energy conversion efficiency of solar cells.

Description

A kind of double anode buffer layer bulk heterojunction organic solar cell and its preparation method

technical field

The invention belongs to the technical field of organic photovoltaic devices, and in particular relates to a bulk heterojunction organic solar cell with double anode buffer layers and a preparation method thereof.

Background technique

Nowadays, traditional energy sources are depleting day by day, environmental pollution is becoming more and more serious, and human beings are facing the double test of energy crisis and environmental pollution. Therefore, looking for green energy sources with low energy consumption, low pollution, and low emissions, such as solar energy, wind energy, water energy, geothermal energy, and tidal energy, has become a need for the development of a low-carbon economy. Among them, solar energy has become a research focus and hotspot for solving energy and environmental problems due to its renewable, clean, and abundant reserves.

A solar cell is a device that converts light energy radiated by the sun into electrical energy, and is one of the most important ways to utilize solar energy. At present, although traditional inorganic solar cells such as silicon and gallium arsenide solar cells have been put into the market, their high cost and high requirements for inorganic semiconductors limit their further development. Organic solar cells are a new type of solar cells developed in the past two decades. Compared with traditional solar cells, they have more advantages and development due to their advantages such as wide source of materials, low cost, simple preparation process, and large-area flexible devices. Space has received more and more attention. The reported energy conversion efficiency of organic solar cells has reached more than 10%, but this figure is far from meeting the requirements for mass production. Therefore, how to improve the energy conversion efficiency of organic solar cells by optimizing the device structure and improving the preparation process has become the focus of research on organic solar cells.

There are many important factors that determine the device performance of organic solar cells, one of which is the effective charge transport in the organic active layer, which depends on the good interfacial properties between the active layer and the anode. Therefore, the researchers introduced an interface layer between the active layer and the anode, that is, the anode buffer layer. Currently commonly used anode buffer layers include PEDOT:PSS and metal oxides with high work function such as MoO ₃ . However, the acidic and hygroscopic properties of PEDOT:PSS degrade the overall performance of the device. _In addition, although MoO3 can effectively transport holes, it cannot effectively block the electron transport from the active layer to the anode, so the device has high carrier recombination.

Contents of the invention

The technical problem to be solved by the present invention is to provide a double anode buffer layer bulk heterojunction organic solar cell and a preparation method thereof. The solar cell introduces a double anode buffer layer, which well modifies the interface between the active layer and the anode ITO, and reduces the barrier between the active layer and the anode. In addition, the dual anode buffer layer is beneficial to the separation of excitons and the transport of carriers, reducing the probability of carrier recombination, so it can effectively improve the energy conversion efficiency of the device.

In order to solve the above-mentioned technical problems, the double-anode buffer layer bulk heterojunction organic solar cell of the present invention adopts a positive structure, and the order from bottom to top is: transparent substrate, transparent conductive anode, anode buffer layer, organic active layer, cathode buffer Layer, metal cathode; It is characterized in that described anode buffer layer is the dual anode buffer layer that PTFE anode buffer layer and MoO ₃ anode buffer layers form; PTFE anode buffer layer is prepared on the transparent conductive anode; MoO ₃ anode buffer layers are prepared in PTFE Between the anode buffer layer and the organic active layer; the thickness of the PTFE anode buffer layer is 0.3-2nm, and the thickness of the MoO ₃ anode buffer layer is 4-10nm.

The thickness of the PTFE anode buffer layer is preferably 1.5 nm.

Described transparent substrate is transparent glass or transparent flexible polymer, and transparent flexible polymer is polyethylene, polyethylene terephthalate, polymethyl methacrylate, polycarbonate, polyurethane, polyester One of imide or polyacrylic acid, or two or more of them are mixed, or two or more of them are prepared layer by layer in sequence.

The transparent conductive anode, whose material is indium tin oxide (ITO), is deposited on a transparent substrate;

The transparent conductive anode has a thickness of 150nm and a sheet resistance of 15Ω/□.

The organic active layer is a mixture of electron donor material PCDTBT and electron acceptor material PC ₇₁ BM at a mass ratio of 1:4, or an electron donor material P3HT and electron acceptor material PC ₆₁ BM at a ratio of 1 :1 mass ratio configuration mixture.

The cathode buffer layer is made of one of Alq3, LiF, small porphyrin molecules, Bphen or BCP, or two or more of these materials are sequentially prepared layer by layer, with a thickness of 1-10 nm.

The metal cathode is made of one of Al, Ca, Ag or Au, or two or more of these materials are prepared layer by layer in sequence, and the thickness is 100nm-200nm.

