A method for improving the toughness of conjugated polymer annealed films

Abstract

This invention discloses a method for improving the toughness of annealed conjugated polymer films. The method includes: mixing a nucleating agent with a conjugated polymer, forming a film, and then annealing it to obtain a modified conjugated polymer film. This invention accelerates the crystallization of the conjugated polymer by adding a nucleating agent, effectively increasing the number of connecting molecules between crystalline regions within the film. The annealed film exhibits higher electrical conductivity and better toughness, even approaching the tensile properties of unmodified conjugated polymer films, thus solving the problem of good electrical properties but poor toughness in annealed conjugated polymer films.

Description

Technical Field

[0001] This invention belongs to the field of conjugated polymer modification technology, specifically, it relates to a method for improving the toughness of annealed conjugated polymer films. Background Technology

[0002] In recent years, the plasticity and deformability of semiconductor materials have attracted widespread attention. Compared with conjugated small-molecule semiconductors, conjugated polymer semiconductors typically possess higher flexibility and solution processability. Therefore, conjugated polymer semiconductors are highly anticipated for the fabrication of high-performance, stretchable and deformable devices, such as wearable or implantable electronic devices like electronic skin and biosensors, as well as deformable field-effect transistors and optoelectronic devices like solar cells. To fabricate high-performance deformable devices, conjugated polymers require good mechanical properties, including elastic modulus, yield point, toughness, and elongation at break. Among these, the tensile properties of conjugated polymers are particularly important. Various defects easily appear in the crystalline structure of conjugated polymers, resulting in poorer electrical properties compared to small-molecule semiconductors. To meet application requirements, conjugated polymers are usually modified to improve their electrical properties. It is well known that the higher the crystallinity and molecular order of a conjugated polymer material, the better its electrical properties. However, methods commonly used to improve crystallinity and molecular order to enhance device performance, such as thermal annealing and solvent vapor annealing, can severely reduce the toughness of conjugated polymer films, thus limiting the application of conjugated polymers in stretchable devices.

[0003] Researchers employ both chemical and physical methods to address the challenge of achieving optimal electrical and mechanical properties in conjugated polymers. Chemical methods primarily involve synthesizing new materials and endowing them with novel molecular structures to improve toughness; however, this approach requires exploring synthetic routes and is relatively difficult to implement. Physical methods, on the other hand, mainly improve the mechanical properties of conjugated polymers by controlling their aggregated structure. This method can be achieved through various processing techniques and is relatively easier to implement.

[0004] Currently, there are two common physical methods for improving the toughness of conjugated polymers: one is to blend the conjugated polymer with elastomer materials to improve the tensile properties of the conjugated polymer. The other is to use high molecular weight conjugated polymers, which can form a large number of connecting chains between the crystalline regions of the conjugated polymer, promote charge transfer between the crystalline regions, and enable the conjugated polymer to withstand tensile stress, thereby improving the electrical and tensile properties of the polymer.

[0005] The first method, which blends conjugated polymers with elastomers, introduces a large amount of insulators (elastomers, such as polymethylsiloxanes) into the conjugated polymers, limiting their application in electronic products.

[0006] In the second method, entanglement occurs between the molecular chains of high-molecular-weight conjugated polymers, and the higher the molecular weight, the stronger the entanglement. Chain entanglement hinders the movement of molecular chains to form regular stacking and crystallization, resulting in limited improvement in the electrical properties of high-molecular-weight conjugated polymers. After the molecular weight reaches a certain level, polymer crystallization becomes difficult, which in turn leads to a decrease in electrical properties.

[0007] Annealing is the most effective and simplest method to improve the electrical performance of conjugated polymer devices. However, neither of the above two methods for improving the toughness of conjugated polymers can solve the problem of decreased toughness of conjugated polymer films after annealing. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a method for improving the toughness of annealed conjugated polymer films. This method solves the problem that while the electrical properties of conjugated polymer films improve after annealing, the elongation at break of the film decreases significantly. The modified conjugated polymer films prepared using this method exhibit better electrical properties than ordinary conjugated polymer films under the same annealing conditions, while maintaining tensile properties similar to those of unmodified conjugated polymer films.

[0009] The technical solution of the present invention is as follows:

[0010] A method for improving the toughness of conjugated polymer annealed films, the method comprising:

[0011] The nucleating agent is mixed with the conjugated polymer, and after forming a film, it is annealed to obtain a modified conjugated polymer film.

