A device structure containing a simple condensed ring small molecule material and its application

Abstract

The present invention relates to a device structure containing a simple fused-ring small molecule material, the structure comprising an active layer having a thickness of 500-600 nm. The active layer comprises a structure in which an electron donor material and an electron acceptor material are blended. The electron acceptor material has the following general structural formula: #imgabs0#. The above-mentioned material is applied to a photoelectric device structure, has a good photoelectric effect, and is suitable for devices with thicker active layers, thereby facilitating roll-to-roll industrial production.

Description

Technical Field

[0001] The present invention relates to the field of organic optoelectronics, and in particular to a device structure containing a simple condensed ring small molecule material and its application. Background Art

[0002] Solar energy is a clean, pollution-free, and inexhaustible energy source. It has been a key focus in addressing the pollution and shortage issues currently facing fossil fuels. Because solar cells can directly convert solar energy into electricity, they have become a crucial research topic within the industry. Currently, organic solar cells (OPVs) are a promising candidate for industrialization. They typically utilize electron donor and electron acceptor materials dissolved in a good solvent and then spin-coated to form a thin-film active layer, thereby creating a bulk heterojunction solar cell device. Compared to inorganic silicon solar cells, organic solar cells offer advantages such as low toxicity and low cost.

[0003] Similarly, organic photodetectors (OPDs) are organic optoelectronic devices that convert incident light into an electrical output signal. Compared to traditional inorganic semiconductor photodetectors, OPDs offer advantages such as low cost, low power consumption, and the ability to be solution-processed and fabricated into flexible devices.

[0004] Optoelectronic devices with a spectral response in the near-infrared region can be widely used in navigation, aviation, aerospace, weapons detection, night vision, communications, atmospheric monitoring, pollution detection, and meteorology. To become a potential alternative to silicon optoelectronic devices, the active layer materials in OPVs and OPDs must have an absorption spectrum exceeding 1100 nm.

[0005] Compared with polymer materials, small molecules have good repeatability and no batch problems. However, narrow-bandgap small molecules, especially small molecule infrared materials with a response range exceeding 1000nm, are extremely rare. At present, the highest specific detection rate of organic small molecule photodetectors that respond above 1000nm is 10 to the 12th power. And the response time performance above 1050nm is still blank. In addition, generally, the effective migration distance of carriers in the active layer material is short. If the thickness of the active layer is too high, it is easy to cause carrier recombination and cause low photoelectric conversion efficiency. The active layer thickness of general OPVs and OPDs is relatively thin, usually around 100-200nm, and this thickness basically cannot realize industrial roll-to-roll process.

[0006] Therefore, there is an urgent need to find a technical solution in which the material used for the active layer can have excellent response in the visible light-near infrared band, and is preferably suitable for optoelectronic devices (OPVs or OPDs, respectively) with thicker (~500nm) active layers while still having good photoelectric conversion efficiency / sensitivity, thereby solving the above-mentioned technical difficulties in this field. Summary of the Invention

[0007] The present invention discloses a device structure containing a simple fused-ring small molecule material. The electron acceptor material in the active layer is a near-infrared material based on a simple fused-ring small molecule. The so-called simple fused-ring refers to a fused ring with no more than three aromatic rings, i.e., a single ring, a binary fused ring, or a ternary fused ring. Furthermore, the device structure exhibits excellent spectral response, particularly in the near-infrared region. It is worth noting that the device structure is suitable for use in organic solar cells or organic photodetectors with active layers exceeding 500 nm, and has roll-to-roll commercialization prospects.

[0008] One object of the present invention is to provide a device structure containing a simple fused ring small molecule material, wherein the device structure comprises an active layer having a thickness of 500-600 nm, wherein the active layer comprises a structure in which an electron donor material and an electron acceptor material are mixed.

