Solvents for dissolving organic semiconducting materials and their use in the preparation of organic optoelectronic devices
By using fluoroalcohol solvents to dissolve organic semiconductor materials and form a dense stacked structure, the environmental and health hazards of traditional solvents are solved, and the performance and stability of organic electrochemical transistors are improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SUN YAT SEN UNIV
- Filing Date
- 2022-03-28
- Publication Date
- 2026-06-12
AI Technical Summary
The aromatic and chlorinated solvents used in the fabrication of existing organic optoelectronic devices are harmful to the environment and human health, and are difficult to effectively dissolve certain organic semiconductor materials with high rigidity π-conjugated systems.
Fluorohydrins are used as solvents for organic semiconductor materials. Their strong hydrogen bond donor capacity and high ionization capacity are utilized to form a dense stacked structure, thereby improving the performance and stability of organic electrochemical transistors.
Fluorohydric alcohol solvents significantly improve the performance and stability of organic electrochemical transistors, are less toxic, environmentally friendly, and suitable for the fabrication of organic optoelectronic devices.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of organic semiconductor material processing technology, specifically relating to solvents used to dissolve organic semiconductor materials and their application in the preparation of organic optoelectronic devices. Background Technology
[0002] Over the past two decades, organic optoelectronic devices such as organic light-emitting diodes (OLEDs), organic photovoltaic cells (OPVs), organic field-effect transistors (OFETs), and organic electrochemical transistors (OECTs) have attracted widespread attention. Among them, organic electrochemical transistors (OECTs), as a type of bioelectronic device, rely on the coupling characteristics of ion and electron flux to achieve excellent conversion capabilities. This requires utilizing channel materials to simultaneously conduct ion and electron charge carriers to achieve self-electrochemical doping.
[0003] Currently, organic semiconductors used in the active layers of organic devices are mainly polymers or small molecules, which are generally prepared by solution deposition. In solution deposition, a solvent is needed to dissolve the organic material, and then a solid thin film is deposited using wet processes such as printing, spin coating, drop casting, and dip coating. Aromatic and chlorinated solvents such as chloroform and chlorobenzene are commonly used in high-performance organic electrochemical transistor devices due to their good solubility for conjugated structures. However, special organic structures such as BBLs possess strong intermolecular interactions and a high-rigidity π-conjugated system without side chains, resulting in poor solubility in solvents such as chloroform and chlorobenzene. Furthermore, these aromatic and chlorinated solvents are toxic and harmful to human health and the environment. Therefore, for environmental protection and human health considerations, it is necessary to use relatively environmentally friendly non-aromatic and non-chlorinated solvents to process optoelectronic devices based on conjugated polymers.
[0004] Fluorohydric alcohols are far less toxic than chlorinated or aromatic solvents, and hold promise as alternatives to aromatic and chlorinated solvents in green and sustainable organic synthesis. Fluorinated alcohols are considered ideal solvents due to their high ionization ability, strong hydrogen bond donor capacity, and environmentally friendly properties; they are also strong hydrogen bond donors due to the strong electron-accepting ability of fluorine atoms. Furthermore, compared to conventional aromatic and chlorinated solvents, fluorohydric alcohols exhibit better solubility for small molecules or polymers with high crystallinity, large conjugated systems, or rigidity. During solvation, the strong π-π interactions between dissolved semiconductors and the enhanced non-covalent intermolecular interactions introduced by the fluorohydric solvent result in a denser, more ordered stacking structure of the semiconductors, which is more conducive to charge transport. Therefore, the development of fluorohydric alcohol solvents for dissolving organic semiconductor materials holds significant application potential. Summary of the Invention
[0005] In order to overcome the shortcomings of the prior art, the primary objective of the present invention is to provide a solvent for organic semiconductor processing.
[0006] A second objective of this invention is to provide the application of the aforementioned solvent in the fabrication of organic optoelectronic devices. This invention introduces novel, environmentally friendly fluoroalcohol solvents with excellent solubility and the ability to form dense packing in the field of organic electrochemical transistors (OECTs) for the fabrication of active layers. By introducing a green fluoroalcohol solvent, the performance of OECT devices is significantly improved compared to traditional chloroform solvents.