[0012] According to the present invention, the conjugated polymer is a semi-crystalline polymer.

[0013] According to the present invention, the nucleating agent is at least one of the following: bicyclo[2.2.1]heptane-2,3-dicarboxylic acid disodium salt (HPN-68L), dibenzyl sorbitol (DBS, Millad 3905), (1,3:2,4)-di(p-methyldibenzyl)sorbitol (MDBS, Millad 3940), di(3,4-dimethyldibenzyl)sorbitol (DMDBS, Millad 3988), 1,3,5-tri-tert-butyltriphenylamine (BTA, Ciba's transparent nucleating agent IRGACLEAR XT386), preferably bicyclo[2.2.1]heptane-2,3-dicarboxylic acid disodium salt (HPN-68L).

[0014] According to the present invention, the conjugated polymer is at least one selected from poly(3-alkylthiophene), polyfluorene, polyselenophene, and poly(p-phenylenevinylene), preferably poly(3-alkylthiophene); the poly(3-alkylthiophene) is, for example, poly(3-hexylthiophene) (P3HT). The conjugated polymer of the present invention is crystallizable, and chain folding can occur during crystallization.

[0015] According to the present invention, the weight-average molecular weight of the conjugated polymer is 3.0 x 10⁻⁶. 4 -12x10 4 g / mol, preferably 4.0 x 10 g / mol. 4 -8.3x10 4 g / mol, for example, 4.0 x 10⁻⁶ g / mol. 4 g / mol, 5.0 x 10 4 g / mol, 5.7 x 10 4 g / mol, 6.0 x 10 4 g / mol, 6.5 x 10 4 g / mol, 7.0 x 10 4 g / mol, 7.5 x 10 4 g / mol, 8.0 x 10 4 g / mol or 8.3 x 10 4 g / mol.

[0016] The nucleating agent of the present invention has good compatibility with conjugated polymers, can be uniformly dispersed in conjugated polymers, and can regulate the crystallization properties of conjugated polymers.

[0017] According to the present invention, the nucleating agent is 0.5-5.0 wt% of the conjugated polymer, exemplarily 0.5 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, 2.5 wt%, 3.0 wt%, 3.5 wt%, 4.0 wt%, 4.5 wt%, or 5.0 wt%.

[0018] According to the present invention, the nucleating agent and the conjugated polymer can be mixed in a solvent; the solvent is selected, for example, from at least one of o-dichlorobenzene and toluene. In this invention, the solvent content is not particularly limited, as long as the nucleating agent and the conjugated polymer are completely dissolved. Exemplarily, the concentration of the conjugated polymer in the solvent is 1-20 mg / mL.

[0019] According to the present invention, thin films can be prepared by spin coating.

[0020] According to the present invention, the annealing temperature is 15-35°C, exemplarily room temperature; the annealing time is 1-8 hours, preferably 1-3 hours.

[0021] According to the present invention, the annealing treatment can be carried out in an atmosphere such as o-dichlorobenzene, chloroform or chlorobenzene, preferably at the saturated vapor pressure of o-dichlorobenzene, chloroform or chlorobenzene.

[0022] According to the present invention, the elongation at break of the modified conjugated polymer film is maintained at a maximum of 96% of the elongation at break of the unmodified conjugated polymer film, for example, at 75-96%.

[0023] In this invention, the unmodified conjugated polymer film refers to a conjugated polymer film that has not been annealed and has not had a nucleating agent added.

[0024] The beneficial effects of this invention are:

[0025] Conjugated polymer films without nucleating agents are referred to as A films (or unmodified conjugated polymer films), while those with nucleating agents are referred to as B films. During spin-coating of conjugated polymer films, the nucleating agent accelerates the crystallization of the conjugated polymer, causing the conjugated polymer molecular chains to pre-align into multiple crystalline regions before they can be regularly arranged. This increases the number of connecting molecules between the conjugated polymer crystalline regions; that is, the number of connecting molecules in B films is higher than in A films.

[0026] Films A and B were annealed to prepare films C and D, respectively. Annealing enhances the mobility of the conjugated polymer molecular chains, and the nucleating agent provides nucleation sites. With the same annealing time, film D exhibits higher crystallinity. During annealing, the amorphous portion of the conjugated polymer moves into the crystalline region, reducing the number of connecting molecules. Film D initially contains more connecting molecules; compared to film C, with the same annealing time, film D contains more connecting molecules, resulting in higher electrical conductivity and better toughness. Compared to the unmodified conjugated polymer film (i.e., film A), film D shows a significant increase in electrical conductivity, while its elongation at break only slightly decreases (maintaining above 75% of the elongation at break of film A).

