A photoelectronic device based on single-molecule chiral biradical and its preparation method

Abstract

The present invention relates to the technical field of optoelectronic devices, and in particular to an optoelectronic device based on a single-molecule chiral biradical and a preparation method thereof, wherein the optoelectronic device comprises an optical microcavity and a luminescent core unit, wherein the luminescent core unit is arranged in the optical microcavity; wherein the optical microcavity comprises a multi-layer dielectric first reflection layer, a transparent spacing layer, and a second reflection layer arranged in sequence longitudinally; there is a gap between the multi-layer dielectric first reflection layer and the transparent spacing layer, and the second reflection layer is stacked on the transparent spacing layer; the luminescent core unit is arranged between the multi-layer dielectric first reflection layer and the transparent spacing layer, and is used to realize electro-induced circularly polarized luminescence. The design enables the circularly polarized light generated by the luminescent core unit in the optical microcavity to be reflected multiple times and propagated effectively, thereby realizing the regulation and enhancement of the circularly polarized luminescence, and effectively ensuring the stability of the optoelectronic device.

Description

Technical Field

[0001] The present invention relates to the technical field of optoelectronic devices, and in particular to an optoelectronic device based on a single-molecule chiral biradical and a preparation method thereof. Background Art

[0002] Optoelectronic devices are various functional devices made by using the electro-photon conversion effect. Single-molecule optoelectronic devices use single molecules or molecular films as conductive channels to achieve the transmission and control of electrons through the photoelectric effect. The core of optoelectronic devices is to control the electronic properties of molecules through external stimuli such as light and electricity to achieve specific functions. Electroinduced circularly polarized luminescence has attracted great attention and interest due to its wide application prospects in optical recognition sensors, optical data storage, quantum computing, and 3D display.

[0003] In the field of single-molecule optoelectronics, various types of electro-circularly polarized optoelectronic devices have been developed, including devices that generate electro-circularly polarized luminescence from electrode plasmons or single molecules. The latter is considered to be one of the most promising strategies to comply with Moore's Law, and it has unique advantages in miniaturization, integration and efficient energy conversion. As a new generation of molecular luminescent materials, organic free radicals have attracted widespread attention in the field of optoelectronics in recent years. Unlike traditional closed-shell molecules, free radical molecules rely on the excitation characteristics of their doublets or higher spin multiplets to exhibit unique electronic excitation and relaxation dynamics. In particular, in terms of optical performance, they have efficient electron-photon conversion capabilities, excellent near-infrared (NIR) emission performance, and magneto-optical effects.

[0004] Based on single-molecule electroinduced circular polarization devices, single-molecule free radicals are used as photoelectric functional centers, combined with chiral structures, to avoid fluorescence quenching caused by free radical aggregation and stimulate circularly polarized light with a specific polarization state. However, although these devices show excellent performance in theory, how to achieve stable free radical electroinduced circularly polarized luminescence at room temperature remains a key issue.

[0005] Therefore, how to optimize the interaction between molecules and electrodes, improve luminescence efficiency and ensure device stability is a technical problem that needs to be urgently solved in single-molecule optoelectronic devices. 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 an optoelectronic device based on a single molecule chiral biradical; the second object of the present invention is to provide a method for preparing an optoelectronic device.

[0007] In order to achieve the first purpose, the technical solution adopted by the present invention is:

[0008] An optoelectronic device based on a single-molecule chiral biradical comprises an optical microcavity and a luminescent core unit, wherein the luminescent core unit is arranged in the optical microcavity;

[0009] Wherein, the optical microcavity comprises a first reflective layer, a transparent spacer layer and a second reflective layer of a multilayer medium arranged in sequence longitudinally;

[0010] There is a gap between the multi-layer dielectric first reflective layer and the transparent spacing layer, and the second reflective layer is stacked on the transparent spacing layer;

[0011] The light-emitting core unit is disposed between the multi-layer dielectric first reflective layer and the transparent spacer layer, and is used to realize electro-induced circularly polarized light emission;

[0012] The above design enables the circularly polarized light generated by the luminescent core unit in the optical microcavity to be reflected multiple times and propagated effectively, thereby realizing the regulation and enhancement of the circularly polarized luminescence.

