Two-color light source monomolecular device based on femtosecond two-photon absorption and preparation method thereof

Abstract

The invention relates to the technical field of photoelectric devices, in particular to a two-color light source monomolecular device based on femtosecond two-photon absorption and a preparation method thereof.The monomolecular device comprises a substrate, a graphene source end electrode and a graphene drain end electrode, and the graphene source end electrode and the graphene drain end electrode form a graphene electrode pair; the graphene electrode pair is arranged on the top layer of the substrate; the bicolor light source takes a polythienyl dendritic molecule of a single-molecule perylene bisimide core as a luminous molecule, and two-NH2 ends of the polythienyl dendritic molecule of the perylene bisimide core are respectively connected with a graphene source end electrode and a graphene drain end electrode through amido bonds, so that the chemical stability of a single-molecule device is remarkably enhanced; the long-term reliability under complex operation conditions can be ensured; according to the preparation method of the two-color light source monomolecular device based on femtosecond two-photon absorption, the operation process is simple and convenient, conditions are controllable, and large-scale production of the monomolecular device is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of optoelectronic devices, and in particular to a two-color light source single-molecule device based on femtosecond two-photon absorption and a preparation method thereof. Background Art

[0002] In recent years, the rapid development of quantum information science and nanotechnology has provided broad prospects for the design and application of new optoelectronic devices. Among them, two-photon absorption (TPA), as an important nonlinear optical effect, has shown great potential in the field of single-molecule devices due to its unique photon-matter interaction mechanism. Two-photon absorption involves the process in which two low-energy photons are absorbed simultaneously and excite electrons to transition to higher energy levels. Compared with single-photon absorption, TPA has deeper light penetration, higher spatial resolution, and selective response to specific wavelengths, making it have important application value in bioimaging, optical data storage, quantum information processing and other fields.

[0003] However, in practical applications, the efficiency of the two-photon absorption effect is limited by many factors, including the optical properties of the material, the wavelength and intensity matching of the light source, etc. Especially for single-molecule devices, the efficiency of TPA is usually low and is easily affected by environmental noise and nonlinear losses. Traditional light source systems usually use single-wavelength high-intensity lasers to excite TPA, but this method has problems such as large energy loss, limited wavelength range, and high risk of material damage. In addition, the optical response characteristics of single-molecule devices are highly dependent on the wavelength and intensity of the light source, and it is difficult to achieve precise control and optimization of the TPA effect with existing technologies.

[0004] In order to solve the above problems, research in recent years has focused on the development of a new dual-color light source system, that is, using the synergistic effect of two photons of different wavelengths to achieve efficient two-photon absorption. Dual-color light sources can not only reduce the demand for high intensity of a single wavelength, reduce material damage and energy loss, but also optimize the TPA effect by precisely controlling the wavelength combination and relative intensity. In addition, the application of dual-color light source systems in single-molecule devices is expected to achieve dynamic regulation of photon absorption and provide technical support for multimodal switching and efficient operation of device functions. Despite this, existing technologies still face the following challenges: low coupling efficiency between dual-color light source systems and single-molecule devices; lack of wavelength and intensity optimization methods for specific molecular systems; and the stability and scalability of the optical response of the device are difficult to meet the needs of practical applications.

[0005] Therefore, there is an urgent need to develop a new type of two-photon absorption dual-color light source single-molecule device to achieve efficient, stable and controllable photon absorption and energy conversion, and promote its application in quantum information processing, nanophotonics and other fields. Summary of the invention

[0006] The present invention aims to solve at least one of the technical problems existing in the related art. To this end, the first object of the present invention is to provide a two-color light source single-molecule device based on femtosecond two-photon absorption; the second object of the present invention is to provide a preparation method of a two-color light source single-molecule device based on femtosecond two-photon absorption.

[0007] In order to achieve the first purpose, the technical solution adopted by the present invention is: Dual-color light source single-molecule devices based on femtosecond two-photon absorption, including: A substrate, a graphene source electrode, and a graphene drain electrode, wherein the graphene source electrode and the graphene drain electrode form a graphene electrode pair, and the graphene electrode pair is arranged on the top layer of the substrate; A two-color light source, wherein the two-color light source uses a single molecule of a polythiophene branched molecule of a perylene imide core as a light-emitting molecule, and two -NH 2 The ends are respectively connected to the graphene source electrode and the graphene drain electrode through amide bonds; The structural formula of the polythienyl dendron molecule with perylene imide core is as follows: ; By chemical decoupling, the polythiophene-based branched molecules with a single molecule perylene imide core are assembled between the graphene source electrode and the graphene drain electrode to form a two-color light source. The luminescence characteristics of the molecules are modulated by electric pumping and femtosecond laser. By changing the wavelength and delay characteristics of the femtosecond laser, the conversion between single-photon absorption and two-photon absorption of the molecules is achieved, thereby changing the molecular radiation transition characteristics. The combination of electroluminescence and femtosecond laser modulation can induce the two-color luminescence of the polythiophene-based branched molecules with a single molecule perylene imide core, thereby realizing a two-color light source at the molecular scale. This two-color light source has unique optical and quantum properties and has broad application prospects in the quantum field. It is expected to solve technical problems such as multi-mode quantum state encoding in quantum communication.

