Europium-terbium nano aggregate co-doped flexible polymer solar cell and method

Abstract

The invention discloses a europium-terbium nano aggregate co-doped flexible polymer solar cell and a method. The method comprises the following steps: (1) fully mixing an active layer material and a rare earth nano aggregate to form a blended solution; (2) cleaning the flexible conductive substrate material; (3) the transparent substrate material in the step (2) is placed on a blade coater for blade coating of a hole transport layer; (4) blade-coating the hole transport layer prepared in the step (3) with the blended solution prepared in the step (1); and (5) preparing an electron transport layer on the rare earth nano aggregate doped active layer prepared in the step (4) through a blade coating method. And (6) evaporating a cathode. The morphology and light absorption of the active layer of the polymer solar cell are optimized by adjusting the blade coating process and the doping amount of the rare earth nano aggregate, and the light absorption capacity, the carrier transport efficiency and the overall photoelectric conversion performance of the polymer solar cell can be effectively improved.

Description

Technical Field

[0001] The present invention specifically relates to a europium-terbium nanoaggregate co-doped flexible polymer solar cell and a method thereof, and relates to the intersection of hybrid material preparation and polymer solar cell preparation technology. Background Art

[0002] With the continued growth in energy demand, solar energy, with its widespread distribution, inexhaustible supply, and clean, pollution-free nature, has attracted widespread attention. Solar cell technology has become a key research area, and polymer solar cells, with their advantages such as light weight, low cost, flexibility, and scalability, have attracted intensive research in both academia and industry. Currently, one of the most efficient polymer solar cell structures is the bulk heterojunction (BHJ) polymer solar cell. This structure consists of a p-type electron donor and an n-type electron acceptor material mixed in a specific ratio, forming a continuous, interpenetrating network. This unique structural design enables more efficient dissociation of photogenerated excitons and improves the mobility of electrons and holes through optimized charge transport pathways, thereby significantly enhancing the photoelectric conversion efficiency of the solar cell. However, the narrow absorption spectra and weak absorption capacity of the donor and acceptor materials in existing BHJ structures have become a bottleneck in improving the efficiency of polymer solar cells. To improve their performance, researchers are continuously exploring new materials and novel preparation methods to achieve more efficient, stable, and mechanically sound polymer solar cells. Among them, doping strategy is one of the important methods to improve the performance of polymer solar cell devices. Doping can adjust the electronic structure, light absorption characteristics, carrier migration efficiency, etc. of the material, thereby improving the photoelectric conversion efficiency and stability of polymer batteries.

[0003] Rare earth elements possess unique optical properties, which are related to the unique extranuclear electron structure of rare earth ions. The 4f layer of rare earth ions' extranuclear electrons is shielded by the 5s and 5p layers, resulting in a distinctive emission spectrum with a very narrow wavelength. This unique shielding mechanism endows rare earth ions with strong charge transfer and magnetic properties, leading to their widespread application in the research and development of functional materials such as optoelectronics, energy storage materials, sensors, and magnetic materials. In photovoltaic devices, rare earth materials can be used as dopants or light absorbers to enhance the light absorption capacity of photovoltaic materials. Due to their large excitation and emission transitions, rare earth elements play a vital role in light absorption and electron energy transfer, effectively improving the performance of photovoltaic devices. Furthermore, rare earth ions exhibit strong fluorescence intensity, long fluorescence lifetime, and tunable spectral characteristics. Rare earth ion-induced block polymer nanoaggregates prepared by self-assembly methods can enhance the fluorescence excitation and emission intensity of rare earth ions, improve fluorescence lifetime, and increase efficiency. Doping rare earth ions into polymer solar cell structures can broaden the spectral absorption range of the device, enhance light absorption, and ultimately improve the performance of polymer solar cells.

[0004] Existing polymer solar cells are manufactured using spin coating, using a rigid glass substrate, making it difficult to fabricate large-area devices. Furthermore, the efficiency and lifespan of these devices are poor due to limitations in the film-making process and material selection. Summary of the Invention

[0005] The present invention aims to address the deficiencies in the prior art and proposes a europium-terbium nanoaggregate co-doped flexible polymer solar cell and method. The method adjusts the active layer morphology of the polymer solar cell by adjusting the scraping process in combination with doping rare earth nanoaggregates, while expanding the spectral absorption range of the active layer, enhancing the light absorption capacity, and providing ultraviolet protection, thereby improving device performance.

