An ionic polymer interfacial doping material, a preparation method and application thereof

Abstract

The application belongs to the technical field of organic photoelectric materials, and particularly discloses an ionic polymer interfacial doping material, a preparation method and application thereof. The ionic polymer interfacial doping material provided by the application has a structural formula I shown in formula I, and after being ionized, the ionic polymer interfacial doping material is doped into a cathode interfacial layer, Br ions can be cleaved from the ionic polymer interfacial doping material to form new chemical bonds with Ag, additional electric dipoles are absorbed, the direction of the additional electric dipoles is the same as the direction of electric dipoles of a nitrogen-containing CIL, double dipoles formed can reduce WF, inhibit dark current leakage, improve charge extraction, and further enhance J SC and FF. The ionic polymer interfacial doping material can also promote the formation of a good phase separation morphology and a high-purity domain, is conducive to the construction of a high-quality interpenetrating network, realizes more efficient and more balanced carrier transport, effectively promotes the dissociation of excitons and inhibits charge recombination. Meanwhile, the ionic polymer interfacial doping material enhances interfacial interaction, optimizes a charge transport path, enhances electron transport performance, and reduces non-radiation voltage loss.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic optoelectronic materials, and particularly relates to an ionic polymer interfacial doping material and a preparation method and application thereof. BACKGROUND

[0002] Although the power conversion efficiency of organic solar cells has been greatly improved, the non-radiative recombination loss at the interface between the photoactive layer and the charge transport layer is still a key bottleneck, which usually limits the open-circuit voltage (Voc) V OC ) and the fill factor (FF) FF ). In particular, the energy level mismatch and poor interface contact at the cathode interlayer (CIL) / active layer junction lead to low charge extraction efficiency and increased charge accumulation, ultimately reducing the device performance. CIL is one of the key factors to achieve high performance and stability of OSC, which can provide energy level alignment at the electrode interface and provide interface dipoles for ohmic contact, effectively reducing the work function (WF) of the cathode, thus promoting efficient electron transfer and collection. Based on these advantages, interface engineering has attracted more and more attention, and recent progress in interface engineering has actually been proven to be an effective method to further improve the PCE and long-term stability of OSC. A suitable interlayer plays a crucial role in constructing various devices based on a given active layer, such as conventional, inverted, semi-transparent and tandem devices. So far, PDINN has become a benchmark for CIL materials due to its inherent advantages such as simple synthesis, clear molecular structure, high electron affinity, and high electron mobility, which has greatly improved the performance of OSC. The wide rigid π-conjugated backbone of PDINN will lead to self-aggregation of ETL, making the film-forming quality of ETL on the active layer still insufficient, and it is difficult to form a tight contact with the active layer and the metal electrode. The non-uniformity of ETL has a great influence on the charge extraction process, and these defects may cause serious leakage current, thereby affecting the performance of the device.

[0003] Therefore, how to modify the benchmark CIL to solve the problems of energy level mismatch, poor interface contact and poor film-forming quality of ETL at the CIL / active layer junction, so as to further improve the power conversion efficiency and long-term stability of organic solar cells, is a technical problem to be solved. SUMMARY

[0004] The present application aims at the above-mentioned deficiencies in the prior art, and provides an ionic polymer interfacial doping material and a preparation method and application thereof. The ionic polymer interfacial doping material has excellent cathode interfacial doping performance, good intermolecular stacking effect, and helps to improve the charge mobility, and has better photovoltaic performance in the test of the three organic solar cells.

[0005] The first object of the present application is to provide an ionic polymer interfacial doping material, the structural formula of which is shown as formula I.

[0006] , wherein n is a natural number of 9-15.

