Photoactive layer conjugated polymer donor, preparation method and application thereof, and semitransparent solar cell device

Abstract

The invention provides a photoactive layer conjugated polymer donor, a preparation method and application thereof, and a semitransparent solar cell device, and belongs to the technical field of organic synthesis. The invention provides a conjugated polymer donor for a photoactive layer, which takes thiophene as a skeleton, enhances the solubility by a long alkyl chain group, belongs to a narrow-band gap donor, is large in weight-average molecular weight, is high in viscosity of the conjugated polymer donor for the photoactive layer, and can be used for preparing an active layer with the same thickness. The conjugated polymer donor of the high-molecular-weight optical active layer can use a lower-concentration solution, so that the material loss of the active layer is reduced, the difficulty and time of proportioning are reduced, the process cost is reduced, the large-scale mass production and industrialization of OPV are facilitated, and the method has huge application potential in semitransparent organic solar cell devices.

Description

Technical Field

[0001] The present invention relates to the technical field of organic synthesis, in particular to a photoactive layer conjugated polymer donor, a preparation method and application thereof, and a semi-transparent solar cell device. Background Art

[0002] Organic photovoltaics (OPVs) are made from common organic elements such as carbon, hydrogen, nitrogen, fluorine, oxygen, and sulfur. They utilize inexpensive, abundant, and easily recyclable raw materials, reducing costs and making them suitable for large-scale production. The active layer of an OPV consists of donor and acceptor components that absorb light at different wavelengths. These components are typically only about 100 nanometers across. This limited light absorption makes it possible to create semi-transparent organic photovoltaics (ST-OPVs). Among the photoactive layer materials, narrowband donor and acceptor materials transmit green light, to which the human eye is more sensitive, and absorb red or near-infrared light to generate electricity. These materials can achieve high visible light transmittance with minimal sacrifice in PCE (power conversion efficiency), effectively balancing light transmission and photovoltaic performance, making them suitable for the preparation of high-performance ST-OPVs. Currently, narrowband acceptors, such as the Y6 series, are developing rapidly, leaving little room for improvement, while narrowband donors still have significant potential for improvement. Therefore, the development of high-quality, scalable, synthesized narrowband donor materials is a primary prerequisite for promoting the application of semi-transparent organic solar cells.

[0003] To further improve the performance of photovoltaic devices, scientists have proposed a series of molecular design strategies to adjust the structure of conjugated polymer donors, including central skeleton modification, side chain engineering, π-bridge modification, and terminal group adjustment. Among them, side chain engineering is a simple and commonly used method. The introduction of side chains not only affects the solubility and crystallinity of the molecules, but also has significant advantages in improving charge mobility. Therefore, appropriate side chain modification can effectively improve photovoltaic performance. However, most of the conjugated polymer donors for the current photoactive layer have small molecular weights and low viscosities, and high-concentration solutions need to be prepared when preparing the active layer. Summary of the Invention

[0004] In light of this, the present invention aims to provide a conjugated polymer donor for a photoactive layer, its preparation method, and application, as well as a semi-transparent solar cell device. The conjugated polymer donor for the photoactive layer provided by the present invention has a high molecular weight and high viscosity. This allows the use of a lower solution concentration for the preparation of an active layer of the same thickness.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a conjugated polymer donor for a photoactive layer having a structure shown in Formula III:

[0007]

[0008] The weight average molecular weight of the conjugated polymer donor in the photoactive layer is 45,000 to 120,000 g / mol.

[0009] Preferably, the weight average molecular weight of the conjugated polymer donor in the photoactive layer is 50,000 to 80,000 g / mol.

[0010] The present invention also provides a method for preparing the conjugated polymer donor for the photoactive layer described in the above technical solution, comprising the following steps:

[0011] Mixing the first monomer, the second monomer, the catalyst and the organic solvent and performing a Stille coupling reaction to obtain the conjugated polymer donor of the photoactive layer;

[0012] The first monomer has a structure shown in Formula I:

[0013]

[0014] The second monomer has a structure shown in Formula II:

[0015]

[0016] Preferably, the molar ratio of the first monomer to the second monomer is 0.8:1 to 1:0.8.