[0027] This invention accelerates the crystallization of conjugated polymers by adding nucleating agents, which can effectively increase the number of connecting molecules between crystalline regions in the film. After annealing, the film (i.e., the modified conjugated polymer film) has higher electrical conductivity and better toughness, and even approaches the tensile properties of the unmodified conjugated polymer film, thus solving the problem of good electrical properties but poor toughness of conjugated polymer films after annealing.

[0028] This invention accelerates the crystallization of conjugated polymers through nucleating agents, increasing the number of connecting chains. This results in a considerable number of connecting chains remaining in the conjugated polymer film after annealing, which function to transport charge carriers and resist stress, thus giving the film high toughness and good electrical properties. This principle is universal and applicable to all crystalline conjugated polymers.

[0029] This invention does not require the introduction of large amounts of insulating materials (such as polymethylsiloxane) into the conjugated polymer, and does not limit the application of conjugated polymers in electronic devices. Attached Figure Description

[0030] Figure 1 These are the DSC curves of the polymer powders in Examples 1-3 and Comparative Examples 1-3.

[0031] Figure 2 The linker chain fraction (f) of the unannealed modified conjugated polymer films in Examples 1-3 and Comparative Examples 1-3 is... TC )Calculation results graph.

[0032] Figure 3 These are optical microscope images of the modified conjugated polymer films in Examples 1-3 and Comparative Examples 1-3, annealed for 1 hour under different tensile forces.

[0033] Figure 4 The figures show the cosine at break (COS) plots of the modified conjugated polymer films in Examples 1-3 and Comparative Examples 1-3 with different annealing times.

[0034] Figure 5 The graphs show the conductivity of the modified conjugated polymer films in Examples 1-3 and Comparative Examples 1-3, which were treated with different annealing times.

[0035] Figure 6 The highest electrical conductivity and corresponding COS value of the modified conjugated polymer films in Examples 1-3 and Comparative Examples 1-3 under annealing conditions, and the electrical conductivity and COS value of the conjugated polymer films under non-annealing conditions.

[0036] Figure 7 The COS diagrams are of the modified conjugated polymer films in Examples 2, 4-5 and Comparative Example 2 with different annealing time treatments. Detailed Implementation

[0037] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0038] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0039] Material:

[0040] Conjugated polymer: poly(3-hexylthiophene) (P3HT), nucleating agent: disodium bicyclo[2.2.1]heptane-2,3-dicarboxylate (HPN-68L)

[0041] Example 1

[0042] P3HT (with a weight-average molecular weight of 3.0 x 10⁻⁶) 4 P3HT (5.0 mg / mL) and HPN-68L were dissolved together in o-dichlorobenzene. The concentration of P3HT was 5.0 mg / mL, and the mass of HPN-68L was 1.0 wt% of P3HT. After stirring, a mixed solution was formed, and the mixed solution was spin-coated into a film. The P3HT film was annealed at room temperature under the saturated vapor pressure of o-dichlorobenzene for 0, 1 h, 2 h, and 3 h to prepare the modified conjugated polymer film. When the annealing time was 1 h, the modified conjugated polymer was named P3HT30k-HPN-1h, which represents a weight-average molecular weight of 3.0 x 10⁻⁶. 4 P3HT membrane with g / mol content, containing 1.0 wt% HPN-68L, and annealed for 1 h.

[0043] When the annealing time is 0h, the modified conjugated polymer film is named P3HT30k-HPN-0h (that is, representing an unannealed film).

[0044] The mixed solution is dried to form a polymer powder, which is then used for DSC testing.

[0045] Example 2

[0046] The difference between Example 2 and Example 1 is that the weight-average molecular weight of P3HT is 5.7 x 10⁻⁶. 4 A modified conjugated polymer film was prepared by applying g / mol of the annealing agent. When the annealing time was 1 h, the modified conjugated polymer was named P3HT57k-HPN-1h.

[0047] Example 3

[0048] The difference between Example 3 and Example 1 is that the weight-average molecular weight of P3HT is 8.3 x 10⁻⁶. 4 A modified conjugated polymer film was prepared by applying g / mol of the solution. When the annealing time was 1 h, the modified conjugated polymer film was named P3HT83k-HPN-1h.