[0013] Furthermore, it also includes a graphene source electrode and a graphene drain electrode, wherein the graphene source electrode and the graphene drain electrode are respectively arranged at the left and right ends of the surface of the first reflective layer of the multilayer medium close to the light-emitting core unit;

[0014] The luminescent core unit is composed of a molecular heterostructure composed of a single molecule of chiral diradical molecules, and the structural formula of the chiral diradical molecules is as follows:

[0015] ;

[0016] The two NH2 ends of the chiral biradical molecule are respectively connected to the graphene source electrode and the graphene drain electrode through amide bonds;

[0017] The chiral diradical molecular compound is named HE-TAE. The compound HE-TAE introduces a helicene group as a large steric protection unit. The unique stereostructure of the helicene not only strengthens the chirality of the molecule, but also optimizes the conjugated structure of the molecule, thereby improving the stability and luminescence performance of the free radical. Its special luminescence mechanism, the radiative transition from the triplet excited state to the triplet ground state is a spin-allowed transition, and the theoretical internal quantum efficiency can reach 100%. It can emit blue fluorescence, making up for the lack of blue light free radical luminescent bodies and the lack that the existing free radical luminescence mechanism is difficult to support high-energy state luminescence.

[0018] Furthermore, the composition of the multi-layer dielectric first reflective layer is selected from SiO2 and TiO2, and the multi-layer dielectric first reflective layer is formed by alternately depositing and stacking SiO2 and TiO2.

[0019] Furthermore, the stacking cycle of the deposition stack is 3 to 5 times, the thickness of the SiO2 deposition is 60 to 80 nm, and the thickness of the TiO2 deposition is 30 to 50 nm.

[0020] Furthermore, the transparent spacer layer is composed of components selected from SiO2.

[0021] Furthermore, the second reflective layer is composed of components selected from Ag.

[0022] In order to achieve the second purpose, the technical solution adopted by the present invention is:

[0023] A method for preparing an optoelectronic device, for preparing any of the above-mentioned optoelectronic devices based on single-molecule chiral biradicals, comprising the following steps:

[0024] S100, preparing a first reflective layer of a multilayer dielectric by using an atomic layer deposition method;

[0025] S200, preparing a light-emitting core unit on the first reflective layer of the multi-layer medium;

[0026] S300, preparing a transparent spacer layer, and preparing a second reflective layer on the transparent spacer layer;

[0027] S400, connecting the transparent spacer layer and the light-emitting core unit to form an optoelectronic device based on single-molecule chiral biradicals.

[0028] Furthermore, step S100 also includes a process of preparing a graphene source terminal electrode and a graphene drain terminal electrode on the multilayer dielectric first reflective layer, and the steps are as follows:

[0029] S101, preparing a graphene array electrode on the first reflective layer of the multilayer medium;

[0030] S102, constructing a nanogap on the graphene array electrode so as to form a graphene source electrode and a graphene drain electrode at two ends of the multilayer dielectric first reflective layer, respectively.

[0031] Furthermore, step S200 includes a process of connecting the chiral bimolecular free radical molecule to the graphene source terminal electrode and the graphene drain terminal electrode via an amide bond, and the steps are as follows:

[0032] S201, dissolving a chiral diradical molecule compound in a mixed solvent of 1-ethyl-3-(3-dimethylaminopropyl)aminoimine and N,N-dimethylformamide to obtain a mixed solution;

[0033] S202, immersing the multilayer dielectric reflective layer obtained in step S102 in the mixed solution, reacting for 36 to 48 hours in an inert gas environment, so that the chiral biradical molecules are respectively connected to the graphene source electrode and the graphene drain electrode through amide bonds, taking out the multilayer dielectric reflective layer, washing and drying, and preparing the luminescent core unit on the multilayer dielectric first reflective layer.

[0034] Furthermore, in step S300, the transparent spacer layer and the second reflective layer are prepared as follows:

[0035] The electron beam evaporation coating method is used to evaporate SiO2 on the surface of the silicon substrate to form a transparent spacer layer, and the magnetron sputtering method is used to sputter Ag with a purity of not less than 99.9% on the surface of the transparent spacer layer;

[0036] Among them, the vapor deposition thickness of SiO2 is 60 to 80 nm, and the sputtering thickness of Ag is 30 to 40 nm.

