CN116514836A - Dibenzoquinoxaline wide-band acceptor material for organic solar cell, and preparation method and application thereof - Google Patents

Abstract

A dibenzoquinoxaline wide-bandgap acceptor material for an organic solar cell, a preparation method and application thereof, comprising the steps of 1: the compound 1 is subjected to twice heating reaction, hydrolysis reaction, decarboxylation reaction, strong base tertiary butyl lithium hydrogen-extracting tin-adding compound and Stille coupling reaction to obtain a final reaction product, namely a compound 6; step 2: reacting the compound 6, anhydrous o-dichlorobenzene, triethyl phosphite, 2-butyl iodooctane, potassium carbonate and anhydrous N, N-dimethylformamide, and treating to obtain BTOR; step 3: qxO2 is prepared in two bottles; step 4: qxO2, anhydrous 1, 2-dichloroethane, vilsmerier reagent, aqueous sodium acetate solution and dichloromethane are prepared to obtain QxO-CHO; step 5: adding QxO-CHO, fluoro-cyano-indenone and anhydrous chloroform for reaction to prepare QxO-2. The prepared QxO-2 was applied to the preparation of solar cell devices.

Description

Dibenzoquinoxaline wide-band acceptor material for organic solar cell, and preparation method and application thereof

Technical Field

The invention belongs to the technical field of solar cell materials, and particularly relates to a preparation method of a dibenzoquinoxaline wide-band acceptor material for an organic solar cell.

Background

The Organic Photovoltaics (OPVs) have the advantages of low cost, flexibility, solution processing and the like, have wide application prospects in a plurality of application scenes such as wearable and photovoltaic Building Integrated (BIPV) and the like, and can form better complementation with the traditional silicon-based photovoltaic device. With the development of active layer material innovation, device optimization process improvement, interface layer material modification, device packaging process exploration and other technologies, organic photovoltaics have made breakthrough research progress in recent years. However, the device efficiency of organic photovoltaics is still relatively low compared to silicon-based solar cells currently produced commercially on a large scale and to perovskite solar cells currently well developed. The improvement of the device efficiency through the regulation and control of the chemical structure of the materials, the optimization of the device process and the like is still a key scientific problem to be solved in organic photovoltaics. Besides the design of new materials, the ternary device and the laminated device are effective means for fully utilizing sunlight, improving photon utilization rate and reducing heat loss.

According to literature investigation, both a theoretical model and a computational simulation show that the optimal cut-off absorption wavelength range of the single junction device is in the range of 900-950nm, wherein the currently developed optimal Y6 and derivative acceptor materials thereof meet the light absorption range in the optimal range. However, the most widely used polymer donor materials matched to this have their cutoff absorption ranges mostly in the range of 700-750nm, so that the blended films of donor materials exhibit significant absorption defects in the 600-750nm range, resulting in reduced photon utilization and improved charge recombination efficiency. In addition, for stacked devices, the development of Y6 derivative acceptor material systems with relatively red-shifted absorption spectra, the design and synthesis of wide bandgap acceptor materials with light absorption complementary to that of narrow bandgap acceptor materials and lower energy loss as pre-cell materials for stacked devices is critical to the fabrication of high efficiency stacked devices. Therefore, the design and synthesis of wide bandgap acceptor materials with high open circuit voltage and low energy loss is of great research importance, both from the perspective of the third component of the ternary device and from the perspective of the suitable pre-cell materials of the stacked device.

In recent years, with the innovation of active layer materials, especially non-fullerene acceptor materials, device performance of organic solar cells has been continuously broken through, and especially single junction photovoltaic device efficiency based on Y6 and its derivative acceptor materials has been obtained to be more than 19%. Through literature research, the great blue shift (-100 nm) of the absorption spectrum of the material can be realized through the regulation and control of alkyl side chains at two ends of the middle core of the Y6 material (such as Y6O molecules). When the electron-deficient Benzothiadiazole (BT) in the middle core of the Y6 molecule is regulated to be a quinoxaline structure with weaker electron pulling capability, the absorption spectrum of the material is blue-shifted by 50nm compared with the Y6 molecule. Wherein a high open circuit voltage (V) of up to 0.934V is obtained using a receptor molecule Qx-2 of the dibenzoquinoxaline intermediate core _oc ) Reduced recombination energy and low energy loss. Based on the method, the intermediate core and side chain regulation strategy is cooperatively utilized to realize the further blue shift of the material absorption spectrum, so that the wide-bandgap acceptor material with high efficiency and low energy loss is obtained, and the method has important research value in the fields of ternary devices, front battery materials of laminated devices and even indoor organic photovoltaics.