The preparation method of the dual anode buffer layer body heterojunction organic solar cell of the present invention comprises the following steps:

① Use toluene, acetone, detergent, deionized water, and isopropanol in sequence to ultrasonically clean the substrate composed of the transparent conductive anode and the transparent substrate, and store the cleaned substrate in isopropanol for later use;

②The cleaned substrate is blown dry with nitrogen, moved into a drying oven for drying, and then plasma treated with a Plasma cleaning machine;

③ Move the treated substrate into the vacuum coating machine, evaporate the PTFE anode buffer layer on the transparent conductive anode, and then evaporate the MoO3 anode buffer layer _on the PTFE anode buffer layer; wherein the evaporation rate of PTFE is The thickness is 0.3~2nm, the evaporation rate of MoO ₃ is The thickness is 4~10nm;

④ Move the above-mentioned substrate on which the double anode buffer layer has been vapor-deposited into the Plasma cleaning machine for plasma treatment;

⑤ Prepare an organic active layer on the MoO ₃ anode buffer layer;

⑥ Move the substrate obtained in step ⑤ into a vacuum coating machine, and sequentially vapor-deposit a cathode buffer layer and a metal cathode on the organic active layer.

In the step 5., spin-coat the mixed solution of the electron donor material PCDTBT and the electron acceptor material PC ₇₁ BM at a mass ratio of 1: ₄ on the MoO anode buffer layer in a nitrogen atmosphere by spin coating, and evenly The speed of the glue machine is 1500rpm/s, and the spin coating time is 40s; the solvent of the mixed solution is o-dichlorobenzene, and the concentration of the solution is PCDTBT:PC ₇₁ BM=8mg/ml:32mg/ml; The solvent was evaporated by lower annealing for 30 minutes to obtain an organic active layer.

In the step ⑤, the electron donor material P3HT and the electron acceptor material PC ₆₁ BM are spin _- coated on the MoO anode buffer layer in a nitrogen atmosphere by spin-coating a mixed solution configured in a mass ratio of 1:1, The speed of the homogenizer is 700rpm/s, and the spin coating time is 36s; the solvent of the mixed solution is o-dichlorobenzene, and the concentration of the solution is P3HT:PC ₆₁ BM=17mg/ml:17mg/ml; then annealed at room temperature for 3h and evaporated The solvent was removed to obtain an organic active layer.

In the described 6. step, Alq is vapor-deposited on the organic active layer Cathode buffer layer, evaporation rate is The thickness of Alq3 is 1nm; the Al metal electrode is evaporated on the Alq3 cathode buffer layer, and the evaporation rate is about Al thickness is 100nm-200nm.

The invention provides a bulk heterojunction organic solar cell with a double anode buffer layer, which greatly improves the performance of the organic solar cell, especially the impact factor and energy conversion efficiency, and has the advantages of simple preparation process, low cost, High efficiency and other advantages.

Compared with the prior art, the present invention has the advantages of:

1. The double anode buffer layer body heterojunction organic solar cell provided by the present invention is composed _of PTFE and MoO3 to form a double anode buffer layer, which improves the surface work function of the anode and excellently modifies the contact between the anode ITO and the active layer. The poor interface energy level ensures good interface performance.

2. The double-anode buffer layer body heterojunction organic solar cell provided by the present invention is composed of PTFE and MoO3 to form a double _- anode buffer layer. Compared with the single _- layer anode buffer layer MoO3, the blocking ability to electrons is greatly improved. It reduces the recombination probability of electrons and holes, thereby improving the energy conversion efficiency of solar cells.

3. The double anode buffer layer body heterojunction organic solar cell provided by the present invention is composed _of PTFE and MoO3 to form a double anode buffer layer. Compared with the traditional anode buffer layer PEDOT:PSS, the chemical properties and physical properties of PTFE are all the same. It is very stable, has moisture resistance, and will not corrode the anode ITO, so the device has better stability.

4. The double-anode buffer layer bulk heterojunction organic solar cell provided by the present invention is composed of PTFE and MoO3 to form a double _- anode buffer layer, which has a wide range of material sources, low cost and simple preparation process.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Fig. 1 is the structural representation of double anode buffer layer bulk heterojunction organic solar cell of the present invention;

Fig. 2 is the J-V curve measured under the light intensity of AM1.5G of embodiment 1 of the double anode buffer layer bulk heterojunction organic solar cell of the present invention and comparative device;

Fig. 3 is a schematic diagram showing that the performance of the double anode buffer layer bulk heterojunction organic solar cell of the present invention changes with the thickness of the PTFE anode buffer layer.

Fig. 4 is the J-V curve measured under the illumination intensity of AM1.5G of the embodiment 2 of the double anode buffer layer bulk heterojunction organic solar cell of the present invention and the comparative device.