[0007] The first objective of this invention is achieved through the following technical solution:
[0008] The present invention provides a solvent for organic semiconductor processing, wherein the solvent is a fluoroalcohol reagent, and the solvent is used to dissolve organic semiconductor materials.
[0009] This invention is the first to propose a novel solvent for the preparation of the active layer of organic electrochemical transistors using a series of fluoroalcohols, namely, using fluoroalcohol solvents to dissolve organic small molecules or polymer semiconductor materials, and then forming a film to prepare OECT devices.
[0010] In a preferred embodiment of the present invention, the solvent for organic semiconductor processing described above is selected from the fluoroalcohol reagents described in formulas (1), (2), (3), (4), (5), (6), (7), (8), (8), (10), (A), (B), and (C), or a composition of the fluoroalcohol reagents:
[0011]
[0012]
[0013] Furthermore, the solvent is selected from the fluoroalcohol reagents of formula (1), formula (2), and formula (3), or a composition of the fluoroalcohol reagents:
[0014]
[0015] Preferably, the organic semiconductor material is a small organic molecule or polymer with a high π-conjugated system. When such organic semiconductor materials are applied to organic electrochemical transistor devices, they exhibit excellent device performance. Furthermore, these solvents are more environmentally friendly and less toxic than traditional aromatic and chlorinated solvents, making them ideal solvents.
[0016] Furthermore, the organic semiconductor material is selected from the indole-dione small molecule gNR represented by formula (I) and / or the perylene imide small molecule represented by formula (II):
[0017]
[0018] Specifically, the organic semiconductor material is selected from the indole-dione small molecule gNR shown in formula (a) and / or the perylene imide small molecule shown in formula (b):
[0019]
[0020] The second objective of this invention is achieved through the following technical solution:
[0021] The present invention also provides the application of the above-mentioned organic semiconductor processing solvent in the preparation of organic optoelectronic devices.
[0022] Preferably, the organic optoelectronic device is an organic electrochemical transistor.
[0023] Research has shown that spin-coating a fluoroalcohol solution containing dissolved organic semiconductor materials onto a glass substrate etched with gold electrodes can prepare densely packed organic semiconductor films at room temperature with good film-forming properties. Further application to OECT devices revealed a significant performance improvement compared to conventional solvents like chloroform. Furthermore, this fluoroalcohol solvent film formation significantly enhances the performance and stability of organic electrochemical transistor devices (compared to the conventional OECT solvent chloroform), and is a relatively environmentally friendly solvent with low toxicity.
[0024] Of course, if the above-mentioned fluoroalcohol solvents are mixed with commonly used solvents such as chloroform and chlorobenzene to form a mixed solvent and then used to prepare organic electronic devices [organic field-effect transistors (OFETs), organic solar cells (OPVs), organic light-emitting diodes (OLEDs), etc.], the film-forming properties can also be improved, thereby improving the device performance.
[0025] The present invention also provides a composition for manufacturing organic optoelectronic devices, the composition comprising the above-mentioned solvent for organic semiconductor processing and organic semiconductor materials.
[0026] Preferably, the organic semiconductor material is a small organic molecule or polymer with a high π-conjugated system.
