Near-infrared light-emitting device based on quantum dot solution and near-infrared light equipment applying near-infrared light-emitting device

Abstract

The invention provides a near-infrared light-emitting device based on a quantum dot solution and application thereof, the near-infrared light-emitting device comprises an excitation light source, a light conversion element and a light guide structure, and the light conversion element comprises an accommodating container and the quantum dot solution accommodated in the accommodating container; a light conversion element and a light guide structure are sequentially arranged on one side of the light emitting surface of the excitation light source in the direction away from the excitation light source; the quantum dot solution contains near-infrared light conversion quantum dots and a dispersion medium, the content of the near-infrared light conversion quantum dots in the quantum dot solution is 0.001-5wt%, and the near-infrared light conversion quantum dots contain ligands; the ligand comprises at least one of a water-soluble ligand and a fat-soluble ligand. The near-infrared light-emitting device takes the infrared light quantum dots as a core light-emitting main body, and has excellent infrared light-emitting efficiency and infrared light-emitting stability.

Description

Technical Field

[0001] The present invention belongs to the field of optical technology, and in particular, relates to a near-infrared light-emitting device based on a quantum dot solution and a near-infrared light device using the same. Background Art

[0002] Near-infrared quantum dots, as a new type of nano-optical material with great potential, are gradually showing their wide application prospects in multiple high-tech and medical fields. This type of quantum dots can achieve emission in the near-infrared band by precisely controlling their size and composition. After being packaged with a backlight source, they can be used as an efficient near-infrared light source to provide strong support for semiconductor detection, physical therapy, medical diagnosis, night vision technology, etc. However, to achieve the widespread application of near-infrared quantum dot light sources, the problems of luminous efficiency and stability must be solved. Solid-state near-infrared quantum dots will cause photon reabsorption and non-radiative recombination due to aggregation effects, thereby reducing their luminous efficiency. In addition, in the process of dispersing them in resin and packaging them with a backlight source, the luminescence performance of quantum dots may be significantly reduced or even quenched under the influence of light, heat and packaging environment, showing poor stability and unable to meet the requirements of practical applications.

[0003] In order to solve these problems, researchers are constantly exploring new quantum dot materials and preparation processes. For example, through surface modification and core-shell structure design, the surface modification of quantum dots is optimized to improve their luminescence stability; by improving the preparation process of near-infrared quantum dots, the size and morphology of quantum dots are optimized to improve the stability of quantum dots in different environments; by doping transition metal ions, the band structure of quantum dots is changed, thereby improving luminescence stability.

[0004] Although the various existing solutions have improved the stability of near-infrared quantum dots to a certain extent, there are certain limitations. These methods that have been successful in improving stability are often accompanied by a decrease in the luminescence efficiency of quantum dots. This is mainly because in the process of pursuing luminescence stability, the internal structure or surface state of quantum dots may be changed to a certain extent, thereby affecting their luminescence efficiency. The decline in luminescence efficiency is undoubtedly a huge obstacle to the application of near-infrared quantum dots in high-brightness light-emitting devices. Because in these applications, quantum dots are not only required to have good stability, but also to have excellent luminescence performance to provide sufficient light intensity and clear images. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a near-infrared light-emitting device based on quantum dot solution and a near-infrared light equipment using the same. The near-infrared light-emitting device uses infrared light quantum dots as the core light-emitting entity and has excellent infrared light emitting efficiency and infrared light emitting stability.

[0006] According to one aspect of the present invention, a near-infrared light-emitting device based on a quantum dot solution is provided, the near-infrared light-emitting device comprising an excitation light source, a light conversion element and a light guiding structure, the light conversion element comprising a containing container and a quantum dot solution contained in the containing container; on one side of a light emitting surface of the excitation light source, a light conversion element and a light guiding structure are sequentially arranged in a direction away from the excitation light source; the quantum dot solution contains near-infrared light conversion quantum dots and a solvent, the content of the near-infrared light conversion quantum dots in the quantum dot solution is 0.001-5wt%, and the near-infrared light conversion quantum dots contain ligands; the ligands include at least one of a water-soluble ligand and a fat-soluble ligand, the water-soluble ligands include at least one of a thiol ligand, an alkylamine ligand, an ethanolamine ligand, a vinyl alcohol ligand, and a carboxyl ligand, and the fat-soluble ligands include at least one of an alkylamine ligand, an alkylammonium salt ligand, and a fatty acid ligand.