[0007] The second object of the present application is to provide a preparation method of an ionic polymer interfacial doping material, characterized by comprising the following steps:

[0008] S1, using 4,7-dibromo-2-(6-bromohexyl)-2H-benzotriazole and 2-tributylstannylthiophene as raw materials, a compound 4 is obtained by Stille coupling reaction:

[0009] ;

[0010] S2, the compound 4 is brominated with N-bromosuccinimide to obtain a compound 5:

[0011] ;

[0012] S3, piperidine occurs nucleophilic substitution with the compound 5 in the presence of potassium carbonate to obtain a compound 6:

[0013] ;

[0014] S4, the compound 6 is subjected to polymerization reaction with 2,5-bis(tributylstannyl)thiophene under the action of tetrakis(triphenylphosphine)palladium catalyst to obtain a compound 7:

[0015] ;

[0016] S5, the compound 7 is subjected to ionization reaction with bromoethane to obtain a compound with the structural formula shown as formula I.

[0017] Further, in step S1, the molar ratio of 4,7-dibromo-2-(6-bromohexyl)-2H-benzotriazole to 2-tributylstannylthiophene is 1: (2-4), and the molar ratio of 4,7-dibromo-2-(6-bromohexyl)-2H-benzotriazole to tetrakis(triphenylphosphine)palladium is 1: (0.05-0.1).

[0018] Further, in step S2, the molar ratio of the compound 4 to N-bromosuccinimide is 1: (2-3).

[0019] Further, in step S3, the molar ratio of the compound 5 to piperidine is 1: (1-3), and the molar ratio of the compound 5 to potassium carbonate is 1: (2-3).

[0020] Further, in step S4, the molar ratio of compound 6 to 2,5-bis(trimethylstannyl)thiophene is 1:(1~1.2), and the molar ratio of compound 6 to tetrakis(triphenylphosphine)palladium is 1:(0.05~0.1).

[0021] Further, in step S5, the mass-volume ratio of compound 7 to bromoethane is 0.05g:(1~2)mL.

[0022] A third object of the present application is to provide an active layer of an organic solar cell, which comprises a first layer and a second layer arranged on the surface of the first layer, the first layer being a mixture of an electron donor material and an electron acceptor material, and the second layer being a mixture of a perylenediimide-based polymer and the ionic polymer interfacial doping material of the present application.

[0023] Further, the mass percentage of the ionic polymer interfacial doping material is 0.25~1% of the perylenediimide-based polymer.

[0024] A fourth object of the present application is to provide the use of the ionic polymer interfacial doping material or the active layer of the organic solar cell as described above in the preparation of an organic solar cell device.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] (1) The ionic piperidine polymer doping material provided by the present application can realize the synergistic control of the phase separation morphology and the photophysical process of the blended film. After ionization, the ionic piperidine polymer doping material is doped into the cathode interfacial layer, the Br ion can be split from the PIP to form a new chemical bond with Ag, and absorb an additional electric dipole, whose direction is the same as that of the electric dipole of the nitrogen-containing CIL. Since the double dipoles can reduce the WF, inhibit the dark current leakage, and improve the charge extraction, the PCE, FF, and Jsc can be enhanced. J SC The ionic piperidine polymer doping material can also promote the formation of a good phase separation morphology and a high-purity domain, which is conducive to the construction of a high-quality interpenetrating network, realizes more efficient and balanced carrier transport, effectively promotes the dissociation of excitons and inhibits the recombination of charges. At the same time, the interface interaction is enhanced, the charge transport path is optimized, the electron transport performance is enhanced, and the non-radiative voltage loss is reduced.

[0027] (2) The novel ionic polymer designed by the structure is a key way to realize the synergistic control of the nanoscale phase separation morphology and the photophysical process, so as to prepare a high-efficiency organic solar cell.

[0028] (3) The synthesis process provided by the present application is simple, easy to purify, and has good practical application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 A process flow diagram for preparing an ionic polymer interface doped material provided by the present invention;

[0030] Figure 2 Compound 3 prepared in this invention 1 H NMR spectrum;

[0031] Figure 3 Compound 4 prepared in this invention 1 H NMR spectrum;

[0032] Figure 4 Compound 5 prepared in this invention 1 H NMR spectrum;

[0033] Figure 5 Compound 6 prepared in this invention 1 H NMR spectrum;

[0034] Figure 6 The LC-MS spectrum of compound 6 prepared in this invention;

[0035] Figure 7 The current density-voltage ratio of the organic solar energy device prepared for this invention J-V )test;

[0036] Figure 8 The external quantum efficiency (EQE) test results of the organic solar energy device prepared in this invention are shown.