[0009] The electron acceptor material has the following structural formula:

[0010]

[0011] in,

[0012] R', R" and R are independently selected from an alkyl group having 1 to 40 carbon atoms, or an alkyl derivative having 1 to 40 carbon atoms;

[0013] One or more carbon atoms in the alkyl derivative are substituted by one or more of hydrogen atoms, oxygen atoms, alkenyl groups, alkynyl groups, aryl groups, hydroxyl groups, amino groups, carbonyl groups, carboxyl groups, ester groups, cyano groups, and nitro groups;

[0014] and / or,

[0015] One or more hydrogen atoms on the alkyl derivative are substituted by one or more of a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an alkenyl group, an alkynyl group, an aryl group, a hydroxyl group, an amino group, a carbonyl group, a carboxyl group, an ester group, a cyano group, and a nitro group;

[0016] Ar is an aromatic group.

[0017] Furthermore, Ar is selected from one of the following structures:

[0018]

[0019] R 11 -R 16 Independently selected from an alkyl group having 1 to 40 carbon atoms, or an alkyl derivative having 1 to 40 carbon atoms;

[0020] One or more carbon atoms in the alkyl derivative are substituted by one or more of hydrogen atoms, oxygen atoms, alkenyl groups, alkynyl groups, aryl groups, hydroxyl groups, amino groups, carbonyl groups, carboxyl groups, ester groups, cyano groups, and nitro groups;

[0021] and / or,

[0022] One or more hydrogen atoms on the alkyl derivative are substituted by one or more of fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, alkenyl groups, alkynyl groups, aryl groups, hydroxyl groups, amino groups, carbonyl groups, carboxyl groups, ester groups, cyano groups, and nitro groups.

[0023] Furthermore, the electron donor material is selected from one of PBDB-T, PM6, PTB7-Th, and J51.

[0024] Furthermore, the device structure containing the simple condensed ring small molecule material further includes at least one of a cathode interface layer or an anode interface layer.

[0025] Furthermore, the cathode interface layer is selected from one of PFN, PFN-Br, ZnO, SnO2, and PDINN.

[0026] Furthermore, the anode interface layer is selected from PEDOT:PSS, MoO x One of them.

[0027] Furthermore, the thickness of the active layer is 500-600 nm.

[0028] Another object of the present invention is to provide an application of the device structure containing the simple fused-ring small molecule material in an organic solar cell.

[0029] Another object of the present invention is to provide an application of the device structure containing the simple fused-ring small molecule material in an organic photodetector.

[0030] The beneficial effects of the present invention are:

[0031] 1. The electron acceptor material of the present invention has a unique benzotriazoloquinoxaline-based structure as a strongly electron-deficient group and contains a classic D-π-A structure, thereby having a broad absorption spectrum (>1100nm) and excellent spectral response in the visible light-near infrared spectral range.

[0032] 2. It was surprisingly discovered that the electron acceptor material of the present invention, after being blended with an electron donor material (such as polymer PTB7-Th) and applied to optoelectronic devices as active layer materials, has a high field-induced hole mobility and is particularly suitable for optoelectronic devices with thicker active layers (>500nm), thus facilitating roll-to-roll industrial production.

[0033] 3. The electron acceptor material of the present invention, when applied to OPVs, is different from common near-infrared electron acceptor materials and can achieve a photoelectric conversion efficiency of up to 4.22%, which is at an advanced level among similar near-infrared materials. When applied to OPDs, the response range of the OPD exceeds 1000nm, and the specific detectivity is as high as 3.5×10 12 Jones, with a response time of 3.7μs, has extremely high sensitivity. Therefore, this electron acceptor material is a class of classic materials with application prospects and can be used in a variety of optoelectronic devices. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below with reference to the examples, but the embodiments and protection of the present invention are not limited thereto. It should be noted that if there are any processes not particularly described in detail below, they can be implemented or understood by those skilled in the art with reference to the prior art.

[0035] Unless otherwise specified, the raw materials and reagents used in the examples of the present invention are common commercially available items.

[0036] The electron donor material PTB7-Th and the interface material PFN-Br described in the present invention are materials and general terms well known to those skilled in the art.