Disclosure of Invention

In order to comprehensively solve the problems, the invention provides a dibenzoquinoxaline wide-band acceptor material for an organic solar cell, and a preparation method and application thereof. Research shows that on the basis of the Y6 molecule of the star small molecule acceptor, the absorption spectrum of the material can be blue shifted by introducing an electron-deficient core with relatively weak electron-pulling capability into the middle core, and the absorption spectrum of the material can be blue shifted by nearly 100nm by replacing alkyl side chains at two ends of the middle core with alkoxy side chains. While the currently well developed Y6 and its derivative acceptor materials exhibit excellent three-dimensional structure molecular packing, lower exciton dissociation driving force and low energy loss. Therefore, the material can fully exert the excellent photoelectric property of the material, and simultaneously, the absorption spectrum of the material is blue-shifted, so that the aim of matching with indoor spectrum is fulfilled, and the material is an important design strategy for constructing a high-efficiency wide-bandgap receptor.

Based on the above, the invention utilizes the cooperative regulation strategy of the middle nucleus, the side chain and the tail end to design and construct a series of wide-bandgap small molecule receptors with compact and ordered molecular structures by utilizing the conventional synthesis technology. At the same time, by matching proper donor materials and fine morphology regulation of the active layer, E is hopefully reduced _loss And realizes the high efficiency of IOPV.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

a dibenzoquinoxaline wide bandgap acceptor material for use in an organic solar cell, having the formula:

a preparation method of dibenzoquinoxaline wide-bandgap acceptor material for organic solar cells comprises the following steps:

step 1: the compound 1 is subjected to twice heating reaction, hydrolysis reaction, decarboxylation reaction, strong base tertiary butyl lithium hydrogen-extracting tin-adding compound and Stille coupling reaction to obtain a final reaction product, namely a compound 6;

step 2: reacting the compound 6, anhydrous o-dichlorobenzene, triethyl phosphite, 2-butyl iodooctane, potassium carbonate and anhydrous N, N-dimethylformamide, and further processing to obtain BTOR;

step 3: adding a compound BTOR and THF solution of lithium aluminum hydride into a two-mouth bottle for reaction to obtain a crude product, and then adding phenanthrene-9, 10-dione for reaction and anhydrous chloroform for preparation to obtain QxO;

step 4: qxO2, anhydrous 1, 2-dichloroethane, vilsmerier reagent, sodium acetate aqueous solution and dichloromethane which are prepared in the step 3 are prepared to obtain QxO-CHO;

step 5: adding the intermediate QxO2-CHO, fluoro-cyano-indenone and anhydrous chloroform prepared in the step 4 for reaction to prepare QxO-2, namely the dibenzoquinoxaline wide-band gap acceptor material.

Preferably, step 2 includes:

step 2.1: adding the compound 6 prepared in the step 1 into a 100mL single-port bottle, and replacing the gas for 3 times under the nitrogen atmosphere;

step 2.2: continuously adding anhydrous o-dichlorobenzene and triethyl phosphite, heating at 160 ℃ for reaction for 12 hours, then distilling off the o-dichlorobenzene and the excessive triethyl phosphite under reduced pressure, adding 2-butyl iodooctane and potassium carbonate, replacing gas for three times under nitrogen atmosphere, adding 15mL of anhydrous N, N-dimethylformamide under nitrogen condition, heating at 100 ℃ for reaction for 12 hours,

step 2.3: TLC detects the reaction progress, the reaction is stopped when the raw materials disappear, the organic phase is extracted for 3 times by ethyl acetate, dried by anhydrous magnesium sulfate for 2 hours, the organic phase is removed by decompression and spin-drying, and simultaneously, an orange transparent oily product BTOR is obtained by using normal hexane as an eluent through a layer-by-layer chromatography.