[0006] In order to achieve the above object, the technical solution of the present invention is as follows: A europium-terbium nanoaggregate co-doped flexible polymer solar cell and method, comprising the following steps: (1) Rare earth europium nanoaggregates and rare earth terbium nanoaggregates are prepared separately, and the active layer material is fully mixed with the rare earth europium nanoaggregates and rare earth terbium nanoaggregates to form a blend solution, and then the blend solution is heated and stirred to make it fully mixed.

[0007] (2) The flexible conductive substrate material is placed in an isopropyl alcohol solution and cleaned using an ultrasonic cleaner. After ultrasonic cleaning, the substrate is blown dry with a nitrogen gun and placed in an oxygen plasma cleaner for UV ozone treatment for 5-10 minutes to improve the adhesion of the substrate material.

[0008] (3) Place the transparent substrate material in step (2) on a doctor blade to apply a hole transport layer. After the coating is completed, place it on a heating table and anneal for 15 minutes.

[0009] (4) The blended solution prepared in step (1) is scraped onto the hole transport layer prepared in step (3), and after scraping, the mixture is annealed on a heating table for 15 minutes.

[0010] (5) An electron transport layer is prepared on the rare earth nanoaggregate doped active layer prepared in step (4) by a scraping method.

[0011] (6) Using an evaporation method, a layer of electrode is evaporated on the surface of the electron transport layer prepared in step (5) as the cathode of the device to obtain a rare earth nanoaggregate doped flexible scraped polymer solar cell.

[0012] In the preparation method, the flexible conductive substrate material is a PEN film (polyethylene naphthalate) or a PET film (polyethylene terephthalate) plated with ITO.

[0013] In the preparation method, the hole electron transport layer adopts PEDOT:PSS (PEDOT is a polymer of 3,4-ethylenedioxythiophene monomer, and PSS is polystyrene sulfonate) or other metal oxide solutions (such as zinc oxide, titanium oxide).

[0014] In the described preparation method, the active layer consists of donor and acceptor materials. The donor material primarily absorbs light energy and generates excitons (electron-hole pairs), which are then transferred to the acceptor material, while holes are transported within the donor material. The donor material is typically a conjugated polymer or small molecule compound, including P3HT, PTB7, and PM6. The acceptor material receives electrons from the donor material and transfers them to the electrode. It is primarily categorized as fullerene acceptors, such as PCBM and PC71BM, and non-fullerene acceptors such as ITIC, IT-4F, and Y6. The active layer solution is prepared using chlorobenzene or chloroform as the solvent, with a concentration of 20-25 mg / mL.

[0015] In the preparation method, the electron transport layer material is selected from PFN-Br or PDINO.

[0016] In the preparation method, the scraping speed is selected to be 10-40 mm / s, and the substrate temperature of the scraping is set to be 30-60°C.

[0017] In the preparation method, rare earth nanoaggregates are synthesized by block copolymer: organic ligand: rare earth chloride in a molar ratio of (1-3): (1-3): (1-2), the block copolymer is PS-b-PMMA, the organic ligands include 1,10-phenanthroline (Phen), 2-thenoyltrifluoroacetone (TTA) and acetylacetone (acac), the rare earth chlorides are europium chloride and terbium chloride, and the solvent is DMF.

[0018] In the preparation method, in step (1), europium nanoaggregate powder, terbium nanoaggregate powder, donor PM6 and acceptor L8-BO are placed in a container, wherein the mass ratio of PM6 to L8-BO is 1:1.2, the total doping amount of europium nanoaggregates and terbium nanoaggregates is 0.5-5%, respectively, chlorobenzene is added as a solvent to prepare a blend solution with a concentration of 20 mg / mL, and the mixed solution is continuously heated and stirred at 50°C for 5-7 hours.

[0019] In the preparation method, in step (1), the total doping amount of europium nanoaggregates and terbium nanoaggregates is 3% respectively.

[0020] In this invention, the doctor blade coating process and the rare earth nanoaggregate doping level are adjusted to optimize the morphology and light absorption of the active layer of polymer solar cells. By adjusting the doctor blade coating process, the prepared active layer film has a uniform and smooth morphology. Simultaneously, by incorporating rare earth nanoaggregates with excellent fluorescence properties and a wide ultraviolet absorption range into the polymer solar cell, the device's light absorption capacity is enhanced and the effects of ultraviolet light on the photoactive layer are effectively reduced, thereby extending the device's service life and improving the long-term stability of the cell. Furthermore, the use of doctor blade coating technology and flexible substrate materials in the polymer solar cell preparation method further promotes the industrialization of polymer solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a synthetic route for the rare earth nanoaggregates described in the present invention.