[0027] Furthermore, the organic semiconductor material is selected from the indole-dione small molecule gNR represented by formula (I) and / or the perylene imide small molecule represented by formula (II):
[0028]
[0029] Specifically, the organic semiconductor material is selected from the indole-dione small molecule gNR shown in formula (a) and / or the perylene imide small molecule shown in formula (b):
[0030]
[0031] Compared with the prior art, the beneficial effects of the present invention are:
[0032] This invention discloses a solvent for dissolving organic semiconductor materials. The solvent is a fluoroalcohol-based reagent. Due to the strong electron-accepting ability of fluorine atoms, the fluoroalcohol solvents of this invention are all strong hydrogen bond donors, exhibiting good solubility for most π-conjugated organic polymers and small molecule materials, superior to solvents such as chloroform and chlorobenzene commonly used in the OECT field. Simultaneously, during the solvation process of the fluoroalcohol solvent, the strong π-π interactions between semiconductors and the specific non-covalent intermolecular interactions introduced by the fluoroalcohol solvent are enhanced, thus facilitating the formation of a denser and more ordered stacking structure of the organic semiconductor material, resulting in a semiconductor thin film with superior performance and significantly improved charge transport capability. Therefore, organic semiconductor materials dissolved by the fluoroalcohol solvent or its composition of this invention are spin-coated onto a substrate to prepare organic electrochemical transistor devices. Compared to chloroform solvents, the steady-state performance and stability of the devices are significantly improved. Furthermore, compared to aromatic and chlorinated solvents commonly used in the field of organic electrochemical transistors, this type of fluoroalcohol solvent is an environmentally friendly solvent, more environmentally friendly, and less toxic, making it an ideal solvent for dissolving organic semiconductor materials. Attached Figure Description
[0033] Figure 1 Cyclic voltammetry curves of OECT devices prepared by dissolving organic semiconductor material gNR in different solvents (trifluoroethanol, hexafluoroisopropanol, perfluorotert-butanol, chloroform);
[0034] Figure 2 The ultraviolet absorption curves of semiconductor thin films prepared by dissolving organic semiconductor material gNR in different solvents (trifluoroethanol, hexafluoroisopropanol, perfluorotert-butanol, chloroform) are shown.
[0035] Figure 3 The GIWAXS spectrum of an OECT device fabricated by dissolving the organic semiconductor material gNR in chloroform solvent;
[0036] Figure 4 The GIWAXS spectrum of an OECT device fabricated by dissolving organic semiconductor material gNR in trifluoroethanol solvent;
[0037] Figure 5 The GIWAXS spectrum of an OECT device fabricated by dissolving the organic semiconductor material gNR in hexafluoroisopropanol solvent;
[0038] Figure 6 The GIWAXS spectrum of an OECT device fabricated by dissolving the organic semiconductor material gNR in perfluorotert-butanol solvent;
[0039] Figure 7IV transfer curves of OECT devices prepared by dissolving organic semiconductor material gNR in different solvents (trifluoroethanol, hexafluoroisopropanol, perfluorotert-butanol, chloroform);
[0040] Figure 8 The normalized transconductance gm of OECT devices prepared by dissolving organic semiconductor material gNR in different solvents (trifluoroethanol, hexafluoroisopropanol, perfluorotert-butanol, chloroform) is measured.
[0041] Figure 9 The stability of OECT devices prepared by dissolving organic semiconductor material gNR in different solvents (trifluoroethanol, hexafluoroisopropanol, perfluorotert-butanol, chloroform) for 1 hour under continuous on-off conditions is shown.
[0042] Figure 10 IV transfer curves of OECT devices prepared by dissolving organic semiconductor material PDI-PEG in different solvents (hexafluoroisopropanol, chloroform). Detailed Implementation
[0043] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.
[0044] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the experimental materials used in the following embodiments are all available through conventional commercial channels.
[0045] Example 1: Application of the fluoroethanol solvent [trifluoroethanol] in the preparation of organic optoelectronic devices
[0046] Organic optoelectronic devices are prepared using indole-dione small molecule gNR as an organic semiconductor material and trifluoroethanol (i.e., 2,2,2-trifluoroethanol) as a solvent for manufacturing organic electrochemical transistors. The structures of the indole-dione small molecule gNR and trifluoroethanol are shown in formula (a) and formula (1), respectively.
[0047]
[0048] The specific preparation process includes the following steps:
[0049] (1) At room temperature, 10 mg of semiconductor material was dissolved in 1 mL of trifluoroethanol (with chloroform as a control) to prepare a 10 mg / mL solution. After complete dissolution, the impurities in the material were filtered out using a 2 μm filter.
[0050] (2) The glass substrate was cleaned in acetone, water, isopropanol and piranha solution in sequence. After drying with nitrogen, a 10 nm Cr layer (as an adhesion promoter) and a 100 nm Au layer were deposited on the substrate in sequence using a thermal evaporation coating instrument as electrodes. Then, a semiconductor thin film (i.e., active layer) was spin-coated on the substrate using the solution in step (1) to prepare an OECT device. The channel width (W) of the device was 39000 μm and the length (L) was 20 μm. The spin-coating parameters were 500 rpm for 5 s and then 1000 rpm for 30 s.