[0008] Furthermore, the graphene source terminal electrode and the graphene drain terminal electrode are nanogap point electrodes.

[0009] Furthermore, it also includes a packaging layer, which covers the graphene electrode pair and the two-color light source.

[0010] Furthermore, the encapsulation layer is selected from hexagonal boron nitride materials.

[0011] Furthermore, the material of the substrate is selected from silicon wafer.

[0012] In order to achieve the second purpose, the technical solution adopted by the present invention is: A method for preparing a two-color light source single-molecule device based on femtosecond two-photon absorption, which is used to prepare any of the above-mentioned two-color light source single-molecule devices based on femtosecond two-photon absorption, comprises the following steps: S100, preparing a graphene array electrode on a substrate; S200, constructing a graphene source electrode and a graphene drain electrode on the graphene array electrode; S300, immersing the graphene source electrode and the graphene drain electrode in a pyridine solution of a polythiophene-based branched compound with a perylene imide core containing a condensation agent, so that single-molecule polythiophene-based branched molecules with a perylene imide core are self-assembled between the graphene source electrode and the graphene drain electrode, thereby obtaining a dual-color light source single-molecule device based on femtosecond two-photon absorption.

[0013] Furthermore, in step S300, the concentration of the pyridine solution of the polythiophene-based dendron compound with a perylene imide core is not less than 0.25 mM.

[0014] Furthermore, in step S300, the condensation agent is selected from 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride.

[0015] Furthermore, the emission spectrum of the two-color light source single-molecule device based on femtosecond two-photon absorption obtained in step S300 is detected using random optical reconstruction microscopy.

[0016] Furthermore, the femtosecond excitation photons of the dual-color light source single-molecule device based on femtosecond two-photon absorption are located in the wavelength range of 1160 to 1630 nm, and the molecular emission peak is located in the wavelength range of 200 nm to 450 nm.

[0017] The above one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects: The present invention provides a dual-color light source single-molecule device based on femtosecond two-photon absorption. The dual-color light source in the single-molecule device is self-assembled by using a polythiophene branched molecule with a single-molecule perylene imide core. The polythiophene branched molecule structure of the perylene imide core contains a controllable charge separation group. Through electric pumping excitation and femtosecond laser combined regulation, the single / double-photon absorption conversion of the molecule is realized, and the molecule is induced to absorb photons of different energies and then transition to emit light, thereby realizing dual-color light-emitting diode (LED) light emission. The amino-NH 2 The amide covalent bond is formed with the carboxyl -COOH at the end of the graphene source electrode and the drain electrode, which significantly enhances the chemical stability of the single-molecule device, thereby ensuring its long-term reliability under complex operating conditions; the graphene source electrode and the graphene drain electrode are nanogap point electrodes, which can achieve miniaturization of the size of the single-molecule device.

[0018] The method for preparing a two-color light source single-molecule device based on femtosecond two-photon absorption provided by the present invention has a simple operation process and controllable conditions, which is conducive to the large-scale production of the device.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of a two-color light source single-molecule device based on femtosecond two-photon absorption provided in Example 2 of the present invention.

[0021] Figure 2 It is the molecular emission spectrum of the two-color light source single-molecule device based on femtosecond two-photon absorption provided in Example 2 of the present invention at a fractional-second wavelength of 1160 nm.

[0022] Figure 3 It is the molecular emission spectrum of the two-color light source single-molecule device based on femtosecond two-photon absorption provided in Example 2 of the present invention at a fractional-second wavelength of 1630 nm.

[0023] Reference numerals: 1. Substrate; 2. Graphene drain electrode; 3. Graphene source electrode; 4. Two-color light source; 5. Encapsulation layer. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme in the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. The following embodiments are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0025] In the following examples, the experimental methods used are conventional methods unless otherwise specified, and are carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials, reagents, etc. used are all commercially available unless otherwise specified.