[0037] The above one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects:

[0038] The present invention provides an optoelectronic device based on a single-molecule chiral biradical, comprising an optical microcavity and a luminescent core unit, wherein the optical microcavity comprises a multilayer dielectric first reflective layer, a transparent layer and a second reflective layer arranged in sequence longitudinally. This design enables the circularly polarized light generated by the luminescent core unit in the optical microcavity to be reflected multiple times and propagated effectively, thereby realizing the regulation and enhancement of the circularly polarized light emission, and effectively ensuring the stability of the optoelectronic device.

[0039] 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

[0040] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 It is a three-dimensional structural diagram of an optoelectronic device based on a single-molecule chiral diradical provided in Example 2 of the present invention.

[0042] Figure 2 4 is a graph showing the relationship between the wavelength and transmittance of the first reflective layer of the multilayer medium provided in Example 2 of the present invention.

[0043] Figure 3This is a current-bias characteristic curve of an optoelectronic device based on a single-molecule chiral diradical provided in Example 2 of the present invention.

[0044] Figure 4 This is a current-bias characteristic curve diagram of the optoelectronic device prepared according to the prior art provided in Example 2 of the present invention.

[0045] Figure 5 The present invention provides a single-molecule chiral biradical optoelectronic device in a square wave V d Normalized fluorescence intensity recorded at (0 / 10 V).

[0046] Figure 6 The optoelectronic device prepared by the prior art provided in Example 2 of the present invention is subjected to a square wave V d Normalized fluorescence intensity recorded at (0 / 10 V).

[0047] Reference numerals:

[0048] 100, optical microcavity; 110, multilayer dielectric first reflective layer; 111, graphene source electrode; 112, graphene drain electrode; 120, transparent spacer layer; 130, second reflective layer; 200, light-emitting core unit. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in 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.

[0050] In the following examples, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0051] Example 1 Preparation of compound HE-TEA.

[0052] The synthetic route of compound HE-TEA is as follows:

[0053]

[0054] Under nitrogen atmosphere, HCl (50 μl) was added dropwise to a dichloromethane (CH2Cl2) solution (10 ml) of HE-TAE-OH-Boc (20 mg, 0.012 mmol) to obtain a mixed system, which was stirred at room temperature and monitored by thin layer chromatography until the reaction was completed. Extraction was performed with dichloromethane and sodium bicarbonate solution, and the organic phases were combined, dried, concentrated, and recrystallized from petroleum ether to obtain HE-TAE-OH.

[0055] 1 H NMR (400 MHz, chloroform- d ) δ 8.43 (dd, J = 12.7, 2.1 Hz, 4H), 8.28 (d, J =2.1 Hz, 2H), 8.09~7.96 (m, 19H), 7.91~7.87 (m, 4H), 7.82 (d, J = 2.2 Hz, 1H),7.59 (dd, J = 7.1, 2.2 Hz, 2H), 7.40 (dd, J = 7.9, 1.9 Hz, 2H), 7.37~7.33 (m,4H), 7.24~7.18 (m, 4H), 5.55 (s, 2H), 4.05 (s, 3H), 2.77 (tt, J = 6.3, 5.4 Hz,4H), 2.65 (tt, J = 7.6, 1.1 Hz, 4H), 1.76 (ttd, J = 7.7, 5.3, 0.9 Hz, 4H), 1.59(d, J = 12.6 Hz, 4H), 1.36 (s, 27H).

[0056] 13 C NMR (100 MHz, chloroform- d ) δ131.77, 131.32, 131.08, 131.05, 131.94, 129.28, 129.22, 129.09, 129.01, 128.21,127.85, 127.66, 127.62, 127.40, 127.31, 126.93, 126.56, 126.34, 31.70, 34.95, 34.72, 34.01, 33.06, 31.51, 31.27.

[0057] Under nitrogen atmosphere, HE-TAE-OH (20 mg, 0.014 mmol) was dissolved in benzene solution (3 mL), and then SnCl2 (13 mg, 0.07 mmol) was added to obtain a mixture. The mixture was stirred at room temperature overnight and purified by flash column chromatography to obtain HE-TAE.