[0037] Figure 9 The image shows the ultraviolet-visible spectrum of the organic solar energy device prepared according to the present invention.

[0038] Figure 10 The electrochemical test results are for the organic solar energy device prepared according to the present invention;

[0039] Figure 11 This is a test image from an atomic force microscope;

[0040] Figure 12 This is a UV-Vis absorption spectrum.

[0041] Figure 13 The thermogravimetric analysis results are for the ionic polymer interface doped material prepared in this invention. Detailed Implementation

[0042] In order to more clearly and intelligibly explain the technical solutions and beneficial effects of the present application, the present application is described in detail below in combination with the drawings and examples. It needs to be made clear that the described reference drawings are only some embodiments of the present application and are only used to explain the present application, and cannot be understood as a limitation on the present application. Unless specifically stated, the equipment and reagents used in the present application are commonly commercially available products in the technical field.

[0043] The present application provides an ionic polymer interfacial doping material with a structural formula as shown in formula I, wherein n is a natural number of 9-15.

[0044] It can be synthesized from starting material compound 3: 4,7-dibromo-2-(6-bromohexyl)-2H-benzotriazole (CAS No.: 890704-02-6), and the specific process route is as follows:

[0045] Step 1, under nitrogen protection, compound 3, 2-tributylstannylthiophene and tetrakis(triphenylphosphine)palladium are added to a flask. Then inject anhydrous toluene, stir the mixture at 110 ℃ for 12 hours. Then quench the mixture with cold deionized water, and extract with dichloromethane three times. The combined organic layer is washed with deionized water three times and dried with anhydrous sodium sulfate. After removing the solvent, the crude product is purified by silica gel column chromatography (eluent: petroleum ether: dichloromethane) to obtain green solid compound 4, . Wherein the molar ratio of compound 3 and 2-tributylstannylthiophene is 1: (2~4), preferably 1:3; the molar ratio of compound 3 and tetrakis(triphenylphosphine)palladium is 1: (0.05~0.1), preferably 1:0.08.

[0046] Step 2, compound 4 is dissolved in chloroform, and N-bromosuccinimide is added in batches under light protection. Stir at room temperature for 4 hours. Then, the mixture is neutralized with water, and extracted with dichloromethane three times. The organic layer is combined, washed with deionized water three times, and then dried with anhydrous sodium sulfate. After removing the solvent, the crude product is purified by silica gel column chromatography (eluent: petroleum ether: dichloromethane) to obtain compound 5 as a light yellow solid,

[0047] . Wherein the molar ratio of compound 4 and N-bromosuccinimide is 1: (2~3), preferably 1:2.5.

[0048] Step 3, compound 5 was dissolved in dimethylformamide (DMF) and potassium carbonate was added. The reaction was heated and stirred to 80 °C and then piperidine was added and the reaction was continued for two hours. The reaction was poured into water and extracted with ethyl acetate three times. The organic layer was washed with water and then dried over anhydrous sodium sulfate. After removing the solvent, the crude product was purified by silica gel column chromatography (eluent: petroleum ether: ethyl acetate) to obtain compound 6 as a yellow solid,

[0049] wherein the molar ratio of compound 5 and piperidine was 1: (1~3), preferably 1:2; the molar ratio of compound 5 and potassium carbonate was 1: (2~3), preferably 1:2.

[0050] Step 4, compound 6 and 2,5-bis (trimethylstannyl) thiophene, tetrakis (triphenylphosphine) palladium were added to anhydrous toluene under nitrogen atmosphere. The reaction mixture was stirred at 110 °C for 12 hours. The reaction was poured into methanol to form a precipitate. The precipitate was then washed with methanol and n-hexane in turn. The precipitate was collected and dried under vacuum at room temperature to obtain compound 7,

[0051] wherein the molar ratio of compound 6 and 2,5-bis (trimethylstannyl) thiophene was 1: (1~1.2), preferably 1:1; the molar ratio of compound 6 and 2,5-bis (trimethylstannyl) thiophene was 1: (1~1.2), preferably 1:1.