[0026] like Figure 1 As shown, a dual-color light source single-molecule device based on femtosecond two-photon absorption includes: A substrate 1, a graphene source electrode 2, and a graphene drain electrode 3, wherein the graphene source electrode 2 and the graphene drain electrode 3 form a graphene electrode pair, and the graphene electrode pair is arranged on the top layer of the substrate; The dual-color light source 4 is composed of a single-molecule polythiophene branched molecule with a perylene imide core as a luminescent molecule, and two -NH 2 The ends are respectively connected to the graphene source electrode and the graphene drain electrode through amide bonds; The structural formula of the polythienyl branched molecule with perylene imide core is as follows: .

[0027] In some embodiments of the present invention, the graphene source electrode 2 and the graphene drain electrode 3 are nanogap point electrodes.

[0028] In some embodiments of the present invention, a packaging layer 5 is further included, and the packaging layer 5 covers the graphene electrode pair and the two-color light source 4.

[0029] In some embodiments of the present invention, the encapsulation layer 5 is selected from hexagonal boron nitride materials.

[0030] In some embodiments of the present invention, the material of the substrate is selected from silicon wafer.

[0031] Example 1 The molecular structure of the polythienyl dendrimer compound with perylene imide core is as follows: 1. Synthesis of Compound III , the process is as follows: Under argon atmosphere, magnesium flakes (75 mmol), anhydrous ether (10 ml) and the mixture containing compound Ⅰ were added into a three-necked flask in sequence. (60 mmol) of ether solution (30 mL), mix well, heat to 45 °C, reflux for 3 h until the magnesium flakes are completely dissolved, and transfer the obtained Grignard reagent to a dropping funnel.

[0032] Take another dry three-necked flask and add anhydrous ether (40 mL), compound II (20 mmol) and 1,3-bis(diphenylphosphinopropane)nickel dichloride (0.2 mmol), argon replacement three times; the system was cooled to 0℃ (ice water bath), and the prepared Grignard reagent was slowly added dropwise (the drop speed was controlled to be 1-2 drops / second to avoid local overheating). After the addition was completed, the temperature was gradually raised to 45℃, and the reaction was refluxed for 6 h. The reaction progress was monitored by TLC. The developing solvent of TLC was a mixture of petroleum ether and ethyl acetate (volume ratio of 10:1). The reaction solution was cooled to 0℃, and dilute hydrochloric acid (10% v / v, 30 mL) was slowly added dropwise to quench. The liquid was separated, and the aqueous phase was extracted with ether (20 mL×3). The organic phases were combined and washed with saturated sodium bicarbonate solution (20 mL×2) until neutral. The organic phase was dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to obtain a crude product.

[0033] The crude product was purified by silica gel column chromatography, the target component was collected, and compound III was obtained after rotary evaporation under reduced pressure.

[0034] 1 H NMR (500 MHz, CDCl 3 ): δ 7.39 (d, J = 4.9 Hz, 1H), 7.20 (d, J = 7.7Hz, 1H), 7.14 (d, J = 7.1 Hz, 1H), 7.07 (d, J = 4.9 Hz, 1H), 6.95 (dd, J = 16.2,7.4 Hz, 2H), 0.37 (s, 18H).

[0035] 13 C NMR (125 MHz, CDCl 3 ): δ 143.94, 143.42, 143.17, 140.46, 136.72, 135.59, 134.30, 133.59, 131.32, 129.19, 127.42, 126.72.

[0036] (TOF-ESI+) (m / z) :C 18 H 24 S 3 Si 2 392.74.

[0037] 2. Synthesis of Compound Ⅴ , the process is as follows: Under nitrogen atmosphere, 15 mL of n-BuLi (20 mmol) in THF was added dropwise to 50 mL of compound III (20 mmol) in tetrahydrofuran (THF) at -78 °C, stirred at this temperature for 0.5 h, and then 15 mL of compound IV was added dropwise. After adding 25 mmol of THF solution, the mixture was stirred at -78 °C for 1 hour, and then the reaction system was slowly warmed to room temperature and stirred overnight. 4 The reaction was quenched with Cl solution (50 mL), and the reaction solution was extracted with ether (150 mL) three times. The organic layers were combined, washed with saturated brine, and dried over anhydrous sodium sulfate for 30 minutes. The sodium sulfate was removed by filtration, and the organic solvent was removed by rotary evaporation to obtain a solid, which was washed with methanol and filtered. After drying, compound V was obtained.

[0038] 1 H NMR (500 MHz, CDCl3): δ 7.35 (s, 1H), 7.26 (d, J = 7.7 Hz, 1H), 7.19 (d, J = 7.1 Hz, 1H), 6.96 (d, J = 7.7 Hz, 1H), 6.91 (d, J = 7.1 Hz, 1H), 1.23(s, 12H), 0.37(s, 18H).