Preferably, step 3 includes:

step 3.1: adding compound BTOR into two bottles, adding anhydrous THF under nitrogen atmosphere, dropwise adding THF solution of lithium aluminum hydride with a constant pressure dropping funnel under ice bath, removing ice bath after the dropwise adding, reflux reacting at 65deg.C for 4 hr,

step 3.2: TLC detects the reaction progress, the reaction is stopped when the raw materials disappear, the organic phase is extracted for 3 times by ethyl acetate, the organic phase is dried by anhydrous magnesium sulfate, the organic phase is removed by decompression and rotation, and the next reaction can be directly carried out without post treatment;

step 3.3: adding phenanthrene-9, 10-diketone into the crude product obtained in the step 3.2, adding 20mL of anhydrous chloroform, and stirring at room temperature for reaction for 6h; TLC detects the reaction progress, the reaction is stopped when the raw materials disappear, the organic phase is removed by decompression, and simultaneously n-hexane and dichloromethane are used as eluent, and a brownish red solid QxO2 is obtained through layer-by-layer chromatography.

Preferably, step 4 includes:

step 4.1: under the protection of nitrogen, adding an intermediate QxO into a two-mouth bottle, pumping and exchanging gas for 3 times, adding anhydrous 1, 2-dichloroethane by a syringe, dropwise adding a Vilsmerier reagent into a reaction system under the protection of argon, stirring at room temperature for reaction for 1h, and then heating at 85 ℃ for reaction for 12h;

step 4.2: TLC detects the reaction progress, the reaction is stopped when the raw materials disappear, the reaction solution is poured into saturated sodium acetate aqueous solution, dichloromethane is added, the reaction solution is extracted for 3 times by distilled water, and the organic phase is dried by anhydrous sodium sulfate for 2 hours; the solvent was removed by filtration and column chromatography to give QxO-CHO as a red-black solid.

Preferably, step 5 includes:

step 5.1: qxO2-CHO and fluoro-cyano-indenone are added into two bottles, the gas is extracted for 3 times, anhydrous chloroform is added, and the mixture is stirred and reacted for 12 hours at room temperature in a dark place;

step 5.2: TLC detects the reaction progress, the raw materials disappear, the reaction is stopped, chloroform is added, distilled water is used for extracting the reaction liquid for 3 times, the organic phase is combined, anhydrous sodium sulfate is dried, the solvent is filtered and removed by spin-drying under reduced pressure, and the green solid QxO-2, namely the dibenzoquinoxaline wide-band acceptor material, is obtained by column chromatography with chloroform and an eluent with PE=1:1.

Preferably, the compound 6 is:

the application of the dibenzoquinoxaline wide-bandgap acceptor material for the organic solar cell is applied to the preparation of an organic solar cell device.

Compared with the prior art, the invention has the beneficial effects that:

1. in the aspect of raw material synthesis, the 3-position alkoxy chain substituted thieno [3,2-b ] thiophene unit can be obtained by a simple two-step method without post-treatment, and compared with the multi-step alkyl chain conversion reaction in the prior art, the method greatly reduces the reaction steps and corresponding post-treatment purification.

2. Compared with the prior art that only the middle core or the side chain is regulated, the method can realize the large blue shift of the material absorption spectrum by cooperatively utilizing the strategy of regulating the middle core and the side chain, and obtain the wide-bandgap receptor material suitable for indoor photovoltaics.

Drawings

The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate the invention and together with the embodiments of the invention, serve to explain the invention.

In the drawings:

FIG. 1 is a flow chart of the material synthesis of the present invention;

FIG. 2 is a schematic diagram of the absorption spectrum of the material of the present invention;

FIG. 3 is a graph of J-V test under standard sunlight of the present invention;

fig. 4 is a flow chart of the method of the present invention.

Detailed Description

The preferred embodiments of the present invention will be described below with reference to the accompanying drawings, it being understood that the preferred embodiments described herein are for illustration and explanation of the present invention only, and are not intended to limit the present invention.

A dibenzoquinoxaline wide bandgap acceptor material for use in an organic solar cell, having the formula:

a preparation method of dibenzoquinoxaline wide-bandgap acceptor material for organic solar cells comprises the following steps:

step 1: and (3) carrying out heating reaction, hydrolysis reaction, decarboxylation reaction, strong alkali tertiary butyl lithium hydrogen drawing tin compound and Stille coupling reaction on the compound 1 twice to obtain a final reaction product, namely a compound 6. The method comprises the following steps:

step 1.1: in a 250ml two-necked flask, compound 1 was added(5 g,19.21 mmol), anhydrous sodium methoxide (1.56 g,28.82 mmol) and displacement of the gas three times under nitrogen atmosphere, 100mL of anhydrous methanol was added, the reaction was heated at 70℃under reflux for 12h, the organic phase was removed by spinning under reduced pressure, and 1-bromodecane (4.67 g,21.131 mmol) and anhydrous N, N-dimethyl were added under argon atmosphereFormamide 30mL, displacing the gas 3 times under nitrogen atmosphere, heating at 80 ℃ for 12h, detecting the reaction by Thin Layer Chromatography (TLC), stopping the reaction when the starting material disappears, extracting the organic phase 3 times with ethyl acetate (150 ml×3), drying the organic phase 2h over anhydrous magnesium sulfate while using dichloromethane: n-hexane (1:3) as eluent, and obtaining colorless transparent oily compound 2 +_ by layer chromatography>Yield 3.54g, 52%;