[0051] (3) The steady-state performance and stability of the OECT device were tested under ambient conditions using a semiconductor parameter analyzer (Keysight B1500A) with 0.1M NaCl aqueous solution and Ag / AgCl particle electrodes as the electrolyte and gate, respectively. Simultaneously, the UV absorption spectrum of the semiconductor thin film was measured using a Shimadzu UV-3600 UV-Vis spectrophotometer, with background measurements performed on a clean glass substrate. Furthermore, the electrochemical activity of the semiconductor thin film was characterized using a CHI620E electrochemical analyzer from Shanghai Chenhua Instruments Co., Ltd.
[0052] Finally, it was found that the device's performance was 2.9 times better than that of the chloroform-prepared device, and its stability under continuous on-off cycles for one hour was nearly 10 times better. Figure 8 and 9 ).
[0053] Example 2: Application of the fluoroalcohol solvent [hexafluoroisopropanol] in the fabrication of organic optoelectronic devices
[0054] Using indole-dione small molecules gNR as organic semiconductor material and hexafluoroisopropanol (i.e., 1,1,1,3,3,3-hexafluoro-2-propanol) as solvent for manufacturing organic electrochemical transistors, organic optoelectronic devices are prepared, wherein the structure of the hexafluoroisopropanol is shown in formula (2):
[0055]
[0056] The specific preparation process includes the following steps:
[0057] (1) At room temperature, 10 mg of semiconductor material was dissolved in 1 mL of hexafluoroisopropanol (with chloroform as a control) to prepare a 10 mg / mL solution. After complete dissolution, the impurities in the material were filtered out using a 2 μm filter.
[0058] (2) The glass substrate was cleaned in acetone, water, isopropanol and piranha solution in sequence. After drying with nitrogen, a 10 nm Cr layer (as an adhesion promoter) and a 100 nm Au layer were deposited on the substrate in sequence using a thermal evaporation coating instrument as electrodes. Then, a semiconductor thin film (i.e., active layer) was spin-coated on the substrate using the solution in step (1) to prepare an OECT device. The channel width (W) of the device was 39000 μm and the length (L) was 20 μm. The spin-coating parameters were 500 rpm for 5 s and then 1000 rpm for 30 s.
[0059] (3) The steady-state performance and stability of the OECT device were tested under ambient conditions using a semiconductor parameter analyzer (Keysight B1500A) with 0.1M NaCl aqueous solution and Ag / AgCl particle electrodes as the electrolyte and gate, respectively. Simultaneously, the UV absorption spectrum of the semiconductor thin film was measured using a Shimadzu UV-3600 UV-Vis spectrophotometer, with background measurements performed on a clean glass substrate. Furthermore, the electrochemical activity of the semiconductor thin film was characterized using a CHI620E electrochemical analyzer from Shanghai Chenhua Instruments Co., Ltd.
[0060] Finally, it was found that the device's performance was 3.2 times better than that of the chloroform-prepared device, and its stability under continuous on- and off conditions for one hour was nearly 10 times better. Figure 8 and 9 ).
[0061] Example 3: Application of the fluoroalcohol solvent [perfluorotert-butanol] in the preparation of organic optoelectronic devices.
[0062] Using indole-dione small molecules gNR as organic semiconductor material and perfluorotert-butanol (i.e., 1,1,1,3,3,3-hexafluoro-2-trifluoromethyl-2-propanol) as solvent for manufacturing organic electrochemical transistors, organic optoelectronic devices are prepared, wherein the structure of the perfluorotert-butanol is shown in formula (3):
[0063]
[0064] The specific preparation process includes the following steps:
[0065] (1) At room temperature, 10 mg of semiconductor material was dissolved in 1 mL of perfluorotert-butanol (with chloroform as a control) to prepare a 10 mg / mL solution. After complete dissolution, the impurities in the material were filtered out using a 2 μm filter.