[0039] 13 C NMR (125 MHz, CDCl 3 ): δ 144.19, 143.46, 142.79, 140.74, 140.17, 134.79, 134.67, 134.26, 133.58, 131.65, 130.17, 127.20, 83.78, 24.83.

[0040] (TOF-ESI+) (m / z): C 24 H 35 BO 2 S 3 Si 2 518.70.

[0041] 3. Synthesis of Compound VI , the process is as follows: Under nitrogen atmosphere, to 20 mL of THF solution of compound III (4 mmol) was added 12 mL of THF solution of iodine chloride (20 mmol). After stirring at room temperature for 1 h, the reactant was added to sodium bicarbonate solution (50 mL), stirred evenly, and 10% sodium sulfite solution was added dropwise until the solution faded. Excess ICl was removed, and the reaction solution was extracted 3 times with 50 mL of ether. The organic layers were combined, washed with saturated brine, and then dried over anhydrous sodium sulfate for 30 minutes. The sodium sulfate was removed by filtration, and the organic solvent was removed by rotary evaporation to obtain a crude product. The crude product was purified by silica gel column chromatography and dried to obtain compound VI.

[0042] 1 H NMR (500 MHz, CDCl 3 ): δ 7.45 (d, J = 4.8 Hz, 1H), 7.31 -7.25 (m,1H), 7.09 (d, J = 4.9 Hz, 1H), 6.70 (dd, J = 12.9, 6.1 Hz, 2H).

[0043] 13 C NMR (125 MHz, CDCl3): δ 141.24, 140.00, 138.31, 137.37, 134.47, 131.91, 130.07, 128.55, 127.90, 126.07, 74.90, 74.79.

[0044] (TOF-ESI+) (m / z) :C 12 H 6 I 2 S 3 500.17.

[0045] 4. Synthesis of Compound VII , the process is as follows: Under nitrogen atmosphere, compound V (20 mmol), compound VI (10 mmol), K 2 CO 3 (20 mmol), Pd(PPh 3 ) 4(0.2 mmol), a mixed solution (110 mL) of toluene and water (the volume ratio of toluene to water is 5:1) was added through a syringe, heated to 110°C, refluxed for 30 h, cooled to room temperature, poured into water, and extracted with dichloromethane (50 mL) three times, the organic layers were combined, dried over anhydrous sodium sulfate, and then dried over anhydrous sodium sulfate for 30 minutes, filtered to remove sodium sulfate, and the organic solvent was removed by rotary evaporation to obtain a crude product, which was purified by silica gel column chromatography and dried to obtain compound VII.

[0046] 1 H NMR (500 MHz, CDCl 3 ): δ 7.68 (d, J = 4.8 Hz, 1H), 7.26 - 7.21 (m,1H), 7.19 -7.12 (m, 1H), 6.99- 6.90 (m, 2H), 0.37 (s, 9H).

[0047] 13 C NMR (125 MHz, CDCl 3 ): δ 143.98, 143.46, 140.89, 140.34, 140.32, 139.93, 139.90, 138.01, 137.33, 137.01, 134.43, 134.37, 134.32, 134.28,133.94, 133.90, 133.88, 133.62, 133.58, 131.34, 129.50, 129.49, 127.94,127.84, 126.74, 126.69, 126.68, 126.50, 126.46, 125.51, 125.42.

[0048] (TOF-ESI+) (m / z) :C 48 H 52 S 9 Si 4 1029.82.

[0049] 5. Synthesis of Compound Ⅷ , the process is as follows: Under nitrogen atmosphere, 10 mL of n-BuLi (10 mmol) THF solution was added dropwise to 25 mL of compound VII (10 mmol) THF solution at -78°C, stirred for 0.5 h, and then 10 mL of compound IV (12.5 mmol) THF solution was added dropwise. After stirring at -78°C for 1 hour, the reaction system was slowly warmed to room temperature and stirred overnight. 4 The reaction was quenched with Cl solution (50 mL), and the reaction solution was extracted with ether (50 mL) three times. The organic layers were combined, washed with saturated brine, and dried over anhydrous sodium sulfate for 30 minutes. The sodium sulfate was removed by filtration, and the organic solvent was removed by rotary evaporation to obtain a solid, which was washed with methanol and filtered to obtain compound VIII.

