Organic semiconductor material and preparation method and application thereof
By introducing oligoglycerol-based side chains into D-A alternating conjugated polymers, the problems of insufficient injection capacity of existing organic semiconductor materials and poor interfacial molecules in hole transport materials are solved, and higher hole injection and charge transport capabilities are achieved, improving the performance of OLED devices.
Patent Information
- Application Number
- CN202510197761.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-21
- Publication Date
- 2025-05-27
AI Technical Summary
When used in hole transport materials, existing organic semiconductor materials have insufficient injection capacity and poor interfacial molecules arrangement, resulting in low charge transport capacity, affecting the performance of OLED devices.
By introducing oligoglycerols as side chains into D-A alternating conjugated polymers, the solubility of the material and the flatness of the membrane layer are improved, thereby improving hole injection and transport capabilities.
It significantly improves the hole injection capacity and charge transport capacity, improves the interface molecular layout, and improves the overall performance of OLED devices.
Smart Images
Figure CN120040729A_ABST
Abstract
Description
Technical Field:
[0001] The present invention relates to the technical field of organic semiconductor material manufacturing, and specifically to an organic semiconductor material, a preparation method thereof, and an application thereof, which have a reasonable process, are easy to prepare, can significantly improve the hole injection ability, improve the molecular arrangement and packing at the interface, enhance the charge transport ability when applied to hole transport materials, and thus improve the performance of OLED devices. Background Art:
[0002] Organic semiconductor materials have outstanding advantages that inorganic semiconductor materials do not have, such as light weight, printability, foldability, etc. They can also adjust optical properties such as optical bandgap and absorption spectrum, and electrical properties such as conductivity and carrier mobility through the regulation of molecular structure. Supercapacitors, organic field-effect transistors (OFETs), organic light-emitting diodes (OLEDs), and perovskite solar cells (PSCs) prepared from them have great development and application space in the fields of flexible sensing, detection, and energy storage. Summary of the Invention:
[0003] The present invention aims at the disadvantages and deficiencies existing in the prior art, and proposes an organic semiconductor material, a preparation method thereof, and an application thereof, which have a reasonable process, are easy to prepare, can significantly improve the hole injection ability, improve the molecular arrangement and packing at the interface, and are thus used for preparing OFETs and OLEDs.
[0004] The present invention is achieved by the following measures:
[0005] An organic semiconductor material, characterized in that the chemical formula of the organic semiconductor material is:
[0006]
[0007] The present invention also proposes a preparation method of the above-mentioned organic semiconductor material, characterized in that the preparation process is as follows:
[0008]
[0009] In the preparation method of the organic semiconductor material of the present invention, process i is the synthesis of 2,7-dibromo-9,9'-bis(2-(2-(2-methoxyethoxy)ethoxy)ethyl)fluorene, i.e., compound 2, which includes the following steps: In a two-necked flask, under Ar protection, 2,7-dibromofluorene (1.5 g, 4.63 mmol) and anhydrous N,N-dimethylformamide (25 mL) are successively added, and NaH (0.51 mg, 12.6 mmol) with a mass fraction of 60% dissolved in mineral oil. After stirring the mixed solution at room temperature for 0.5 hour, 2-(2-(2-methoxyethoxy)ethoxy)ethyl-4-methylbenzenesulfonate (3.49 g, 11.5 mmol) is added, and stirring is continued for 24 hours. Water is added to terminate the reaction, and the mixture is extracted with dichloromethane, dried over MgSO4, and distilled under reduced pressure. The crude product is purified by column chromatography (CH2Cl2 / MeOH 9 / 1) to obtain compound 2.
