Optoelectronic device based on the luminescence of a single lanthanide-doped nanoparticle and preparation method thereof

Abstract

The present invention relates to the technical field of optoelectronic devices, and provides an optoelectronic device based on the luminescence of a single lanthanide-doped nanoparticle and a preparation method thereof. Based on graphene dot electrodes, a molecular heterojunction is introduced, and the molecular heterojunction includes a single lanthanide element-doped nanoparticle. The structure of the single lanthanide element-doped nanoparticle is a sandwich core-shell structure, where the sandwich core is a gold nanosheet; the shell is a matrix doped with a lanthanide element. The gold nanosheet encapsulated inside the single lanthanide element-doped nanoparticle has surface plasmon resonance effect and high conductivity, which not only plays a better conductive role, but also can enhance the luminescence effect by using the plasmon resonance effect.

Description

Technical Field

[0001] The present invention relates to an optoelectronic device based on the luminescence of a single lanthanide-doped nanoparticle and a preparation method thereof, belonging to the technical field of optoelectronic devices. Background Art

[0002] With the continuous progress of nanotechnology, electrochemiluminescence devices have gradually become an important research direction in the field of optoelectronic devices due to their unique optoelectronic properties. In particular, lanthanide-doped nanoparticles not only exhibit long photoluminescence lifetimes and narrow emission bandwidths but also possess excellent chemical stability due to the encapsulation of the nanoparticles, making them an ideal choice for electrochemiluminescence materials. The core mechanism of upconversion luminescence in lanthanide-doped nanoparticles lies in the use of two different lanthanide ions with matching energy levels as sensitizers and activators, respectively, and achieving upconversion luminescence through efficient energy transfer between them. However, existing luminescent particles are mostly arranged in a stacked state, with relatively close distances between the luminescent particles and mutual influence between the particles, resulting in poor electrical conductivity of the particles, which can cause problems such as poor power supply stability and low luminescence efficiency.

[0003] CN116744755B discloses an optoelectronic device based on a single perovskite quantum dot and a preparation method thereof. However, for an optoelectronic device based on a single perovskite quantum dot, the luminescent point is single, and the luminescence efficiency still needs to be improved.

[0004] In view of the deficiencies of existing electrochemiluminescence devices in terms of electrochemiluminescence efficiency and stability, which to a certain extent limit their wide application. To solve this problem, it is urgent to provide a new solution for realizing high-performance electrochemiluminescence devices through innovative material design and process optimization. Summary of the Invention

[0005] Aiming at the above deficiencies of the existing technology, the purpose of the present invention is to provide an optoelectronic device based on the luminescence of a single lanthanide-doped nanoparticle and a preparation method thereof.

[0006] According to an embodiment of the present invention, the first solution is provided as follows:

[0007] A preparation method of an optoelectronic device based on the luminescence of a single lanthanide-doped nanoparticle, comprising the following steps:

[0008] S1. Prepare a graphene dot electrode on a transparent insulating layer on a substrate layer;

[0009] S2. Introduce a molecular heterojunction into the graphene dot electrode to form a graphene dot electrode - molecular heterojunction array;

[0010] The molecular heterojunction is composed of a bridging molecule and a single lanthanide-doped nanoparticle. Through an amide condensation reaction, the bridging molecule is connected to the graphene dot electrode, and then an esterification reaction occurs between the single-terminal mercapto group and the carboxyl group on the surface of the single lanthanide-doped nanoparticle, connecting the bridging molecule to the single lanthanide-doped nanoparticle;

[0011] The structure of the single lanthanide-doped nanoparticle is a sandwich core-shell structure, where the sandwich core is a gold nanosheet and the shell is a matrix doped with lanthanide elements; matrix;

[0012] S3. Cover a protective layer on the upper surface of the graphene dot electrode-molecular heterojunction array to obtain an optoelectronic device based on the electroluminescence upconversion of a single lanthanide-doped nanoparticle.

[0013] Further, in step S2, the preparation of the single lanthanide-doped nanoparticle includes the following steps:

[0014] S221. React a gold nanovesicle, a yttrium source solution containing a doped lanthanide element, a fluorine source, and a sodium source through a hydrothermal reaction in a nitrogen environment to prepare a precursor containing a gold nanovesicle;

[0015] S222. Calcinate the precursor in a nitrogen environment to obtain @a gold nanosheet intermediate, where the gold nanosheet is formed by the transformation of the gold nanovesicle during calcination, and its shape is a flat sheet, and R1 and R2 are lanthanide elements.

[0016] Further, S223. Perform surface treatment on the @gold nanosheet intermediate obtained in step S222 to remove @the amorphous layer on the surface of the gold nanosheet intermediate and introduce carboxyl groups;

[0017] The steps of removing the amorphous layer and introducing carboxyl groups are to react the @gold nanosheet intermediate with an alkaline solution and then wash it with deionized water and ethanol multiple times until the solution is neutral;

[0018] After that, react it with a citric acid solution and then wash it with deionized water until the solution is neutral, and perform centrifugal separation to obtain a single lanthanide-doped nanoparticle: @gold nanosheet.