[0050] 1 H NMR (500 MHz, CDCl 3 ): δ 7.68 (d, J = 4.8 Hz, 3H), 7.55 (s, 1H), 7.33 (d, J = 6.2 Hz, 1H), 7.26 - 7.20 (m, 4H), 6.99 - 6.90 (m, 6H), 1.23 (s, 12H), 0.37 (s, 36H).

[0051] 13 C NMR (125 MHz, CDCl 3 ): δ 143.98, 143.46, 140.47, 140.34, 140.32, 140.12, 139.93, 139.91, 138.46, 137.37, 137.03, 134.35, 134.33, 134.32,134.28, 133.94, 133.90, 133.62, 133.58, 132.92, 132.52, 132.21, 129.50,129.49, 128.80, 126.72, 126.69, 126.68, 126.50, 126.46, 126.11, 125.40,83.78, 24.83.

[0052] (TOF-ESI+) (m / z) :C 54 H 63 BO 2 S 9 Si 4 1155.79.

[0053] VI. Synthesis of Compound Ⅹ , the process is as follows: Under nitrogen atmosphere, compound IX was added into the three-necked flask. (10 mmol), iodine (0.5 mmol) and sulfuric acid (98%, 45 ml) were added and stirred at room temperature for 2 h to obtain a mixed solution. The temperature was raised to 80°C, and bromine (30 mmol) was added dropwise within 1 h. The mixture was reacted at 80°C for 16 h. After cooling to room temperature, the reaction solution was slowly poured into ice water (3 L) to obtain a precipitate. The crude product was filtered and further separated by column chromatography to obtain compound X.

[0054] 1 H NMR (500 MHz, CDCl 3 ): δ 8.68 (s, 1H), 8.50 (d, J = 8.2 Hz, 1H), 8.01 (dd, J = 23.5, 8.3 Hz, 1H).

[0055] 13 C NMR (125 MHz, CDC l3 ): δ 164.68, 163.85, 134.05, 133.23, 130.72, 130.71, 130.59, 129.51, 129.27, 125.38, 125.23, 121.78, 121.42, 118.12.

[0056] (TOF-ESI+) (m / z) C 24 H 6 Br 2 O 6 550.11.

[0057] VII. Synthesis of Compound Ⅻ , the route is as follows: Under nitrogen atmosphere, imidazole (15 g) was heated to 90°C, compound X (2 mmol) was added to dissolve, and compound XI was added. (4.4 mmol), mixed evenly, heated to 180 ° C, stirred for 4 h, cooled to room temperature, added water (10 mL) to quench the reaction, and then added HCl (1 mL) for acidification. Stirred for 12 h, filtered to obtain a solid, washed with distilled water until neutral to obtain a crude product, which was further purified by column chromatography to obtain compound Ⅻ.

[0058] 1 H NMR (500 MHz, CDCl 3): δ 8.63 (d, J = 8.6 Hz, 1H), 8.26 (s, 1H), 8.06 (dd, J = 12.8, 8.6 Hz, 1H), 7.44 - 7.38 (m, 2H), 7.02 (dt, J = 8.5, 1.0Hz, 2H), 5.20 (t, J = 4.9 Hz, 1H), 3.17 (td, J = 5.6, 4.8 Hz, 2H), 2.62 (tt,J = 7.8, 1.0 Hz, 2H), 1.82 (tt, J = 7.9, 5.8 Hz, 2H).

[0059] 13 C NMR (125 MHz, CDCl 3 ): δ 164.41, 163.46, 156.39, 134.98, 134.54,133.36, 131.48, 131.38, 130.38, 130.23, 129.38, 128.93, 128.28, 128.10,126.64, 123.88, 123.83, 122.71, 118.30, 79.54, 40.36, 32.72, 29.99, 28.30.

[0060] (TOF-ESI+) (m / z) C 52 H 46 Br 2 N 4 O 8 1014.77.

[0061] IX. Synthesis of Compound ⅩⅢ , the route is as follows: In a nitrogen atmosphere, compound VIII (2 mmol), compound XII (1 mmol), K 2 CO 3 (2 mmol), Pd(PPh 3 ) 4 (0.02 mmol). A mixture of toluene and water (volume ratio of toluene to water is 5:1) (11 mL) was added via a syringe, heated to 110°C, and refluxed for 30 h. After cooling to room temperature, the reaction mixture was poured into water and extracted three times with dichloromethane (15 mL). The organic layer was dried over anhydrous sodium sulfate, and the solvent was removed. The crude product was purified by silica gel column chromatography to obtain compound XIII.