[0010] In the preparation method of the organic semiconductor material of the present invention, process ii is the synthesis of poly(3,4-ethylenedioxythiophene-2,5-diyl-alt-9,9-bis-(2-(2-(2-methoxyethoxy)ethoxy)ethyl)fluorene-2,7-diyl), i.e., compound PEF-2TEG, which specifically includes the following steps: In a 250 ml two-necked flask, according to the equivalent ratio (molar ratio) of 1:1, compound 2 (1 g, 1.62 mmol) and EDOT (0.173 ml, 1.62 mmol) are successively added, and 2.5 equivalent ratio of potassium acetate (0.397 g, 4.05 mmol) is added. The inside of the flask is deoxygenated, and then anhydrous N,N-dimethylacetamide (12 ml) is added. The mixed solution is deoxygenated, and then 0.05 equivalent of the precatalyst Pd(OAc) 2 (0.081 mmol, 18.18 mg) is added, and the inside of the flask is deoxygenated again. The mixed solution is heated to 80 °C and reacted for 48 hours under Ar. After the reaction solution is cooled, it is washed with water, and then placed in a Soxhlet extractor and purified successively with n-hexane, acetone, and dichloromethane. Finally, the dichloromethane solution is rotary evaporated under low pressure and vacuum dried for 12 h to obtain the polymer PEF-2TEG.
[0011] The present invention also proposes an application of the organic semiconductor material as described above, characterized in that a PLED device using the organic semiconductor material as a hole transport layer, and a glass substrate with an indium tin oxide ITO coating is provided in the PLED device. A zinc oxide ZnO layer, a super yellow layer, a PEF-2TEG layer, and a 100 nm Al electrode evaporation coating layer are successively provided on the surface of the glass substrate with the indium tin oxide ITO coating from bottom to top.
[0012] The PLED device of the present invention is prepared through the following steps: First, a glass substrate with an indium tin oxide (ITO) coating is ultrasonically cleaned with deionized water, acetone, and isopropyl alcohol, and then treated with oxygen plasma for 10 minutes. Before spin coating, all solutions are magnetically stirred at 55 °C for 12 hours; on a clean ITO glass plate, first, an ethanol solution of zinc acetylacetonate at 20 mg / ml is spin coated at 2000 rpm (revolutions per minute) for 60 s to form a film, and after removal, it is annealed at 120 °C in air for 30 seconds to prepare a zinc oxide (ZnO) layer; then, a toluene solution of 4 mg / ml super yellow (trade name) is spin coated thereon at 2000 rpm for 60 s; subsequently, a 2 mg / ml PEF-2TEG anhydrous acetonitrile solution is spin coated at 2000 rpm for 60 seconds, and thereafter, a 100 nm Al electrode is deposited by evaporation.
[0013] The present invention also proposes an application of the above-mentioned organic semiconductor material, characterized in that an organic field effect transistor OFETs is prepared by using the above-mentioned organic semiconductor material, including the following steps: using a prefabricated substrate in the form of bottom contact and bottom gate, which uses n-type doped silicon as the gate, SiO 2 as the dielectric layer, interdigital evaporated gold source and drain electrodes, with channel lengths of 5 μm, 10 μm, and 20 μm. The prefabricated substrate is ultrasonically cleaned with deionized water, acetone, and isopropyl alcohol for 10 minutes and set aside. Respectively, 13 mmol / L trichloro(octadecyl)silane toluene solution (OTS) is dropped on different substrates, waiting for 2 minutes, and then cleaned with toluene solvent to obtain an OTS self-assembled film, and a 10 mg / ml PEF-2TEG chloroform solution is spin coated thereon at a speed of 1000 rpm for 60 s and dried at room temperature.
[0014] In summary, the present invention can adopt a substituent group with interface regulation ability and connect it to the D-A alternating conjugated polymer in the form of a side chain, which can improve the hole injection ability while enhancing the hole transport ability, improve the molecular arrangement and packing at the interface, enhance the charge transport ability, and thus improve the performance of the OLED device. Description of the Drawings:
[0015] Attached Figure 1 is the 1H NMR spectrum (400 Hz) of the compound PEF-2TEG in CDCl3 in the present invention. Detailed Embodiments:
[0016] The present invention will be further described below in conjunction with the drawings and embodiments.