[0007] The near-infrared light-emitting device of this scheme uses a quantum dot solution containing near-infrared quantum dots as a light-conversion element. In order to enable the above-mentioned near-infrared light-emitting device to meet the luminous intensity requirements of practical applications, in this scheme, the content of near-infrared light-conversion quantum dots in the quantum dot solution is made to reach 0.001~5wt%. On this basis, in order to enable the above-mentioned light-conversion element to maintain good luminous stability during use, this scheme further selects specific ligand types, and combines these ligands on the surface of near-infrared light-conversion quantum dots, which can adjust the distribution of near-infrared light-conversion quantum dots in the quantum dot solution, so that the near-infrared quantum dots can maintain good dispersion uniformity in the quantum dot solution, and can stably maintain a certain spacing distance between each other for a certain period of time, thereby optimizing the recombination probability of electrons and holes, improving the luminous efficiency, and facilitating the near-infrared light-conversion quantum dots to spread heat, and can also reduce the probability of light decay of near-infrared light-conversion quantum dots due to the small distance between the near-infrared light-conversion quantum dots.

[0008] Compared with general solid-state quantum dot light-conversion elements, the near-infrared light-emitting device of this scheme utilizes the heat dissipation effect of the quantum dot solution solvent. Under the premise of not affecting the luminescence performance of the near-infrared light-conversion quantum dots, it can not only slow down the heat from the laser light source to a certain extent, but also effectively guide the self-heating of the quantum dots, thereby achieving the purpose of alleviating the local heating of the near-infrared light-conversion quantum dots. In addition, the preparation of the quantum dot solution is simple, which can simplify the manufacturing process of the light-conversion element. After long-term storage, the quantum dot solution may precipitate, stratify, etc. The operator can use simple physical mixing methods such as shaking and oscillating to redistribute the near-infrared light-conversion quantum dots evenly in the quantum dot solution.

[0009] Preferably, among the water-soluble ligands, the thiol ligand comprises thioglycolic acid.

[0010] Preferably, among the water-soluble ligands, the amine ligand includes triethanolamine.

[0011] Preferably, among the water-soluble ligands, the vinyl alcohol ligand includes polyvinyl alcohol.

[0012] Preferably, among the water-soluble ligands, the carboxyl ligand includes carboxyl-polyethylene glycol.

[0013] Preferably, among the fat-soluble ligands, the alkylamine ligand includes octylamine.

[0014] Preferably, among the fat-soluble ligands, the alkylammonium salt ligand includes hexadecyltrimethylammonium bromide.

[0015] Preferably, among the fat-soluble ligands, the fatty acid ligand includes oleic acid.

[0016] Preferably, the ligand includes a water-soluble ligand, and the solvent of the quantum dot solution includes at least one of water, alcohol compounds, amide compounds, ether compounds, and sulfoxide compounds.

[0017] Preferably, the ligand includes a fat-soluble ligand, and the solvent of the quantum dot solution includes at least one of a benzene compound, an alkane compound, a halogenated hydrocarbon compound, and an organosilicon compound.

[0018] Based on the selection of ligands, the solvent component material type of the quantum dot solution is further optimized, and the ligands on the surface of the near-infrared light-converting quantum dots are fully stretched in the solvent of the quantum dot solution, so that the ligands form an antenna-like structure on the surface of the near-infrared light-converting quantum dots, which can not only enable the ligands to better play the improvement effect on the near-infrared light-converting quantum dots and improve the luminescence performance of the near-infrared light-converting quantum dots, but also improve the distribution of the near-infrared light-converting quantum dots in the quantum dot solution under the action of the "antenna" structure, and widen the distance between the near-infrared light-converting quantum dots, which is not only conducive to the propagation of light in the solvent of the quantum dot solution, but also can effectively reduce the occurrence of luminescence quenching of the near-infrared light-converting quantum dots, and improve the luminescence stability of the light-converting element. In the quantum dot solution, the ligands and the solvent components are matched in the above-mentioned manner, and the polarities of the matched ligands and the solvent components are similar, so that the quantum dot solution has good dispersion uniformity, thereby, on the one hand, the luminescence performance of the quantum dot solution and the luminescence stability of the quantum dots can be improved, and on the other hand, the quantum dot solution can be made clear, which is conducive to the propagation of light in the solvent, thereby improving the luminescence performance of the quantum dot solution.