Fig. 5 is a schematic diagram of the relationship between the performance of the double anode buffer layer bulk heterojunction organic solar cell of the present invention and the thickness of the MoO ₃ anode buffer layer.

detailed description

As shown in Figure 1, the double-anode buffer layer bulk heterojunction organic solar cell of the present invention adopts a positive structure, and the order from bottom to top is: transparent substrate, transparent conductive anode, double-anode buffer layer, organic active layer, cathode Buffer layer, metal anode. The first layer of the double anode buffer layer is a PTFE anode buffer layer, which is prepared on a transparent conductive anode, and its thickness ranges from 0.3 to 2 nm; the second layer is an MoO ₃ anode buffer layer, which is prepared on a PTFE anode buffer layer, and its thickness ranges from 4-10nm; the organic active layer is formed by mixing electron donor materials and electron acceptor materials, and is prepared on the MoO ₃ anode buffer layer.

Wherein the organic active layer in embodiment 1 is prepared by mixing the donor material PCDTBT and the acceptor material PC ₇₁ BM, the mass percent of the PCDTBT:PC ₇₁ BM mixed solution is 1:4, the solvent is o-dichlorobenzene, the solution The concentration is PCDTBT:PC ₇₁ BM=8mg/ml:32mg/ml, and the mixed solution is heated and stirred at 60°C for 12h. In Example 5, the active layer is prepared by mixing the donor material P3HT and the acceptor material PC ₆₁ BM, the mass percentage of the P3HT:PC ₆₁ BM mixed solution is 1:1, the solvent is o-dichlorobenzene, and the concentration of the solution is P3HT:PC ₆₁ BM=17mg/ml:17mg/ml, the mixed solution was stirred at room temperature for 14h.

Example 1:

The preparation method of the double-anode buffer layer bulk heterojunction organic solar cell is as follows: firstly, toluene, acetone, detergent, deionized water, and isopropanol are used in sequence to form a substrate composed of a transparent substrate and an indium tin oxide (ITO) transparent conductive anode. The slices were ultrasonically cleaned, each step was 20 min. After the cleaned substrate was blown dry with nitrogen, it was moved into a drying oven to dry for 20 minutes. The substrate was then treated with a Plasma cleaner for 5 min. The double anode buffer layer is prepared by vacuum evaporation. Firstly, the treated substrate is moved into a vacuum coating machine and the PTFE anode buffer layer is evaporated on the transparent conductive anode. The evaporation rate of PTFE is Then evaporate MoO ₃ anode buffer layer on the PTFE anode buffer layer, the evaporation rate of MoO ₃ is After the evaporation is completed, the thickness of the PTFE anode buffer layer is 1.5nm, and the thickness _of the MoO3 anode buffer layer is 5nm. Move the substrate on which the double anode buffer layer has been evaporated into the Plasma cleaning machine, and process it for 2 minutes. The electron donor material PCDTBT and the electron acceptor material PC ₇₁ BM are dissolved in o-dichlorobenzene at a mass percentage of 1:4 to obtain a mixed solution with a concentration of PCDTBT:PC ₇₁ BM=8mg/ml:32mg/ml, and the mixed solution Heat and stir at 60°C for 12h; then move the substrate into a glove box (nitrogen atmosphere), and prepare a PCDTBT:PCB ₇₁ M organic active layer on the MoO ₃ anode buffer layer by spin coating at a speed of 1500rpm/s for 40s , with a thickness of about 90nm. After spin-coating to form a film, put the substrate on a heating plate for thermal annealing (70°C, 30min), so as to evaporate excess solvent and form a good phase-separated structure in the organic active layer. After annealing, the substrate is moved into a vacuum coating machine, and the cathode buffer layer Alq3 (thickness is 1 nm, evaporation rate is ) and metal cathode Al (thickness is 120nm, evaporation rate is ). After the metal cathode Al evaporation is completed, stay in the glove box for 15 minutes to cool the substrate and prevent the Al electrode from being oxidized in the air. The prepared device has an effective area of 0.05 cm ² . The devices were tested under 100mw/cm ² AM1.5 simulated light, the current density-voltage (JV) curve was measured by Keithley2400 digital source meter, and the test process was carried out in the atmospheric environment. The device structure of the present invention is: transparent substrate/ITO/PTFE (thickness 1.5nm)/MoO ₃ (thickness 5nm)/PCDTBT:PC ₇₁ BM/Alq3 (thickness 1nm)/Al (thickness 120nm). The JV curves measured by the device of the present invention and the comparative device are shown in FIG. 2 . Comparative example 1:

The substrate composed of the cleaned transparent substrate and the ITO transparent conductive anode was blown dry with nitrogen, dried for 20 minutes and processed with a Plasma cleaning machine for 5 minutes, then moved into a vacuum coating machine to evaporate the anode buffer layer MoO ₃ (thickness: 5nm, the evaporation rate is ). Move the substrate on which the anode buffer layer MoO ₃ is evaporated into the Plasma cleaning machine, and process it for 2 minutes. Then the substrate was moved into a glove box (nitrogen atmosphere), and an organic active layer was prepared on the anode buffer layer by spin coating. The organic active layer is prepared by mixing the electron donor material PCDTBT and the electron acceptor material PC ₇₁ BM, the mass percentage of PCDTBT:PC ₇₁ BM mixed solution is 1:4, the solvent is o-dichlorobenzene, the organic active layer PCDTBT:PC ₇₁ BM was prepared by spin-coating method, the rotating speed was 1500rpm/s, the time was 40s, and the thickness was about 90nm. Then thermal annealing (70°C, 30min) was performed. On the organic active layer, the cathode buffer layer Alq3 (thickness is 1nm, evaporation rate is ) and metal cathode Al (thickness is 120nm, evaporation rate is ). The fabricated device was measured under standard conditions (AM1.5, 100mw/cm ² ), and the JV curve data was collected using a Keithley2400 digital source meter. The comparative device structure is: transparent substrate/ITO/MoO ₃ (thickness 5nm)/PCDTBT:PC ₇₁ BM/Alq3 (thickness 1nm)/Al (thickness 120nm).

Comparative example 2:

The substrate composed of the cleaned transparent substrate and the ITO transparent conductive anode was blown dry with nitrogen, dried for 20 minutes and treated with a Plasma cleaning machine for 5 minutes, and then spin-coated the anode buffer layer polyethylenedioxythiophene ( PEDOT:PSS) (rotating speed is 3000rpm/s, time is 60s), heated at 120°C for 10min. Then the substrate was moved into the glove box (nitrogen atmosphere), and the organic active layer was prepared on the anode buffer layer by spin coating; the organic active layer was prepared by mixing the electron donor material PCDTBT and the electron acceptor material PC ₇₁ BM, PCDTBT : The mass percentage of the PC ₇₁ BM mixed solution is 1:4, the solvent is o-dichlorobenzene, and the organic active layer PCDTBT:PC ₇₁ BM is prepared by spin coating, the rotating speed is 1500rpm/s, the time is 40s, and the thickness is about 90nm; Then thermal annealing (70°C, 30min) was performed. On the active layer, the cathode buffer layer Alq3 (thickness is 1nm, evaporation rate is ) and metal cathode Al (thickness is 120nm, evaporation rate is ). The fabricated device was measured under standard conditions (AM1.5, 100mw/cm ² ), and the JV curve data was collected using a Keithley2400 digital source meter. The comparative device structure is: transparent substrate/ITO/PEDOT:PSS/PCDTBT:PC ₇₁ BM/Alq3 (thickness 1nm)/Al (thickness 120nm).

Table 1 is a comparison of the data results of Example 1 and Comparative Example 1 and Comparative Example _2. The results show that the dual anode buffer layer is combined with PTFE anode buffer layer and MoO3 anode buffer layer. Compared with the single _- layer anode buffer layer MoO3, The short-circuit current of the device is increased by 9.3%, the fill factor is increased by 9.8%, and the energy conversion efficiency is increased by 25%. Compared with the traditional anode buffer layer PEDOT:PSS, the short-circuit current is increased by 14.3%, the fill factor is increased by 8.83%, and the energy conversion efficiency is increased by 26.3%. .

Table 1 is the result comparison of the inventive structure device of embodiment 1 and the comparison device performance test

Jsc(mA/cm ² ) Voc(V) FF(%) PCE(%) Embodiment 1 device 12.926 0.896 63.12 7.311 Device of Comparative Example 1 11.823 0.861 57.48 5.850 Device of Comparative Example 2 11.310 0.882 58.00 5.787