[0066] (2) The glass substrate was cleaned in acetone, water, isopropanol and piranha solution in sequence. After drying with nitrogen, a 10 nm Cr layer (as an adhesion promoter) and a 100 nm Au layer were deposited on the substrate in sequence using a thermal evaporation coating instrument as electrodes. Then, a semiconductor thin film (i.e., active layer) was spin-coated on the substrate using the solution in step (1) to prepare an OECT device. The channel width (W) of the device was 39000 μm and the length (L) was 20 μm. The spin-coating parameters were 500 rpm for 5 s and then 1000 rpm for 30 s.
[0067] (3) The steady-state performance and stability of the OECT device were tested under ambient conditions using a semiconductor parameter analyzer (Keysight B1500A) with 0.1M NaCl aqueous solution and Ag / AgCl particle electrodes as the electrolyte and gate, respectively. Simultaneously, the UV absorption spectrum of the semiconductor thin film was measured using a Shimadzu UV-3600 UV-Vis spectrophotometer, with background measurements performed on a clean glass substrate. Furthermore, the electrochemical activity of the semiconductor thin film was characterized using a CHI620E electrochemical analyzer from Shanghai Chenhua Instruments Co., Ltd.
[0068] Finally, it was found that the device's performance was 2.3 times better than that of the chloroform-prepared device, and its stability under continuous on- and off conditions for one hour was more than 10 times better. Figure 8 and 9 ).
[0069] Example 4: Application of the fluoroalcohol solvent [hexafluoroisopropanol] in the fabrication of organic optoelectronic devices
[0070] Organic optoelectronic devices are prepared using perylene imide-based small molecule PDI-PEG as an organic semiconductor material and hexafluoroisopropanol (i.e., 1,1,1,3,3,3-hexafluoro-2-propanol) as a solvent for manufacturing organic electrochemical transistors. The structure of the perylene imide-based small molecule PDI-PEG is shown in formula (b).
[0071]
[0072] The specific preparation process includes the following steps:
[0073] (1) At room temperature, 10 mg of semiconductor material was dissolved in 1 mL of hexafluoroisopropanol (with chloroform as a control) to prepare a 10 mg / mL solution. After complete dissolution, the impurities in the material were filtered out using a 2 μm filter.
[0074] (2) The glass substrate was cleaned in acetone, water, isopropanol and piranha solution in sequence. After drying with nitrogen, a 10 nm Cr layer (as an adhesion promoter) and a 100 nm Au layer were deposited on the substrate in sequence using a thermal evaporation coating instrument as electrodes. Then, a semiconductor thin film (i.e., active layer) was spin-coated on the substrate using the solution in step (1) to prepare an OECT device. The channel width (W) of the device was 39000 μm and the length (L) was 20 μm. The spin-coating parameters were 500 rpm for 5 s and then 1000 rpm for 30 s.
[0075] (3) The steady-state performance and stability of the OECT device were tested under ambient conditions using a semiconductor parameter analyzer (Keysight B1500A) with 0.1M NaCl aqueous solution and Ag / AgCl particle electrodes as the electrolyte and gate, respectively. Simultaneously, the UV absorption spectrum of the semiconductor thin film was measured using a Shimadzu UV-3600 UV-Vis spectrophotometer, with background measurements performed on a clean glass substrate. Furthermore, the electrochemical activity of the semiconductor thin film was characterized using a CHI620E electrochemical analyzer from Shanghai Chenhua Instruments Co., Ltd.
[0076] Finally, it was found that the device's performance was 1.6 times better than that of the chloroform-prepared device, and the device remained stable during continuous on-off switching within one hour. Figure 10 ).
[0077] Experiment Example 1 Performance Test
[0078] As shown in Examples 1-3, gNR (structure as shown in Formula (a), n=4) was dissolved in trifluoroethanol, hexafluoroisopropanol, perfluorotert-butanol and chloroform respectively, and then an organic thin film was spin-coated on ITO conductive glass. Cyclic voltammetry curves of the four thin films were then tested.
[0079] The curve obtained from the test is as follows Figure 1 As shown, the normalized current intensity in the CV curve indicates that the organic film prepared with fluoroalcohol solvent has stronger electrochemical activity, which is consistent with the trend of device performance changes.