[0049] Example 4

[0050] The difference between Example 4 and Example 2 is that the mass of HPN-68L is P3HT (the weight-average molecular weight of P3HT is 5.7 x 10⁻⁶). 4 The modified conjugated polymer was prepared by annealing a 2.0 wt% (g / mol) solution for 0, 1 h, 2 h, and 3 h. When the annealing time was 1 h, the modified conjugated polymer film was named P3HT57k-HPN2-1h.

[0051] Example 5

[0052] The difference between Example 5 and Example 2 is that the mass of HPN-68L is P3HT (the weight-average molecular weight of P3HT is 5.7 x 10⁻⁶). 4 The modified conjugated polymer was prepared by annealing a 5.0 wt% (g / mol) film for 0, 1 h, 2 h, and 3 h. When the annealing time was 1 h, the modified conjugated polymer film was named P3HT57k-HPN5-1h.

[0053] Comparative Example 1

[0054] P3HT (P3HT has a weight-average molecular weight of 3.0 x 10⁻⁶) 4 A P3HT solution (g / mol) was dissolved in o-dichlorobenzene and stirred until homogeneous to form a P3HT solution. The solution was spin-coated into a film, and the P3HT film was annealed at room temperature under the saturated vapor pressure of o-dichlorobenzene for 0, 1, 2, and 3 hours to prepare a modified conjugated polymer film. When the annealing time was 1 hour, the modified conjugated polymer film was named P3HT30k⁻¹h. The P3HT solution was dried to form a polymer powder for DSC testing.

[0055] Comparative Example 2

[0056] The difference between Comparative Example 2 and Comparative Example 1 is that the weight-average molecular weight of P3HT is 5.7 x 10⁻⁶. 4 The modified conjugated polymer film was prepared by applying g / mol. When the annealing time was 1 h, the modified conjugated polymer film was named P3HT57k-1h.

[0057] Comparative Example 3

[0058] The difference between Comparative Example 3 and Comparative Example 1 is that the weight-average molecular weight of P3HT is 8.3 x 10⁻⁶. 4 The modified conjugated polymer was prepared by applying g / mol. When the annealing time was 1 h, the modified conjugated polymer film was named P3HT83k-1h.

[0059] Test Example 1

[0060] The polymer powders prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to DSC testing, and the test results are as follows: Figure 1 As shown (where P3HT30K, P3HT57K, and P3HT83K correspond to the polymer powders in Comparative Examples 1-3, respectively, and P3HT30K-HPN, P3HT57K-HPN, and P3HT83K-HPN correspond to the polymer powders in Examples 1-3, respectively), from Figure 1As can be seen from the comparison between Example 1 and Comparative Example 1, or Example 2 and Comparative Example 2, or Example 3 and Comparative Example 3, after adding HPN-68L, the crystallization temperature T of the three different molecular weights of P3HT decreased. c The increases in all values ​​indicate that HPN-68L has a nucleating effect on P3HT of different molecular weights and can be used as an effective nucleating agent for P3HT. The temperature at the intersection of the baseline tangent and the exothermic high-temperature side in the DSC curve is T. onset After adding HPN-68L to the three samples, T onset With T c The difference (T) onset -T c The decrease in the values ​​indicates that the addition of HPN-68L can effectively accelerate the crystallization of P3HT.

[0061] Test Example 2

[0062] The linker chain fraction (f) of the unannealed modified conjugated polymer films in Examples 1-3 and Comparative Examples 1-3 TC )calculate:

[0063] The Huang-Brown model was used to calculate the change in the linker fraction in P3HT films with HPN-68L added (see references [1, 2]). Relevant parameters were obtained from DSC measurements and parameters from other references (see reference [3]). Based on the molecular structure characteristics of P3HT, the critical distance required for calculation in the model was set to l. c +l a (See reference [3]), where l c For the thickness of the crystal region, l a Given the thickness of the amorphous region, calculations show that the tie-chain fraction (f) TC All of these increase with increasing weight-average molecular weight of P3HT, as shown in the calculation results. Figure 2 As shown, the Huang-Brown model can effectively estimate the linkage fraction of P3HT thin films. From... Figure 2 It can be seen that after adding HPN-68L, the fraction of connecting chains in P3HT films of different molecular weights increased, indicating that the number of connecting chains in the P3HT film increased, proving that adding HPN-68L can effectively increase the number of connecting chains in the conjugated polymer P3HT.