[0058] 1 H NMR (400 MHz, chloroform- d ) δ 8.45 (d, J = 2.2 Hz, 2H), 8.14 (d, J = 2.2 Hz, 2H), 8.08~8.06 (m, 2H), 8.05~7.94 (m, 18H), 7.93 (d, J = 2.2 Hz, 1H), 7.91~7.88 (m, 3H), 7.79 (s, 2H), 7.59 (dd, J = 7.1, 2.2 Hz, 2H), 7.38~7.33 (m, 4H), 7.32~7.26 (m, 2H), 7.24~7.18 (m, 4H), 4.05 (s, 3H), 2.77 (tt, J = 6.3, 5.4Hz, 4H), 2.65 (tt, J= 7.6, 1.1 Hz, 4H), 1.76 (ttd, J = 7.7, 5.3, 0.9 Hz, 4H),1.59 (d, J = 12.6 Hz, 4H), 1.36 (d, J = 4.8 Hz, 27H).

[0059] 13 C NMR (100 MHz, chloroform- d ) δ 131.77, 131.48, 131.08, 131.05, 130.94, 130.69, 130.46, 129.98, 129.56,129.28, 129.09, 129.01, 127.85, 127.31, 126.78, 126.56, 126.38, 31.70, 34.96, 34.79, 34.01, 33.06, 31.58, 31.27.

[0060] The synthetic route of the above HE-TAE-OH-Boc is as follows:

[0061]

[0062] Under nitrogen atmosphere, a tetrahydrofuran (THF) solution (3 mL) of HE-Boc (663 mg, 1.0 mmol) was slowly added dropwise to a tetrahydrofuran (THF) solution (10 mL) of magnesium (Mg) strips (60 mg, 2.5 mmol) and I2 (12 mg, 0.05 mmol), and the mixture was heated to 80 °C for 2 h. Then, a tetrahydrofuran solution of TAE (201 mg, 0.4 mmol) was added to the above mixed system. After overnight reaction, the reaction mixture was cooled to room temperature, and a saturated aqueous solution of ammonium chloride was added to quench the excess magnesium. Then, the mixture was extracted with dichloromethane and an aqueous solution of ammonium chloride, and the organic phases were combined, dried, and concentrated, and then purified by column chromatography to obtain HE-TAE-OH-Boc.

[0063] The structural formula of TEA is as follows:

[0064] .

[0065] 1 H NMR (400 MHz, chloroform- d ) δ 8.45 (d, J = 2.2 Hz, 2H), 8.42 (d, J = 2.1 Hz,2H), 8.28 (d, J = 2.1 Hz, 2H), 8.08~7.96 (m, 19H), 7.91~7.88 (m, 4H), 7.82(d, J = 2.2 Hz, 1H), 7.59 (dd, J = 7.1, 2.2 Hz, 2H), 7.40 (dd, J = 7.9, 1.9 Hz, 2H), 7.37~7.34 (m, 4H), 7.24~7.19 (m, 4H), 5.55 (s, 2H), 5.21 (t, J = 4.9 Hz,2H), 4.05 (s, 3H), 3.18 (td, J = 5.7, 4.8 Hz, 4H), 2.65 (ddt, J = 8.8, 8.0, 1.1Hz, 4H), 1.80 (tt, J = 7.9, 5.7 Hz, 4H), 1.41 (s, 18H), 1.36 (s, 27H).

[0066] 13 C NMR (100 MHz, chloroform- d ) δ 131.77, 131.32, 131.08, 131.05, 131.94, 129.28, 129.22, 129.09, 129.01,128.21, 127.85, 127.66, 127.62, 127.40, 127.31, 126.93, 126.56, 34.95, 34.72, 33.69, 31.51, 31.27, 29.66, 28.30.

[0067] The synthetic route of the above HE-Boc is as follows:

[0068]

[0069] Under nitrogen atmosphere, 11,14-dibromohexaspirene (484 mg, 1.0 mmol), trimethylsilyl acetylene (TMS) (49 mg, 0.5 mmol), Pd(PPh3)2Cl2 (35 mg, 0.05 mmol), CuI (9 mg, 0.04 mmol) in triethylamine solution (20 mL) was reacted at 90 °C for 12 h. After cooling, the reactants were poured into water and extracted three times with dichloromethane. The solid obtained after combining, drying and concentrating the organic phase was dissolved in ethanol, 20 mg K2CO3 was added, and the reaction was carried out at room temperature for 1 d. The excess ethanol was removed and extracted three times with dichloromethane. Then, the organic phases were combined, dried and concentrated, and purified by column chromatography to obtain HE-EL.