[0052] It should be noted that the starting material can be commercially available or can be synthesized by oneself. In the present application, 3,6-dibromo-1,2-phenylenediamine (CAS: 69272-50-0) was used for synthesis, and the specific process was as follows:

[0053] Under nitrogen (N2) atmosphere, 3,6-dibromo-1,2-phenylenediamine was dissolved in acetic acid and stirred at room temperature (RT) for 20 minutes, and then sodium nitrite was dissolved in water and added dropwise in batches. Stirring was carried out at room temperature for 8 hours. The reaction was poured into water and extracted with dichloromethane three times. The organic layer was washed with water and then dried over anhydrous sodium sulfate. After removing the solvent, drying was carried out in a vacuum oven to obtain compound 2 as a light pink solid,

[0054] wherein the molar ratio of 3,6-dibromo-1,2-phenylenediamine and sodium nitrite was 1: (2~4), preferably 1:2.

[0055] Then, compound 2 is dissolved in dimethylformamide, and potassium carbonate is added. Heating and stirring to 60 ℃, then adding 1,6-dibromo hexane, continue to react for two hours. Pour the reaction into water, and extract with ethyl acetate three times. The organic layer is washed with water, and then dried with anhydrous sodium sulfate. After removing the solvent, the crude product is purified by silica gel column chromatography (eluent: petroleum ether: dichloromethane) to obtain white solid compound 3, 4,7-dibromo-2-(6-bromohexyl)-2H-benzotriazole,

[0056] , wherein the molar ratio of compound 2 and the potassium carbonate is 1: (1~3), preferably 1:2, and the molar ratio of compound 2 and the 1,6-dibromoethane is 1: (1~2), preferably 1:1.2.

[0057] The prepared compound 7 is subjected to ionization reaction with bromoethane to obtain a compound shown in formula I, n is a natural number of 9-15, named PIP, which is an alcohol-soluble ionomer, the enhanced interfacial interaction optimizes the charge transport path, enhances the electronic transport performance, and reduces the non-radiative voltage loss. Compound PIP is doped into the cathode interfacial material perylene diimide-based polymer such as PDINN to form a good phase separation morphology and a high-purity domain, which is conducive to constructing a high-quality interpenetrating network, realizing more efficient and more balanced carrier transport, effectively promoting the dissociation of excitons and inhibiting charge recombination. It can be completely used for the preparation of organic solar cell devices.

[0058] The preparation method described above can obtain the compound shown in formula I provided by the application, and the preparation process flow is as shown in Figure 1 .

[0059] The application examples in the present application have achieved some positive effects in research and development or use, and indeed have great advantages compared with the prior art. The following content is described in combination with data, graphs and the like in the test process, including material synthesis and device preparation.

[0060] In the following examples, unless otherwise specified, the "water" used is deionized water.

[0061] In the following tests of the present application, the hydrogen nuclear magnetic resonance spectrum test is carried out on the AVANCE NEO 400MHz nuclear magnetic resonance spectrometer of Bruker Company in Germany, and deuterated chloroform (CDCl3) is used as the solvent, and tetramethylsilane (TMS) is used as the standard.

[0062] The liquid chromatography test is carried out by using Shimadzu LCMS-2010EV liquid chromatograph-mass spectrometer.

[0063] Example 1

[0064] The embodiment provides an ionic polymer interface doping material and a preparation method, and the specific process is as follows:

[0065] (1) Synthesis of compound 2:

[0066] Compound 1: 3,6-dibromo-1,2-phenylenediamine (5 g, 18.80 mmol) was dissolved in 50 mL of acetic acid under a nitrogen (N2) atmosphere, stirred at room temperature (RT) for 20 minutes, then sodium nitrite (2.60 g, 37.6 mmol) was dissolved in water (15 mL) and slowly added dropwise in batches. Stirring at room temperature for 8 hours. Pour the reaction into water, extract with dichloromethane three times. The organic layer is washed with water and then dried over anhydrous sodium sulfate. After removing the solvent, dry in a vacuum oven to obtain compound 2 as a light pink solid. (4.58 g, yield: 88%)