¹ H NMR(300MHz,CDCl ₃ )δ7.57(d,J＝5.3Hz,1H),7.22(d,J＝5.3Hz,1H),4.40(t,J＝5.6Hz,2H),3.89(s,3H),1.29–1.26(m,16H),0.89–

0.88(m,3H).

step 1.2: into a 100ml two-necked flask, compound 2 was introduced(3 g,8.46 mmol), lithium hydroxide monohydrate (710 mg,16.92 mmol), and the gas was replaced three times under nitrogen atmosphere, 30mL of anhydrous Tetrahydrofuran (THF), and 10mL of distilled water were added. The reaction solution was heated at 65℃for 12 hours under reflux, the organic phase was removed by spin-drying under reduced pressure, the reaction solution was neutralized to weakly acidic with 15% aqueous hydrochloric acid, the organic phase was extracted 3 times with ethyl acetate (150 mL. Times.3), the organic phase was dried over anhydrous magnesium sulfate for 2 hours, and the organic phase was removed by spin-drying under reduced pressure, and recrystallized with n-hexane to give Compound 3>2.74g, yield 95%.

¹ H NMR(400MHz,CDCl ₃ )δ7.64(d,J＝5.3Hz,1H),7.29(d,J＝1.4Hz,1H),7.28(s,1H),5.33(s,1H),4.54(d,J＝7.5Hz,2H),1.91–1.80(m,2H),1.63–1.26(m,11H),1.03–0.92(m,6H).

Step 1.3: into a 100ml two-necked flask, compound 3 was introduced(2.5 g,7.34 mmol), silver carbonate (81.1 mg, 0.254 mmol),glacial acetic acid (0.34 mL,0.0587 mmol) was replaced three times with gas under nitrogen and dimethyl sulfoxide (DMSO) 15mL was added. The reaction mixture was heated at 130℃for 12h, detected by Thin Layer Chromatography (TLC) to find the starting material disappeared, the reaction was stopped, the organic phase was extracted 3 times with ethyl acetate (150 mL. Times.3), dried over anhydrous magnesium sulfate for 2h, the organic phase was removed by spin-drying under reduced pressure, and simultaneously n-hexane was used as eluent to give colorless transparent oily compound 4 by layer chromatographyYield 2g, 92%.

¹ H NMR(400MHz,CDCl ₃ )δ7.38(dd,J＝5.1,1.5Hz,1H),7.19(d,J＝5.1Hz,1H),6.29(d,J＝1.5Hz,1H),4.09(t,J＝6.6Hz,2H),1.90–1.81(m,2H),1.52–1.45(m,2H),1.37–1.27(m,14H),0.90(t,J＝6.8Hz,3H).

Step 1.4: into a 100ml two-necked flask, compound 4 was introduced(2 g,6.75 mmol) and the atmosphere was replaced three times under nitrogen, 20mL of anhydrous Tetrahydrofuran (THF) and 20mL of anhydrous diethyl ether were added. The reaction mixture was cooled at-65℃for 30 minutes, and tert-butyllithium reagent (5.18 mL, 1.3M) was added dropwise at-65℃and reacted at-65℃for 2 hours, followed by quenching the reaction with 4mL of saturated aqueous ammonium chloride solution at room temperature after adding tributyltin chloride (2.01 mL,7.425 mmol) at-65℃and extracting the organic phase 3 times with ethyl acetate (150 mL. Times.3), drying the organic phase with anhydrous magnesium sulfate for 2 hours, and spin-removing the organic phase under reduced pressure to give Compound 5 ]>Can be directly put into the next reaction without any sum treatment.