[0070] 1 H NMR (400 MHz, chloroform- d ) δ 8.37 (dd, J = 9.3, 2.1 Hz, 2H), 8.31 (d, J= 8.8Hz, 1H), 8.06~7.94 (m, 9H), 7.70 (dd, J = 8.3, 1.9 Hz, 1H), 7.62 (dd, J = 7.0,2.2 Hz, 1H), 3.24 (s, 1H).

[0071] 13 C NMR (100 MHz, chloroform- d ) δ 7, 126.74, 126.70, 126.38, 126.35, 121.41,121.20, 78.93, 78.30.

[0072] Under nitrogen atmosphere, HE-EL (430 mg, 1.0 mmol), 3-(4-bromophenyl)-tert-butylpropylcarbamate (313 mg, 1.0 mmol), Pd(PPh3)2Cl2 (35 mg, 0.05 mmol), CuI (9 mg, 0.04 mmol) in triethylamine solution (20 mL) was reacted at 90 °C for 12 h. After cooling, the reactant was poured into water and extracted three times with dichloromethane. The organic phases were then combined, dried, concentrated, and purified by column chromatography to obtain HE-Boc.

[0073] 1 H NMR (400 MHz, chloroform- d ) δ 8.45 (d, J = 2.2 Hz, 1H), 8.38 (d, J = 2.3 Hz,1H), 8.31 (dd, J = 8.4, 0.7 Hz, 1H), 8.05~7.96 (m, 8H), 7.89 (dd, J = 7.1, 0.8Hz, 1H), 7.70 (dd, J = 8.3, 1.9 Hz, 1H), 7.59 (dd, J= 7.1, 2.2 Hz, 1H), 7.38~7.33 (m, 2H), 7.24~7.18 (m, 2H), 5.21 (t, J = 4.9 Hz, 1H), 3.18 (td, J = 5.7,4.9 Hz, 2H), 2.66 (tt, J = 7.7, 1.0 Hz, 2H), 1.80 (tt, J = 7.9, 5.6 Hz, 2H), 1.41(s, 9H).

[0074] 13 C NMR (100 MHz, chloroform- d ) δ 128.56, 128.47, 128.31, 128.26, 128.17, 127.23, 127.20, 126.91,126.87, 126.74, 126.70, 126.38, 126.35, 120.89, 120.70, 120.20, 91.19, 88.36,79.54, 40.36, 33.68, 29.99, 28.31.

[0075] Example 2 Preparation of optoelectronic devices based on single-molecule chiral diradicals.

[0076] like Figure 1 As shown, an optoelectronic device based on a single-molecule chiral biradical comprises an optical microcavity 100 and a light-emitting core unit 200, wherein the light-emitting core unit 200 is disposed in the optical microcavity 100;

[0077] The optical microcavity 100 comprises a first reflective layer 110, a transparent spacer layer 120 and a second reflective layer 130 which are arranged in sequence in a longitudinal direction.

[0078] There is a gap between the multi-layer dielectric first reflective layer 110 and the transparent spacing layer 120, and the second reflective layer 130 is stacked on the transparent spacing layer 120;

[0079] The light-emitting core unit 200 is disposed between the multi-layer dielectric first reflective layer 110 and the transparent spacer layer 120 to realize electro-induced circularly polarized light emission;

[0080] It also includes a graphene source electrode 111 and a graphene drain electrode 112, wherein the graphene source electrode 111 and the graphene drain electrode 112 are respectively arranged at the left and right ends of the surface of the multilayer dielectric first reflective layer 110 close to the light-emitting core unit;

[0081] The luminescent core unit 200 is composed of a molecular heterostructure composed of a single molecule of chiral diradical molecules, and the structural formula of the chiral diradical molecules is as follows:

[0082] ;

[0083] The two NH2 ends of the chiral biradical molecule are respectively connected to the graphene source electrode 111 and the graphene drain electrode 112 through amide bonds.

[0084] A preparation process of an optoelectronic device based on a single-molecule chiral biradical is as follows:

[0085] 1. On SiO2, 70 nm SiO2 and 40 nm TiO2 were deposited in sequence using the atomic layer deposition (ALD) method for 5 times to form the first reflective layer of the multi-layer dielectric.