[0017] Conjugated polymer organic semiconductor materials have high thermal stability, good environmental adaptability, and are more suitable for preparing polymer light-emitting diodes by low-cost solution processing technologies such as laser thermal transfer and inkjet printing, showing great potential in large-area flexible display products. OLEDs are multi-layer structures composed of an anode, a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), and a cathode. The matching of the preparation, energy levels, and film layer flatness among these structures plays a crucial role in improving device performance. Excellent hole transport materials can reduce the energy barrier with ITO, improve the hole injection efficiency, balance the hole transport rate and the electron transport rate, so as to effectively recombine in the emission layer and achieve improvements in the efficiency, lifespan, and brightness of the device. The alternating arrangement of donors and acceptors in alternating conjugated polymers can effectively promote charge transfer, showing significant advantages as hole transport materials, and their synthesis and development have been the main research directions in recent years. Ethylenedioxythiophene as a donor and fluorene as an acceptor can synthesize typical alternating conjugated polymers. Although there have been reports of synthesizing high-yield materials by direct alkylation method at temperatures below 100°C, the introduced alkyl side chains only provide single solubility, and the energy levels of the polymer have poor matching with ITO, resulting in its inability to be used as a hole transport material in OLEDs and OFETs.
[0018] In order to fully utilize the performance of alternating conjugated polymers and promote their development and application, in the present invention, oligoglycerol is introduced as a side chain at the 9th carbon of the fluorene monomer in the alternating conjugated polymer to improve the solubility of the polymer while reducing the intermolecular distance, improving the flatness of the film layer, and further enhancing the performance of OLED and OFET devices.
[0019] Example 1:
[0020] This example provides an organic semiconductor material, its preparation method and application. The organic semiconductor material in this example is obtained through the following scheme:
[0021] The monomer synthesis and direct arylation polycondensation of the polymer are as shown below:
[0022]
[0023] Process i is the synthesis of 2,7-dibromo-9,9'-bis(2-(2-(2-methoxyethoxy)ethoxy)ethyl)fluorene (Compound 2), which specifically includes: In a two-necked flask, under Ar protection, 2,7-dibromo-fluorene (1.5 g, 4.63 mmol) and anhydrous N,N-dimethylformamide (25 mL) were successively added, and NaH (0.51 mg, 12.6 mmol) with a mass fraction of 60% dissolved in mineral oil. After stirring the mixed solution at room temperature for 0.5 hours, p-2-(2-(2-methoxyethoxy)ethoxy)ethyl-4-methylbenzenesulfonate (3.49 g, 11.5 mmol) was added, and stirring was continued for 24 hours. The reaction was terminated by adding water, extracted with dichloromethane, dried over MgSO4, distilled under reduced pressure, and the crude product was purified by column chromatography (CH2Cl2 / MeOH 9 / 1) to obtain Compound 2.
[0024] Process ii is the synthesis of poly(3,4-ethylenedioxythiophene-2,5-diyl-alt-9,9-bis-(2-(2-(2-methoxyethoxy)ethoxy)ethyl)fluorene-2,7-diyl), namely Compound PEF-2TEG, which specifically includes the following steps: In a 250 ml two-necked flask, according to an equivalent ratio of 1:1, the equivalent ratio described in this example is the molar ratio, and Compound 2 (1 g, 1.62 mmols), EDOT (0.173 ml, 1.62 mmols) were successively added, and 2.5 equivalent ratios of potassium acetate (0.397 g, 4.05 mmol) were added. The inside of the flask was deoxygenated, and then anhydrous N,N-dimethylacetamide (12 ml) was added. The mixed solution was deoxygenated, and then 0.05 equivalent of the precatalyst Pd(OAc) 2 (0.081 mmol, 18.18 mg) was added, and the inside of the flask was deoxygenated again. The mixed solution was heated to 80 °C and reacted under Ar for 48 hours. After the reaction solution was cooled, it was washed with water, and then placed in a Soxhlet extractor and purified successively with n-hexane, acetone, and dichloromethane. Finally, the dichloromethane solution was rotary evaporated under low pressure and vacuum dried for 12 h to obtain the polymer PEF-2TEG. Among them, PEF-2OCT is the performance of the poly(dioctylfluorene-EDOT) conjugated polymer material, that is, the two branches of fluorene are octyl groups.
[0025] Table 1 Performance of the synthesized polymers
[0026]
[0027] The n value calculated for the polymer molecular weight based on the molar molecular weight Mn measured by gel permeation chromatography is 364. As can be seen from Table 1, replacing the dioctyl group with a glycerol-based side chain causes the infrared absorption spectrum of the polymer to shift to the blue, indicating that the material arrangement is more regular and the degree of aggregation is lower. The highest occupied orbital energy level of the polymer is -5.3 eV, lower than that of the dioctyl side chain (-5.47 eV) and more matched with the value of -4.7 eV of ITO.