[0019] Preferably, the near-infrared light-converting quantum dots contain at least one of the elements lead, silver, mercury, indium, sulfur, selenium, arsenic, and tellurium.

[0020] Preferably, the near-infrared conversion quantum dots include at least one of PbS quantum dots, PbSe quantum dots, PbTe quantum dots, Ag2S quantum dots, HgTe quantum dots, and InAs quantum dots.

[0021] Preferably, the near-infrared light-conversion quantum dots include at least two of PbS quantum dots, PbSe quantum dots, PbTe quantum dots, Ag2S quantum dots, HgTe quantum dots, and InAs quantum dots. Introducing multiple types of near-infrared light-conversion quantum dots into the quantum dot solution can achieve a wider range of color coverage and more precise color control, and can adjust the types of near-infrared light-conversion quantum dots and ligands according to actual luminescence requirements, providing more flexible design and application possibilities. However, when different types of near-infrared light-conversion quantum dots are used in combination, the wavelength of the emission light of one near-infrared light-conversion quantum dot is likely to overlap with the wavelength of the excitation light of another near-infrared light-conversion quantum dot. The emission light within the overlapping range will be absorbed by other near-infrared light-conversion quantum dots as excitation light, resulting in a problem of decreased intensity of the light within the overlapping range. By regulating the types of ligands of near-infrared conversion quantum dots, on the one hand, the compatibility between different types of near-infrared conversion quantum dots can be improved. On the other hand, it is beneficial to modify the quantum dots with ligands, effectively increase the Stoke's shift of the near-infrared conversion quantum dots, inhibit the second exciton absorption that is commonly present in near-infrared conversion quantum dots, reduce the overlap between the emission spectra and excitation spectra of different near-infrared conversion quantum dots, and improve the luminescence efficiency of the quantum dot solution.

[0022] Preferably, the number of carbon atoms in the main carbon chain of the ligand is 3 to 18. For example, the number of carbon atoms in the main carbon chain of the ligand is 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18.

[0023] Preferably, the number of carbon atoms in the main carbon chain of the ligand is 10 to 18. For example, the number of carbon atoms in the main carbon chain of the ligand is 10, 11, 12, 13, 14, 15, 16, 17 or 18. By selecting a ligand with a long carbon chain, the steric hindrance between the near-infrared light-converting quantum dot particles can be increased, which can make light more easily diffuse in the quantum dot solution and reduce the probability of aggregation of quantum dot particles, so as to improve the dispersibility of the near-infrared light-converting quantum dots in the quantum dot solution. This increases the difficulty of transferring the resonance energy between the near-infrared light-converting quantum dots, thereby increasing the Stoke's shift, reducing the absorption of the second exciton peak, and improving the luminescence efficiency; it is also beneficial to transfer the heat generated by the near-infrared light-converting quantum dots through the solvent of the quantum dot solution, preventing the near-infrared light-converting quantum dots from being too hot and causing luminescence attenuation or even quenching.

[0024] Preferably, when the ligand includes a water-soluble ligand, the water-soluble ligand includes at least one of a thiol ligand and a carboxyl ligand; when the ligand includes a fat-soluble ligand, the fat-soluble ligand includes at least one of oleic acid and oleylamine.

[0025] Preferably, the emission wavelength of the quantum dot solution is 900-1700 nm. For example, the emission wavelength of the quantum dot solution is 900 nm, 1000 nm, 1100 nm, 1200 nm, 1300 nm, 1400 nm, 1500 nm, 1600 nm or 1700 nm.

[0026] Preferably, the quantum dot solution also includes a light diffusion material, which includes at least one of silicone microspheres, silica microspheres, polystyrene microspheres, polymethyl methacrylate (PMMA) microspheres, titanium dioxide particles, zinc oxide particles, barium sulfate particles, glass microspheres, aluminum oxide particles, and zirconium oxide particles. By introducing light diffusion materials into the quantum dot solution, the diffusion of light can be enhanced, thereby improving the luminous efficiency and light absorption efficiency of the near-infrared light conversion quantum dots, and the spatial distance between the near-infrared light conversion quantum dot particles can be increased, thereby improving the dispersibility and stability of the near-infrared light conversion quantum dots.