[0017] Preferably, the molar ratio of the first monomer to the catalyst is 8:1 to 16:1.

[0018] Preferably, the catalyst comprises tetrakistriphenylphosphine palladium.

[0019] Preferably, the temperature of the Stille coupling reaction is 90-110° C., and the time is 8-14 h.

[0020] Preferably, the temperature of the Stille coupling reaction is 90° C., and the time is 10 to 12 hours.

[0021] The present invention also provides the use of the conjugated polymer donor of the photoactive layer described in the above technical solution in an organic solar cell.

[0022] The present invention also provides a semi-transparent solar cell device, comprising a substrate, a transparent electrode, a first organic semiconductor material layer, an active layer, a second organic semiconductor material layer, an electrode layer and an anti-reflection layer stacked in sequence, wherein the active layer comprises the photoactive layer conjugated polymer donor described in the above technical solution.

[0023] The present invention provides a conjugated polymer donor for a photoactive layer. Compared with the prior art, the present invention has the following beneficial effects:

[0024] The photoactive layer conjugated polymer donor of the present invention has thiophene as the skeleton and uses long alkyl chain groups to enhance solubility. It is a narrow band gap donor with a large weight average molecular weight. The high molecular weight photoactive layer conjugated polymer donor has high viscosity. When preparing an active layer of the same thickness, a high molecular weight photoactive layer conjugated polymer donor can use a lower concentration solution. A lower concentration solution can be used to reduce the loss of active layer materials, while reducing the difficulty and time of ingredient preparation and the process cost. This is conducive to the large-scale mass production and industrialization of OPV and has great application potential in semi-transparent organic solar cell devices.

[0025] The present invention also provides a method for preparing the conjugated polymer donor for the photoactive layer described in the above technical solution. This method rapidly prepares high-purity, high-yield photoactive layer materials through a Stille coupling reaction. The preparation method of the present invention is simple, highly versatile, and highly operable. Furthermore, the method of the present invention not only improves the synthesis yield of the conjugated polymer donor for the photoactive layer but also significantly reduces costs. Therefore, the preparation method of the present invention is of great significance for promoting the large-scale production of organic solar cell devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the reaction principle for preparing the conjugated polymer donor for the photoactive layer of the present invention;

[0027] Figure 2 This is a diagram showing the structure of a semi-transparent solar cell device prepared using the conjugated polymer donor P1 for the photoactive layer obtained in Example 1;

[0028] Figure 3 This is the JV curve of the semi-transparent solar cell prepared with the conjugated polymer donor P1 for the photoactive layer obtained in Example 1 (15nm silver electrode);

[0029] Figure 4 This is a transmittance curve of a semi-transparent solar cell prepared with the conjugated polymer donor P1 for the photoactive layer obtained in Example 1 (15 nm silver electrode);

[0030] Figure 5 This is a performance comparison chart of a semi-transparent solar cell prepared using the conjugated polymer donor P1 for the photoactive layer obtained in Example 1 and a commercially available product;

[0031] Figure 6 This is a JV curve of a non-transparent solar cell prepared using the conjugated polymer donor P2 for the photoactive layer obtained in Example 2;

[0032] Figure 7 This is a JV curve of a non-transparent solar cell prepared using the conjugated polymer donor P3 for the photoactive layer obtained in Example 3;

[0033] Figure 8This is a JV curve of a non-transparent solar cell prepared using the conjugated polymer donor P4 for the photoactive layer obtained in Example 4;

[0034] Figure 9 This is a comparison chart of the absorption curves of the conjugated polymer donors P1, Y6 and PM6 for the photoactive layer obtained in Example 1. DETAILED DESCRIPTION

[0035] The present invention provides a conjugated polymer donor for a photoactive layer having a structure shown in Formula III:

[0036]

[0037] The weight average molecular weight of the conjugated polymer donor in the photoactive layer is 45,000 to 120,000 g / mol.