[0019] Further, in step S1, a plasma nanorod array grid layer is introduced between the substrate layer and the transparent insulating layer;

[0020] S101. Spin-coat a photoresist on the surface of the substrate layer and perform ultraviolet lithography to obtain a square nanorod array, and then obtain a plasma nanorod array grid layer through thermal resistance evaporation coating;

[0021] S102. Deposit SiO on the plasma nanoarray gate layer 2 to obtain a transparent insulating layer.

[0022] Furthermore, in step S2, a plasma nanoantenna is introduced onto the graphene dot electrode;

[0023] S211. Spin-coat polymethyl methacrylate on the surface of the graphene dot electrode, and perform etching above the graphene dot electrode to obtain a graphene dot electrode device with collinear gold nanorods on the surface;

[0024] S212. Sputter-coat the graphene dot electrode device with a gold target to obtain a plasma nanoantenna.

[0025] Furthermore, in step S2, the molecular heterojunction is introduced through the following steps:

[0026] S201. Place the graphene dot electrode, bridging molecule, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide in anhydrous pyridine under a nitrogen atmosphere, and react for 24 h to 48 h under light-shielded conditions to obtain a bridging molecule device;

[0027] S202. Place the bridging molecule device, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and a single lanthanide-doped nanoparticle in anhydrous pyridine under a nitrogen atmosphere, and react for 24 h to 48 h under light-shielded conditions to connect the single lanthanide-doped nanoparticle to the bridging molecule device through a thioester bond to obtain a graphene dot electrode-molecular heterojunction array.

[0028] According to the embodiments of the present invention, using the method for preparing an optoelectronic device based on the luminescence of a single lanthanide-doped nanoparticle in the first scheme provided by the present invention, the second scheme is as follows:

[0029] An optoelectronic device based on the luminescence of a single lanthanide-doped nanoparticle, comprising a substrate layer, a transparent insulating layer, and an array layer composed of a graphene dot electrode and a molecular heterojunction arranged in sequence from bottom to top;

[0030] Both ends of the molecular heterojunction are respectively connected to the graphene dot electrode through amide bonds to form a graphene dot electrode-molecular heterojunction array;

[0031] The molecular heterojunction is composed of a bridging molecule and a single lanthanide-doped nanoparticle, and the structural formula of the single lanthanide-doped nanoparticle is @ gold nanosheet;

[0032] The single lanthanide-doped nanoparticle has a sandwich core-shell structure, the sandwich core is a gold nanosheet, and the shell is a lanthanide-doped Matrix; the gold nanosheet is in the shape of a flat sheet;

[0033] Among them, gold nanosheets are encapsulated in co-doped In the sphere, R1 is any one of ytterbium (Yb), neodymium (Nd) or cerium (Ce), and R2 is any one of erbium (Er), thulium (Tm) or europium (Eu).

[0034] Furthermore, a pair of plasma nanoantennas are arranged on the graphene point electrode, and the plasma nanoantennas are arranged in the high line direction of the upper surface of the graphene point electrode. The graphene point electrode includes a graphene source terminal electrode and a graphene drain terminal electrode.

[0035] A pair of plasma nanoantennas are respectively arranged on the graphene source electrode and the graphene drain electrode;

[0036] The plasma nanoantenna is a pair of colinear metal films, and the material is gold.

[0037] Furthermore, a plasma nano-array gate layer is provided between the substrate layer and the transparent insulating layer, wherein the plasma nano-array gate layer comprises a square nano-column array, and the square nano-column array is in a strip shape and covers the substrate layer;

[0038] The material of the square nanocolumn array of the plasma nanoarray gate layer is selected from any one of gold and silver, and the thickness of the plasma nanoarray gate layer is 20-60nm;

[0039] SiO deposited on the plasma nanoarray gate layer 2 The thickness of the transparent insulating layer is 30-50nm.

[0040] Furthermore, the graphene point electrode is arranged on the upper surface of the transparent insulating layer;

[0041] Metal electrodes are also arranged at both ends of the graphene point electrode, and the metal electrodes are a pair, which are arranged at the outer ends of the graphene source electrode and the graphene drain electrode respectively;

[0042] The electrode material of the metal electrode is selected from any one of Cu, Cr and Au, and the thickness thereof is 30-100 nm.

[0043] Compared with the prior art, the technical solution provided by this application has beneficial effects.

[0044] 1. Connect a single lanthanide-doped nanoparticle between graphene point electrodes, inject electrons through the metal electrode, induce the rare earth ion electrons in the single nanoparticle as a sensitizer to transition to an excited state high energy level, and transfer them to the rare earth ion as an activator through multiple non-radiative transitions, so that it transitions to a higher excited state energy level and finally releases high-energy photons, achieving efficient energy transfer.