[0067] (2) Synthesis of compound 3

[0068] Compound 2 (4.58 g, 16.54 mmol) was dissolved in 50 mL of dimethylformamide (DMF) and potassium carbonate (4.57 g, 33.08 mmol) was added. Heat and stir to 60 °C, then add 1,6-dibromohexane (6.05 g, 24.81 mmol) and continue to react for two hours. Pour the reaction into water and extract with ethyl acetate three times. The organic layer is washed with water and then dried over anhydrous sodium sulfate. After removing the solvent, the crude product is purified by silica gel column chromatography (eluent: petroleum ether: dichloromethane) to obtain white solid compound 3. (2.11 g, 30%). 1 H NMR (400 MHz, CDCl3)δ(ppm): 7.45 (s, 2H), 4.79 (s, 2H), 3.39 (s, 2H), 2.17 (s, 2H), 1.86 (s, 2H),1.46 (d, 4H).Compound 3 1 H NMR as Figure 2 indicated.

[0069] (3) Synthesis of compound 4

[0070] Compound 3 (2.11 g, 4.95 mmol), tributyl(thiophene-2-yl)stannane (4.62 g, 12.38 mmol) and Pd(PPh3)4(100 mg) were added into a flask under nitrogen protection. Then toluene (30 mL) was injected and the mixture was stirred at 110 °C for 12 h. Then the mixture was quenched with cold deionized water and extracted with dichloromethane for three times. The combined organic layers were washed with deionized water for three times and dried over anhydrous sodium sulfate. After removal of the solvent, the crude product was purified by silica gel column chromatography (eluent: petroleum ether:dichloromethane) to give compound 4 as a green solid. (1.57 g, 71% yield for this step). 1 H NMR (400 MHz, CDC13) δ (ppm): 8.09 (t, 2H), 7.64 (d, 2H), 7.39 (d, 2H), 7.19 (p, 2H), 4.84 (td, 2H), 3.40 (td, 2H), 2.29-2.17 (m, 2H), 1.88 (tq, 2H), 1.52-1.15 (m, 4H). H NMR spectrum of compound 4 is shown in 1 H NMR spectrum of compound 4 is shown in Figure 3 H NMR spectrum of compound 4 is shown in

[0071] (4) Synthesis of compound 5

[0072] Compound 4 (1.57 g, 3.53 mmol) was dissolved in 20 mL of chloroform and N-bromosuccinimide (1.64 g, 9.19 mmol) was added portionwise under dark condition. It was stirred at room temperature for 4 h. Subsequently, the mixture was neutralized with water and extracted with dichloromethane for three times. The organic layers were combined, washed with deionized water for three times and dried over anhydrous sodium sulfate. After removal of the solvent, the crude product was purified by silica gel column chromatography (eluent: petroleum ether:dichloromethane) to give compound 5 as a light yellow solid. (1.78 g, 84% yield for this step). 1 H NMR (400 MHz, CDC13) δ (ppm): 8.09 (t, 2H), 7.64 (d, 2H), 7.39 (d, 2H), 7.19 (p, 2H), 4.84 (td, 2H), 3.40 (td, 2H), 2.29-2.17 (m, 2H), 1.88 (tq, 2H), 1.52-1.15 (m, 4H). H NMR spectrum of compound 4 is shown in 1 H NMR spectrum of compound 4 is shown in Figure 4 H NMR spectrum of compound 4 is shown in

[0073] (5) Synthesis of compound 6

[0074] Compound 5 (1.78 g, 2.95 mmol) was dissolved in 20 mL of dimethylformamide (DMF) and potassium carbonate (0.82 g, 5.9 mmol) was added. The reaction was heated and stirred to 80 °C, then piperidine (0.50 g, 5.9 mmol) was added and the reaction was continued for two hours. The reaction was poured into water and extracted with ethyl acetate three times. The organic layer was washed with water and then dried over anhydrous sodium sulfate. After removing the solvent, the crude product was purified by silica gel column chromatography (eluent: petroleum ether: ethyl acetate) to obtain compound 6 as a yellow solid. (1.54 g, 86% yield for this step). 1 H NMR (400 MHz, CDCl3) δ(ppm): 7.80 (dt, 2H), 7.64–7.42 (m, 2H), 7.12 (q, 2H), 4.79 (t, 2H), 2.51–2.22 (m, 6H), 2.17 (q, 2H), 1.56 (t, 6H), 1.41 (q, 8H).Compound 6 1 H NMR spectrum as shown in Figure 5 LC-MS spectrum as shown in Figure 6 .