[0062] 1<h2 style=";text-align:left;direction:ltr">H NMR (500 MHz, CDCl<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> ) :δ<h2 style=";text-align:left;direction:ltr"> 1 <h2 style=";text-align:left;direction:ltr"> H NMR (500 MHz, Chloroform-d) δ 8.62 (d, J = 8.6 Hz, 2H), 8.01 (d, J = 8.6 Hz, 2H), 7.68 (d, J = 4.8 Hz, 3H), 7.44 -7.38 (m, 3H), 7.30 - 7.22 (m, 3H), 7.20 - 7.14 (m, 3H), 7.09 - 6.98 (m, 6H), 6.94 (dd, J = 15.9, 7.4 Hz, 6H), 5.20 (t, J = 4.9 Hz, 3H), 3.17 (td, J = 5.6, 4.8 Hz, 3H), 2.62 (tt, J = 7.7, 1.0 Hz, 3H), 1.82 (tt, J = 7.9, 5.8 Hz, 3H), 0.37 (s, 36H).<h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr">

[0063] <h2 style=";text-align:left;direction:ltr"> 13 <h2 style=";text-align:left;direction:ltr"> C NMR (125 MHz, CDCl<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> ) δ 166.82, 165.14, 156.50, 143.98, 143.46,140.92, 139.59, 139.05, 138.73, 138.63, 138.36, 137.28, 135.02, 134.11,134.01, 134.00, 133.94, 133.64, 133.52, 132.32, 132.24, 131.48, 129.58,129.53, 129.50, 129.38, 128.59, 128.42, 128.38, 128.28, 127.77, 127.60, 127.50, 127.35, 127.27, 126.98, 126.86, 126.45, 126.07, 125.52, 124.95, 124.37, 122.19, 120.71, 79.55, 40.22, 32.69, 29.66, 28.30.<h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr"> (TOF-ESI+) (m / z) :C<h2 style=";text-align:left;direction:ltr"> 148 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 148 <h2 style=";text-align:left;direction:ltr"> N<h2 style=";text-align:left;direction:ltr"> 4 <h2 style=";text-align:left;direction:ltr"> O<h2 style=";text-align:left;direction:ltr"> 8 <h2 style=";text-align:left;direction:ltr"> S<h2 style=";text-align:left;direction:ltr"> 18 <h2 style=";text-align:left;direction:ltr"> Yes<h2 style=";text-align:left;direction:ltr"> 8 <h2 style=";text-align:left;direction:ltr"> 2912.59.<h2 style=";text-align:left;direction:ltr">

[0064] 10. Removal of the protecting group of compound XIII to obtain a polythienyl dendrimer compound with a perylene imide core , the process is as follows: Under nitrogen atmosphere, compound XIII (5 mmol) and 50% trifluoroacetic acid in dichloromethane solution (20 mL) were added to a double-necked flask. After stirring at room temperature for 2 h, saturated sodium bicarbonate solution was added for extraction and repeated washing until it became neutral. The organic layer was collected and the solvent was removed by rotary evaporation to obtain a polythienyl branched compound with a perylene imide core.

[0065] 1 H NMR (500 MHz, CDCl 3 ): δ 7.60 -7.53 (m, 1H), 7.48 (dd, J = 5.1, 1.7Hz, 1H), 7.44 - 7.38 (m, 1H), 7.35 - 7.25 (m, 4H), 7.18 (d, J = 5.9 Hz, 1H), 7.11 (dd, J = 1.83 (tt, J =7.6, 5.3 Hz, 1H).

[0066] 13 C NMR (125 MHz, CDCl 3 ): δ 166.82, 165.14, 140.92, 139.05, 138.79,138.78, 138.36, 137.53, 137.28, 134.27, 134.23, 133.52, 133.35, 132.32,132.24, 131.70, 129.58, 129.50, 129.38, 128.79, 128.60, 128.43, 128.42,128.38, 128.28, 128.05, 127.77, 127.60, 127.50, 127.35, 127.27, 126.98,126.86, 126.45, 125.79, 125.66, 125.01, 124.95, 124.37, 122.19, 120.71,41.70, 33.06, 33.01.

[0067] (TOF-ESI+) (m / z) C 114 H 68 N 4 O 4 S 18 2134.90.

[0068] Example 2 Preparation of a two-color light source single-molecule device based on femtosecond two-photon absorption includes the following steps: S100, preparing a graphene array electrode on a substrate; S200, constructing a graphene source electrode and a graphene drain electrode on the graphene array electrode; S300, immersing the graphene source electrode and the graphene drain electrode in a pyridine solution of a polythiophene-based branched compound with a perylene imide core containing a condensation agent, so that single-molecule polythiophene-based branched molecules with a perylene imide core are self-assembled between the graphene source electrode and the graphene drain electrode, thereby obtaining a dual-color light source single-molecule device based on femtosecond two-photon absorption.