[0045] 2. Through the gold nanorod plasma antenna above the graphene nanodot electrode and the silver plasmonic nanorod array grid layer below, the optoelectronic device couples the excellent upconversion luminescence ability of single lanthanide-doped nanoparticles with the surface plasmon resonance effect, improving the luminescence intensity of the optoelectronic device at the single-molecule level.

[0046] 3. The lanthanide-doped nanoparticles prepared by this application have good optical stability in electrochemiluminescence and can still maintain stable luminescence performance under long-term illumination, which is beneficial to improving the stability and service life of optoelectronic devices.

[0047] 4. The gold nanosheets encapsulated inside the single lanthanide-doped nanoparticles have surface plasmon resonance effect and high conductivity, which not only play a better role in conduction, but also can enhance the luminescence effect by using the plasmon resonance effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0049] Among them:

[0050] Figure 1 is a schematic three-dimensional structure diagram of an optoelectronic device based on the luminescence of single lanthanide-doped nanoparticles in an embodiment;

[0051] Figure 2 is an I-V curve diagram of an optoelectronic device based on the luminescence of single lanthanide-doped nanoparticles in an embodiment;

[0052] Figure 3 is an energy level diagram of the upconversion luminescence process of an optoelectronic device based on the luminescence of single lanthanide-doped nanoparticles in an embodiment;

[0053] Figure 4 is an upconversion luminescence lifetime diagram of an optoelectronic device based on the luminescence of single lanthanide-doped nanoparticles in an embodiment;

[0054] Figure 5 is a preparation process diagram of an optoelectronic device based on single lanthanide-doped nanoparticles in an embodiment;

[0055] Figure 6 is a doped lanthanide element identification diagram of an optoelectronic device based on single lanthanide-doped nanoparticles in an embodiment.

[0056] Reference numerals:

[0057] 1. Substrate layer; 2. Plasmonic nanorod array gate layer; 3. Transparent insulating layer; 4. Graphene dot electrode; 5. Plasmonic nanoantenna; 6. Metal electrode; 7. Molecular heterojunction; 8. Protective layer. Specific embodiments

[0058] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this application.

[0059] Regarding the deficiencies still existing in the electroluminescence efficiency and stability of the existing electroluminescent upconversion devices, by redesigning the structure of the nanoparticles, optimizing the ratio of the internal sensitizer to the activator, and reasonably designing the electric field distribution, the power supply stability is improved and the overall luminescence effect is enhanced, providing a new way for the development of new high-performance optoelectronic devices.

[0060] In the following embodiments, the experimental methods used are all conventional methods unless otherwise specified, and the materials, reagents, etc. used can be obtained from commercial sources unless otherwise specified.

[0061] The Schlenk technique is an experimental technique for providing an inert environment and vacuum conditions. All chemical reactions in this application are carried out using the standard Schlenk technique in a dry solvent and an inert gas atmosphere.

[0062] Example 1 Preparation of single lanthanide-doped nanoparticles.

[0063] The preparation route of single lanthanide-doped nanoparticles is as follows:

[0064] Add a silver nitrate (AgNO 3 , 0.002 mmol, 0.1 mM) solution and sodium citrate (0.2 mM, 0.004 mmol) successively into a dry two-necked flask equipped with a stir bar, and let it stand at room temperature to form silver colloid. Then add sodium borohydride (NaBH 4 , 0.5 mL, 100 mM) as a reducing agent, and stir rapidly to form uniform silver nanoparticles. Then add an ammonium hydroxide solution (0.5 mL, 100 mM) to adjust the particle size, and obtain uniformly sized silver seeds by centrifugation. Subsequently, heat the above reaction system to 65 °C, and then slowly dropwise add chloroauric acid (HAuCl 4, 10 mM, 0.01 mmol) solution. After the reaction, pure gold nanovesicles were obtained by centrifugation and washing with deionized water. The size of the gold nanovesicles was 15 - 30 nm.

[0065] The structure of the gold nanovesicles is as Figure 5 shown.

[0066] The gold nanovesicles (10 mM, 0.01 mmol) were mixed with a diluted nitrate solution ( , 0.2 mmol, , 0.08 mmol, , 0.02 mmol) in a dry two-necked flask. Ammonium fluoride ( , 1.6 mmol) and sodium chloride (NaCl, 0.4 mmol) were added successively as the sources of fluorine and sodium. Subsequently, EDTA (0.1 mmol) was added as a complexing agent to increase the stability of the solution. Through hydrothermal reaction, in an environment filled with nitrogen, the reaction was carried out at 180 °C for 12 hours to promote the complete reaction and generate the Na(Yb / Er) x Y y F z precursor, and the size of the precursor was 25 - 40 nm.