[0037] Example 1

[0038] A NTQ containing a fused ring small molecule material, the preparation reaction formula of which is as follows:

[0039]

[0040] Synthesis route of compound 2:

[0041] 1 (3 g, 6.3 mmol) was placed in a clean 250 ml two-necked flask, along with reduced iron powder (4.2 g, 75.6 mmol) and 80 ml of glacial acetic acid. The mixture was stirred thoroughly and heated to 80°C for 6 h. After the reaction was complete and cooled to room temperature, the reaction mixture was poured into a large amount of ice water, filtered, and washed three times with deionized water. After drying, a yellow solid 2 (2.0 g, 5.04 mmol) was obtained with an approximately 84% yield. The mixture was then directly processed into the next step.

[0042] Synthesis route of compound 3:

[0043] Compound 2 (2.0 g, 5.04 mmol) was added to a clean 250 ml two-necked flask, along with 5,10-diethyltetradecane-7,8-dione (1.4 g, 5.04 mmol) and 80 ml of glacial acetic acid. After thorough stirring, the mixture was heated to 100°C and allowed to react for 72 h. After completion of the reaction, the mixture was poured into deionized water to quench the reaction, followed by extraction twice with dichloromethane. A sufficient amount of saturated sodium bicarbonate solution was added to the organic phase. After the acetic acid reaction was complete, the mixture was extracted three times with dichloromethane. Anhydrous sodium sulfate was added to the organic phase, filtered, and the solvent was removed using a rotary evaporator. Further purification was performed by silica gel chromatography using a mixture of petroleum ether and dichloromethane as the eluent to obtain 3 (2.1 g, 3.28 mmol) as a white solid in approximately 65% yield. 1 HNMR(400MHz,CDCl3)δ(ppm): 4.85(d,J=8Hz,2H),3.02(d,J=8Hz,4H),2.46-2.40(m,1H),2.27-2.20(m,2H),1.49-1.26(m,24H),0.98-0.93(m,9H),0.89-0.83(m,9H).

[0044] Synthesis route of compound 4:

[0045] Under nitrogen protection, compound 3 (0.66 g, 1 mmol) and D (1.1 g, 2.5 mmol) were dissolved in 25 ml of ultra-dry o-xylene, and then cesium carbonate (2.63 g, 8 mmol), pivalic acid (0.1 g, 1 mmol), tris dibenzylideneacetone palladium (0.0875 g, 0.1 mmol) and tris (2-methoxyphenyl) phosphine (0.075 g, 0.2 mmol) were added in sequence. After sufficient stirring, the temperature was raised to 110 ° C and the reaction was allowed to proceed overnight. After completion of the reaction, the reactant was poured into water to quench, extracted three times with dichloromethane, and the solvent was removed by rotary evaporation. Using dichloromethane and petroleum ether as eluents, further purification was carried out by silica gel chromatography to obtain a dark green solid 4 (0.73 g, 0.54 mmol) with a yield of 68%. 1H NMR (400MHz, CDCl3) δ (ppm): 9.86 (s,2H),9.01-8.98(m,2H),7.61-7.59(m,2H),4.96-4.93(m,2H),3.18-3.14(m,4H),2.37-2.29(m,3H),2.10-1.95(m,8H),1.56-1 .50(m,16H),1.41-1.33(m,9H),1.14-1.09(m,4H),1.03-0.91(m,46H),0.85-0.71(m,9H),0.67-0.64(m,12H),0.59-0.56(m,6H).

[0046] Synthesis route of compound 5:

[0047] Under nitrogen protection, 4 (170 mg, 0.124 mmol) was dissolved in 30 ml of chloroform, and then 5,6-difluoro-3-(dicyanomethylene)indone (0.17 g, 0.75 mmol) and 1 ml of pyridine were added. The temperature was raised to 60°C and refluxed in the dark for 4 h. After the reaction, the reactants were poured into ice methanol for recrystallization, and then filtered to obtain a crude product. The crude product was then further purified by silica gel chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent. The product was recrystallized in methanol, ethanol, and isopropanol as solvents to obtain a dark purple solid product 5 (177 mg, 0.1 mmol) with a yield of 80%. 1 HNMR(400MHz, CDCl3)δ(ppm):9.12-9.09(m,2H),8.91(s,2H),8.54-8.51(m,2H),7.68-7.64(m,4H),5.02-4.93(m,2H),3.26-3.19(m,4H),2.35- 2.32(m,1H),2.26-2.19(m,2H),2.17-2.02(m,8H),1.56-1.50(m,16H), 1.41-1.33(m,9H),1.14-1.09(m,4H),1.03-0.91(m,46H),0.85-0.71(m, 9H),0.67-0.64(m,12H),0.59-0.56(m,6H).