[0069] The specific process of step S100 is as follows: The copper foil was ultrasonically cleaned with acetone and isopropanol for 10 minutes each, then soaked in 5% dilute hydrochloric acid for 5 minutes to remove the oxide layer, and finally rinsed with deionized water and dried with nitrogen. The dried copper foil was placed in a chemical vapor deposition reaction chamber, heated to 1000°C, and H 2 (flow rate 200 sccm) and Ar (flow rate 200 sccm), annealing time 60 min; introduce methane as carbon source, flow rate 20 sccm, hydrogen flow rate 200 sccm, maintain 1000 ° C, 20 min, turn off heating, in H 2 / Ar atmosphere and cooled to room temperature at a rate of 50°C / min to obtain a single-layer graphene; The above-mentioned single-layer graphene was pasted onto a clean quartz plate with transparent tape, polymethyl methacrylate (PMMA) was spin-coated on the single-layer graphene, and the coating was performed at 4000 revolutions per minute for 40 seconds using a glue spreader, and the glue was baked on a heating table at 180°C for 2 min. The excess PMMA and graphene on the back of the copper foil were etched by oxygen plasma to obtain a PMMA-single-layer graphene-copper foil structure, which was cut into 1 cm×1 cm small pieces, placed in a 1M ferric chloride solution to dissolve the copper foil on the back, soaked in 0.1 M HCl for 10 minutes to remove metal ions, and then rinsed with deionized water for 3 times to obtain a PMMA-supported single-layer graphene film, which was transferred to a silicon wafer covered with 300 nm silicon oxide, and soaked in 1% HCl for 5 minutes, rinsed with deionized water, and soaked in 0.01 M KOH for 2 minutes. After rinsing with deionized water, it was allowed to stand, dried, and debonded to obtain a graphene-silicon wafer layer; The graphene surface was spin-coated with photoresist (3000 rpm × 40 s), pre-baked at 180°C for 1 min, and exposed to UV light at 80 mJ / cm² using a strip mask, developed with methyl isobutyl ketone diluted with isopropyl alcohol (the volume ratio of methyl isobutyl ketone to isopropyl alcohol was 1:3), and fixed with isopropyl alcohol to obtain a graphene dot electrode.

[0070] The graphene point electrodes are subjected to oxygen plasma etching and electrical burnout to remove the exposed graphene, and each pair of electrodes is subjected to a continuity test using a probe station and a source meter to obtain a graphene nanogap point electrode array.

[0071] The graphene nanogap dot array electrode includes a graphene source terminal electrode and a graphene drain terminal electrode. The conductivity of the graphene array electrode is tested at a voltage of 50 mV, and the substrate with a conductivity of the order of 10 μA is screened out for subsequent steps.

[0072] The specific process of S300 is as follows: The selected graphene nanogap dot array electrode was placed in a two-necked flask, and 5 ml of 1-(3-dimethylaminopropyl)-3-2-ethylcarbodiimide hydrochloride and 5 ml of 0.5 mM pyridine solution of the polythiophene dendron compound with perylene imide core were added to the two-necked flask. The mixture was reacted in a nitrogen atmosphere for 48 h to make the -NH 2 An amide covalent bond was formed with the -COOH at the end of the graphene nanogap point electrode, and the electrode was washed three times with deionized water and acetone and dried with nitrogen to obtain a dual-color light source single-molecule device based on femtosecond two-photon absorption.

[0073] The emission spectrum of a two-color light source single-molecule device based on femtosecond two-photon absorption was detected using stochastic optical reconstruction microscopy. The process is as follows: After the femtosecond laser is split by a semi-transmitting and semi-reflecting mirror, it is modulated into a light pulse of a specific wavelength by an optical parametric amplifier. The time delay of the two light pulses reaching the molecular device is regulated by a pulse delay system. The two light pulses are focused on a two-color light source single-molecule device based on femtosecond two-photon absorption through a coupling lens. Generally speaking, the pulse wavelength is matched with the energy level of the molecule to regulate the pulse delay system. When the time delay of the light pulse reaching the molecular device reaches the femtosecond level, it can trigger the two-color light source constructed of polythienyl branched molecules based on perylene imide core to absorb two photos, so that the molecule can transition to a higher energy level after absorbing photons, and achieve transition luminescence.