[0038] In the present invention, the weight average molecular weight of the conjugated polymer donor of the photoactive layer is preferably 50,000 to 80,000 g / mol, specifically 45,000, 50,000, 60,000, 80,000 or 120,000 g / mol.

[0039] The photoactive layer conjugated polymer donor of the present invention has a thiophene skeleton and a long alkyl chain group to enhance solubility. It has a large weight-average molecular weight and is soluble in chloroform, toluene, tetrahydrofuran, o-xylene, and dichloromethane. For example, its solubility in chloroform is greater than 10 mg / mL. Compared with existing narrow-band organic solar cell photoactive layer conjugated polymer donors, it has the advantages of high solubility, good film-forming properties, and low cost. It makes the production and processing of semi-transparent organic solar cell devices easier and has great application potential in semi-transparent organic solar cell devices.

[0040] The present invention also provides a method for preparing the conjugated polymer donor for the photoactive layer described in the above technical solution, comprising the following steps:

[0041] Mixing the first monomer, the second monomer, the catalyst and the organic solvent and performing a Stille coupling reaction to obtain the conjugated polymer donor of the photoactive layer;

[0042] The first monomer has a structure shown in Formula I:

[0043]

[0044] The second monomer has a structure shown in Formula II:

[0045]

[0046] In the present invention, unless otherwise specified, the raw materials used are commercially available products in the art.

[0047] Figure 1 This is the reaction principle diagram for preparing the conjugated polymer donor (PCE10-2F) for the photoactive layer of the present invention. The monomers BDT-2F and F-TT undergo Stille coupling reaction to obtain PCE10-2F.

[0048] In the present invention, the molar ratio of the first monomer to the second monomer is preferably 0.8:1 to 1:0.8, and specifically may be 1:1.

[0049] In the present invention, the molar ratio of the first monomer to the catalyst is preferably 8:1 to 16:1, specifically 8:1, 10:1, 12:1, 14:1 or 16:1.

[0050] In the present invention, the catalyst preferably comprises tetrakistriphenylphosphine palladium.

[0051] In the present invention, the organic solvent preferably includes toluene and N,N-dimethylformamide. The present invention has no particular limitation on the amount of the organic solvent used, as long as it can mix the raw materials uniformly.

[0052] In the present invention, the temperature of the Stille coupling reaction is preferably 90-110° C., specifically 90, 100 or 110° C., and the time is preferably 8-14 h, specifically 8, 10, 12 or 14 h.

[0053] In the present invention, the first monomer, the second monomer, the catalyst and the organic solvent are preferably added into a container, and then nitrogen blowing is performed before stirring and dissolving. The nitrogen blowing time is preferably 5 to 10 minutes.

[0054] In the present invention, the Stille coupling reaction is preferably carried out in an oil bath with stirring. The present invention has no particular limitation on the stirring parameters, and parameters well known to those skilled in the art may be used.

[0055] After the Stille coupling reaction is completed, the present invention preferably further includes post-treatment, which preferably includes: naturally cooling the obtained Stille coupling reaction liquid to room temperature, sequentially performing a first precipitation and a first solid-liquid separation, purifying the obtained solid to obtain a crude product, sequentially performing a second precipitation and a second solid-liquid separation on the crude product, and drying the obtained solid to obtain the conjugated polymer donor for the photoactive layer.

[0056] In the present invention, the solvent for the first precipitation is preferably methanol; the first solid-liquid separation method preferably includes vacuum filtration; the purification method is preferably Soxhlet extraction, and the reagents for the Soxhlet extraction preferably include n-hexane, acetone and chloroform.