[0048] Comparative Example 1

[0049] A BTQ containing a fused ring small molecule material, the preparation reaction formula of which is as follows:

[0050]

[0051] Synthesis route of compound 2:

[0052] To a clean 250ml two-necked flask, add reduced iron powder (4.2g, 75.6mmol) and 80ml of glacial acetic acid, stir thoroughly, and heat to 80°C for 6h. After the reaction is complete and the mixture cools to room temperature, pour it into a large amount of ice water, filter it, and wash it three times with deionized water. After drying, a yellow solid 2 (1.54g, 5mmol) is obtained with a yield of approximately 79%, which is then directly processed into the next step.

[0053] Synthesis route of compound 3:

[0054] 2 (1.54 g, 5 mmol) was added to a clean 250 ml two-necked flask, along with 5,10-diethyltetradecane-7,8-dione (1.41 g, 5 mmol) and 80 ml of glacial acetic acid. After thorough stirring, the mixture was heated to 100°C and allowed to react for 72 h. After completion of the reaction, the mixture was poured into deionized water to quench the reaction, and then extracted twice with dichloromethane. A sufficient amount of saturated sodium bicarbonate solution was added to the organic phase. After the acetic acid reaction was complete, the mixture was extracted three times with dichloromethane. Anhydrous sodium sulfate was added to the organic phase, filtered, and the solvent was removed using a rotary evaporator. Further purification was performed by silica gel chromatography using a mixture of petroleum ether and dichloromethane as the eluent to obtain 3 (1.91 g, 3.35 mmol) as a white solid. 1 H NMR (400MHz, CDCl3) δ (ppm): 3.03 (d, J = 4Hz, 4H), 2.29-2.24 (m, 2H), 1.49-1.26 (m, 24H), 0.98-0.93 (m, 9H), 0.89-0.83 (m, 9H).

[0055] Synthesis route of compound 4:

[0056] Under nitrogen protection, 3 (0.46 g, 0.8 mmol) and D (0.94 g, 2.2 mmol) were dissolved in 25 ml of ultra-dry o-xylene, and then cesium carbonate (2.1 g, 6.4 mmol), pivalic acid (0.08 g, 0.8 mmol), tris dibenzylideneacetone dipalladium (0.07 g, 0.08 mmol) and tris (2-methoxyphenyl) phosphine (0.06 g, 0.16 mmol) were added in sequence. After sufficient stirring, the temperature was raised to 110 ° C and the reaction was allowed to proceed overnight. After completion of the reaction, the reactant was poured into water to quench, extracted three times with dichloromethane, and the solvent was removed by rotary evaporation. Using dichloromethane and petroleum ether as eluents, further purification was carried out by silica gel chromatography to obtain a dark green solid 4 (0.69 g, 0.54 mmol) with a yield of 68%. 1H NMR (400MHz, CDCl3) δ (ppm): 9.87 (s,2H),9.21-8.19(m,2H),7.63-7.62(m,2H),3.18-3.16(d,J=8Hz,4H),2.37-2.29(m,2H),2.1 0-1.95(m,8H),1.58-1.50(m,12H),1.41-1.33(m,6H),1.03-0.91(m,40H),0.84-0.73(m,12H), 0.67-0.64(m,12H),0.59-0.56(m,6H).