[0086] Based on the principle of Transfer Matrix Method (TMM), the propagation and interference effects of light in the multilayer structure composed of SiO2 and TiO2 were analyzed through simulation, and the transmittance at different wavelengths was calculated; the parameters considered included the wavelength range of light (200-1000 nm) and the wavelength interval of 1 nm; the refractive indexes of air, SiO2 and TiO2 were set to 1.0, 1.45 and 2.35 respectively, and it was assumed to be independent of wavelength; the thickness of SiO2 layer and TiO2 layer were 70 nm and 40 nm respectively, and the number of periods was 5. The total transfer matrix of the first reflective layer of the multilayer medium was calculated by the transfer matrix method, and the reflectivity, transmittance and absorptivity were obtained.

[0087] The relationship between the wavelength (200-1000 nm) of the first reflection layer of the multilayer medium and the transmittance is plotted using MATLAB software, as shown in Figure 2 As shown, the results show that the transmission characteristics of light at different wavelengths show the interference effect of transmittance changing with wavelength. The peaks and valleys reflect the influence of the first reflection layer of the multi-layer medium on light propagation, which provides a theoretical basis for the design of optoelectronic devices.

[0088] 2. Using chemical vapor deposition, grow a single layer of graphene on copper foil, spin-coat the single layer of graphene with polymethyl methacrylate (PMMA), and use a reactive plasma etcher to etch it to obtain a PMMA-graphene-copper foil structure; cut the PMMA-graphene-copper foil structure and place it in a FeCl3 solution for oxidation, and soak it in a hydrochloric acid solution, an alkaline solution, and pure water to obtain a PMMA-graphene structure; transfer the PMMA-graphene structure to the first reflective layer of the multilayer medium, and naturally air dry and remove the glue to obtain a graphene film. Among them, there are two methods for removing the glue: (1) heating the substrate after graphene transfer with an acetone solution at 120°C for 8 minutes to remove the glue; (2) placing it in a heating furnace at 400-500°C for 1-2 minutes to remove the glue; this embodiment uses the method in (1) above to remove the glue.

[0089] Photoresist was spin-coated on the graphene film, and strips were formed by UV etching. The film was then placed in a reactive ion etcher for etching. After the photoresist was spin-coated, electrodes were formed by UV etching, and 10 nm platinum and 90 nm silver electrodes were evaporated by a thermal resistance evaporation coating machine to obtain graphene array electrodes. The conductivity of the obtained graphene array electrodes was tested at a voltage of 50 mV, and graphene array electrodes with a conductivity of 10 μA were selected for subsequent processes.

[0090] 3. Use an electron beam exposure machine to etch and develop the selected graphene array electrodes to obtain graphene array electrodes with dotted lines between electrode pairs. The dotted lines etched by the electron beam exposure machine are 150 nm long and 5 nm wide, located between each pair of silver electrodes. The developer used for development is methyl isobutyl ketone diluted with isopropyl alcohol, the volume ratio of methyl isobutyl ketone to isopropyl alcohol is 1:3, and the fixing solution is isopropyl alcohol; the graphene point electrodes with dotted lines are etched with oxygen plasma, and the graphene point electrodes are repeatedly tested for continuity by the source meter and the probe station to obtain graphene nano-gap point electrodes. The source meter input voltage is 50 mV. When the test shows that the current between every ten pairs of electrodes is on the order of several μA, it can be considered that a graphene nano-gap point electrode pair that can continue to be used has been obtained.

[0091] The nanogap edge of the graphene nanogap point electrode is functionalized with carboxyl groups during the preparation process, and then a chiral diradical molecule with an amino terminal is introduced. Through an amide condensation reaction, the chiral diradical molecule is covalently linked to the carboxyl groups at both ends of the graphene electrode to form an amide bond, and finally a stable graphene-molecule-graphene single molecule heterojunction is formed in the gap of the graphene point electrode. The formation of the amide bond needs to be carried out under anhydrous and oxygen-free conditions, and a carbodiimide derivative, 1-(3-dimethylaminopropyl)-3-2-ethylcarbodiimide hydrochloride, needs to be added as an activator. Its main functions include: 1. Activating the carboxyl group, making it easier for the carboxyl group to undergo condensation reaction with the amino group; 2. Dehydration promotes the efficient formation of amide bonds to ensure the smooth progress of the reaction.