[0022] Figure 2 This is a TEM image of the undoped active layer film prepared by the blade coating method in Example 4 of the present invention.

[0023] Figure 3 This is a TEM image of the europium nanoaggregate-doped active layer film prepared by the blade coating method in Example 4 of the present invention.

[0024] Figure 4 This is a TEM image of the europium-terbium nanoaggregate co-doped active layer film prepared by the doctor blade method in Example 5 of the present invention.

[0025] Figure 5This is an AFM image of the undoped active layer film prepared by the blade coating method in Example 4 of the present invention.

[0026] Figure 6 This is an AFM image of the europium nanoaggregate-doped active layer film prepared by the doctor blade method in Example 4 of the present invention.

[0027] Figure 7 This is an AFM image of the europium-terbium nanoaggregate co-doped active layer film prepared by the doctor blade method in Example 5 of the present invention.

[0028] Figure 8 Schematic diagram of the preparation of polymer solar cells using the blade coating method of the present invention.

[0029] Figure 9 This is a schematic diagram of the structural principle of the flexible scraping polymer solar cell described in the present invention.

[0030] Figure 10 These are the structural formulas of the donor material PM6 and the acceptor material L8-BO described in Examples 4 and 5 of the present invention.

[0031] Figure 11 This is a graph showing the change in efficiency of devices doped with different amounts of europium nanoaggregates in Example 4 of the present invention.

[0032] Figure 12 This is a graph showing the change in efficiency of devices co-doped with different amounts of europium-terbium nanoaggregates in Example 5 of the present invention.

[0033] Figure 13 Graph showing the voltage and current density of the undoped polymer solar cell and the europium-terbium nanoaggregate co-doped solar cell in Example 5 of the present invention. DETAILED DESCRIPTION

[0034] The present invention is described in detail below with reference to specific embodiments.

[0035] Example 1: Preparation of amphiphilic block polymer PS-b-PMMA (1) Preparation of polystyrene (PS) chains: Weigh an appropriate amount of reversible addition fragmentation chain transfer agent (RAFT) and initiator AIBN into a round-bottom flask. Add dioxane as a solvent to the flask, then quickly dropwise add styrene monomer to the flask. After the addition is complete, seal the flask with a rubber stopper. Flow nitrogen through the flask for 40 minutes to remove the air inside the flask. Maintain a nitrogen atmosphere and heat the flask at 60°C to 80°C for 6 hours. After the reaction is complete, pour the reaction solution into a beaker, add excess methanol for washing, and precipitate PS. Then, place the PS in a vacuum drying oven at 60°C for 8 hours to remove the organic solvent.

[0036] (2) Preparation of amphiphilic block polymer PS-b-PMMA: Weigh appropriate amounts of the product PS from step (1) and the initiator AIBN into a round-bottom flask, add dioxane as a solvent to the flask, shake the flask until the PS is completely dissolved, then add methyl methacrylate (MMA) monomer, and seal the flask with a rubber stopper. Then, pass nitrogen gas through the flask for 40 minutes to expel the air from the flask. Place the flask in a nitrogen atmosphere in an oil bath at 80°C and heat for 8 hours. Pour the reaction solution into a beaker and add excess petroleum ether for washing. precipitate to obtain PS-b-PMMA. Place the beaker in a vacuum drying oven at 60°C for 8 hours to remove the organic solvent, and obtain pure PS-b-PMMA powder.

[0037] Example 2: Preparation of rare earth europium nanoaggregates A certain amount of the amphiphilic block polymer PS-b-PMMA prepared in Example 1, europium chloride, phen, and TAA were weighed and placed in a flask at a molar ratio of 1:1:1:3. DMF was added as the reaction solvent. The flask containing the reaction solution was then placed in a 60°C oil bath and reacted for 6 hours to produce a europium nanoaggregate mixed solution. The reaction solution was washed with ethanol, the supernatant removed by centrifugation, and dried in a vacuum oven at 45°C for 8 hours to obtain a rare earth europium nanoaggregate powder.