Example 2

The preparation method of the double-anode buffer layer bulk heterojunction organic solar cell is as follows: firstly, toluene, acetone, detergent, deionized water, and isopropanol are used in sequence to form a substrate composed of a transparent substrate and an indium tin oxide (ITO) transparent conductive anode. The slices were ultrasonically cleaned, each step was 20 min. The substrate composed of the cleaned transparent substrate and the ITO transparent conductive anode was blown dry with nitrogen, dried for 20 minutes and treated with a Plasma cleaning machine for 5 minutes, and then moved into a vacuum coating machine to evaporate and deposit a PTFE anode buffer layer (thickness: 0.3nm, the evaporation rate is ) and MoO ₃ anode buffer layer (thickness is 5nm), the evaporation rate is ). The substrate was moved into a Plasma cleaning machine, and after being treated for 2 minutes, the organic active layer PCDTBT:PCB ₇₁ M was prepared on the MoO ₃ anode buffer layer by the same method as in Example 1. Afterwards, the substrate is moved into a vacuum coating machine, and the cathode buffer layer Alq3 (thickness is 1 nm, and the evaporation rate is ) and metal cathode Al (thickness is 120nm, evaporation rate is ). The fabricated device was measured under standard conditions (AM1.5, 100mw/cm ² ), and the JV curve data was collected using a Keithley2400 digital source meter. The device structure is: transparent substrate/ITO/PTFE (thickness 0.3nm)/MoO ₃ (thickness 5nm)/PCDTBT:PC ₇₁ BM/Alq3 (thickness 1nm)/Al (thickness 120nm). The measured JV curve of the device of Example 2 is shown in FIG. 3 .

Example 3

The preparation method of the double-anode buffer layer bulk heterojunction organic solar cell is as follows: firstly, toluene, acetone, detergent, deionized water, and isopropanol are used in sequence to form a substrate composed of a transparent substrate and an indium tin oxide (ITO) transparent conductive anode. The slices were ultrasonically cleaned, each step was 20 min. The substrate composed of the cleaned transparent substrate and the ITO transparent conductive anode was blown dry with nitrogen, dried for 20 minutes and treated with a Plasma cleaning machine for 5 minutes, and then moved into a vacuum coating machine to evaporate and deposit a PTFE anode buffer layer (thickness: 1.0nm, the evaporation rate is ) and MoO ₃ anode buffer layer (thickness is 5nm, evaporation rate is ). The substrate was moved into a Plasma cleaning machine, and after being treated for 2 minutes, the organic active layer PCDTBT:PC ₇₁ BM was prepared on the MoO ₃ anode buffer layer by the same method as in Example 1. On the organic active layer, the cathode buffer layer Alq3 (thickness is 1nm, evaporation rate is ) and metal cathode Al (thickness is 120nm, evaporation rate is ). The fabricated device was measured under standard conditions (AM1.5, 100mw/cm ² ), and the JV curve data was collected using a Keithley2400 digital source meter. The device structure is: transparent substrate/ITO/PTFE (thickness 1.0nm)/MoO ₃ (thickness 5nm)/PCDTBT:PC ₇₁ BM/Alq3 (thickness 1nm)/Al (thickness 120nm). The measured JV curve of the device of Example 3 is shown in FIG. 3 .

Example 4

The preparation method of the double-anode buffer layer bulk heterojunction organic solar cell is as follows: firstly, toluene, acetone, detergent, deionized water, and isopropanol are used in sequence to form a substrate composed of a transparent substrate and an indium tin oxide (ITO) transparent conductive anode. The slices were ultrasonically cleaned, each step was 20 min. The substrate composed of the cleaned transparent substrate and the ITO transparent conductive anode was blown dry with nitrogen, dried for 20 minutes and treated with a Plasma cleaning machine for 5 minutes, and then moved into a vacuum coating machine to evaporate and deposit a PTFE anode buffer layer (thickness: 2.0nm, the evaporation rate is ) and MoO ₃ anode buffer layer (thickness 5nm, evaporation rate is ). The substrate was moved into a Plasma cleaning machine, and after being treated for 2 minutes, the organic active layer PCDTBT:PC ₇₁ BM was prepared on the MoO ₃ anode buffer layer by the same method as in Example 1. On the organic active layer, the cathode buffer layer Alq3 (thickness is 1nm, evaporation rate is ) and metal cathode Al (thickness is 120nm, evaporation rate is ). The fabricated device was measured under standard conditions (AM1.5, 100mw/cm ² ), and the JV curve data was collected using a Keithley2400 digital source meter. The device structure is: transparent substrate/ITO/PTFE (thickness 2.0nm)/MoO ₃ (thickness 5nm)/PCDTBT:PC ₇₁ BM/Alq3 (thickness 1nm)/Al (thickness 120nm). The measured JV curve of the device of Example 4 is shown in FIG. 3 .