[0064] 【1】Huang,Y.;Brown,N.The effect of molecular weight on slow crackgrowth in linear polyethylene homopolymers.J.Mater.Sci.1988,23,3648-3655.

[0065] 【2】Huang, Y.; Brown N.Dependence of slow crack growth in polyethyleneon butyl branch density:morphology and theory.J.Polym.Sci.Part B:Polym.Phys.1991,29,129-137.

[0066] 【3】Gu, K.; Snyder CR; Onorato, J.; Luscombe, CK; Bosse, AW; Loo, YL. Assessing the Huang-Brown description of the tie chains for charge transportin conjugated polymers. ACS Macro Lett. 2018, 7, 1333-1338.

[0067] Test Example 3

[0068] The tensile properties of the modified conjugated polymer films in Examples 1-3 and Comparative Examples 1-3 were tested, and the elongation at break of the modified conjugated polymer films was determined using an optical microscope. The test results are as follows: Figure 3 and Figure 4 As shown.

[0069] The specific testing procedure was as follows: The modified conjugated polymer films (annealed for 1 hour) from Examples 1-3 and Comparative Examples 1-3 were laminated from a glass substrate onto a polydimethylsiloxane (PDMS) sheet to form a P3HT-PDMS composite. The composite was stretched using a stretching machine, and the surface morphology of the film was observed using an optical microscope. The optical microscope test results are as follows: Figure 3 As shown, the strain at which cracks appear in the composite is the cosine stress (COS) of the modified conjugated polymer film. From... Figure 3 Images b, 3d, and 3f show that no HPN-68L aggregates were observed in the optical microscope images, indicating that HPN-68L was uniformly dispersed in P3HT after annealing.

[0070] Figure 4 The COS diagrams are for the modified conjugated polymer films in Examples 1-3 and Comparative Examples 1-3, which were annealed for different times (0h, 1h, 2h, and 3h, respectively). Figure 4As can be seen, compared with P3HT57k (i.e., Comparative Example 2) and P3HT83k (i.e., Comparative Example 3), after adding HPN-68L, the COS of the P3HT-HPN prepared by this invention (i.e., P3HT57k-HPN in Example 2 and P3HT83k-HPN in Example 3) is much better than that of pure P3HT under the same annealing time. This indicates that adding a low content (1.0 wt%) of HPN-68L significantly improves the tensile properties of the annealed P3HT film. However, for P3HT30k (i.e., Comparative Example 1) with a lower weight-average molecular weight, the tensile properties of the film (i.e., P3HT30k-HPN in Example 1) decreases after adding HPN-68L. Therefore, this invention requires the use of conjugated polymers with high weight-average molecular weights when preparing modified conjugated polymers. Conjugated polymers with low weight-average molecular weights have poor toughness and are not suitable for preparing tensile devices.

[0071] Test Example 4

[0072] The conductivity of the modified conjugated polymer films from Examples 1-3 and Comparative Examples 1-3, which were annealed for different times (0h, 1h, 2h, and 3h), was tested. The conductivity σ of the films was measured using the four-probe method. The test results are as follows: Figure 5 As shown, from Figure 5 It can be seen that the conductivity of the modified conjugated polymer films in Examples 1-3 and Comparative Examples 1-3 increased rapidly after annealing, but decreased again with prolonged annealing time. However, the annealing time for achieving optimal conductivity differed for modified conjugated polymers prepared with different molecular weights of P3HT. P3HT30k-HPN and P3HT57k-HPN showed the highest conductivity after 1 hour of annealing, while P3HT83k-HPN showed the highest conductivity after 2 hours of annealing. Furthermore, under the same annealing time, the conductivity of the modified conjugated polymer films prepared in Examples 1-3 was higher than that of the pure P3HT films (i.e., Comparative Examples 1-3).