[0038] Example 3: Preparation of rare earth terbium nanoaggregates The amphiphilic block polymer PS-b-PMMA, terbium chloride, phen, and acac were placed in a flask at a molar ratio of 1:1:1:3. DMF was added as the reaction solvent. The flask containing the reaction solution was then placed in a 60°C oil bath and allowed to react for 6 hours to produce a terbium nanoaggregate mixed solution. The reaction solution was washed with ethanol, the supernatant removed by centrifugation, and dried in a vacuum oven at 45°C for 8 hours to obtain a rare earth terbium nanoaggregate powder.

[0039] Example 4: Preparation of europium nanoaggregates-doped flexible polymer solar cell devices by blade coating (1) Weigh an appropriate amount of europium nanoaggregate powder, the donor PM6, and the acceptor L8-BO into a glass bottle, add chlorobenzene as a solvent, wherein the mass ratio of PM6 to L8-BO is 1:1.2, and the doping amount of europium nanoaggregates accounts for 0.5%, 1%, 1.5%, 2%, 3%, 4% and 5% by mass, respectively, to prepare a blend solution with a concentration of 20 mg / mL. The mixed solution is heated and stirred continuously at 50°C for 5-7 hours.

[0040] (2) The transparent PET substrate coated with ITO was placed in an isopropyl alcohol solution and cleaned using an ultrasonic cleaner. After ultrasonic cleaning, the substrate was blown dry with a nitrogen gun and placed in an oxygen plasma cleaner for UV ozone treatment for 5-10 minutes to improve the adhesion of the substrate material.

[0041] (3) Place the transparent substrate material in step (2) on a doctor blade and apply a layer of PEDOT:PSS as a hole transport layer at a speed of 30 mm / s. After coating, place it on a heating table and anneal at 150°C for 15 min.

[0042] (4) The blended solution prepared in step (1) is scraped onto the hole transport layer prepared in step (3) at a scraping speed of 20 mm / s. After the scraping is completed, the mixture is annealed on a heating table at 100°C for 15 min.

[0043] (5) A layer of PDINO solution was prepared as an electron transport layer on the europium nanoaggregate doped active layer prepared in step (4) by scraping at a speed of 30 mm / s.

[0044] (6) A 100 nm thick aluminum electrode was evaporated on the surface of the electron transport layer prepared in step (5) as the cathode of the device to obtain a europium nanoaggregate-doped flexible scraped polymer solar cell.

[0045] In the present invention, the europium nano-aggregates doped flexible polymer solar cell device prepared by optimizing the morphology and light absorption of the active layer of the flexible polymer solar cell has a flexible substrate compared with the common spin-coated cell device and can be prepared on a large area. By doping europium nano-aggregates in the active layer of the device, the morphology of the active layer is characterized at the same time, such as Figure 3 and Figure 6 The TEM and AFM images of the device with 3% europium nanoaggregate doping show that the crystallinity of the active layer of the doped europium nanoaggregate is improved, and a fine phase separation structure appears, thereby improving the absorption of light and the generation of charges. The final conversion efficiency of the device reaches 12.23%, which is 9.6% higher than that of the undoped device.

[0046] Example 5: Preparation of europium-terbium nanoaggregates co-doped flexible polymer solar cell devices by blade coating (1) Appropriate amounts of europium nanoaggregate powder, terbium nanoaggregate powder, donor PM6, and acceptor L8-BO were weighed and placed in a glass bottle, where the mass ratio of PM6 to L8-BO was 1:1.2, and the total doping amounts of europium nanoaggregates and terbium nanoaggregates were 0.5%, 1%, 1.5%, 2%, 3%, 4%, and 5%, respectively. Chlorobenzene was added as a solvent to prepare a blend solution with a concentration of 20 mg / mL. The mixed solution was heated and stirred at 50°C for 5-7 hours.

[0047] (2) The transparent PET substrate coated with ITO was placed in an isopropyl alcohol solution and cleaned using an ultrasonic cleaner. After ultrasonic cleaning, the substrate was blown dry with a nitrogen gun and placed in an oxygen plasma cleaner for UV ozone treatment for 5-10 minutes to improve the adhesion of the substrate material.

[0048] (3) Place the transparent substrate material in step (2) on a doctor blade and apply a layer of PEDOT:PSS as a hole transport layer at a speed of 30 mm / s. After coating, place it on a heating table and anneal at 150°C for 15 min.

[0049] (4) The blended solution prepared in step (1) is scraped onto the hole transport layer prepared in step (2) at a scraping speed of 20 mm / s. After the scraping is completed, the mixture is annealed on a heating table at 100°C for 15 min.