Table 2 is the result comparison of the invention structure device performance test of embodiments 1-4

Jsc(mA/cm ² ) Voc(V) FF(%) PCE(%) Embodiment 1 device 12.926 0.896 63.12 7.311 Embodiment 2 device 11.935 0.867 60.56 6.268 Embodiment 3 device 12.304 0.886 63.89 6.967 Embodiment 4 device 11.649 0.882 61.26 6.294

Example 5

The preparation method of the double-anode buffer layer bulk heterojunction organic solar cell is as follows: firstly, toluene, acetone, detergent, deionized water, and isopropanol are used in sequence to form a substrate composed of a transparent substrate and an indium tin oxide (ITO) transparent conductive anode. The slices were ultrasonically cleaned, each step was 20 min. The substrate composed of the cleaned transparent substrate and the ITO transparent conductive anode was blown dry with nitrogen, and dried for 20 minutes. After the substrate was processed with a Plasma cleaning machine for 5 minutes, it was moved into a vacuum coating machine to evaporate and deposit a PTFE anode buffer layer (thickness is 1.5nm, the evaporation rate is ) and MoO ₃ anode buffer layer (thickness is 5nm, evaporation rate is ). Move the substrate on which the double anode buffer layer has been evaporated into the Plasma cleaning machine, and process it for 2 minutes. The electron donor material P3HT and the electron acceptor material PC ₆₁ BM are dissolved in o-dichlorobenzene at a mass percentage of 1:1 to obtain a mixed solution with a concentration of P3HT:PC ₆₁ BM=17mg/ml:17mg/ml, and the mixed solution Stir at room temperature for 14 h; then move the substrate into a glove box (nitrogen atmosphere), and prepare a P3HT:PC ₆₁ BM organic active layer on the MoO ₃ anode buffer layer by spin coating at a speed of 700 rpm/s for 36 s with a thickness of about 230nm; after spin-coating to form a film, place it in a glove box for 3h to evaporate the solvent. On the organic active layer, the cathode buffer layer Alq3 (thickness is 1nm, evaporation rate is ) and metal cathode Al (thickness is 120nm, evaporation rate is ). The fabricated device was measured under standard conditions (AM1.5, 100mw/cm ² ), and the JV curve data was collected using a Keithley2400 digital source meter. The device structure of the present invention is: transparent substrate/ITO/PTFE (thickness 1.5nm)/MoO ₃ (thickness 5nm)/P3HT:PC ₆₁ BM/Alq3 (thickness 1nm)/Al (thickness 120nm). The JV curves measured by the device of the present invention and the comparative device are shown in FIG. 4 .

Comparative example 3

The substrate composed of the cleaned transparent substrate and the transparent conductive anode ITO was blown dry with nitrogen, dried for 20 minutes and processed with a Plasma cleaning machine for 5 minutes, and then moved into a vacuum coating machine to evaporate the anode buffer layer MoO ₃ (thickness: 5nm, the evaporation rate is ). Move the substrate on which the anode buffer layer MoO ₃ is evaporated into the Plasma cleaning machine, and process it for 2 minutes. The electron donor material P3HT and the electron acceptor material PC ₆₁ BM are dissolved in o-dichlorobenzene at a mass percentage of 1:1 to obtain a mixed solution with a concentration of P3HT:PC ₆₁ BM=17mg/ml:17mg/ml, and the mixed solution Stir at room temperature for 14 h; then move the substrate into a glove box (nitrogen atmosphere), and prepare a P3HT:PC ₆₁ BM organic active layer on the MoO ₃ anode buffer layer by spin coating at a speed of 700 rpm/s for 36 s with a thickness of about 230nm; then placed in the glove box for 3h to evaporate the solvent. On the organic active layer, the cathode buffer layer Alq3 (thickness is 1nm, evaporation rate is ) and metal cathode Al (thickness is 120nm, evaporation rate is ). The fabricated device was measured under standard conditions (AM1.5, 100mw/cm ² ), and the JV curve data was collected using a Keithley2400 digital source meter. The comparative device structure is: transparent substrate/ITO/MoO ₃ (thickness 5nm)/P3HT:PC ₆₁ BM/Alq3 (thickness 1nm)/Al (thickness 120nm).

Table 3 is the data result comparison of embodiment 5 and comparative example 3, and the result shows, for organic active layer material P3HT:PC ₆₁ BM, with PTFE anode buffer layer and MoO _The anode buffer layer is combined into double anode buffer layer, compared to With a single-layer anode buffer layer, the short-circuit current of the device is increased by 17.6%, the fill factor is increased by 6.47%, and the energy conversion efficiency is increased by 26.6%.