[0027] Preferably, the content of the light diffusion material in the quantum dot solution is 0.5-5wt%. For example, the content of the light diffusion material in the quantum dot solution is 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt% or 5wt%.

[0028] Preferably, a filter element is further provided between the light-converting element and the light-guiding structure; the filter element satisfies that the infrared light transmittance is ≥50% and the visible light transmittance is ≤80%. The above-mentioned filter element is provided on the light-emitting side of the accommodating container in order to regulate the light emission of the near-infrared light-emitting device. In this solution, the infrared light emitted by the light-converting element can pass through the filter element and be emitted from the near-infrared light-emitting device via the light-guiding structure, thereby realizing infrared light irradiation of the near-infrared light-emitting device. When the visible light from the excitation light source reaches the filter element, it can be reflected by the filter element and will not be emitted along the light-guiding structure. Based on this, when the near-infrared light-emitting device is applied to some beauty instruments, facial or eye therapy equipment, the user will not see the visible light when using the near-infrared light-emitting device to irradiate the face or eyes, and will not experience discomfort such as glare due to the visible light irradiation, thereby improving the comfort of use.

[0029] Preferably, the near-infrared light-emitting device based on the quantum dot solution further comprises a refrigeration system, and the refrigeration system is arranged outside the light conversion element.

[0030] According to another aspect of the present invention, there is provided a near-infrared light device, comprising the above-mentioned near-infrared light-emitting device, wherein the near-infrared light device is an imager, a diagnostic and therapeutic instrument, a physical therapy instrument, a beauty instrument, or a hair growth instrument. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0032] Example 1 Treatment Group 1A The present treatment group provides a near-infrared light-emitting device, which includes a housing, an excitation light source, a light conversion element, a refrigeration system, a Fresnel lens, and an optical fiber, wherein the excitation light source, the light conversion element, the filter element, and the Fresnel lens are all arranged inside the housing, the housing includes a closed first end and a second end with an opening connected to the outside, the excitation light source is arranged near the first end, the light emitting surface of the excitation light source faces the second end, and the light conversion element, the filter element, the Fresnel lens, and the optical fiber are arranged in sequence on one side of the light emitting surface of the excitation light source. The refrigeration system is arranged outside the light conversion element, and the emission wavelength of the near-infrared light-emitting device is within the range of 900 to 1700 nm.

[0033] The excitation light source is an excitation chip that can emit 808 nm excitation light. The light power of the excitation chip under standard working conditions is 1W / cm 2 One end of the optical fiber extends into the housing, and the other end extends from the opening at the second end of the housing. The filter element is an infrared high-transmittance filter (manufacturer: Euro-optics, manufacturer's product brand: long-wave pass filter @840nm), and the infrared light (wavelength range 900~1700 nm) transmittance of the filter element is 80%~98%, and the visible light transmittance is 0%~10%.

[0034] The light conversion element includes a quantum dot solution and a container for containing the quantum dot solution, and a hollow light-transmitting rectangular structure is used as the container. The quantum dot solution includes near-infrared light conversion quantum dots bound to ligands and a solvent. The ligand is triethanolamine; the solvent is deionized water; the infrared light conversion quantum dots are PbS quantum dots, and the emission spectrum of the PbS quantum dots has a main peak wavelength of 1300 nm, an emission spectrum wavelength range of 1150 nm~1450 nm, and a half-peak width of 141 nm; the content of near-infrared light conversion quantum dots in the quantum dot solution is 0.001wt%.

[0035] In this embodiment, different near-infrared light-emitting devices were prepared with the content of infrared light-converting quantum dots and the type of ligands in the quantum dot solution as variables, and the product numbers and the specific conditions of the corresponding quantum dot solutions and ligands are shown in Table 1. Among the near-infrared light-emitting devices prepared in this treatment group, except for the variables shown in Table 1, the materials, structures, and connection and installation relationships of other components are strictly kept consistent.

[0036] Table 1. Specific information of each product number and corresponding variables in Example 1

[0037] Test Example 1 1. Test subjects The light conversion elements prepared in the treatment groups 1A to 3A and the comparison groups 1-1A to 1-8A in Example 1 were used as test objects.

