A method and apparatus for controlling the crystal packing of bisnaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophenes

Abstract

The application discloses a method and device for regulating and controlling a double naphtho[2,3-B:2',3'-F]thieno[3,2-B]thiophene crystal accumulation, and belongs to the technical field of manufacturing of organic field effect transistors. Cmc 21, the cell parameters are a=17.4282(10), b=11.7950(7), c=7.4744(4), alpha=90 degrees, gamma=90 degrees, beta=90 degrees, Z=4, V=1536.48. The device prepared from the crystal 2 of the application is completely free of gate voltage dependence, that is, the material has a high charge concentration, and the gate voltage cannot regulate the change of the current between the source and the drain. Finally, through the above method, the functional diversity and application potential of DNTT in the organic field effect transistor are increased.

Description

Technical Field

[0001] This invention relates to the field of organic field-effect transistor manufacturing technology, and in particular to a method and apparatus for controlling the stacking of bis(naphtho[2,3-B:2′,3′-F]thiopheno[3,2-B]thiophene crystals. Background Technology

[0002] The crystal stacking mode of organic semiconductor materials is a core factor determining their carrier transport performance, stability, and overall device performance, directly affecting the performance limits and industrialization potential of organic electronic devices such as organic field-effect transistors, flexible displays, and organic photodetectors. Dinaphtho[2,3-B:2′,3′-F]thieno[3,2-B]thiophene (DNTT), as a high-performance and classic p-type fused-ring thienoaromatic organic semiconductor, possesses great potential to become a core material for high-performance organic electronic devices due to its rigid planar conjugated framework, reasonable molecular orbital distribution, and the regulatory effect of sulfur atoms.

[0003] The superior performance of DNTT is closely related to its intermolecular crystal stacking behavior. The strong π-π conjugation in its molecular structure and the interaction between sulfur atoms give it a natural tendency to crystallize, resulting in carrier mobilities of 1.0–16.4 cm⁻¹ in vacuum-deposited thin films and single-crystal devices. 2 ·V -1 ·s -1 The on / off ratio is as high as 10. 8 In addition, its transport properties are comparable to those of amorphous silicon; at the same time, the deep HOMO energy level gives it excellent air stability and heat resistance, which can resist oxygen and water vapor erosion, withstand annealing at 160 ℃ and maintain the stability of film morphology and performance, and the core structure is easy to functionalize and modify, making it suitable for a variety of processing techniques.

[0004] However, in existing technologies, DNTT crystal stacking is mostly done through natural growth, which easily leads to problems such as disordered crystal orientation, numerous stacking defects, and uneven grain size. This results in large dispersion of carrier mobility and poor device consistency, making it difficult to fully utilize its intrinsic performance advantages. At the same time, existing control methods are either complex and costly to operate or have low control precision, making it impossible to achieve precise and controllable adjustment of the crystal stacking method. This seriously restricts the application of DNTT in the large-scale integration and industrialization of multifunctional organic electronic devices.

[0005] Therefore, the crystal stacking control of DNTT is a key breakthrough for fully releasing its material advantages and promoting its industrial application. This patent addresses the shortcomings of existing DNTT crystal stacking control technologies by providing a method for controlling the crystal stacking of bis(naphtho[2,3-B:2′,3′-F]thiopheno[3,2-B]thiophene). By precisely controlling the crystal orientation of DNTT, its thermal, electrical, and optical properties can be effectively controlled, further exploring the material potential of DNTT, providing technical support for the fabrication of high-performance organic electronic devices, and promoting the practical development of organic semiconductor materials. Summary of the Invention

[0006] The purpose of this invention is to address the technical deficiencies in the prior art by providing a method for controlling the stacking of bis(naphtho[2,3-B:2′,3′-F]thiopheno[3,2-B]thiophene crystals.

[0007] Another object of the present invention is to provide an apparatus used in the above-described control method.

[0008] The technical solution adopted to achieve the purpose of this invention is: A bisnaphtho[2,3-B:2′,3′-F]thiopheno[3,2-B]thiophene crystal, wherein the structural formula of the bisnaphtho[2,3-B:2′,3′-F]thiopheno[3,2-B]thiophene is as follows: ; The crystal is an orthorhombic crystal system with space group . Cmc 21, with unit cell parameters a=17.4282 Å, b=11.7950 Å, c=7.4744 Å, α=γ=90°, β=90°, and unit cell volume V=1536.48 ų.