Table 3 is the result comparison of the inventive structure device of embodiment 5 and the comparative device performance test

Example 6

The preparation method of the double anode buffer layer bulk heterojunction organic solar cell is as follows: dry the substrate composed of the cleaned transparent substrate and the ITO transparent conductive anode with nitrogen, dry it for 20 minutes, and treat the substrate with a Plasma cleaning machine for 5 minutes. Move into the vacuum coating machine and vapor-deposit PTFE anode buffer layer (thickness is 0.8nm, evaporation rate is ) and MoO ₃ anode buffer layer (thickness is 4nm, evaporation rate is ). The same method as in Example 1 was used to prepare the organic active layer PCDTBT:PC ₇₁ BM on the MoO ₃ anode buffer layer. On the organic active layer, the cathode buffer layer Alq3 (thickness is 1nm, evaporation rate is ) and metal cathode Al (thickness is 120nm, evaporation rate is ). The fabricated device was measured under standard conditions (AM1.5, 100mw/cm ² ), and the JV curve data was collected using a Keithley2400 digital source meter. The device structure is: transparent substrate/ITO/PTFE (thickness 0.8nm)/MoO ₃ (thickness 4nm)/PCDTBT:PC ₇₁ BM/Alq3 (thickness 1nm)/Al (thickness 120nm). The measured JV curve of the device of Example 6 is shown in FIG. 5 .

Example 7

The preparation method of the double anode buffer layer bulk heterojunction organic solar cell is as follows: dry the substrate composed of the cleaned transparent substrate and the ITO transparent conductive anode with nitrogen, dry it for 20 minutes, and treat the substrate with a Plasma cleaning machine for 5 minutes. Move into the vacuum coating machine and vapor-deposit PTFE anode buffer layer (thickness is 0.8nm, evaporation rate is ) and MoO ₃ anode buffer layer (thickness is 5nm, evaporation rate is ). The same method as in Example 1 was used to prepare the organic active layer PCDTBT:PC ₇₁ BM on the MoO ₃ anode buffer layer. On the organic active layer, the cathode buffer layer Alq3 (thickness is 1nm, evaporation rate is ) and metal cathode Al (thickness is 120nm, evaporation rate is ). The fabricated device was measured under standard conditions (AM1.5, 100mw/cm ² ), and the JV curve data was collected using a Keithley2400 digital source meter. The device structure is: transparent substrate/ITO/PTFE (thickness 0.8m)/MoO ₃ (thickness 5nm)/PCDTBT:PC ₇₁ BM/Alq3 (thickness 1nm)/Al (thickness 120nm). The measured JV curve of the device of Example 7 is shown in FIG. 5 .

Example 8

The preparation method of the double anode buffer layer bulk heterojunction organic solar cell is as follows: dry the substrate composed of the cleaned transparent substrate and the ITO transparent conductive anode with nitrogen, dry it for 20 minutes, and treat the substrate with a Plasma cleaning machine for 5 minutes. Move into the vacuum coating machine and vapor-deposit PTFE anode buffer layer (thickness is 0.8nm, evaporation rate is ) and MoO ₃ anode buffer layer (thickness is 10nm, evaporation rate is ). The same method as in Example 1 was used to prepare the organic active layer PCDTBT:PC ₇₁ BM on the MoO ₃ anode buffer layer. On the organic active layer, the cathode buffer layer Alq3 (thickness is 1nm, evaporation rate is ) and metal cathode Al (thickness is 120nm, evaporation rate is ). The fabricated device was measured under standard conditions (AM1.5, 100mw/cm ² ), and the JV curve data was collected using a Keithley2400 digital source meter. The device structure is: transparent substrate/ITO/PTFE (thickness 0.8m)/MoO ₃ (thickness 10nm)/PCDTBT:PC ₇₁ BM/Alq3 (thickness 1nm)/Al (thickness 120nm). The measured JV curve of the device of Example 8 is shown in FIG. 5 .

The results of Examples 6-8 show that changing the thickness of the MoO ₃ anode buffer layer within the allowable range does not have a great impact on the performance of the device.

Table 4 is the result comparison of the invention structure device performance test of embodiment 6～8

Jsc(mA/cm ² ) Voc(V) FF(%) PCE(%) Embodiment 6 device 11.750 0.877 63.69 6.566 Embodiment 7 device 11.643 0.871 65.89 6.681 Embodiment 8 device 11.899 0.879 63.50 6.640

The present invention is not limited to the above examples, and the cathode buffer layer material can also be one of LiF, porphyrin small molecule, Bphen, BCP, or two or more of them can be prepared layer by layer sequentially. The metal cathode material can also be one of Al, Ca, Ag, Au, or prepared layer by layer from two or more of these materials in sequence. The transparent substrate can also be a transparent flexible polymer substrate, and the transparent flexible polymer material includes polyethylene, polyethylene terephthalate, polymethyl methacrylate, polycarbonate, polyurethane , polyimide or polyacrylic acid, or by mixing two or more of them, or by layer by layer of two or more of them in sequence.