[0028] This example also provides an OLED application of the organic compound as described above. The inverted device structure based on PEF-2TEG as the hole transport layer is ITO / ZnO / Super yellow / PEF-2TEG / Al (100 nm). First, the glass substrate with an indium tin oxide (ITO) coating is ultrasonically cleaned with deionized water, acetone, and isopropyl alcohol, and then treated with oxygen plasma for 10 minutes. Before spin coating, all solutions are magnetically stirred at 55 °C for 12 hours. On a clean ITO glass plate, first, a 20 mg / ml ethanol solution of zinc acetylacetonate is spin-coated at 2000 rpm (revolutions per minute) for 60 s to form a film, and after removal, it is annealed in air at 120 °C for 30 seconds to prepare a zinc oxide (ZnO) layer. Then, a 4 mg / ml toluene solution of super yellow (trade name) is spin-coated on it at 2000 rpm for 60 s. Subsequently, a 2 mg / ml anhydrous acetonitrile solution of PEF-2TEG is spin-coated at 2000 rpm for 60 seconds. Thereafter, a 100 nm Al electrode is deposited by evaporation. The performance of the PLED is tested using a Keithley 4200 analysis system, and the obtained performance is shown in Table 1.
[0029] Table 1 Luminescence properties of PLEDs
[0030]
[0031]
[0032] Example 2:
[0033] This example presents another application of the compound PEF-2TEG obtained as in Example 1: preparing organic field effect transistors (OFETs) based on the PEF-2TEG material, and the method is as follows:
[0034] A prefabricated substrate in the form of bottom contact and bottom gate is used, which uses n (electron)-type doped silicon (Si) as the gate and SiO 2It is a dielectric layer, and interdigital gold (Au) is evaporated as the source and drain electrodes. The channel lengths are 5 μm, 10 μm, and 20 μm. The prefabricated substrate is ultrasonically cleaned with deionized water, acetone, and isopropyl alcohol for 10 minutes and then set aside. 13 mmol / L trichloro(octadecyl)silane toluene solution (OTS) is respectively dropped on different substrates, waited for 2 minutes, cleaned with toluene solvent, and 10 mmol / L pentafluorobenzenethiol ethanol solution (PFBT) is dropped on a part of the substrates, left for 2 minutes, and then cleaned with ethanol solution. Self-assembled films of OTS and OTS / PFBT are respectively prepared. And a 10 mg / ml PEF-2TEG chloroform solution is spin-coated thereon at a speed of 1000 rpm for 60 s and dried at room temperature. The OFET device is tested using a Keithley 4200 analyzer, and the data are shown in Table 2.
[0035] Table 2 Performance of field-effect transistors prepared from PEF-2TEG
[0036]
[0037] Table 2 shows that for the organic field-effect transistors OFETs prepared from the PEF-2TEG material in this example, the turn-on voltage of 3.6 eV is very low among existing OFET products.
[0038] The present invention can adopt a substituent group with interface regulation ability and connect it to the D-A alternating conjugated polymer in the form of a side chain, which can improve the hole injection ability while improving the hole transport ability, improve the molecular arrangement and packing at the interface, enhance the charge transport ability, and further improve the performance of the OLED device.
Claims
1. An organic semiconductor material, characterized in that The chemical formula of the organic semiconductor material is:
2. A method for preparing an organic semiconductor material as claimed in claim 1, characterized in that: The preparation process is as follows:
3. The method for preparing an organic semiconductor material according to claim 2, characterized in that The synthesis of 2,7-dibromo-9,9'-di(2-(2-(2-methoxyethoxy)ethoxy)ethyl)fluorene, i.e., compound 2. Specifically, under Ar protection, 2,7-dibromofluorene (1.5 g, 4.63 mmol) and anhydrous N,N-dimethylformamide (25 mL) were added to a two-necked flask in sequence, and NaH (0.51 mg, 12.6 mmol) with a mass fraction of 60% was dissolved in mineral oil. After the mixed solution was stirred at room temperature for 0.5 hours, 2-(2-(2-methoxyethoxy)ethoxy)ethyl-4-methylbenzenesulfonate (3.49 g, 11.5 mmol) was added and stirred for 24 hours. Water was added to terminate the reaction, and the mixture was extracted with dichloromethane, dried with MgSO4, and distilled under reduced pressure. The crude product was purified by column chromatography (CH2Cl2 / MeOH 9 / 1) to obtain compound 2.