[0057] In the present invention, the second precipitating agent is preferably methanol; the second solid-liquid separation method preferably includes vacuum filtration; and the drying method is preferably vacuum drying. The present invention does not particularly limit the specific parameters of the vacuum drying, and methods familiar to those skilled in the art can be used.

[0058] The present invention also provides the use of the conjugated polymer donor of the photoactive layer described in the above technical solution in an organic solar cell.

[0059] The conjugated polymer donor of the photoactive layer of the present invention is a narrow bandgap donor with an absorption peak at 680 nm. It has higher transmittance to visible light and can be used to prepare semi-transparent organic photovoltaic devices with high light transmittance.

[0060] The present invention also provides a semi-transparent solar cell device, comprising a substrate, a transparent electrode, a first organic semiconductor material layer, an active layer, a second organic semiconductor material layer, an electrode layer and an anti-reflection layer stacked in sequence, wherein the active layer comprises the photoactive layer conjugated polymer donor described in the above technical solution.

[0061] In the present invention, the substrate is preferably a glass substrate.

[0062] In the present invention, the transparent electrode is preferably indium tin oxide (ITO), indium tin nitride (IZO), zinc fluoride titanate (FTO), zinc oxide (ZnO), graphene or silver nanowires, and the graphene is more preferably a single layer or few-layer graphene, and the number of layers of the few-layer graphene is preferably 2 to 10 layers.

[0063] In the present invention, the thickness of the transparent electrode is preferably 60 nm.

[0064] In the present invention, the first organic semiconductor material layer preferably includes 2-PACz ((2-(9H-carbazol-9-yl)ethyl)phosphonic acid).

[0065] In the present invention, the thickness of the first organic semiconductor material layer is preferably 10 nm.

[0066] In the present invention, the active layer preferably includes an acceptor Y6, and the mass ratio of the photoactive layer conjugated polymer donor and the acceptor Y6 in the active layer is preferably 1:1.5 to 1:2.5, specifically 1:1.5, 1:2 or 1:2.5.

[0067] In the present invention, the thickness of the active layer is preferably 30 nm.

[0068] In the present invention, the second organic semiconductor material layer preferably includes PDINO (3,3'-(1,3,8,10-tetraanthraquinone[2,1,9-DEF:6,5,10-D'E'F']diisoquinoline-2,9(1H,3H,8H,10H)-diyl)bis(N,N-dimethylpropane-1-amine oxide)).

[0069] In the present invention, the thickness of the second organic semiconductor material layer is preferably 10 nm.

[0070] In the present invention, the electrode layer preferably includes gold (Au), silver (Ag) or aluminum (Al).

[0071] In the present invention, the thickness of the electrode layer is preferably 15 nm.

[0072] In the present invention, the anti-reflection layer is preferably molybdenum oxide (MoO3).

[0073] In the present invention, the thickness of the molybdenum oxide in the anti-reflection layer is preferably 10 nm.

[0074] The present invention has no special limitation on the preparation method of the semi-transparent solar cell device, and a method well known to those skilled in the art can be used.

[0075] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0076] Sources of reagents in the examples: Monomers BDT-2F and F-TT were purchased from Shanghai Bidex Pharmaceutical Technology Co., Ltd.; analytical grade solvents toluene, N,N-dimethylformamide (DMF), methanol, chloroform, acetone, and n-hexane were purchased from Sinopharm Group; and the catalyst tetrakistriphenylphosphine palladium was purchased from Anaiji Chemical.