[0057] Synthesis route of compound 5:

[0058] Under nitrogen protection, 4 (130 mg, 0.1 mmol) was dissolved in 30 ml of chloroform, and then 5,6-difluoro-3-(dicyanomethylene)indone (138 mg, 0.6 mmol) and 1 ml of pyridine were added. The temperature was raised to 60°C and refluxed in the dark for 4 h. After the reaction, the reactants were poured into ice methanol for recrystallization, and then filtered to obtain a crude product. The crude product was then further purified by silica gel chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent. The product was recrystallized in methanol, ethanol, and isopropanol as solvents to obtain a black solid product 5 (132 mg, 0.09 mmol) with a yield of 78%. 1 H NMR (400MHz, CDCl3) δ (ppm): 9.35-9.33 (m, 2H), 8.91 (s, 2H), 8.54-8.51 (m, 2H), 7.68-7.64 (m, 4H), 3.29-3.21(m,4H),2.26-2.19(m,2H),2.17-2.02(m,8H),1.58-1.50(m,12H),1.41-1.33 (m,6H),1.03-0.91(m,40H),0.84-0.73(m,12H),0.67-0.64(m,12H),0.59-0.56(m,6H).

[0059] Comparative Example 2

[0060] As Comparative Example 2, a benzobisthiadiazole-containing molecule DSBBT was prepared.

[0061] The chemical structure of DSBBT is shown below:

[0062]

[0063] The preparation method is similar to that of Example 1, except that the core structure in Example 1 is replaced by the core structure in Comparative Example 2.

[0064] Comparative Example 3

[0065] The molecular structure SNTI reported in the prior art (Lv. Ruizhi, Geng Shuixing, Chen Hongzheng. et al., Sol. RRL 2020, 4, 200286) was used as comparative example 3.

[0066] The chemical structure of SNTI is shown below:

[0067]

[0068] The preparation method is similar to that of Example 1, except that the core structure in Example 1 is replaced by the core structure in Comparative Example 3.

[0069] Test Example 1

[0070] The NTQ, BTQ, and DSBBT obtained in Example 1 and Comparative Examples 1-2 were used as electron acceptor materials in organic photovoltaic cell devices with ITO as anode, as OPV and OPD, and their performance was tested.

[0071] The device structures of the above OPV and OPD are:

[0072] ITO (20 nm) / PEDOT:PSS (30 nm) / PTB7-Th:NTQ or BTQ or SNTI (1:2, m / m, 120 nm) / PFN-Br (5 nm) / Al (80 nm).

[0073] The device preparation method is carried out using methods well known to those skilled in the art.

[0074] For the above device structure, at 100mW / cm 2 The OPV performance was tested under the conditions of AM 1.5 simulated sunlight using methods well known to those skilled in the art. The results are shown in Table 1.

[0075] Table 1 Performance data of electron acceptor materials used in OPV of Example 1 and Comparative Examples 1-2

[0076]

[0077]

[0078] As can be seen from Table 1, when Example 1 and Comparative Examples 1-2 were tested under the same conditions, the OPV performance of the NTQ device was significantly superior to the other two. In particular, the short-circuit current of the NTQ device was nearly 450 times higher than that of the comparative DSBBT device.

[0079] In addition, when the SNTI of material comparative example 3 reported in the reference literature (Lv. Ruizhi, Geng Shuixing, Chen Hongzheng. et al., Sol. RRL 2020, 4, 200286) is used as the electron acceptor material of the active layer, the PCE of the prepared OPV device is reported to be only 0.05%. Although there are certain differences between the device structure adopted in the literature and the technical solution of the present invention, the significant difference in technical effects from Example 1 also shows that the performance of SNTI in comparative example 3 as an OPV must be unsatisfactory.

[0080] In summary, the NTQ near-infrared material proposed in the present invention is at an advanced level in the performance of OPV devices as electron acceptor materials.

[0081] The OPD performance of the device structure was tested by applying a negative bias voltage between the ITO and Al metal electrodes using methods well known to those skilled in the art. The results are shown in Table 2.

[0082] Table 2 Comparison of the data of the electron acceptor materials used in OPD devices of Example 1 and Comparative Examples 1-2

[0083]

[0084] As can be seen from Table 2, when tested under identical conditions in Example 1 and Comparative Examples 1-2, the dark current performance of the OPD devices obtained using the NTQ device is an order of magnitude higher than that of the two comparative examples, demonstrating that the NTQ OPD device significantly outperforms the other two. The specific detectivity and response time data for Example 1 are also very satisfactory.