4. The method for preparing an organic semiconductor material according to claim 2, characterized in that: The synthesis of poly(3,4-ethylenedioxythiophene-2,5-diyl-alt-9,9-di-(2-(2-(2-methoxyethoxy)ethoxy)ethyl)fluorene-2,7-diyl) or compound PEF-2TEG specifically includes the following steps: in a 250 ml two-necked flask, compound 2 (1 g, 1.62 mmols) and EDOT (0.173 ml, 1.62 mmols) are added in sequence at an equivalent ratio of 1:1, and potassium acetate (0.397 g, 4.05 mmol) of 2.5 equivalents is added, the flask is deoxygenated, and then anhydrous N,N-dimethylacetamide (12 ml) is added to deoxygenate the mixed solution, and then 0.05 equivalents of precatalyst Pd(OAc)2 (0.081 mmol, 18.18 mg) is added, and the flask is deoxygenated again. The mixed solution is heated to 80° C. under Ar and reacted for 48 hours. The reaction solution was cooled and washed with water, and then placed in a Soxhlet extractor, and purified with n-hexane, acetone, and dichloromethane in sequence. Finally, the dichloromethane solution was rotary evaporated at low pressure and vacuum dried for 12 hours to obtain the polymer PEF-2TEG.
5. An application of the organic semiconductor material according to claim 1, characterized in that: A PLED device using the organic semiconductor material as described above as a hole transport layer is provided in the PLED device, wherein a glass substrate with an indium tin oxide (ITO) coating is provided, and a zinc oxide (ZnO) layer, a PEF-2TEG layer and an Al electrode vapor-deposited layer are sequentially provided on the surface of the glass substrate with the indium tin oxide (ITO) coating from bottom to top.
6. A PLED device as claimed in claim 5, characterized in that: It was prepared by the following steps: first, the glass substrate with indium tin oxide (ITO) coating was ultrasonically cleaned with deionized water, acetone and isopropanol, and then treated with oxygen plasma for 10 minutes. Before spin coating, all solutions were magnetically stirred at 55°C for 12 hours; on the clean ITO glass plate, 20 mg / ml ethanol solution of zinc acetylacetonate was first spin-coated at 2000 rpm (revolutions per minute) for 60 seconds to form a film, and then annealed at 120°C in air for 30 seconds to prepare a zinc oxide (ZnO) layer; then 4 mg / ml super yellow (trade name) toluene solution was spin-coated at 2000 rpm for 60 seconds; then 2 mg / ml PEF-2TEG anhydrous acetonitrile solution was spin-coated at 2000 rpm for 60 seconds, and then a 100 nm Al electrode was evaporated and deposited.
7. A use of the organic semiconductor material as claimed in claim 1, characterized in that: The organic field effect transistors (OFETs) are prepared by using the organic semiconductor material as described above, including the following steps: using a prefabricated substrate in the form of a bottom contact bottom gate, which uses n-type doped silicon as a gate, SiO2 as a dielectric layer, and interdigitated gold Au evaporated as a source and drain electrode, and the channel length is 5um, 10um and 20um. The prefabricated substrate is ultrasonically cleaned with deionized water, acetone, and isopropanol for 10 minutes and set aside. 13mmol / L trichloro(octadecyl)silane toluene solution (OTS) is dropped on different sediments respectively, waited for 2 minutes, and washed with toluene solvent. A part of the sediment is dripped with 10mmol / L pentafluorobenzenethiol ethanol solution (PFBT), left for 2 minutes, and then washed with ethanol solution. OTS self-assembled films and OTS / PFBT self-assembled films are prepared respectively, and 10mg / ml PEF-2TEG chloroform solution is spin-coated thereon at a speed of 1000rpm for 60s, and dried at room temperature.