[0009] In the above technical solution, the crystal orientation is based on the a-axis, b-axis, and c-axis, corresponding to crystal orientations

[100] ,

[010] , and

[001] , respectively; the crystal planes are based on the crystal axis as the vertical reference, and the typical interplanar spacing is d.

[100] =17.4282 Å, d

[010] =11.7950 Å, d

[001] =7.4744 Å, the shortest distance between two S atoms in the crystal is 4.20 Å, and the packing factor APF=0.62.

[0010] Another aspect of the present invention includes a method for controlling the stacking of bis(2,3-B:2′,3′-F)thiophene[3,2-B]thiophene crystals. A carrier gas enters a reaction chamber and is ionized by plasma. At the same time, the powdered DNTT material in the material zone of the reaction chamber is heated. The ionized carrier gas carries gaseous DNTT from the material zone to the growth zone in the reaction chamber. The gaseous DNTT crystallizes in the growth zone to obtain [2,3-B:2′,3′-F]thiophene[3,2-B]thiophene crystals.

[0011] In the above technical solution, the carrier gas is nitrogen, oxygen or hydrogen.

[0012] In the above technical solution, the flow rate of the carrier gas is 100-400 sccm.

[0013] In the above technical solution, the power of the plasma is 5-30W, and the gas pressure in the reaction chamber is 0.5-2 Pa.

[0014] In the above technical solution, the heating rate of the material zone is 6-30℃ / min, the heating range is 190-210℃, and the temperature is maintained for 90-120 minutes. Another aspect of the present invention includes a device used in the control method, comprising a reaction chamber, a plasma arranged sequentially outside the reaction chamber along the gas inlet direction, a material zone arranged inside the reaction chamber, and a growth zone, wherein a gas inlet and a gas outlet are respectively provided at both ends of the reaction chamber, and a heating mechanism is provided in the material zone.

[0015] In the above technical solution, a quartz plate is placed in the growth region, and the crystal is deposited on the quartz plate.

[0016] Another aspect of the invention includes an organic field-effect transistor comprising the bis(naphtho[2,3-B:2′,3′-F]thiopheno[3,2-B]thiophene crystal.

[0017] In the above technical solution, the organic field-effect transistor comprises, from top to bottom, a silicon wafer modified with trimethoxy(octadecyl)silane, a crystal, and a gold electrode.

[0018] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention provides a novel stacking method for bis(naphtho[2,3-B:2′,3′-F]thiopheno[3,2-B]thiophene) crystals. Specifically, this invention aims to effectively control the electrical and optical properties of DNTT by precisely controlling its crystal orientation, thereby further exploring the material potential of DNTT. This invention prepares DNTT molecules by ionizing a carrier using a physical vapor transport method. Compared to the conventional crystal phase (crystal phase 1), crystal phase 2 exhibits unique electrical and optical properties. This invention provides a new technical method for controlling the crystal phase of organic semiconductor materials, further exploring their material potential.

[0019] 2. This invention ionizes the carrier gas during physical gas-phase transport, creating a plasma state. DNTT molecules in the gas phase are excited or partially ionized during transport, altering their charge distribution and intermolecular interaction potential. Compared to the conventional crystal phase 1 formed primarily by van der Waals forces and π-π stacking interactions of neutral molecules, ionization introduces long-range Coulomb interactions, significantly altering intermolecular adsorption energy, diffusion kinetics, and nucleation barriers. This suppresses the preferential growth of thermodynamically stable crystal phases, prompting DNTT molecules to stack in new spatial orientations and arrangements, thus forming a new crystal phase 2 with a unique crystal stacking structure. This crystal phase control method achieves precise control over crystal stacking at the level of intermolecular forces and crystal growth kinetics, resulting in bis(naphtho[2,3-B:2′,3′-F]thiopheno[3,2-B]thiophene) crystals exhibiting electrical and optical properties distinct from conventional crystal phases. This provides a new technical path for crystal phase control and performance optimization of organic semiconductor materials.