[0038] 2. Test items (1) Light decay test: The test conditions are as follows: ① Using 808nm laser as the excitation light source, the light power is 1W / cm 2 ; ② Use an infrared spectrometer (brand: Ocean Optics, model: NIR1700) as the test equipment, an integrating sphere as the light collecting device, the integration time is 100ms, and the test range is 900~1700nm; ③ The sample to be tested is placed horizontally in the test area of ​​the UV spectrophotometer, and the excitation light source irradiates the sample to be tested horizontally at a fixed distance; ④ Collect data: collect the maximum intensity of the main peak of the light-emitting element at the beginning, recorded as I1, and collect the maximum intensity of the main peak of the light-emitting element after 3 hours of testing, recorded as I2.

[0039] The light decay rate of the light decay test is calculated according to the following formula: Light decay rate = (I1-I2) / I1×100%. The smaller the light decay rate, the better the luminous stability of the light conversion element.

[0040] 3. Test results The test results are shown in Table 2. The data processing method of the I1 value (the maximum luminous intensity value of the main peak of the emission spectrum of the test object collected at the beginning of the test) shown in Table 2 is as follows: the I1 measured by the light conversion element of the treatment group 2A in this test example is used as the control value, which is recorded as 100%, and the corresponding I1 values ​​measured by other test objects are recorded at the ratio of their equivalent to the control value. Table 2. Test result statistics of this test case

[0041] 4. Result analysis: By comparing the test performance of treatment groups 1A~3A with comparison groups 1-1A~1-8A in Table 2, it can be found that compared with the light-conversion elements provided by comparison groups 1-1A~1-8A, the light-conversion elements provided by treatment groups 1A~3A have better infrared light emitting efficiency and infrared light emitting stability.

[0042] In the test objects of this test example, the test objects are grouped according to the same ligand type. Based on this, the comparison group 1-1A, the treatment group 1A, the treatment group 2A, the treatment group 3A and the comparison group 1-2A are divided into the same group for comparison, the comparison group 1-3A, the comparison group 1-4A and the comparison group 1-5A are divided into the same group for comparison, and the comparison group 1-6A, the comparison group 1-7A and the comparison group 1-8A are divided into the same group for comparison. Based on the data shown in Table 2, in the same group, with the increase of the content of the near-infrared light conversion quantum dots, the light decay rate of the light conversion element shows an overall upward trend. This is because the luminescence of the near-infrared light conversion quantum dots is accompanied by heat generation, and the heat generated reacts on the near-infrared light conversion quantum dots, which will cause the luminescence intensity of the near-infrared light conversion quantum dots to decrease. Among them, in the control group using triethanolamine as a ligand, when the content of near-infrared light-converting quantum dots does not exceed 5%, the light decay rate of the light-converting element can be maintained within a relatively low numerical range, indicating that in the test object using triethanolamine as a ligand, based on the working stability and luminous intensity of the light-converting element, the content of near-infrared light-converting quantum dots can reach 5%. This is because when the ligand of the near-infrared light-converting quantum dots is triethanolamine, the dispersion uniformity of the near-infrared quantum dots in the quantum dot solution can be improved, thereby increasing the quantum dot content that can be accommodated in the quantum dot solution. However, in the control group using octadecyl phosphoric acid and thiophene-3-boric acid as ligands, the light decay rate corresponding to the test object with a content of 5% of near-infrared light-converting quantum dots is significantly improved, which shows that in the above two control groups, it is explained that in the test objects using octadecyl phosphoric acid and thiophene-3-boric acid as ligands, when the content of near-infrared light-converting quantum dots can reach 5%, the working stability of the light-converting element is poor, and it is difficult to maintain its luminous intensity without significant decay after working for a period of time.

[0043] The above results indicate that, in the test objects, the use of triethanolamine as a ligand for near-infrared light conversion quantum dots can effectively improve the luminescence quenching caused by the increased concentration of near-infrared light conversion quantum dots, thereby enabling the near-infrared light conversion quantum dots in the light conversion element to reach a higher concentration value, and a higher concentration of near-infrared light conversion quantum dots can increase the luminescence intensity limit value of the light conversion element.