[0080] As shown in Examples 1-3 and Comparative Example 1, gNR (structure as shown in Formula (a), n=4) was dissolved in trifluoroethanol, hexafluoroisopropanol, perfluorotert-butanol and chloroform respectively, and then an organic thin film was spin-coated on glass. The ultraviolet absorption of the four thin films was then tested.
[0081] The curve obtained from the test is as follows Figure 2 As shown, the four curves are generally similar, but the film prepared with fluorinated alcohol solvent exhibits a new shoulder peak, and the peak as a whole shows a blue shift, indicating that the fabricated device has more ordered aggregation and better stacking.
[0082] This can be demonstrated by two-dimensional grazing-incidence wide-angle X-ray scattering. Figure 3-6 (GIWAXS spectrum) Thin films prepared with fluoroethanol solvents (trifluoroethanol, hexafluoroisopropanol, perfluorotert-butanol) also exhibit a more compact packing and significantly improved charge transport capacity compared to chloroform.
[0083] Meanwhile, the IV transfer curve of the OECT device is as follows: Figure 7 As shown in the figure, the transfer characteristic curves demonstrate that the OECT prepared in fluoroethanol solvents (trifluoroethanol, hexafluoroisopropanol, perfluorotert-butanol) exhibits superior performance compared to the conventional solvent chloroform.
[0084] The final performance graphs of the devices prepared by spin coating with the four solvents are shown below. Figure 8 and 9 As shown, the device performance (normalized transconductance g) prepared with fluoroalcohol solvent was found to be... m Compared to devices prepared with chloroform, the stability is significantly improved, and the initial current retention rate (i.e., stability) within one hour is almost ten times that of chloroform: the stability of chloroform-based devices is 7%, while the stability of devices based on trifluoroethanol, hexafluoroisopropanol and perfluorotert-butanol is 64%, 62% and 75%, respectively.
[0085] As shown in Example 4, PDI-PEG (structure shown in formula (b), n=4) was dissolved in hexafluoroisopropanol and chloroform, respectively, and then an organic electrochemical transistor was fabricated by spin-coating an organic thin film onto the device. The performance was tested as shown in the figure. Figure 10 As shown, the device performance (normalized transconductance g) prepared with hexafluoroisopropanol solvent was found to be... m The device is significantly improved compared to the one prepared by chloroform, and the stability of the device remains unchanged for one hour.
[0086] In summary, this invention provides a class of fluoroalcohol solvents for film deposition in organic electrochemical transistors. These solvents exhibit high solubility for organic semiconductor materials, and the films prepared from them demonstrate denser packing and more significant charge transport capabilities. Compared to traditional chloroform solvents, these solvents provide superior device performance and stability for the fabrication of organic electrochemical transistor devices. Therefore, this type of fluoroalcohol solvent shows great potential for applications in organic field-effect transistors (OFETs), organic solar cells (OPVs), and organic light-emitting diodes (OLEDs).
[0087] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.
Claims
1. A solvent for organic semiconductor processing, characterized in that, The solvent is a fluoroalcohol-based reagent, and the solvent is used to dissolve organic semiconductor materials; The fluoroalcohol reagent is selected from the fluoroalcohol reagents of formula (1), formula (2), and formula (3), or a composition of the fluoroalcohol reagent: ； The organic semiconductor material is selected from the indole-dione small molecule gNR represented by formula (I) and / or the perylene imide small molecule represented by formula (II): 。 2. The solvent for organic semiconductor processing according to claim 1, characterized in that, The organic semiconductor material is selected from the indole-dione small molecule gNR shown in formula (a) and / or the perylene imide small molecule shown in formula (b): 。 3. The use of the organic semiconductor processing solvent according to any one of claims 1-2 in the preparation of organic optoelectronic devices.
4. The application according to claim 3, characterized in that, The organic optoelectronic device is an organic electrochemical transistor.
5. A composition for manufacturing organic optoelectronic devices, characterized in that, The composition comprises the organic semiconductor processing solvent as described in claim 1 and the organic semiconductor material.