[0075] (6) Synthesis of compound 7

[0076] Compound 6 (60.85 mg, 0.1 mmol) and 2,5-bis(trimethylstannyl)thiophene (40.98 mg, 0.1 mmol), Pd(PPh3)4(5 mg) were added to anhydrous toluene (5 mL) under nitrogen atmosphere. The reaction mixture was stirred at 110 °C for 12 hours. The reaction was poured into methanol to form a precipitate. The precipitate was then washed with methanol and n-hexane in turn. The precipitate was collected and dried under vacuum at room temperature.

[0077] (7) Synthesis of compound PIP

[0078] 50 mg of compound 7 was dissolved in a mixed solvent of 15 mL of toluene and 15 mL of methanol, and then 1 mL of bromoethane was added. The mixture was stirred at 60 °C for 24 hours. After the reaction was completed, the reaction solution was concentrated and precipitated in n-hexane. The solid was collected and vacuum dried for 12 hours. The obtained polymer was characterized as follows:

[0079] The molecular weight characterization data are as follows: the weight average molecular weight is 5843 Da, the number average molecular weight is 10016 Da, and the polymer molecular weight distribution index is 1.71; as shown in Figure 13 the mass of PIP at a temperature of 265.5 °C is 95% of the original, asFigure 12 As shown, PIP exhibits a broad absorption in the range of 400-650 nm with a maximum absorption peak at 497 nm.

[0080] Example 2

[0081] The present embodiment provides a small-molecule organic solar cell device.

[0082] The organic solar cell device comprises an ITO substrate, a PEDOT:PSS layer, an active layer, an electron transport layer and an electrode which are sequentially stacked, and the specific preparation process is as follows:

[0083] (1) After the ITO glass (indium tin oxide conductive glass) is cleaned by ultrasonic wave, the ITO is treated by oxygen-plasma, and PEDOT:PSS (poly(3,4-ethylenedioxythiophene): poly(styrenesulfonic acid) (Xi'an Yurui Solar Energy Technology Co., Ltd., PEDOT:PSS AI4083, product number: 306020, a mixed solution prepared when purchased) is spin-coated on the ITO at 5000 rpm, and the substrate with a surface film thickness of about 40 nm is obtained by annealing at 150°C for 15 minutes.

[0084] (2) Then, the donor material D18 and the acceptor L8-BO (the structural formula is shown below) are mixed as a binary organic solar device (the mass ratio of the donor material to the acceptor material and the additive is preferably 1:1:1), and the mixed solution (the total concentration of the donor and the acceptor is 20 mg / mL) is prepared by adding the mixed solvent of diiodomethane-trichloromethane (the volume ratio of diiodomethane to trichloromethane is 0.3 μL:100 μL), and the blended solution is coated on the substrate of step (1) by spin coating at a speed of 2000 rpm to form an active layer with a thickness of about 130 nm on the surface of the substrate.

[0085] (3) The substrate obtained in step (2) is placed in a 60 nm culture dish, and then 60 μL of chlorobenzene is evenly coated on the surface, followed by solvent vapor annealing (85°C, 5 min), and then an electron transport layer PDINN thin film is coated on the active layer by spin coating at a speed of 3000 rpm, and the PDINN+PIP thin film (the mass ratio of PDINN to PIP is preferably (1:0.005), and the film thickness is about 10 nm. Finally, a 100 nm thick silver layer is deposited on the electron transport layer by evaporation.

[0086] The specific solar cell efficiency is shown in Table 1 (the equipment used in the laboratory of the present application is a solar simulator, and a silicon solar cell is used for calibration, and all tests are measured under 1 simulated sunlight, 100 mW / cm 2 ).

[0087] ;

[0088] ;

[0089] .