[0067] The Na(Yb / Er) x Y y F z precursor has a structure as Figure 5 shown.

[0068] The above precursor was heated to 850 °C at a heating rate of 1 °C / min and calcined at high temperature for 4 hours. During the calcination process, the gold nanovesicles would transform into flat gold nanosheets, and at the same time, a matrix doped with Yb / Er matrix, @gold nanosheet intermediate with a size of 15 - 35 nm was formed.

[0069] The @gold nanosheet intermediate has a structure as Figure 5 shown.

[0070] The @gold nanosheet intermediate was dispersed in a sodium hydroxide (NaOH, 1.5 M) solution with a volume ratio of 1:10 and stirred at room temperature or 60 °C for 10 hours to remove the possible amorphous layer on the particle surface. Finally, the particles were washed with deionized water and ethanol multiple times until the solution was neutral to ensure that there was no residual alkaline solution on the particles.

[0071] Further, 30 mL of 2 mM citric acid solution was added and stirred at room temperature for 12 hours. After the reaction was completed, the particles were recovered by centrifugation (10000 rpm, 10 min) and washed 3 times with deionized water to finally obtain single lanthanide-doped nanoparticles: @ gold nanosheets, with Y:Yb:Er at 10:8:1.

[0072] The structure of the @ gold nanosheets is as Figure 5 shown.

[0073] The particle surface has carboxyl groups (–COOH), and the purpose of introducing carboxyl groups is to form thioester bonds with the sulfhydryl groups of the bridging molecules in the subsequent steps.

[0074] Except for the ratio changing due to the amount of doped elements, the synthesis processes and conditions of other verification ratio schemes are the same as those in Example 1. The gold nanovesicles are all (10 mM, 0.01 mmol), and the chemical agents used are all prepared by weighing a certain amount of chemical substances and then preparing a solution with a fixed volume. The amounts of specific reactants for other ratios are as follows.

[0075] Ratio 2:

[0076] The number of moles is: =0.204 mmol, =0.075 mmol, =0.021 mmol, =1.7 mmol, [NaCl]=0.4 mmol, [EDTA]=0.15 mmol;

[0077] The solvent configuration concentration: =20.4 mM, =7.5 mM, =2.1 mM, =170 mM, [NaCl]=40 mM, [EDTA]=15 mM.

[0078] The product @ gold nanosheets. Y:Yb:Er is 68:25:7.

[0079] Ratio 3:

[0080] The number of moles is: =0.234 mmol, =0.06 mmol, =0.006 mmol, =1.8 mmol, [NaCl]=0.4 mmol, [EDTA]=0.15 mmol;

[0081] Concentration: =23.4 mM, =6 mM, =0.6 mM, =180 mM, [NaCl]=40 mM, [EDTA]=15 mM.

[0082] Product @ Gold nanosheets. Y:Yb:Er is 78:20:2.

[0083] Meanwhile, in order to compare the experimental effects, single nanoparticles doped with lanthanide elements without gold nanosheets were also prepared. The process conditions used were the same as those in Example 1, except that gold nanovesicles were not added, and the chemical formulation ratio used was the same as that in Formulation 3.

[0084] The nitrates of Yb and Er used in the preparation can be replaced with the nitrates of Nd and Tm or Ce and Eu. By using the same process and process parameters, @ Gold nanosheets or @ Gold nanosheets.

[0085] The dosage of gold nanovesicles and the molar ratio of the transition metal elements doped in the matrix are 1 - 3:60, and the ratio used in Example 1 is 2:60;

[0086] The transition metal elements are any one or more of yttrium (Y), ytterbium (Yb), erbium (Er), neodymium (Nd), thulium (Tm), cerium (Ce), and europium (Eu).

[0087] The structural formula of the single nanoparticles doped with lanthanide elements @ Gold nanosheets, such as Figure 6 shown.

[0088] The structure of the single nanoparticles doped with lanthanide elements is a sandwich core - shell structure. The sandwich core is a gold nanosheet; the shell is a matrix doped with lanthanide elements.

[0089] The gold nanosheets are encapsulated in the co - doped sphere. R1 is any one of ytterbium (Yb), neodymium (Nd), or cerium (Ce), and R2 is any one of erbium (Er), thulium (Tm), or europium (Eu).

[0090] When selecting elements, the optimal matching pairs are those with higher luminescence efficiency.

[0091] Group 1: R1 is ytterbium (Yb), R2 is erbium (Er);

[0092] In Group Two, R1 is neodymium (Nd) and R2 is thulium (Tm);

[0093] In Group Three, R1 is cerium (Ce) and R2 is europium (Eu).

[0094] The surface plasmon resonance phenomenon of nanomaterials stems from the coupled oscillation of their free electrons and incident light, and has significant optical property differences and application potential. In this application, the gold nanosheets encapsulated inside a single nanoparticle not only play a better conductive role in electrochemiluminescence upconversion but also can enhance the luminescence effect by utilizing the plasmon resonance effect.