[0044] Example 2 This embodiment refers to the near-infrared light-emitting device prepared in the treatment group 2A to prepare a near-infrared light-emitting device. The infrared light-emitting device prepared in this embodiment is different from the infrared light-emitting device prepared in the treatment group 2A as a control. The only difference is that this embodiment uses the type of ligand and the type of solvent as variables to prepare different near-infrared light-emitting devices. The product number and the specific conditions of the corresponding ligand and solvent are shown in Table 3. Among the near-infrared light-emitting devices prepared in this treatment group, except for the variables shown in Table 3, the materials, structures, and connection and installation relationships of other components are strictly consistent. For the convenience of comparison, Table 3 also contains the relevant information of the near-infrared light-emitting device of the treatment group 2A.

[0045] Table 3. Specific information of each product number and corresponding variables in Example 2

[0046] Note: The “ / ” in the ligand type column indicates that the near-infrared photoconversion quantum dots used in this group do not contain ligands.

[0047] Test Example 2 1. Test subjects The light conversion elements prepared in treatment groups 1B to 3B, treatment group 2A, comparison group 2-1B, and comparison group 2-2B in Example 2 were used as test objects.

[0048] 2. Test items (1) Light decay test: The test equipment, test conditions, and test operations used in the optical attenuation test of this test example are consistent with those in the optical attenuation test of Test Example 1.

[0049] 3. Test results The test results are shown in Table 4. The data processing method of the I1 value (the maximum luminous intensity value of the main peak of the emission spectrum of the test object collected at the beginning of the test) shown in Table 4 is as follows: the I1 measured by the light conversion element of the treatment group 2A in this test example is used as the control value, which is recorded as 100%, and the corresponding I1 values ​​measured by other test objects are recorded at the ratio of their equivalent to the control value.

[0050] Table 4. Test result statistics of this test case

[0051] 4. Result analysis: By comparing the test performance of treatment groups 1B~3B, treatment group 2A, comparison group 2-1B, and comparison group 2-2B in Table 4, it can be found that compared with the light-conversion elements provided by comparison group 2-1B and comparison group 2-2B, the light-conversion elements provided by treatment groups 1B~3B and treatment group 2A have better infrared light emitting efficiency and infrared light emitting stability.

[0052] In the test objects of this test example, the test objects were grouped according to the same solvent type, based on which treatment group 2A, treatment group 1B and comparison group 2-1B were divided into the same group for comparison, and treatment group 2B, treatment group 3B and comparison group 2-2B were divided into the same group for comparison. Based on the data shown in Table 4, in the same group, compared with near-infrared light-conversion quantum dots without ligands, near-infrared light-conversion quantum dots containing water-soluble ligands or fat-soluble ligands have better infrared light emitting efficiency.

[0053] Further, by comparing the light decay rates of the light conversion elements provided by treatment group 2A and treatment group 1B, it can be found that the luminescence stability of the light conversion element provided by treatment group 2A is better than that of treatment group 1B, which indicates that when a near-infrared light conversion quantum dot water-soluble ligand containing triethanolamine is used, the type of solvent component material of the quantum dot solution includes deionized water, which can improve the luminescence performance of the quantum dot solution and the luminescence stability of the quantum dots. By comparing the light decay rates of the light conversion elements provided by treatment groups 2B~3B, it can be found that the luminescence stability of the light conversion element provided by treatment group 2B is better than that of treatment group 3B, which indicates that when a near-infrared light conversion quantum dot water-soluble ligand containing octylamine is used, the type of solvent component material of the quantum dot solution includes toluene, which can improve the luminescence performance of the quantum dot solution and the luminescence stability of the quantum dots. In summary, by further matching the types of solvent component materials of the ligand and the quantum dot solution, the inventive performance and luminescence stability of the light conversion element can be improved.

[0054] Example 3 This embodiment refers to the near-infrared light-emitting device prepared in the treatment group 2B to prepare a near-infrared light-emitting device. The infrared light-emitting device prepared in this embodiment is different from the infrared light-emitting device prepared in the treatment group 2B as a control, and the only difference is that this embodiment uses the type of ligand and the type of solvent as variables to prepare different infrared light-emitting devices. The product number and the specific conditions of the corresponding ligand and solvent are shown in Table 5. In addition to the variables shown in Table 5, the near-infrared light-emitting device prepared in this embodiment and the near-infrared light-emitting device prepared in the treatment group 4B as a control are strictly consistent in terms of materials, structures, and connection and installation relationships of other components. For ease of comparison, Table 5 also contains relevant information about the near-infrared light-emitting device of the treatment group 2B.