Step 1.5: compound 5Transfer to a 100mL two-necked flask and add 4, 7-dibromo-5, 6-dinitrobenzo [ c ]][1,2,5]Thiadiazole (1.037 g,2.7 mmol), tribenzylideneDipalladium acetylacetonate (Pd) ₂ (dba) ₃ ) (99 mg,0.108 mmol), triphenylphosphine (66 mg,0.216 mmol) was replaced with nitrogen three times, and 20mL of anhydrous toluene was added to allow the reaction mixture to react by heating at 85℃for 12 hours, and TLC was used to detect the progress of the reaction, and the reaction was stopped after the disappearance of the starting material. The reaction solution was poured into 200mL of anhydrous methanol to give a brownish red solid precipitate, and the filter cake was purified by layer-by-layer chromatography in an eluent of methylene chloride: n-hexane (1:4) to give colorless transparent oily compound 6->Yield 990g, 45%.

¹ H NMR(400MHz,CDCl ₃ )δ7.61(s,2H),6.44(s,2H),4.00(t,J＝4.7Hz,4H),1.84–1.73(m,2H),1.55–1.41(m,8H),1.40–1.25(m,12H),1.01–0.69(m,16H).

Step 2: the compound is preparedAnhydrous o-dichlorobenzene, triethyl phosphite, 2-butyl iodooctane and potassium carbonate and anhydrous N, N-dimethylformamide are reacted, and further treatment is carried out to obtain BTOR. Comprising the following steps:

step 2.1: into a 100mL single-necked flask, the compound 6 prepared in step 1 was added(900 mg,1.104 mmol) and displacing the gas 3 times under nitrogen;

step 2.2: 6mL of anhydrous o-dichlorobenzene (3.67 g,22.08 mmol) was further added, the reaction was heated at 160℃for 12 hours, o-dichlorobenzene and excess triethyl phosphite were distilled off under reduced pressure, and 2-butyliodooctane (1.64 g,5.52 mmol), potassium carbonate (763 mg,5.52 mmol) was added, the gas was replaced three times under nitrogen atmosphere, 15mL of anhydrous N, N-Dimethylformamide (DMF) was added under nitrogen, and the reaction was heated at 100℃for 12 hours;

step 2.3: TLC checked the progress of the reaction, found the starting material disappeared, stopped the reaction, and the organic phase was extracted 3 times with ethyl acetate (150 mL. Times.3), dried over anhydrous magnesium sulfate for 2h, the organic phase was spun down under reduced pressure, and simultaneously, by chromatography layer by layer using n-hexane as eluent, the colorless and transparent oily product BTOR 744mg was obtained in 62% yield, BTOR formula:

¹ H NMR(400MHz,CDCl ₃ )δ6.30(s,2H),4.54(d,J＝7.2Hz,4H),4.16(t,J＝6.5Hz,4H),2.08–2.01(m,2H),1.93–1.86(m,4H),1.36–1.24(m,34H),0.94–0.81(m,26H),0.70–0.57(m,18H).

step 3: adding a compound BTOR and THF solution of lithium aluminum hydride into a two-mouth bottle for reaction to obtain a crude product, and continuously adding phenanthrene-9, 10-dione for reaction and anhydrous chloroform to prepare QxO. Comprising the following steps:

step 3.1: a two-port 100mL bottle was charged with compound BTOR (360 mg,0.331 mmol), anhydrous THF was added under nitrogen atmosphere, and a THF solution of lithium aluminum hydride (126 mg,3.31 mmol) was added dropwise with a constant pressure dropping funnel under ice bath, after the addition was completed, the ice bath was removed, and the reaction was refluxed at 65℃for 4 hours,

step 3.2: TLC detects the progress of the reaction, and the reaction was stopped, and the organic phase was extracted 3 times with ethyl acetate (150 mL. Times.3), dried over anhydrous magnesium sulfate for 2h, and the organic phase was removed by spin-drying under reduced pressure, and the next reaction was carried out without work-up.

Step 3.3: to the crude product of step 3.2 was added phenanthrene-9, 10-dione (207 mg,0.993 mmol), 20mL of anhydrous chloroform was added, and the reaction was stirred at room temperature for 6 hours. TLC was used to check the progress of the reaction, it was found that the starting material disappeared, the reaction was stopped, the organic phase was removed by spinning under reduced pressure, and simultaneously, a reddish brown solid QxO, yield 220mg, yield 54% was obtained by layer-by-layer chromatography using n-hexane: dichloromethane (1:10) as eluent. The structural formula is as follows:

¹ H NMR(400MHz,CDCl ₃ )δ9.78(d,J＝7.9Hz,2H),8.72(d,J＝8.0Hz,2H),7.95(t,J＝7.4Hz,2H),7.86(t,J＝7.5Hz,2H),6.36(s,2H),4.69(d,J＝7.8Hz,4H),4.26(t,J＝6.6Hz,4H),2.26–2.19(m,2H),2.04–1.99(m,4H),1.51–1.37(m,34H),1.08–0.98(m,26H),0.77–0.73(m,4H),0.70–0.63(m,14H).

step 4: qxO2, anhydrous 1, 2-dichloroethane, vilsmerier reagent, aqueous sodium acetate solution and dichloromethane prepared in step 3 are prepared to obtain QxO-CHO. Comprising the following steps:

step 4.1: in a 250mL two-necked flask, intermediate (QxO 2), (220 mg) was introduced under nitrogen, the gas was purged 3 times, and 30mL of anhydrous 1, 2-dichloroethane was introduced using a syringe. And the Vilsmerier reagent prepared in advance is added into the reaction system dropwise under the protection of argon, and the reaction is stirred for 1h at room temperature, and then the reaction is heated for 12h at 85 ℃.

Step 4.2: TLC detects the progress of the reaction, found the starting material disappeared, stopped the reaction, and the reaction solution was poured into 30mL of saturated aqueous sodium acetate, 80mL of methylene chloride was added and the reaction solution was extracted 3 times with distilled water (100×3), and the organic phase was dried over anhydrous sodium sulfate for 2 hours. The solvent was removed by filtration and reduced pressure, and column chromatography gave QxO-CHO as a red-black solid in 81% yield. QxO2-CHO has the structural formula:

¹ H NMR(300MHz,CDCl ₃ )δ10.13(s,2H),9.82(d,J＝7.6Hz,2H),8.76(d,J＝7.8Hz,2H),7.98(t,J＝7.6Hz,2H),7.89(t,J＝7.1Hz,2H),4.92(d,J＝7.3Hz,4H),4.62(t,J＝6.1Hz,4H),2.26–2.19(m,2H),2.04–1.99(m,4H),1.51–1.37(m,34H),1.08–0.98(m,26H),0.77–0.73(m,4H),0.70–0.63(m,14H).

step 5: adding the intermediate QxO2-CHO, fluoro-cyano-indenone and anhydrous chloroform prepared in the step 4 for reaction to prepare QxO-2. Comprising the following steps:

step 5.1: in a 100mL two-necked flask, intermediate 3 (100 mg,0.078 mmol), fluoro-cyanoindanone (89 mg, 0.3838 mmol) was placed, the mixture was purged with gas 3 times, 30mL of anhydrous chloroform was added, and the reaction was stirred at room temperature under dark conditions for 12 hours.

Step 5.2: TLC checked the progress of the reaction, found the starting material disappeared, stopped the reaction, 50mL of chloroform was added and the reaction solution was extracted 3 times with distilled water (100X 3), the organic phases were combined, and the organic phase was dried over anhydrous sodium sulfate for 2h. The solvent was filtered and spun off under reduced pressure and column chromatography was performed with Chloroform (CF)/pe=1:1 eluent to give QxO-2 as a green solid, the dibenzoquinoxaline wide band acceptor material, in 81% yield. QxO-2 has the structural formula:

¹ H NMR(400MHz,CDCl ₃ )δ9.62–9.57(m,2H),9.38(s,2H),8.80–

8.74(m,2H),8.48–8.38(m,2H),7.99–7.91(m,4H),7.59(t,J＝7.6Hz,2H),4.99(t,J＝6.5Hz,4H),4.86(d,J＝6.9Hz,4H),2.33–2.27(m,2H),1.78–1.70(m,4H),1.44–1.20(m,40H),1.09–0.97(m,14H),0.93–0.81(m,12H),0.79–0.65(m,12H).

and (3) experimental verification:

and (3) experimental verification:

1. absorption spectrum and electrochemical cyclic voltammetry test:

the absorption spectra of QxO-2 materials in chloroform dilute solution and film state were tested by ultraviolet-visible (UV-vis) spectrophotometry respectively as shown in fig. 2, and the corresponding data are summarized in table 1. Wherein, the maximum absorption peak (. Lamda.) of QxO-2 in the solution _max ) Located at 714nm. When in a film state, the maximum absorption peaks of the material are respectively red shifted to 766nm, which shows that the material has obvious pi-pi accumulation in a solid state, and is favorable for obtaining good charge transmission property.