[0090] From the data in Table 1, it can be seen that the compound PIP prepared by the application is applied to PDINN as a doping material, and the photoelectric conversion efficiency of the binary photovoltaic device. This kind of polymer doping material has a unique advantage in the commercialization of organic solar cells.

[0091] Table 1. Photovoltaic parameters of the best performance of devices of PIP doped PDINN with different proportions.

[0092]

[0093] Note: V OC Voc is the open circuit voltage, J SC Jsc is the short circuit current density, FF FF is the fill factor, PCE η is the functional conversion efficiency.

[0094] The donor D18 and the acceptor L8-BO are mixed as a binary organic solar device (the mass ratio of the donor to the acceptor material and the additive is preferably 1:1:1), and then the PIP prepared in Example 1 is doped into the PDINN binary device to prepare an organic solar device (the mass ratio of PDINN:PIP is preferably 1:0.005), and PDINN:PIP is 1:0, 1:0.0025, 1:0.0075, 1:0.01 as a comparison group, and then the J-V curve is measured under 1 simulated sunlight (SAN-EI, XES-40S2-CE) 100 mW / cm 2 (AM 1.5G) irradiation intensity, and the current-voltage (J-V) characteristics are measured using a Keithley 2450 source table).

[0095] The results are shown in Figure 7 From the figure, it can be seen that the performance of the compound PIP prepared by the application after doping is significantly improved compared with PDINN. In photodynamics, it can be analyzed that the device of the compound PIP doped PDINN has a larger exciton diffusion coefficient and a faster exciton dissociation process compared with the device based on PDINN.

[0096] As Figure 8The figure shows the external quantum efficiency (EQE) test results: the EQE spectrum was analyzed using a certified Newport IPCE measurement system. High-sensitivity EQE was measured using an integrated system (PECT-600, Enlitech), where the photocurrent is amplified and modulated via a locked instrument. This test corroborates the EQE spectrum of the PIP-doped PDINN device compared to the integral of the solar spectrum (AM 1.5 G) with respect to the PDINN-based device. J The values ​​obtained from the sc curve and the JV curve are consistent, with an error of less than 5%. This means that PIP doping into PDINN can make its internal charge transfer more efficient and generate more charge carriers.

[0097] like Figure 9 The UV-Vis spectra are shown below: the UV-Vis absorption spectra of the solution and the thin film were recorded using a Hitachi U-4100 spectrophotometer. The optical absorption spectra of the thin film were prepared by spin-coating a methanol solution (1.0 mg / mL, 1500 rpm) onto a quartz plate. UV-Vis absorption spectra of PDINN, PDINN+0.25%PIP, PDINN+0.50%PIP, PDINN+0.75%, and PDINN+1.00%PIP were measured using a UV spectrophotometer. PIP exhibited strong absorption in the 400-600 nm range.

[0098] like Figure 10 The electrochemical test results are shown below: A three-electrode system (glassy carbon electrode as working electrode, Ag / Ag) was used on the CHI660D electrochemical workstation. + The electrode was used as a reference electrode and a platinum wire counter electrode. A nitrogen-saturated solution of 0.1 mol / L tetrabutylammonium hexafluorophosphate in acetonitrile was used as the electrolyte. Cyclic voltammetry (CV) was performed at a scan rate of 100 mV / s, using a ferrocene-ferrocene salt (Fc / Fc) method. + As an internal standard, its absolute energy compared to vacuum is -4.8 eV. The HOMO and LUMO energy levels of the material are determined according to the following equations:

[0099]

[0100] Measurements were taken using the cyclic voltammetry method, such as... Figure 10 As shown, for PDINN, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels are -5.8 eV and -3.83 eV, respectively. For PIP, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels are -5.83 eV and -3.92 eV, respectively.

[0101] like Figure 11The atomic force microscope test figure is shown: the film topography figure is measured by Park NX10 atomic force microscope. The R q values of PDINN, PDINN+0.25%PIP, PDINN+0.50%PIP, PDINN+0.75%, PDINN+1.00%PIP are 2.51 nm, 2.36 nm, 2.07 nm, 2.12 nm, 2.50 nm respectively. The surface roughness of PDINN+0.50%PIP is the lowest, which indicates that the flat and uniform surface of PDINN+0.50%PIP film promotes the formation of excellent physical and electronic contact between ETL and active layer, thereby reducing interface defects and inhibiting interface charge recombination.