[0050] (5) A layer of PDINO solution was prepared as an electron transport layer on the europium / terbium nanoaggregate doped active layer prepared in step (4) by scraping at a speed of 30 mm / s.

[0051] (6) A 100 nm thick aluminum electrode was evaporated on the surface of the electron transport layer prepared in step (5) as the cathode of the device to obtain a europium / terbium nanoaggregate co-doped flexible scraped polymer solar cell.

[0052] In the present invention, the morphology and light absorption of the active layer of the flexible polymer solar cell are optimized to characterize the morphology of the active layer, such as Figure 4 and Figure 7 , TEM and AFM images of the europium / terbium nanoaggregate co-doped device with a doping amount of 3%. The phase separation structure of the active layer morphology of the co-doped device was further optimized to form a continuous interpenetrating network structure. The efficiency of the prepared europium / terbium nanoaggregate co-doped flexible polymer solar cell device was further improved over the device doped with a single rare earth nanoaggregate. Finally, the conversion efficiency of the europium / terbium nanoaggregate co-doped flexible device reached 12.64%, an increase of 11.8% compared with the undoped device.

[0053] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all such improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A method for preparing europium-terbium nanoaggregates co-doped flexible polymer solar cells, characterized in that: The following steps are involved: (1) preparing rare earth europium nanoaggregates and rare earth terbium nanoaggregates respectively, fully mixing the active layer material with the rare earth europium nanoaggregates and rare earth terbium nanoaggregates to form a blend solution, and then heating and stirring the blend solution to fully mix it; (2) The flexible conductive substrate material is placed in an isopropyl alcohol solution and cleaned using an ultrasonic cleaner; the substrate after ultrasonic cleaning is blown dry with a nitrogen gun and placed in an oxygen plasma cleaner for ultraviolet ozone treatment for 5-10 minutes to improve the adhesion of the substrate material; (3) Place the transparent substrate material in step (2) on a doctor blade to apply a hole transport layer, and after the coating is completed, place it on a heating table and anneal for 15 minutes; (4) Scrape the blended solution prepared in step (1) onto the hole transport layer prepared in step (3), and anneal on a heating table for 15 minutes after the scraping is completed; (5) preparing an electron transport layer on the rare earth nanoaggregate doped active layer prepared in step (4) by a doctor blade coating method; (6) Using an evaporation method, a layer of electrode is evaporated on the surface of the electron transport layer prepared in step (5) as the cathode of the device to obtain a rare earth nanoaggregate doped flexible scraped polymer solar cell.

2. The preparation method according to claim 1, characterized in that The flexible conductive substrate material is a PEN film or a PET film coated with ITO.

3. The preparation method according to claim 1, characterized in that The hole transport layer uses PEDOT:PSS or other metal oxide solutions.

4. The preparation method according to claim 1, characterized in that The electron transport layer material is selected as PFN-Br or PDINO.

5. The preparation method according to claim 1, characterized in that The scraping speed is selected at 10-40 mm / s, and the substrate temperature is set at 30-60°C.

6. The preparation method according to claim 1, characterized in that Rare earth nanoaggregates are synthesized by block copolymer: organic ligand: rare earth chloride in a molar ratio of (1-3): (1-3): (1-2). The block copolymer is PS-b-PMMA, the organic ligands include 1,10-phenanthroline (Phen), 2-thenoyltrifluoroacetone (TTA) and acetylacetone (acac), the rare earth chlorides are europium chloride and terbium chloride, and the solvent is DMF.

7. The preparation method according to claim 1, characterized in that In step (1), europium nanoaggregate powder, terbium nanoaggregate powder, donor PM6 and acceptor L8-BO are placed in a container, wherein the mass ratio of PM6 to L8-BO is 1:1.2, the total doping amount of europium nanoaggregates and terbium nanoaggregates is 0.5-5%, respectively, chlorobenzene is added as a solvent to prepare a blend solution with a concentration of 20 mg / mL, and the mixed solution is continuously heated and stirred at 50°C for 5-7 hours.

8. The preparation method according to claim 7, characterized in that In the preparation method, in step (1), the total doping amount of europium nanoaggregates and terbium nanoaggregates is 3% respectively. 9 . A europium-terbium nanoaggregate co-doped flexible polymer solar cell prepared according to the method of any one of claims 1 to 8 .

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