The invention utilizes electrochemical cyclic voltammetry test technology. The QxO-2 material was tested for its electrochemical energy level in the solid state, with the highest occupied orbital (HOMO) and lowest unoccupied orbital (LUMO) levels of QxO-2 being-5.60 and-3.82 eV, respectively, and exhibited a better absorption spectrum complementation and energy level matching with the polymer donor D18.

Table 1QxO-2 absorption spectra of materials and electrochemical energy level data in solid state

2. Preparation and performance characterization of photovoltaic devices:

the prepared organic photoelectric receptor compound QxO-2 is used as an electron acceptor for preparing a solar cell device: the structure of the forward device is ITO/PEDOT, PSS/donor material, acceptor material

PNDIT-F3N/Ag. The specific preparation process of the device comprises the following steps: firstly, ITO (indium tin oxide) conductive glass is pretreated, and the specific steps are as follows: firstly, the ITO glass is sequentially cleaned by liquid detergent, deionized water, acetone and isopropanol solvent for 20 minutes respectively, taken out, dried by a nitrogen gun and treated by ultraviolet-ozone for 20 minutes. A layer of PEDOT/PSS solution was then spin-coated onto the pretreated ITO glass and heated on a hot plate at 150deg.C for 10 minutes, and transferred to a vacuum glove box. The chloroform solution of the mixture of the compound QxO-2 prepared in the example and the donor material was spin-coated on the surface of the substrate as an active layer (100 nm), then a layer of 6nm PNDIT-F3N was spin-coated on the surface of the active layer as an electron transport layer, and finally a metal electrode Ag having a thickness of 70nm was evaporated. The vacuum degree is kept below 2X 10-4Pa during the evaporation process. Device performance was tested under standard solar (AM 1.5G) irradiation conditions using a computer controlled Keithley 2400 digital source table.

Solar cell performance comparison (light intensity 100 mW/cm) prepared by using organic photoelectric compound QxO-2 as acceptor material and D18 as donor material ² M1.5G) device structure is ITO/ZnO/PFN-Br/donor material, acceptor material/MoOx/Ag, current density-voltage (J-V) test curves are shown in FIG. 3, and relevant parameters are shown in Table 2. The photovoltaic device based on D18: qxO-2 obtains open-circuit voltage larger than 0.8V, has potential of being used as an indoor light wide-band acceptor material, and can be used as a third component additive to construct a high-efficiency ternary device or used as a front battery material to construct a high-efficiency layer-obtaining device. Although the preliminary device efficiency is relatively low, the high-efficiency low-energy loss wide with further improved efficiency is expected to be obtained through subsequent detailed device process optimization and active layer morphology regulation and controlBand gap receptors.

TABLE 2J-V test Curve parameter Table based on QxO-2 devices

The foregoing has shown and described the basic principles, principal features and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present invention, and various changes and modifications may be made without departing from the spirit and scope of the invention, which is defined in the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims (8)

1. A dibenzoquinoxaline wide band acceptor material for an organic solar cell,

the method is characterized in that: the molecular formula is:

2. a preparation method of a dibenzoquinoxaline wide-bandgap acceptor material for an organic solar cell is characterized by comprising the following steps: the method comprises the following steps:

step 1: the compound 1 is subjected to twice heating reaction, hydrolysis reaction, decarboxylation reaction, strong alkali tertiary butyl lithium hydrogen drawing tin-adding compound and Stille coupling reaction to obtain a final reaction product, namely a compound 6;

step 2: reacting the compound 6, anhydrous o-dichlorobenzene, triethyl phosphite, 2-butyl iodooctane, potassium carbonate and anhydrous N, N-dimethylformamide, and further processing to obtain BTOR;

step 3: adding a compound BTOR and THF solution of lithium aluminum hydride into a two-mouth bottle for reaction to obtain a crude product, and then adding phenanthrene-9, 10-dione for reaction and anhydrous chloroform for preparation to obtain QxO;

step 4: qxO2, anhydrous 1, 2-dichloroethane, vilsmerier reagent, sodium acetate aqueous solution and dichloromethane which are prepared in the step 3 are prepared to obtain QxO-CHO;

step 5: adding the intermediate QxO2-CHO, fluoro-cyano-indenone and anhydrous chloroform prepared in the step 4 for reaction to prepare QxO-2, namely the dibenzoquinoxaline wide-band gap acceptor material.