[0095] The gold nanosheets are co-doped inside the sphere, with a unique two-dimensional structure and a strong local surface plasmon resonance effect, which can significantly enhance the light field intensity, improve the energy transfer efficiency and the upconversion luminescence performance. At the same time, its excellent conductivity, thermal stability and large surface area endow it with higher functionalization potential and optical signal enhancement ability. Lanthanide ions with energy absorption and transfer capabilities, including ytterbium (Yb), neodymium (Nd) or cerium (Ce), are selected as sensitizers, and erbium (Er), thulium (Tm) or europium (Eu) with matching energy levels and long fluorescence lifetimes are selected as activators. A core-shell structure is designed to optimize the spatial distribution of the sensitizer and the activator, improve the energy transfer efficiency, reduce non-radiative losses, and enhance the electron-photon conversion efficiency, thereby achieving efficient and stable electrochemiluminescence upconversion.

[0096] Example 2: Structure of an optoelectronic device for electrochemiluminescence upconversion based on a single nanoparticle doped with lanthanide elements.

[0097] As Figure 1 shown, an optoelectronic device for electrochemiluminescence upconversion based on a single nanoparticle doped with lanthanide elements includes a substrate layer 1, a plasmonic nanoarray grid layer 2, and a transparent insulating layer 3 arranged in sequence from bottom to top;

[0098] Among them, the plasmonic nanoarray grid layer 2 includes a square nanopillar array, the square nanopillar array is strip-shaped, covers the substrate layer 1, and the transparent insulating layer 3 is arranged on the upper surface of the plasmonic nanoarray grid layer 2;

[0099] An array layer composed of graphene dot electrodes 4 and molecular heterojunctions 7 is also arranged on the transparent insulating layer 3;

[0100] The graphene dot electrodes 4 are arranged on the side edges in the width direction of the upper surface of the transparent insulating layer 3, and both ends of the molecular heterojunction 7 are connected to the graphene dot electrodes 4 through amide bonds to form a graphene dot electrode-molecular heterojunction array.

[0101] Metal electrodes 6 are arranged on the outer side edges in the width direction of the upper surface of the graphene dot electrodes 4.

[0102] On the upper surface of the graphene dot electrode 4 in the high-line direction, a plasmonic nanoantenna 5 is provided.

[0103] Among them, the molecular heterojunction 7 is composed of a bridging molecule and a single nanoparticle doped with a lanthanide element. Both ends of the bridging molecule are an amino group and a mercapto group, and the carbon chain length n is 3, 4 or 5; the amino group of the bridging molecule is covalently connected to the graphene electrode by amide, and then an esterification reaction occurs between the single-terminal mercapto group and the carboxyl group on the surface of the single nanoparticle doped with a lanthanide element to form a thioester bond.

[0104] The substrate layer 1 is a substrate of a P-type doped silicon substrate (P-type Si) with a 300 nm SiO 2 oxide layer;

[0105] The material of the plasmonic nanoarray gate layer 2 is selected from Ag, and its thickness is 40 nm;

[0106] The transparent insulating layer 3 is deposited by silicon dioxide, and its thickness is 30 nm;

[0107] The plasmonic nanoantenna 5 is a Au thin film, with an end width of 13 nm, a length of 76 nm, and a thickness of 26 nm;

[0108] The material of the metal electrode 6 is selected from Au, and its thickness is 70 nm;

[0109] The protective layer 8 is an h-BN protective layer with a thickness of 100 nm.

[0110] Example 3 Preparation of an optoelectronic device based on the electrochemiluminescence of a single nanoparticle doped with a lanthanide element

[0111] The specific process is as follows:

[0112] There is no particular limitation on the type of the substrate, as long as the purpose of the present application can be achieved. For example, the substrate can be an atomically flat silicon wafer, mica or sapphire.

[0113] S1, in this example, a substrate of a P-type doped silicon substrate (P-type Si) with a 300 nm SiO 2 oxide layer is selected, placed in a piranha solution at 110 °C and heated for 4 h, then taken out, ultrasonically cleaned with ultrapure water, and then dried with nitrogen for standby. The piranha solution is a mixed solution prepared by mixing 35% H 2 O 2 and concentrated H 2 SO 4 in a volume ratio of 3:7;

[0114] Using ultraviolet lithography, a square nanocolumn array is etched on the surface of the substrate. The square nanocolumn array is strip-shaped. Subsequently, Ag with a thickness of 40 nm is deposited by thermal resistance evaporation coating to obtain a plasma nanoarray grid layer;

[0115] The upper surface of the plasma nanoarray grid layer is coated by electron beam evaporation coating to prepare a transparent insulating layer with a thickness of 30 nm; the thickness of the transparent insulating layer is 30 nm to 50 nm.