[0077] Example 1

[0078] The preparation of the conjugated polymer donor P1 for the photoactive layer comprises the following steps:

[0079] 0.4 mmol of BDT-2F, 0.4 mmol of F-TT and Pd(PPH3) (0.032 mmol) were dissolved in a mixed solvent of 10 mL of toluene and 2 mL of DMF, and nitrogen was purged for 5 minutes to remove oxygen in the apparatus. Subsequently, the reaction mixture was heated to 90°C and stirred for a Stille coupling reaction for 8 hours. After the reaction was completed, the mixture solution was cooled to room temperature and poured into 300 mL of methanol for precipitation. The crude product was collected by vacuum filtration and purified by Soxhlet extraction using n-hexane, acetone and chloroform as extractants. The chloroform solution of the polymer was precipitated into 300 mL of methanol again to obtain a dark purple solid product P1. The polymer was collected by vacuum filtration and vacuum dried to obtain the photoactive layer conjugated polymer donor P1 with a synthesis yield of 68% and a purity greater than 99%.

[0080] The photoactive layer conjugated polymer donor P1 of this embodiment is used to prepare a semi-transparent solar cell device, including a glass substrate, a transparent electrode ITO (thickness 60 nm), a first organic semiconductor material layer 2-PACz (thickness 10 nm), an active layer (including P1 and Y6, the mass ratio of P1 and Y6 is 1:1.5, the thickness is 100 nm, and the solvents are chloroform, toluene, tetrahydrofuran, o-xylene and dichloromethane, respectively), a second organic semiconductor material layer PDINO (thickness 10 nm), an electrode layer Ag (thickness 15 nm) and an anti-reflection layer molybdenum oxide (thickness 10 nm) stacked in sequence. Figure 2 This is a structural diagram of a semi-transparent solar cell device prepared using the conjugated polymer donor for the photoactive layer obtained in Example 1.

[0081] Figure 3 This is the JV curve of the semi-transparent solar cell prepared with the conjugated polymer donor P1 for the photoactive layer obtained in Example 1 (15nm silver electrode). It can be seen that the semi-transparent solar cell prepared in this example has good power generation performance.

[0082] Figure 4 This is a transmittance curve of a semi-transparent solar cell prepared with the conjugated polymer donor P1 for the photoactive layer obtained in Example 1 (15nm silver electrode). It can be seen that the semi-transparent solar cell prepared in this example has good light transmittance.

[0083] Example 2

[0084] The same as Example 1, except that the Stille coupling reaction time was 10 h, and the photoactive layer conjugated polymer donor P2 was obtained with a synthesis yield of 73% and a purity greater than 99%.

[0085] The preparation of a semi-transparent solar cell device using P2 is the same as in Example 1, except that P1 is replaced by P2.

[0086] Figure 6 This is a JV curve diagram of a non-transparent solar cell prepared with the conjugated polymer donor P2 for the photoactive layer obtained in Example 2. It can be seen that the semi-transparent solar cell prepared in this example has good power generation performance.

[0087] Example 3

[0088] The same as Example 1, except that the Stille coupling reaction time was 12 h, and the photoactive layer conjugated polymer donor P3 was obtained with a synthesis yield of 70% and a purity greater than 99%.

[0089] The preparation of a semi-transparent solar cell device using P3 is the same as in Example 1, except that P1 is replaced by P3.

[0090] Figure 7 This is a JV curve diagram of a non-transparent solar cell prepared with the conjugated polymer donor P3 for the photoactive layer obtained in Example 3. It can be seen that the semi-transparent solar cell prepared in this example has good power generation performance.

[0091] Example 4

[0092] The same as Example 1, except that the Stille coupling reaction time was 14 h, and the photoactive layer conjugated polymer donor P4 was obtained with a synthesis yield of 73% and a purity greater than 99%.

[0093] The preparation of a semi-transparent solar cell device using P4 is the same as in Example 1, except that P1 is replaced by P4.

[0094] Figure 8 This is a JV curve diagram of a non-transparent solar cell prepared with the conjugated polymer donor P4 for the photoactive layer obtained in Example 4. It can be seen that the semi-transparent solar cell prepared in this example has good power generation performance.