[0020] 3. First, compared to the conventional crystalline phase (phase 1), controllable growth of another DNTT crystalline phase (phase 2) was achieved. Second, compared to the conventional crystalline phase (phase 1), the thermal stability of phase 2 is significantly improved. Third, compared to the conventional crystalline phase (phase 1), the fluorescence spectrum of phase 2 shows a significant red shift, and the fluorescence lifetime is significantly increased. Fourth, organic field-effect transistor devices were fabricated using both crystals. The device fabricated using phase 1 exhibits conventional gate voltage dependence (i.e., organic field-effect transistor characteristics), while the device fabricated using phase 2 shows no gate voltage dependence (i.e., the material has a high charge concentration, and the gate voltage cannot control the change in current between the source and drain). Ultimately, through the above methods, the functional diversity and application potential of DNTT in organic field-effect transistors are increased. Attached Figure Description

[0021] Figure 1 This is the molecular structure of DNTT.

[0022] Figure 2 This is a schematic diagram of the device in Example 2.

[0023] Figure 3The following are packing diagrams of the crystals of Example 1 and Comparative Example 1 along the a-axis, b-axis, and c-axis, where a) is crystal 1, b) is crystal 2, and c) is the packing diagram of the space group of crystal 2.

[0024] Figure 4 Thermal stability analysis of the crystals of Example 1 and Comparative Example 1.

[0025] Figure 5 The fluorescence spectra of the crystals of Example 1 and Comparative Example 1 are shown.

[0026] Figure 6 The fluorescence lifetime of the crystals in Example 1 and Comparative Example 1 is given.

[0027] Figure 7 This is a schematic diagram of the transistor structure in Example 3; Figure 8 The images show X-ray single-crystal diffraction patterns and theoretical comparison diagrams of the crystals in Example 1 and Comparative Example 1, where a) is crystal 1 and b) is crystal 2.

[0028] Figure 9 The diagram shows the electrical performance test results of the transistor made from crystal 1 in Comparative Example 1, where a) is the transfer curve and b) is the output curve.

[0029] Figure 10 The diagram shows the electrical performance test results of the transistor made from crystal 2 in Example 1, where a) is the transfer curve and b) is the output curve. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0031] Example 1 A method for controlling the stacking of bis(naphtho[2,3-B:2′,3′-F]thiopheno[3,2-B]thiophene) crystals includes the following steps: Nitrogen gas flow rate is 100 sccm, plasma power is 10W, gas pressure is 1 Pa, powdered DNTT material is placed in a material zone, the material zone is heated from 20℃ to 200℃ over 30 minutes and held for 120 minutes, nitrogen gas carries gaseous DNTT into a growth zone to slowly grow micron-sized single-crystal bis(naphtho[2,3-B:2′,3′-F]thiopheno[3,2-B]thiophene crystals (the growth zone does not require heating and grows naturally), denoted as crystal 2 (or crystal phase 2). The structural formula of the bis(naphtho[2,3-B:2′,3′-F]thiopheno[3,2-B]thiophene is as follows: Figure 1 As shown.

[0032] Example 2 like Figure 2As shown, this embodiment provides the device used in the control method described in Embodiment 1, including a reaction chamber, a plasma arranged sequentially outside the reaction chamber along the gas inlet direction, a material zone arranged inside the reaction chamber, and a growth zone. The reaction chamber is provided with a gas inlet and a gas outlet at both ends, and the material zone is provided with a heating mechanism.

[0033] Example 3 like Figure 7 As shown, an organic field-effect transistor is constructed using the apparatus described in Example 2. At a nitrogen flow rate of 20 sccm, powdered DNTT material is placed in the material zone. The material zone is heated from 20°C to 190°C over 30 minutes and held for 120 minutes. Nitrogen gas carries the material into the growth zone, where micron-sized single-crystal bis(naphtho[2,3-B:2′,3′-F]thiopheno[3,2-B]thiophene crystals are slowly grown on a silicon wafer (silicon dioxide) modified with trimethoxy(octadecyl)silane. A gold electrode is prepared and transferred to the crystal surface of Example 1 or Comparative Example 1. The crystal serves as an organic semiconductor, constructing an organic field-effect transistor with a bottom-gate top-contact structure.