[0116] The material of the transparent insulating layer is selected from any one of alumina material and silica material. In this embodiment, silica is used.

[0117] Ag is used as the material of the plasma nanoarray grid layer, and the thickness of the plasma nanoarray grid layer is 20 nm to 60 nm. Ag has lower plasma loss and higher quality factor, which can effectively reduce the absorption and scattering loss of photon energy during propagation, and can form an extremely narrow plasma resonance mode in the visible to near-infrared band. Through this plasma resonance effect, the Ag nanoarray can selectively enhance the optical mode matching the target transition wavelength, making the optical signal corresponding to this wavelength significantly enhanced during emission. At the same time, the excellent thermal conductivity of Ag enables it to efficiently dissipate heat, preventing performance degradation caused by local overheating, thereby further ensuring the stable optoelectronic performance of the device during long-term operation. The local field enhancement effect of the Ag nano-column array directly reflects the energy transfer process and up-conversion luminescence behavior in a single lanthanide-doped nanoparticle, significantly reducing the electroluminescence threshold of the molecular heterojunction, and thus ensuring more stable and efficient optoelectronic performance of the single-molecule electroluminescence up-conversion device.

[0118] The copper foil is cleaned with acetic acid to remove the surface oxide, and then a single-layer graphene is obtained by chemical vapor deposition on the surface of the copper foil;

[0119] Using polymethyl methacrylate (PMMA) as a transfer medium, the graphene layer on the copper foil is transferred to the insulating layer by wet transfer technology;

[0120] A strip-shaped graphene electrode layer with a thickness of 0.7 nm is prepared on the graphene film by using an ultraviolet lithography machine and a reactive ion etching machine;

[0121] An Au metal electrode with a thickness of 70 nm is prepared on the graphene strip layer by using an ultraviolet lithography machine and a magnetron sputtering coater;

[0122] A gap of 40 - 50 nm is formed in the obtained graphene electrode layer by electron beam exposure and reactive ion etching to obtain a graphene dot electrode;

[0123] The etched gap size is matched with the molecular heterojunction design, and the etched gap is controlled according to the particle size of the prepared single lanthanide-doped nanoparticle.

[0124] The graphene dot electrode includes a graphene source terminal electrode and a graphene drain terminal electrode located at both ends in the length direction;

[0125] Using electron beam lithography, a pattern with a terminal width of 13 nm, a length of 76 nm, and a thickness of 26 nm is etched on the surface of the graphene nanodot electrode in the high line direction. Subsequently, magnetron sputtering coating is used to obtain a plasmonic nanoantenna made of Au.

[0126] S2. Connect the graphene source terminal electrode and the graphene drain terminal electrode to both ends of the molecular heterojunction through amide bonds to obtain a graphene dot electrode-molecular heterojunction array.

[0127] Place the graphene dot electrode in the reaction system, and then add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and a bridging molecule, N 2 Under a gas atmosphere, anhydrous pyridine is injected into the reaction system to obtain a mixed solution 2. The mixed solution is placed in the dark and reacted for 24 h to 48 h to obtain a bridging molecule device.

[0128] Place the bridging molecule device in the reaction system, and then add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and a single lanthanide-doped nanoparticle to the reaction system, N 2 Under a gas atmosphere, anhydrous pyridine is injected into the reaction system to obtain a mixed solution. The mixed solution is placed in the dark and reacted for 24 h to 48 h to connect the single lanthanide-doped nanoparticle and the bridging molecule device through a thioester bond to obtain a graphene dot electrode-molecular heterojunction array.

[0129] The single lanthanide-doped nanoparticle described above is prepared using the method in Example 1 @gold nanosheets or nanoparticle I.

[0130] S3. Cover the upper surface of the dried graphene dot electrode-molecular heterojunction array with a protective layer to cover a 100-nm-thick h-BN protective layer to obtain an optoelectronic device based on the electroluminescence upconversion of single lanthanide-doped nanoparticles. h-BN has good optical transparency. While preventing damage to the device from the external environment, it can prevent current leakage and reduce interference noise.

[0131] Perform a volt-ampere characteristic test on the obtained optoelectronic device for the electroluminescence upconversion of single lanthanide-doped nanoparticles to obtain as Figure 2The shown I / V curve graph indicates that the lanthanide-doped single nanoparticles provided by the present invention are connected to graphene dot electrodes, and an optoelectronic device for electrochemically induced upconversion luminescence of the lanthanide-doped single nanoparticles provided by the present invention is successfully fabricated.

[0132] Detection Example 1

[0133] Perform electrochemically induced upconversion luminescence detection on the optoelectronic device for electrochemically induced upconversion luminescence of the lanthanide-doped single nanoparticles obtained in Example 2.