[0092] The preparation process of the molecular heterojunction is as follows: a graphene nanogap point electrode is placed in a three-necked flask, a chiral diradical compound (1 mg) and 1-(3-dimethylaminopropyl)-3-2-ethylcarbodiimide hydrochloride (1.5 mg) are added to the three-necked flask in an inert argon atmosphere, and then N,N-dimethylformamide (10 ml) is slowly injected into the three-necked flask, stirred evenly, and reacted for 48 hours to connect the chiral diradical molecule to the graphene point electrode through an amide bond to obtain a graphene-molecule-graphene single molecule heterojunction, that is, a graphene point electrode-molecule heterojunction array, and the surface is rinsed with acetone and ultrapure water and blown dry to obtain a multilayer dielectric first reflective layer containing a luminescent core unit.

[0093] Fourth, 70 nm SiO2 was deposited on the surface of the silicon (Si) substrate by electron beam evaporation to obtain a SiO2 transparent spacer layer, and 35 nm Ag with a purity of 99.9% was sputtered on the surface of the SiO2 transparent spacer layer by magnetron sputtering to obtain a second reflective layer. The second reflective layer and the transparent spacer layer on the silicon substrate were gently peeled off using a PMMA film, and then the surface of the PMMA film was bonded to a PDMS stamp to achieve an effective transfer of the second reflective layer and the transparent spacer layer structure.

[0094] 5. In a glove box environment, use an optical microscope to align the second reflective layer and the transparent spacer layer with the light-emitting core unit, place the multi-medium first reflective layer on a heating platform, and perform dry annealing at 120°C for 2.5 hours to obtain an optoelectronic device based on single-molecule chiral diradicals.

[0095] 6. Determination of current-bias characteristic curve.

[0096] The optoelectronic device based on the single-molecule chiral biradical provided in this embodiment was tested using an Agilent 4155C semiconductor tester and an ST-500-probe station. The test results are as follows: Figure 3As shown; the optoelectronic device prepared according to the technical solution provided by the public patent (CN116744755A), the test results Figure 4 shown.

[0097] 7. Detection of electro-induced circularly polarized luminescence.

[0098] Electrical device: Phase-locked amplifier, providing 0~10 V working power supply.

[0099] Optical device: NI-FN single-photon detection microscope, single-photon detector, gated counter, optical fiber, monochromator.

[0100] Detection optical path: The optical signal enters the NI-FN single-photon detection microscope vertically. After the microscope adjusts the optical parameters such as the polarization state of the light, the outgoing optical signal is transmitted to the single-photon counter through the optical fiber, and the data is accurately collected through the gated counter to achieve efficient capture and statistics of single-photon data.

[0101] The optoelectronic device based on single-molecule chiral biradicals provided by the present invention is placed on a photoelectric detection platform, and an electrical probe is connected to a graphene source electrode and a graphene drain electrode to form an electrical circuit of graphene source electrode-probe-locked amplifier-probe-single-molecule heterojunction-graphene drain electrode.

[0102] When the phase-locked amplifier provides a 10 V operating voltage, the optical signal vertically enters the NI-FN single-photon detection microscope and passes through the built-in quarter-wave plate and polarizer of the microscope. Using the super-resolution microscopy technology of single-molecule electrochemiluminescence, the position of the single molecule is determined and the optical signal is observed through the single-photon detector; the outgoing optical signal is transmitted to the CNT-91 single-photon counter through the optical fiber, and the data is accurately collected through the gated counter.

[0103] The polarizer is driven to rotate by a motor, and the light signal collected by the charge coupled device camera (CCD) shows extinction, which verifies that it is electro-induced circularly polarized luminescence. The optoelectronic device based on the single-molecule chiral biradical provided in this embodiment and the optoelectronic device prepared according to the technical solution provided by the patent disclosure (CN116744755A) are respectively tested for electro-induced circularly polarized luminescence under a periodic square wave signal. The data collection results of the CNT-91 single photon counter are compared, and the effective enhancement of the circularly polarized light signal by the optical microcavity is successfully verified. The results are as follows: Figure 5 and Figure 6 shown.