3. The method for preparing the dibenzoquinoxaline wide bandgap acceptor material for organic solar cells according to claim 2, wherein the method comprises the steps of: the step 2 comprises the following steps:

step 2.1: adding the compound 6 prepared in the step 1 into a 100mL single-port bottle, and replacing the gas for 3 times under the nitrogen atmosphere;

step 2.2: continuously adding anhydrous o-dichlorobenzene and triethyl phosphite, heating at 160 ℃ for reaction for 12 hours, then distilling off the o-dichlorobenzene and the excessive triethyl phosphite under reduced pressure, adding 2-butyl iodooctane and potassium carbonate, replacing gas for three times under nitrogen atmosphere, adding 15mL of anhydrous N, N-dimethylformamide under nitrogen condition, heating at 100 ℃ for reaction for 12 hours,

step 2.3: TLC detects the reaction progress, the reaction is stopped when the raw materials disappear, the organic phase is extracted for 3 times by ethyl acetate, dried by anhydrous magnesium sulfate for 2 hours, the organic phase is removed by decompression and spin-drying, and simultaneously, an orange transparent oily product BTOR is obtained by using normal hexane as an eluent through a layer-by-layer chromatography.

4. A method for preparing a dibenzoquinoxaline wide bandgap acceptor material for an organic solar cell according to claim 3, wherein: the step 3 comprises the following steps:

step 3.1: adding compound BTOR into two bottles, adding anhydrous THF under nitrogen atmosphere, dropwise adding THF solution of lithium aluminum hydride with a constant pressure dropping funnel under ice bath, removing ice bath after the dropwise adding, reflux reacting at 65deg.C for 4 hr,

step 3.2: TLC detects the reaction progress, the reaction is stopped when the raw materials disappear, the organic phase is extracted for 3 times by ethyl acetate, the organic phase is dried by anhydrous magnesium sulfate, the organic phase is removed by decompression and rotation, and the next reaction can be directly carried out without post treatment;

step 3.3: adding phenanthrene-9, 10-diketone into the crude product obtained in the step 3.2, adding 20mL of anhydrous chloroform, and stirring at room temperature for reaction for 6h; TLC detects the reaction progress, the reaction is stopped when the raw materials disappear, the organic phase is removed by decompression, and simultaneously n-hexane and dichloromethane are used as eluent, and a brownish red solid QxO2 is obtained through layer-by-layer chromatography.

5. The method for preparing the wide-bandgap acceptor material yyyy for the organic solar cell according to claim 4, wherein the method comprises the following steps: step 4 comprises:

step 4.1: under the protection of nitrogen, adding an intermediate QxO into a two-mouth bottle, pumping and exchanging gas for 3 times, adding anhydrous 1, 2-dichloroethane by a syringe, dropwise adding a Vilsmerier reagent into a reaction system under the protection of argon, stirring at room temperature for reaction for 1h, and then heating at 85 ℃ for reaction for 12h;

step 4.2: TLC detects the reaction progress, the reaction is stopped when the raw materials disappear, the reaction solution is poured into saturated sodium acetate aqueous solution, dichloromethane is added, the reaction solution is extracted for 3 times by distilled water, and the organic phase is dried by anhydrous sodium sulfate for 2 hours; the solvent was removed by filtration and column chromatography to give QxO-CHO as a red-black solid.

6. The method for preparing the dibenzoquinoxaline wide bandgap acceptor material for an organic solar cell according to claim 5, wherein: the step 5 comprises the following steps:

step 5.1: qxO2-CHO and fluoro-cyano-indenone are added into two bottles, the gas is extracted for 3 times, anhydrous chloroform is added, and the mixture is stirred and reacted for 12 hours at room temperature in a dark place;

step 5.2: TLC detects the reaction progress, the raw materials disappear, the reaction is stopped, chloroform is added, distilled water is used for extracting the reaction liquid for 3 times, the organic phase is combined, anhydrous sodium sulfate is dried, the solvent is filtered and removed by spin-drying under reduced pressure, and the green solid QxO-2, namely the dibenzoquinoxaline wide-band acceptor material, is obtained by column chromatography with chloroform and an eluent with PE=1:1.

7. The method for preparing the dibenzoquinoxaline wide bandgap acceptor material for an organic solar cell according to claim 6, wherein: the compound 6 is:

8. an application of dibenzoquinoxaline wide-bandgap acceptor material for organic solar cells, which is characterized in that: the method is applied to the preparation of the organic solar cell device.