[0085] Test Example 2

[0086] Furthermore, the NTQ obtained in Example 1 was used as an electron acceptor material in OPV devices with different active layer thicknesses. The device structure was: ITO (20 nm) / PEDOT: PSS (30 nm) / PTB7-Th: NTQ (1:2, m / m) / PFN-Br (5 nm) / Al (80 nm).

[0087] The photoelectric performance of the active layer was tested at different thicknesses. The results are shown in Table 3.

[0088] Table 3 Performance data of the electron acceptor material of Example 1 applied to OPVs with different active layer thicknesses

[0089]

[0090] The data in Table 3 show that the PCE of NTQ in OPV devices with varying active layer thicknesses decreases very slightly, maintaining the PCE of all three devices at nearly the same level. This demonstrates that NTQ, as an electron acceptor material, effectively reduces the recombination probability of charge carriers, thereby preventing a significant decrease in Jsc and FF and maintaining PCE stability. Therefore, this material is suitable for use in optoelectronic devices with thicker active layers (~500nm), facilitating roll-to-roll industrial production.

[0091] The above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications may be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A device structure containing a simple fused-ring small molecule material, characterized in that: The device structure containing the simple condensed ring small molecule material includes an active layer, the thickness of the active layer is 100-600 nm, and the active layer includes a structure in which an electron donor material and an electron acceptor material are mixed. The electron acceptor material has the following structural formula: in, R', R" and R are independently selected from an alkyl group having 1 to 40 carbon atoms, or an alkyl derivative having 1 to 40 carbon atoms; One or more carbon atoms in the alkyl derivative are substituted by one or more of hydrogen atoms, oxygen atoms, alkenyl groups, alkynyl groups, aryl groups, hydroxyl groups, amino groups, carbonyl groups, carboxyl groups, ester groups, cyano groups, and nitro groups; and / or, One or more hydrogen atoms on the alkyl derivative are substituted by one or more of a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an alkenyl group, an alkynyl group, an aryl group, a hydroxyl group, an amino group, a carbonyl group, a carboxyl group, an ester group, a cyano group, and a nitro group; Ar is an aromatic group.

2. The device structure containing a simple fused-ring small molecule material according to claim 1, characterized in that: The Ar is selected from one of the following structures: R 11 -R 16 Independently selected from an alkyl group having 1 to 40 carbon atoms, or an alkyl derivative having 1 to 40 carbon atoms; One or more carbon atoms in the alkyl derivative are substituted by one or more of hydrogen atoms, oxygen atoms, alkenyl groups, alkynyl groups, aryl groups, hydroxyl groups, amino groups, carbonyl groups, carboxyl groups, ester groups, cyano groups, and nitro groups; and / or, One or more hydrogen atoms on the alkyl derivative are substituted by one or more of fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, alkenyl groups, alkynyl groups, aryl groups, hydroxyl groups, amino groups, carbonyl groups, carboxyl groups, ester groups, cyano groups, and nitro groups.

3. The device structure containing a simple fused-ring small molecule material according to claim 1, characterized in that: The electron donor material is selected from one of PBDB-T, PM6, PTB7-Th, and J51.

4. The device structure containing a simple fused-ring small molecule material according to claim 1, characterized in that: The device structure containing the simple condensed ring small molecule material further includes at least one of a cathode interface layer and an anode interface layer.

5. The device structure containing a simple fused-ring small molecule material according to claim 4, characterized in that: The cathode interface layer is selected from one of PFN, PFN-Br, ZnO, SnO2, and PDINN.

6. The device structure containing a simple fused-ring small molecule material according to claim 4, characterized in that: The anode interface layer is selected from PEDOT:PSS, MoO x One of them.

7. The device structure containing a simple fused-ring small molecule material according to claim 1, characterized in that: The thickness of the active layer is 500-600 nm.

8. Use of the device structure containing the simple fused-ring small molecule material according to any one of claims 1 to 7 in an organic solar cell.

9. Use of the device structure containing the simple fused-ring small molecule material according to any one of claims 1 to 7 in an organic photodetector.

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