[0134] In the experiment, first, a bias voltage of 0 - 5 V (V b ) is applied to the single molecule between the metal source and drain electrodes by using a KEYSIGHT B1500A semiconductor parameter analyzer to induce molecular luminescence. The emitted photon signals are guided to a CCD spectrometer for collection and recording through a high-sensitivity optical system of a 100x oil immersion objective lens. The bias voltage regulates the luminescence color and efficiency by affecting the non-linear relationship of the multiphoton absorption process. The outer shell of the core-shell structure passivates surface defects and isolates the environmental quenching effect, making the influence of the bias voltage on the luminescence behavior more controllable, while improving the luminescence stability and efficiency. During the process of electrochemically induced upconversion luminescence, the injection and recombination / collision of carriers cause Yb 3+ as a sensitizer to reach the excited state 2 F 7 / 2 from the ground state 2 F 5 / 2 . Subsequently, the energy is transferred to the activator Er 3+ non-radiatively, enabling Er 3+ to transition from 4 I 15 / 2 or a lower energy state of a higher energy level to a higher energy level such as 4 I 11 / 2 , 4 F 9 / 2 , 4 I 7 / 2 , etc. If Er 3+ first reaches the intermediate state 4 I 11 / 2 , it can also absorb energy to enter a higher excited energy level, and then return to the ground state or a lower energy level through non-radiative transitions to achieve upconversion luminescence, as shown in Figure 3 . In addition, the bias voltage directly determines the injection efficiency of electrons and holes and the efficiency of the upconversion process by affecting the charge injection efficiency and the local electric field strength. At low bias voltages, insufficient charge injection results in weak or even invisible upconversion luminescence; as the bias voltage increases, the local electric field is enhanced, improving the energy transfer efficiency and the collision probability of excited state particles, thereby significantly enhancing the upconversion luminescence intensity.

[0135] By measuring the position of the emission peak in the spectrum, the wavelength (λ) of the photons can be extracted, and then the spectral energy can be calculated using the formula to calculate the spectral energy,

[0136] where,

[0137] E photon : the energy of the photon, in joules (J) or electron volts (eV);

[0138] h : Planck's constant, approximately 6.626×10 -34 joule - seconds (J·s);

[0139] c: the speed of light, approximately 3×10 8 meters per second (m / s);

[0140] λ: the wavelength of the photon, in meters (m).

[0141] Determine the energy of the input electrons through the input bias voltage ;

[0142] where,

[0143] E electron : the energy of the electron, in joules (J) or electron volts (eV);

[0144] e: elementary charge, approximately 1.602×10 -19 coulombs (C);

[0145] V b : the bias voltage, in volts (V).

[0146] Meanwhile, the lifetime of the up - conversion luminescence of a single lanthanide - doped nanoparticle under the condition of electric - field excitation is detected by a photon counter, as Figure 4 shown.

[0147] The comparison of the doping of each component and the luminescence efficiency is listed in Table 1.

[0148] Table 1:

[0149]

[0150] The technical features of the above - mentioned embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above - mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0151] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A method for preparing a photoelectric device based on lanthanide-doped single nanoparticle luminescence, characterized in that: The steps include: S1, preparing graphene dot electrodes on the transparent insulating layer on the substrate layer; S2, introducing a molecular heterojunction into the graphene point electrode to form a graphene point electrode-molecular heterojunction array, The molecular heterojunction is composed of a bridging molecule and a single nanoparticle doped with a lanthanide element. The bridging molecule is connected to the graphene point electrode through an amide condensation reaction, and then an esterification reaction occurs between the single-terminal thiol group and the carboxyl group on the surface of the single nanoparticle doped with the lanthanide element, so that the bridging molecule is connected to the single nanoparticle doped with the lanthanide element. The structure of the single nanoparticle doped with lanthanide elements is a sandwich core-shell structure, wherein the sandwich core is a gold nanosheet and the shell is a lanthanide element doped Matrix; S3. Covering the upper surface of the graphene point electrode-molecule heterojunction array with a protective layer to obtain a photoelectric device based on lanthanide-doped single nanoparticle electro-upconversion luminescence.

2. The method for preparing a photoelectric device based on lanthanide-doped single nanoparticle luminescence according to claim 1, characterized in that: In step S2, the preparation of a single lanthanide-doped nanoparticle comprises the following steps: S221, preparing a precursor containing gold nanocapsules by hydrothermal reaction in a nitrogen environment with a gold nanocapsule and a yttrium source solution doped with a lanthanide element, a fluorine source and a sodium source; S222, calcining the precursor in a nitrogen environment to obtain @Gold nanosheet intermediate, the gold nanosheet is formed by the transformation of gold nanovesicles during the calcination process, has a flat sheet shape, and R1 and R2 are lanthanide elements.