[0055] Table 5. Details of product numbers and corresponding variables in Example 3

[0056] Note: The ligand types used in treatment groups 1C~4C are polymers, and the number of carbon atoms in the main carbon chain of the polymer is controlled within the range shown in Table 5.

[0057] Test Example 3 1. Test subjects The light conversion elements prepared in treatment groups 1C to 8C and treatment group 2B in Example 3 were used as test objects.

[0058] 2. Test items (1) Light decay test: The test equipment, test conditions, and test operations used in the optical attenuation test of this test example are consistent with those in the optical attenuation test in Test Example 1.

[0059] 3. Test results The test results are shown in Table 6. The data processing method of the I1 value (the maximum luminous intensity value of the main peak of the emission spectrum of the test object collected at the beginning of the test) shown in Table 6 is as follows: the I1 measured by the light conversion element of the treatment group 2B in this test example is used as the control value, which is recorded as 100%, and the corresponding I1 values ​​measured by other test objects are recorded at the ratio of their equivalent to the control value.

[0060] Table 6. Test result statistics of this test case

[0061] 4. Result analysis: By comparing the test performance of treatment groups 1C~8C and treatment group 2B in Table 6, it can be found that selecting the appropriate type of ligand is beneficial to improving the initial luminescence intensity of near-infrared light-converting quantum dots. Furthermore, in the test objects of this test example, the test objects are grouped according to the same type of ligand, and the treatment groups 1C~4C in which the quantum dots contain water-soluble ligands are divided into the same group for comparison, and the treatment groups 5C~8C and treatment group 2B in which the quantum dots contain fat-soluble ligands are divided into the same group for comparison. Based on the data shown in Table 6, it can be found that in the same group, as the number of carbon atoms in the main carbon chain of the ligand increases, the light decay rate of the light-converting element shows an overall upward trend. And when the number of carbon atoms in the main carbon chain of the selected ligand is 10~18, the light decay rate of the corresponding light-converting element is smaller, and the light emission of the light-converting element is more stable.

[0062] This shows that based on the appropriate ligand type, further optimization of the ligand main carbon chain length and the use of ligands with 10 to 18 carbon atoms in the main carbon chain can improve the dispersion uniformity of the near-infrared light conversion quantum dots, thereby reducing the light decay rate of the near-infrared light conversion quantum dots and improving the working stability of the light conversion element.

[0063] Example 4 This embodiment refers to the near-infrared light-emitting device prepared in the treatment group 2B to prepare a near-infrared light-emitting device. The infrared light-emitting device prepared in this embodiment is compared with the infrared light-emitting device prepared in the treatment group 2B as a control, and the difference is only that: this embodiment uses the type of ligand and the type of light diffusion material as variables to prepare different near-infrared light-emitting devices, and the specific conditions of the product number and the corresponding ligand and light diffusion material are shown in Table 7. In addition to the variables shown in Table 7, the near-infrared light-emitting device prepared in this embodiment is strictly consistent with the near-infrared light-emitting device prepared in the treatment group 2B to which it is compared in terms of materials, structures, and connection and installation relationships of other parts. For ease of comparison, Table 7 also contains relevant information about the near-infrared light-emitting devices of the treatment groups 2B and 7C. Among them, the average particle size D50 of the light diffusion material shown in Table 7 is 300nm, and the content of the light diffusion material shown in Table 7 in the quantum dot solution is 3.5wt%.

[0064] Table 7. Specific information of each product number and corresponding variables in Example 4

[0065] Note: The “ / ” in the column for the type of light diffusion material indicates that the quantum dot solution used in this group does not contain light diffusion material.

[0066] Test Example 4 1. Test subjects The light conversion elements prepared in treatment groups 1D to 6D, treatment group 2A, and treatment group 2B in Example 4 were used as test objects.

[0067] 2. Test items (1) Light decay test: The test equipment, test conditions, and test operations used in the optical attenuation test of this test example are consistent with those in the optical attenuation test in Test Example 1.