[0104] 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. An optoelectronic device based on a single-molecule chiral biradical, characterized in that: It comprises an optical microcavity and a light-emitting core unit, wherein the light-emitting core unit is arranged in the optical microcavity; Wherein, the optical microcavity comprises a first reflective layer, a transparent spacer layer and a second reflective layer of a multilayer medium arranged in sequence longitudinally; There is a gap between the multi-layer dielectric first reflective layer and the transparent spacing layer, and the second reflective layer is stacked on the transparent spacing layer; The light-emitting core unit is disposed between the multi-layer dielectric first reflective layer and the transparent spacer layer, and is used to realize electro-induced circularly polarized light emission; The optoelectronic device based on the single-molecule chiral biradical further comprises a graphene source electrode and a graphene drain electrode, wherein the graphene source electrode and the graphene drain electrode are respectively arranged at the left and right ends of the surface of the first reflective layer of the multilayer medium close to the light-emitting core unit; The luminescent core unit is composed of a molecular heterostructure composed of a single molecule of chiral diradical molecules, and the structural formula of the chiral diradical molecules is as follows: ； The two NH2 ends of the chiral biradical molecule are respectively connected to the graphene source electrode and the graphene drain electrode through amide bonds.

2. The optoelectronic device based on single-molecule chiral biradicals according to claim 1, characterized in that: The composition of the multi-layer dielectric first reflective layer is selected from SiO2 and TiO2, and the multi-layer dielectric first reflective layer is formed by alternately depositing and stacking SiO2 and TiO2.

3. The optoelectronic device based on single-molecule chiral biradicals according to claim 2, characterized in that: The stacking cycle of the deposition stack is 3 to 5 times, the thickness of the SiO2 deposition is 60 to 80 nm, and the thickness of the TiO2 deposition is 30 to 50 nm.

4. The optoelectronic device based on single-molecule chiral biradicals according to claim 1, characterized in that: The transparent spacer layer is composed of components selected from SiO2.

5. The optoelectronic device based on single-molecule chiral biradicals according to claim 1, characterized in that: The second reflective layer has a component selected from Ag.

6. A method for preparing an optoelectronic device, characterized in that: The method for preparing an optoelectronic device based on a single-molecule chiral biradical as claimed in any one of claims 1 to 5 comprises the following steps: S100, preparing a first reflective layer of a multilayer dielectric by using an atomic layer deposition method; S200, preparing a light-emitting core unit on the first reflective layer of the multi-layer medium; S300, preparing a transparent spacer layer, and preparing a second reflective layer on the transparent spacer layer; S400, connecting the transparent spacer layer and the light-emitting core unit to form an optoelectronic device based on single-molecule chiral biradicals.

7. The method for preparing an optoelectronic device according to claim 6, characterized in that: Step S100 also includes a process of preparing a graphene source terminal electrode and a graphene drain terminal electrode on the multilayer dielectric first reflective layer, and the steps are as follows: S101, preparing a graphene array electrode on the first reflective layer of the multilayer medium; S102, constructing a nanogap on the graphene array electrode so as to form a graphene source electrode and a graphene drain electrode at two ends of the multilayer dielectric first reflective layer, respectively.

8. The method for preparing an optoelectronic device according to claim 6, characterized in that: Step S200 includes a process of connecting the chiral bimolecular free radical molecule to the graphene source terminal electrode and the graphene drain terminal electrode via an amide bond, and the steps are as follows: S201, dissolving a chiral diradical molecule compound in a mixed solvent of 1-ethyl-3-(3-dimethylaminopropyl)aminoimine and N,N-dimethylformamide to obtain a mixed solution; S202, immersing the multilayer dielectric reflective layer obtained in step S102 in the mixed solution, reacting for 36 to 48 hours in an inert gas environment, so that the chiral biradical molecules are respectively connected to the graphene source electrode and the graphene drain electrode through amide bonds, taking out the multilayer dielectric reflective layer, washing and drying, and preparing the luminescent core unit on the multilayer dielectric first reflective layer.

9. The method for preparing an optoelectronic device according to claim 6, characterized in that: In step S300, the transparent spacer layer and the second reflective layer are prepared as follows: The electron beam evaporation coating method is used to evaporate SiO2 on the surface of the silicon substrate to form a transparent spacer layer, and the magnetron sputtering method is used to sputter Ag with a purity of not less than 99.9% on the surface of the transparent spacer layer; Among them, the vapor deposition thickness of SiO2 is 60 to 80 nm, and the sputtering thickness of Ag is 30 to 40 nm.

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