3. The method for preparing a photoelectric device based on lanthanide-doped single nanoparticle luminescence according to claim 2, characterized in that: include: S223, the step S222 obtained @Gold nanosheet intermediates undergo surface treatment to remove @The amorphous layer on the surface of the gold nanosheet intermediate and the introduction of carboxyl groups, The step of removing the amorphous layer and introducing carboxyl groups is to @After the gold nanosheet intermediate reacts with the alkali solution, it is washed with deionized water and ethanol several times until the solution is neutral; After reacting with citric acid solution, the solution was washed with deionized water until it was neutral, and centrifuged to obtain single nanoparticles doped with lanthanide elements: @Gold nanosheets.

4. The method for preparing a photoelectric device based on lanthanide-doped single nanoparticle luminescence according to claim 1, characterized in that: In step S1, a plasma nanoarray gate layer is introduced between the substrate layer and the transparent insulating layer; S101, spin-coating photoresist on the surface of the substrate layer and performing ultraviolet lithography to obtain a square nanorod array, and performing thermal resistance evaporation coating to obtain a plasma nanoarray gate layer; S102, depositing SiO2 on the plasma nanoarray gate layer to obtain a transparent insulating layer.

5. The method for preparing a photoelectric device based on lanthanide-doped single nanoparticle luminescence according to claim 1, characterized in that: In step S2, a plasma nanoantenna is introduced on the graphene point electrode; S211, spin-coating polymethyl methacrylate on the surface of the graphene point electrode, and etching above the graphene point electrode to obtain a graphene point electrode device with collinear gold nanorods on the surface; S212, sputtering-coating the graphene point electrode device using a gold target to obtain a plasma nanoantenna.

6. The method for preparing a photoelectric device based on lanthanide-doped single nanoparticle luminescence according to claim 1, characterized in that: include: In step S2, the molecular heterojunction is introduced by the following steps: S201, placing the graphene dot electrode, the bridging molecule and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide in anhydrous pyridine under a nitrogen atmosphere, and reacting for 24 h to 48 h in a light-proof condition to obtain a bridging molecule device; S202. Place the bridging molecular device, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and single nanoparticles doped with lanthanide elements in anhydrous pyridine under a nitrogen atmosphere, and react for 24 h to 48 h in a light-proof condition, so that the single nanoparticles doped with lanthanide elements are connected to the bridging molecular device through a thioester bond to obtain a graphene point electrode-molecular heterojunction array.

7. A photoelectric device based on lanthanide-doped single nanoparticle luminescence, characterized in that: It includes a substrate layer, a transparent insulating layer and an array layer composed of graphene point electrodes and molecular heterojunctions arranged in sequence from bottom to top; The two ends of the molecular heterojunction are respectively connected to the graphene point electrodes through amide bonds to form a graphene point electrode-molecular heterojunction array; The molecular heterojunction is composed of a bridging molecule and a single nanoparticle doped with a lanthanide element. The structural formula of the single nanoparticle doped with a lanthanide element is @Gold nanosheets; The single nanoparticle doped with lanthanide elements is a sandwich core-shell structure, wherein the sandwich core is a gold nanosheet and the shell is a lanthanide element doped Matrix; the gold nanosheet is in the shape of a flat sheet; Among them, gold nanosheets are encapsulated in co-doped In the sphere, R1 is any one of ytterbium, neodymium or cerium, and R2 is any one of erbium, thulium or europium.

8. The optoelectronic device based on lanthanide-doped single nanoparticle luminescence according to claim 7, characterized in that: include: A pair of plasma nanoantennas are also arranged on the graphene point electrode, and the plasma nanoantennas are arranged in the high line direction of the upper surface of the graphene point electrode. The graphene point electrode includes a graphene source terminal electrode and a graphene drain terminal electrode. A pair of plasma nanoantennas are respectively arranged on the graphene source electrode and the graphene drain electrode; The plasma nanoantenna is a pair of colinear metal films, and the material is gold.

9. The optoelectronic device based on lanthanide-doped single nanoparticle luminescence according to claim 7, characterized in that: include: A plasma nano-array gate layer is arranged between the substrate layer and the transparent insulating layer, wherein the plasma nano-array gate layer comprises a square nano-column array, and the square nano-column array is in a strip shape and covers the substrate layer; The material of the square nanocolumn array of the plasma nanoarray gate layer is selected from any one of gold and silver, and the thickness of the plasma nanoarray gate layer is 20-60nm; The thickness of the SiO2 transparent insulating layer deposited on the plasma nano-array gate layer is 30-50 nm.

10. The optoelectronic device based on lanthanide-doped single nanoparticle luminescence according to claim 8, characterized in that: include: The graphene point electrode is arranged on the upper surface of the transparent insulating layer; Metal electrodes are also arranged at both ends of the graphene point electrode, and the metal electrodes are a pair, which are arranged at the outer ends of the graphene source electrode and the graphene drain electrode respectively; The electrode material of the metal electrode is selected from any one of Cu, Cr and Au, and the thickness thereof is 30-100 nm.

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