[0074] When the bias voltage is 2V, the corresponding wavelength of the femtosecond laser is modulated to 1160 nm (the corresponding photon energy is 1.07 eV), and the delay of the two-way light is controlled to be above picoseconds by a time delay device. The molecular emission spectrum of the dual-color light source single-molecule device based on femtosecond two-photon absorption provided in this embodiment is as follows: Figure 2 As shown, the molecular emission peak is around 450nm.

[0075] When the bias voltage is 2V, the corresponding wavelength of the femtosecond laser is modulated to 1630 nm (the corresponding photon energy is 0.76eV), and the delay of the two-way light is controlled by a time delay device at the femtosecond level. The molecular emission spectrum of the dual-color light source single-molecule device based on femtosecond two-photon absorption provided in this embodiment is as follows: Figure 3 As shown, the molecular emission peak is around 300nm.

[0076] Under the condition of constant bias voltage, the spectrum of the dual-color light source single-molecule device based on femtosecond two-photon absorption provided by the present invention varies with the wavelength of femtosecond light modulation and the optical path delay, and reflects the conversion between single-photon and two-photon absorption of the polythienyl branched molecules of the perylene imide core, thus realizing the light-emitting function of the dual-color light-emitting diode. Figure 2 and Figure 3 The results show that the polythiophene-based branched molecules with perylene imide cores are successfully connected between graphene nanogap point electrodes, and the performance of the dual-color light source single-molecule device based on femtosecond two-photon absorption provided by the present invention can be regulated by bias voltage and modulated light parameters.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A two-color light source single-molecule device based on femtosecond two-photon absorption, characterized in that: include: A substrate, a graphene source electrode, and a graphene drain electrode, wherein the graphene source electrode and the graphene drain electrode form a graphene electrode pair, and the graphene electrode pair is arranged on the top layer of the substrate; A two-color light source, wherein the two-color light source uses a single-molecule perylene imide core polythiophene branched molecule as a light-emitting molecule, and the two -NH2 ends of the polythiophene branched molecule of the perylene imide core are respectively connected to the graphene source terminal electrode and the graphene drain terminal electrode through amide bonds; The structural formula of the polythienyl branched molecule with perylene imide core is as follows: 。 2. The dual-color light source single-molecule device based on femtosecond two-photon absorption as claimed in claim 1, characterized in that: The graphene source terminal electrode and the graphene drain terminal electrode are nano-gap point electrodes.

3. The dual-color light source single-molecule device based on femtosecond two-photon absorption according to claim 1, characterized in that: It also includes a packaging layer, which covers the graphene electrode pair and the two-color light source.

4. The dual-color light source single-molecule device based on femtosecond two-photon absorption as claimed in claim 3, characterized in that: The encapsulation layer is selected from hexagonal boron nitride materials.

5. The dual-color light source single-molecule device based on femtosecond two-photon absorption as claimed in claim 1, characterized in that: The material of the substrate is selected from silicon wafer.

6. A method for preparing a dual-color light source single-molecule device based on femtosecond two-photon absorption, characterized in that: The method for preparing a dual-color light source single-molecule device based on femtosecond two-photon absorption as claimed in any one of claims 1 to 5 comprises the following steps: S100, preparing a graphene array electrode on a substrate; S200, constructing a graphene source electrode and a graphene drain electrode on the graphene array electrode; S300, immersing the graphene source electrode and the graphene drain electrode in a pyridine solution of a polythiophene-based branched compound with a perylene imide core containing a condensation agent, so that single-molecule polythiophene-based branched molecules with a perylene imide core are self-assembled between the graphene source electrode and the graphene drain electrode, thereby obtaining a dual-color light source single-molecule device based on femtosecond two-photon absorption.

7. The method for preparing a dual-color light source single-molecule device based on femtosecond two-photon absorption according to claim 6, characterized in that: In step S300, the concentration of the pyridine solution of the polythienyl dendron compound with a perylene imide core is not less than 0.25 mM.

8. The method for preparing a dual-color light source single-molecule device based on femtosecond two-photon absorption according to claim 6, characterized in that: In step S300, the condensation agent is selected from 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride.

9. The method for preparing a dual-color light source single-molecule device based on femtosecond two-photon absorption according to claim 6, characterized in that: The emission spectrum of the two-color light source single-molecule device based on femtosecond two-photon absorption obtained in step S300 is detected using random optical reconstruction microscopy.

10. The method for preparing a dual-color light source single-molecule device based on femtosecond two-photon absorption according to claim 9, characterized in that: The femtosecond excitation photons of the dual-color light source single-molecule device based on femtosecond two-photon absorption are located in the wavelength range of 1160 to 1630 nm, and the molecular emission peak is located in the wavelength range of 200 nm to 450 nm.

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