[0034] Comparative Example 1 A method for controlling the stacking of bis(naphtho[2,3-B:2′,3′-F]thiopheno[3,2-B]thiophene) crystals includes the following steps: Powdered DNTT material is placed in a material zone at a nitrogen flow rate of 300 sccm. The material zone is heated from 20°C to 190°C over 30 minutes and maintained at 190°C for 60 minutes. Nitrogen gas carries the DNTT material into a growth zone to slowly grow micron-sized single-crystal bis(naphtho[2,3-B:2′,3′-F]thiopheno[3,2-B]thiophene crystals, denoted as crystal 1 (or crystal phase 1). The crystal growth in this comparative example also uses the apparatus of Example 2, but without the need to activate the plasma.

[0035] Application Example 1 like Figure 3 The diagram shows the packing diagrams of the crystals from Example 1 and Comparative Example 1 along the a-axis, b-axis, and c-axis. Figure 3 It can be seen that the crystal orientations of the two crystalline phases are significantly different. Crystal 2 is an orthorhombic crystal system with space group . Cmc 21, with unit cell parameters a=17.4282 Å, b=11.7950 Å, c=7.4744 Å, α=γ=90°, β=90°, and unit cell volume V=1536.48 ų. The crystal orientations of crystal 2 are based on the a, b, and c axes, corresponding to crystal orientations

[100] ,

[010] , and

[001] , respectively; the crystal planes are perpendicular to the crystal axes, with a typical interplanar spacing of d.

[100] =17.4282 Å, d

[010] =11.7950 Å, d

[001] =7.4744 Å. From the perspective of spatial packing, the shortest distance between two S atoms in crystal 2 is 4.20 Å, the packing factor APF = 0.62, and the crystal phase orientation is well consistent. Figure 3 As shown in c), C: C-centered lattice, with additional lattice points located at ( 1 / 2, 1 / 2,0), m: mirror perpendicular to a axis (

[100] ); c: c sliding surface perpendicular to b axis (

[010] ) (translation component is c / 2); 21: 21 helical axis along c axis (

[001] ) (rotation 180° + translation c / 2).

[0036] Crystal 1 is a monoclinic crystal with space group P21 (space group number 4). Its cell parameters are a = 6.187(4) Å, b = 7.662(6) Å, c = 16.21(1) Å, α = γ = 90.000°, β = 92.49(2)°, and cell volume V = 767.706 Å. 3 The crystal orientations of this crystal are referenced to the a, b, and c axes, corresponding to the crystal orientations

[100] ,

[010] , and

[001] , respectively; the crystal planes are referenced to the crystal axes, with a typical interplanar spacing of d.

[100] =6.187(4) Å, d

[010] =7.662(6) Å、d

[001] =16.21(1) Å. From the perspective of spatial packing, the shortest distance between two S atoms in this crystal is 3.82 Å (the distance between two S atoms is calculated from the atomic fraction coordinates), the packing factor APF≈0.60 (calculated based on the van der Waals radii of C, H, and S atoms and the unit cell volume), the molecules are arranged in a monoclinic regular pattern, and the crystal phase orientation is well consistent.

[0037] Application Example 2 Thermal stability tests of crystals in Example 1 and Comparative Example 1: like Figure 4 As shown, thermogravimetric analysis was performed on crystal 1 and crystal 2 under a nitrogen atmosphere at a heating rate of 5 °C / min. The results showed that crystal 2 of the present invention has a high thermal decomposition temperature and excellent thermal stability, which can meet the requirements of high-temperature preparation processes such as vacuum evaporation and physical vapor transport.

[0038] Application Example 3 like Figure 5 and Figure 6 As shown, the photophysical properties of the crystals in Example 1 and Comparative Example 1 were tested: At room temperature, appropriate amounts of crystal 1 and crystal 2 were taken out respectively, and the photophysical properties of the two solid-state crystal phases were tested using a steady-state / transient fluorescence spectrometer FLS1000. Figure 5 and Figure 6It can be seen that, compared with crystal 1, the maximum emission peak of crystal 2 is significantly red-shifted, and the fluorescence lifetime of crystal 2 is significantly longer.