[0095] A comparison of the conjugated polymer donor for the photoactive layer obtained in the present invention and commercially available products is shown in Table 1. It can be seen that the cost of commercially available products is over 1,000 yuan per 100 mg, while the cost of the conjugated polymer donor for the photoactive layer prepared in the present invention is as low as less than 500 yuan per 100 mg. Furthermore, the conjugated polymer donor for the photoactive layer prepared in the present invention has a narrow bandgap donor with a large weight-average molecular weight, using thiophene as a backbone and long alkyl chain groups to enhance solubility. High-molecular-weight conjugated polymer donors for the photoactive layer have high viscosity, allowing the preparation of active layers of the same thickness using lower-concentration solutions. This has great potential for application in semi-transparent organic solar cell devices.

[0096] Table 1 Comparison of the conjugated polymer donors for the photoactive layer obtained in the present invention and commercially available products

[0097]

[0098] Note: The concentrations in Table 1 refer to the total concentration of the conjugated polymer donor and acceptor, and the volume of solution required to prepare a 100 nm active layer is the same.

[0099] The semi-transparent solar cell device was prepared using commercially available products, which was the same as Example 1, except that P1 was replaced by the commercially available product.

[0100] Figure 5 This is a performance comparison chart of the semi-transparent solar cell prepared with the conjugated polymer donor P1 for the photoactive layer obtained in Example 1 and commercially available products. It can be seen that compared with the devices made with the PCE10-2F donor sold by other manufacturers, the devices made with the donor of the present invention have better power generation performance.

[0101] Figure 9 This is a comparison chart of the absorption curves of the photoactive layer conjugated polymer donors P1 and Y6 and the active layer donor PM6 obtained in Example 1. It can be seen that the photoactive layer conjugated polymer donor prepared by the present invention is a narrow bandgap donor with an absorption peak at around 680nm, and has higher transmittance to visible light. It is the best choice for making highly transmittance semi-transparent organic photovoltaic devices, while PM6 is a wide bandgap donor with an absorption peak at 550-600nm.

[0102] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation thereto. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications shall also be considered within the scope of protection of the present invention.

Claims

1. A conjugated polymer donor for a photoactive layer having a structure shown in Formula III: The weight average molecular weight of the conjugated polymer donor in the photoactive layer is 45,000 to 120,000 g / mol.

2. The conjugated polymer donor for the photoactive layer according to claim 1, characterized in that: The weight average molecular weight of the conjugated polymer donor in the photoactive layer is 50,000 to 80,000 g / mol.

3. The method for preparing the conjugated polymer donor for the photoactive layer according to claim 1 or 2, characterized in that: The following steps are involved: Mixing the first monomer, the second monomer, the catalyst and the organic solvent and performing a Stille coupling reaction to obtain the conjugated polymer donor of the photoactive layer; The first monomer has a structure shown in Formula I: The second monomer has a structure shown in Formula II:

4. The preparation method according to claim 3, characterized in that The molar ratio of the first monomer to the second monomer is 0.8:1 to 1:0.

8.

5. The preparation method according to claim 3 or 4, characterized in that The molar ratio of the first monomer to the catalyst is 8:1 to 16:

1.

6. The preparation method according to claim 3, characterized in that The catalyst includes tetrakistriphenylphosphine palladium.

7. The preparation method according to claim 3, characterized in that The temperature of the Stille coupling reaction is 90-110° C., and the reaction time is 8-14 hours.

8. The preparation method according to claim 7, characterized in that The temperature of the Stille coupling reaction is 90° C. and the reaction time is 10 to 12 hours.

9. Use of the conjugated polymer donor for photoactive layer according to claim 1 or 2 in organic solar cells.

10. A semi-transparent solar cell device, characterized in that: The invention comprises a substrate, a transparent electrode, a first organic semiconductor material layer, an active layer, a second organic semiconductor material layer, an electrode layer and an anti-reflection layer which are stacked in sequence, wherein the active layer comprises the photoactive layer conjugated polymer donor according to claim 1 or 2.

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