[0073] Figure 6 The figures show the highest electrical conductivity and corresponding COS values ​​of the modified conjugated polymer films in Examples 1-3 and Comparative Examples 1-3 under annealing conditions (i.e., P3HT30k-HPN-1h, P3HT57k-HPN-1h, P3HT83k-HPN-2h, P3HT30k-1h, P3HT57k-1h, P3HT83k-2h), and the electrical conductivity and COS values ​​under non-annealing conditions (i.e., P3HT30k-0h, P3HT57k-0h, P3HT83k-0h). Figure 6 It can be seen that the present invention can improve the weight-average molecular weight of 5.7 x 10⁻⁶. 4 g / mol and 8.3 x 10 4The electrical conductivity and elongation at break of P3HT at g / mol were improved, while the effect on improving the weight-average molecular weight of 3.0 x 10⁻⁶ g / mol was also improved. 4 The addition of g / mol of P3HT had no effect on the elongation at break. For example, the σ and COS of P3HT57k-HPN-1h were 4.1 S / cm and 115%, respectively, while those of P3HT57k-1h were 2.3 S / cm and 67%, respectively. This means that after adding the nucleating agent HPN-68L, the conductivity and elongation at break of the P3HT57k-HPN film after annealing were both higher than those of P3HT57k. The σ and COS of P3HT57k-0h (unannealed) were 1.0 S / cm and 120%, respectively. This means that the conductivity of P3HT57k-HPN-1h was 4.1 times that of P3HT57k-0h, while the tensile properties and elongation at break were almost the same as those of P3HT57k-0h (i.e., maintaining 96% of the elongation at break of P3HT57k-0h).

[0074] The σ and COS of P3HT83k-HPN-2h are 4.9 S / cm and 125%, respectively, while those of P3HT83k-2h are 4.5 S / cm and 80%, respectively. This means that after adding the nucleating agent, the conductivity of the P3HT83k-HPN film slightly increases after annealing, while the elongation at break is significantly improved. In contrast, the σ and COS of P3HT83k-0h (unannealed) are 1.7 S / cm and 160%, respectively. Therefore, the conductivity of P3HT83-HPN-2h is 2.9 times that of P3HT83k-0h, while the tensile properties remain at 80% of the elongation at break of P3HT83k-0h.

[0075] Depend on Figure 5 and Figure 6 It is known that by adding a small amount (1.0 wt%) of nucleating agent HPN-68L, the electrical properties of higher molecular weight P3HT films can be improved after annealing, while the tensile properties remain at more than 80% of those of unmodified films. This solves the problem that the tensile properties are severely reduced when conjugated polymers are used to improve electrical properties through annealing.

[0076] Test Example 5

[0077] Figure 7 The COS changes of modified conjugated polymer films (i.e., Comparative Example 2 (P3HT57k), Example 2 (P3HT57k-HPN), Example 4 (P3HT57k-HPN2), and Example 5 (P3HT57k-HPN5) samples) with HPN-68L nucleating agent contents of 0, 1.0 wt%, 2.0 wt%, and 5.0 wt%, respectively, after annealing for different times were recorded. Figure 7As can be seen, after adding a high proportion of nucleating agent, namely samples P3HT57k-HPN2 and P3HT57k-HPN5, the COS decreased with increasing annealing time. After annealing for the same time, the higher the nucleating agent content in the modified conjugated polymer, the lower the COS, indicating that adding 1.0wt% HPN-68L has the best effect on improving the toughness of the conjugated polymer.

[0078] The embodiments of the present invention have been described above by way of example. However, the scope of protection of the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for improving the toughness of conjugated polymer annealed films, characterized in that, The method includes: A modified conjugated polymer film was prepared by mixing a nucleating agent with a conjugated polymer, forming a thin film, and then annealing it. The nucleating agent is disodium bicyclo[2.2.1]heptane-2,3-dicarboxylic acid; The conjugated polymer is poly(3-hexylthiophene). The weight-average molecular weight of the conjugated polymer is 4.0 x 10⁻⁶. 4 -8.3x10 4 g / mol.

2. The method according to claim 1, characterized in that, The nucleating agent is present in an amount of 0.5-5.0 wt% of the conjugated polymer.

3. The method according to claim 1, characterized in that, The nucleating agent and the conjugated polymer are mixed in a solvent; the solvent is selected from at least one of o-dichlorobenzene and toluene.

4. The method according to claim 1, characterized in that, The annealing temperature is 15~35℃, and the annealing time is 1-8h.

5. The method according to claim 1, characterized in that, Annealing is performed in an atmosphere of o-dichlorobenzene, chlorobenzene, or chloroform.

6. The method according to claim 1, characterized in that, The elongation at break of the modified conjugated polymer film is maintained at up to 96% of that of the unmodified conjugated polymer film.

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