[0039] Application Example 4 The transistors fabricated from crystal 1 in Comparative Example 1 and crystal 2 in Example 1 were tested for their electrical performance at room temperature and atmospheric pressure using an Agilent B1500 electrical performance testing system. The results are as follows: Figure 9 and Figure 10 As shown, by Figure 9 As shown in a), the transistor device fabricated from crystal 1 exhibits a significant gate voltage dependence (source-drain voltage is -60 V, gate voltage changes from +60 V to -60 V, and then back from -60 V to +60 V). Experimental results show that the transistor's threshold voltage is near 0 V, and the source-drain current can be significantly modulated by adjusting the gate voltage, demonstrating typical field-effect modulation characteristics. Correspondingly, from Figure 9 As shown in b), its output characteristic curves exhibit a clear hierarchical distribution under different gate voltages (0V, -10V, -20V, -30V, -40V, -50V, -60V in sequence). The source and drain currents increase significantly with the increase of gate voltage. Overall, it exhibits typical organic field-effect transistor output characteristics, indicating that the carrier transport process can be effectively controlled by the gate voltage.

[0040] Depend on Figure 10 As shown in a), the device transfer curve of the transistor device fabricated by crystal 2 shows no significant gate voltage dependence in the range of -60V to +60V (source-drain voltage is -60V, gate voltage changes from +60V to -60V, and then back from -60V to +60V). Experimental results indicate that the field-effect modulation effect is not significant. Figure 10 As shown in b), the output curves basically overlap under different gate voltages (0V, -10V, -20V, -30V, -40V, -50V, -60V in sequence). The source and drain currents do not change significantly with the gate voltage. Overall, it exhibits ohmic conductivity characteristics and does not show the gate-controlled output characteristics of a typical field-effect transistor.

[0041] The above description is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A bis(naphtho[2,3-B:2′,3′-F]thiopheno[3,2-B]thiophene crystal, characterized in that, The structural formula of the bis(naphtho[2,3-B:2′,3′-F]thiopheno[3,2-B]thiophene is: ； The crystal is an orthorhombic crystal system with space group . Cmc 21, with unit cell parameters a = 17.4282 Å, b = 11.7950 Å, c = 7.4744 Å, α = γ = 90°, β = 90°, and unit cell volume V = 1536.48 Å. 3 .

2. The crystal according to claim 1, characterized in that, The crystal orientations are referenced to the a-axis, b-axis, and c-axis, corresponding to crystal orientations [100], [010], and [001], respectively; the crystal planes are perpendicular to the crystal axis, and the interplanar spacing is d. [100] =17.4282 Å, d [010] =11.7950 Å, d [001] =7.4744 Å, the shortest distance between two S atoms in the crystal is 4.20 Å, and the packing factor APF=0.

62.

3. The method for controlling the stacking of bis(naphtho[2,3-B:2′,3′-F]thiopheno[3,2-B]thiophene crystals as described in any one of claims 1 or 2, characterized in that, The carrier gas enters the reaction chamber and is ionized by plasma. At the same time, the powdered DNTT material in the material zone of the reaction chamber is heated. The ionized carrier gas carries the gaseous DNTT from the material zone to the growth zone in the reaction chamber. The gaseous DNTT crystallizes in the growth zone to obtain [2,3-B:2′,3′-F]thiophene[3,2-B]thiophene crystals.

4. The control method according to claim 3, characterized in that, The carrier gas is nitrogen, oxygen, or hydrogen.

5. The control method according to claim 3, characterized in that, The flow rate of the carrier gas is 100-400 sccm.

6. The control method according to claim 3, characterized in that, The plasma power is 5-30W, and the gas pressure in the reaction chamber is 0.5-2 Pa.

7. The control method according to claim 3, characterized in that, The heating rate of the material zone is 6-30℃ / min, the heating range is 190-210℃, and the temperature is maintained for 90-120min.

8. The apparatus used in the control method according to any one of claims 4-7, characterized in that, It includes a reaction chamber, a plasma zone outside the reaction chamber, a material zone inside the reaction chamber, and a growth zone arranged sequentially along the air inlet direction. An air inlet and an air outlet are respectively provided at both ends of the reaction chamber, and a heating mechanism is provided in the material zone.

9. An organic field-effect transistor, characterized in that, The transistor comprises a bis(naphtho[2,3-B:2′,3′-F]thiopheno[3,2-B]thiophene crystal as described in any one of claims 1 or 2.

10. The organic field-effect transistor according to claim 9, characterized in that, From top to bottom, the structure includes a silicon wafer modified with trimethoxy(octadecyl)silane, a bis(naphtho[2,3-B:2′,3′-F]thiopheno[3,2-B]thiophene crystal, and a gold electrode.

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