[0102] As shown in Figure 12 , it is the ultraviolet spectrum characterization figure, the ultraviolet-visible light absorption spectrum of PDINN, PIP and different PDINN:PIP ratio mixed cathode interlayer. PIP shows a wide absorption in the range of 400-650 nm, and the maximum absorption peak is located at 497 nm, which has a red shift of 20 nm compared with the maximum absorption peak of PDINN located at 477 nm.

[0103] The above not involved, applicable to the prior art.

[0104] Although some specific embodiments of the present application have been described in detail by examples, those skilled in the art should understand that the above examples are only for illustration, not for limiting the scope of the present application, and those skilled in the art can make various modifications or supplements to the described specific embodiments or replace them with similar ways, but will not deviate from the direction of the present application or exceed the scope defined by the appended claims. Those skilled in the art should understand that any modification, equivalent replacement, improvement, etc. made according to the technical essence of the present application to the above embodiments shall be included in the protection scope of the present application.

Claims

1. An ionic polymer interface doped material, characterized in that, The structural formula of the ionic polymer interface doped material is shown in Formula I: Formula I, Where n is a natural number between 9 and 15.

2. A method for preparing the ionic polymer interface doped material according to claim 1, characterized in that, Includes the following steps: S1. Using 4,7-dibromo-2-(6-bromohexyl)-2H-benzotriazole and 2-tributylmethyltinylthiophene as starting materials, compound 4 was obtained via Stille coupling reaction: ； S2. Compound 4 is brominated with N-bromosuccinimide to give compound 5: ； S3, piperidine undergoes nucleophilic substitution with compound 5 in the presence of potassium carbonate to give compound 6: ； S4. Compound 6 was polymerized with 2,5-bis(trimethyltinyl)thiophene in the presence of a tetra(triphenylphosphine)palladium catalyst to obtain compound 7: ； S5. The compound obtained by ionizing compound 7 with bromoethane has the structural formula shown in Formula I.

3. The preparation method according to claim 2, characterized in that, In step S1, the molar ratio of 4,7-dibromo-2-(6-bromohexyl)-2H-benzotriazole to 2-tributyltinylthiophene is 1:(2~4); the catalyst used in the Stille coupling reaction is tetra(triphenylphosphine)palladium, and the molar ratio of 4,7-dibromo-2-(6-bromohexyl)-2H-benzotriazole to tetra(triphenylphosphine)palladium is 1:(0.05~0.1).

4. The preparation method according to claim 2, characterized in that, In step S2, the molar ratio of compound 4 to N-bromosuccinimide is 1:(2~3).

5. The preparation method according to claim 2, characterized in that, In step S3, the molar ratio of compound 5 to piperidine is 1:(1~3), and the molar ratio of compound 5 to potassium carbonate is 1:(2~3).

6. The preparation method according to claim 2, characterized in that, In step S4, the molar ratio of compound 6 to 2,5-bis(trimethyltinyl)thiophene is 1:(1~1.2), and the molar ratio of compound 6 to tetra(triphenylphosphine)palladium is 1:(0.05~0.1).

7. The preparation method according to claim 2, characterized in that, In step S5, the mass-to-volume ratio of compound 7 to bromoethane is 0.05 g:(1~2) mL.

8. An active layer of an organic solar cell, characterized in that, The active layer includes a first layer and a second layer disposed on the surface of the first layer. The first layer is a mixture of an electron donor material and an electron acceptor material, and the second layer is a mixture of a perylene diimide-based polymer and the ionic polymer interface doping material of claim 1.

9. The active layer of the organic solar cell as described in claim 8, characterized in that, The mass percentage of the ionic polymer interface doped material is 0.25-1% of the perylene diimide-based polymer.

10. The use of the ionic polymer interface doping material as described in claim 1 or the active layer of the organic solar cell as described in any one of claims 8-9 in the fabrication of organic solar cell devices.

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