The Invention The invention has been illustrated by the above examples. It should be noted that the embodiments are only used to illustrate and describe the present invention, and are not limited to the above examples. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A double-anode buffer layer bulk heterojunction organic solar cell, which adopts a positive-type structure, from bottom to top: transparent substrate, transparent conductive anode, anode buffer layer, organic active layer, cathode buffer layer, metal cathode ; It is characterized in that the anode buffer layer is a double anode buffer layer composed _of PTFE anode buffer layer and MoO3 anode buffer layer; PTFE anode buffer layer is prepared on a transparent conductive anode; MoO3 anode buffer layer is prepared _on PTFE anode buffer layer and Between the organic active layers; the thickness of the PTFE anode buffer layer is 0.3-2nm, and the thickness of the MoO ₃ anode buffer layer is 4-10nm. 2. The double anode buffer layer bulk heterojunction organic solar cell according to claim 1, characterized in that the thickness of the PTFE anode buffer layer is preferably 1.5 nm. 3. The double anode buffer layer body heterojunction organic solar cell according to claim 1, characterized in that the transparent substrate is transparent glass or transparent flexible polymer. 4. The double anode buffer layer body heterojunction organic solar cell according to claim 3, characterized in that the transparent flexible polymer is polyethylene, polyethylene terephthalate, polymethyl methacrylate, polycarbonate One of ester, polyurethane, polyimide or polyacrylic acid, or two or more of them are mixed, or two or more of them are prepared layer by layer in sequence. 5. The double anode buffer layer bulk heterojunction organic solar cell according to claim 1, characterized in that the transparent conductive anode is made of indium tin oxide and deposited on a transparent substrate. 6. The dual anode buffer layer bulk heterojunction organic solar cell according to claim 1, wherein the organic active layer is composed of electron donor material PCDTBT and electron acceptor material PC ₇₁ BM according to 1:4 The mixture configured by mass ratio, or the mixture configured by electron donor material P3HT and electron acceptor material PC ₆₁ BM according to a mass ratio of 1:1. 7. double anode buffer layer bulk heterojunction organic solar cell according to claim 1, is characterized in that described cathode buffer layer, its material is a kind of in Alq3, LiF, porphyrin small molecule, Bphen or BCP , or prepared layer by layer from two or more materials in sequence, with a thickness of 1-10 nm; the metal cathode is made of one of Al, Ca, Ag or Au, or two or more of them The material is prepared layer by layer in sequence, and the thickness is 100nm-200nm. 8. A method for preparing a double anode buffer layer body heterojunction organic solar cell as claimed in claim 1, comprising the following steps: ① Use toluene, acetone, detergent, deionized water, and isopropanol in sequence to ultrasonically clean the substrate composed of the transparent conductive anode and the transparent substrate, and store the cleaned substrate in isopropanol for later use; ②The cleaned substrate is blown dry with nitrogen, moved into a drying oven for drying, and then plasma treated with a Plasma cleaning machine; ③ Move the treated substrate into the vacuum coating machine, evaporate the PTFE anode buffer layer on the transparent conductive anode, and then evaporate the MoO3 anode buffer layer _on the PTFE anode buffer layer; wherein the evaporation rate of PTFE is The thickness is 0.3~2nm, the evaporation rate of MoO ₃ is The thickness is 4~10nm; ④ Move the above-mentioned substrate on which the double anode buffer layer has been vapor-deposited into the Plasma cleaning machine for plasma treatment; ⑤ Prepare an organic active layer on the MoO ₃ anode buffer layer; ⑥ Move the substrate obtained in step ⑤ into a vacuum coating machine, and sequentially vapor-deposit a cathode buffer layer and a metal cathode on the organic active layer. 9. the preparation method of double anode buffer layer body heterojunction organic solar cell according to claim 8, it is characterized in that in described step 5. adopt the method for spin-coating electron donor material PCDTBT and electron acceptor material in nitrogen atmosphere The bulk material PC ₇₁ BM is spin-coated on the MoO ₃ anode buffer layer with a mass ratio of 1:4, the speed of the homogenizer is 1500rpm/s, and the spin-coating time is 40s; the solvent of the mixed solution is Chlorobenzene, the concentration of the solution is PCDTBT:PC ₇₁ BM=8mg/ml:32mg/ml; then annealing at 70°C for 30min to evaporate the solvent to obtain an organic active layer. 10. The method for preparing a double anode buffer layer bulk heterojunction organic solar cell according to claim 8, characterized in that in the step 5, the electron donor material P3HT and electron Acceptor material PC ₆₁ BM is spin-coated on the MoO ₃ anode buffer layer according to the mass ratio configuration of 1:1, the speed of homogenizer is 700rpm/s, and the spin-coating time is 36s; The solvent of described mixed solution is o Dichlorobenzene, the concentration of the solution is P3HT:PC ₆₁ BM=17mg/ml:17mg/ml; then anneal at room temperature for 3 hours to evaporate the solvent to obtain an organic active layer.