[0068] 3. Test results The test results are shown in Table 8. The data processing method of the I1 value (the maximum luminous intensity value of the main peak of the emission spectrum of the test object collected at the beginning of the test) shown in Table 8 is as follows: the I1 measured by the light conversion element of the treatment group 2A in this test example is used as the control value, which is recorded as 100%, and the corresponding I1 values ​​measured by other test objects are recorded at the ratio of their equivalent to the control value.

[0069] Table 8. Test result statistics of this test case

[0070] 4. Result analysis: In the test objects of this test example, the test objects were grouped according to the same ligand type, and treatment groups 1D~3D and treatment group 2B were divided into the same group for comparison, and treatment groups 4D~6D and treatment group 2A were divided into the same group for comparison. Based on the data shown in Table 8, it can be found that in the same group, adding light diffusion materials to the quantum dot solution is beneficial to improving the initial luminescence intensity of the near-infrared light conversion quantum dots, because the light diffusion material can enhance the diffusion of light in the quantum dot solution, thereby improving the light absorption efficiency and luminescence efficiency of the near-infrared light conversion quantum dots.

[0071] Furthermore, in the same group, compared with other light diffusion materials, the use of glass microspheres as light diffusion materials is beneficial to both improving the luminous efficiency of near-infrared light conversion quantum dots and reducing the light decay rate of near-infrared light conversion quantum dots, thereby improving the luminous efficiency and luminous stability of the light conversion element. This is because glass microspheres have good compatibility with near-infrared light conversion quantum dots, and are not prone to quenching near-infrared light conversion quantum dots due to the introduction of light diffusion materials into the quantum dot solution.

[0072] Example 5 Treatment Group 1E The near-infrared light-emitting device prepared in this treatment group is prepared with reference to the near-infrared light-emitting device prepared in treatment group 2B. The difference between the near-infrared light-emitting device prepared in this treatment group and the near-infrared light-emitting device prepared in treatment group 2B as the control is that the quantum dot solution includes four near-infrared light-converting quantum dots, InAs-1250, PbS-1300, PbS-1400, and PbSe-1450, and the mass ratio is InAs-1250: PbS-1300: PbS-1400: PbSe-1450 = 1.8: 1.5: 1.2: 1. In addition, these four near-infrared light-converting quantum dots are all bound to ligands, and the ligands are all octylamine.

[0073] In this embodiment, different infrared light-emitting devices are prepared using the type of ligand bound to each near-infrared light-converting quantum dot as a variable. The product numbers and the specific conditions of the corresponding ligands and solvents are shown in Table 9. In addition to the variables shown in Table 9, the near-infrared light-emitting device prepared in this embodiment and the near-infrared light-emitting device prepared in the treatment group 1E against which it is compared are strictly consistent in terms of materials, structures, and connection and installation relationships of other components.

[0074] Among them, the information of near-infrared light-converting quantum dots shown in Table 9 is as follows: InAs-1250 is an InAs quantum dot, and the main peak wavelength of the emission spectrum of the InAs quantum dot is 1250 nm, the wavelength range of the emission spectrum is 1120~1430 nm, and the half-peak width is 132 nm; PbS-1300 is a PbS quantum dot, and the main peak wavelength of the emission spectrum of the PbS quantum dot is 1300 nm, the wavelength range of the emission spectrum is 1150 nm~1450 nm, and the half-peak width is 141 nm; PbS-1400 is a PbS quantum dot, and the main peak wavelength of the emission spectrum of the PbS quantum dot is 1400 nm, the wavelength range of the emission spectrum is 1240 nm~1620 nm, and the half-peak width is 140 nm; PbSe-1450 is a PbSe quantum dot, and the main peak wavelength of the emission spectrum of the PbSe quantum dot is 1450 nm, the emission spectrum wavelength range is 1330~1610nm, and the half-peak width is 141nm.

[0075] Table 9. Details of product numbers and corresponding variables in Example 5

[0076] Note: The “ / ” in the ligand type column indicates that the near-infrared photoconversion quantum dots used in this group are not bound to ligands.

[0077] Test Example 5 1. Test subjects The light conversion elements prepared in treatment groups 1E to 2E and comparison group 5-1E in Example 5 were used as test objects.

[0078] 2. Test items (1) Light decay test: The test equipment, test conditions, and test operations used in the light decay test of this test example are consistent with those in the light decay test of Test Example 1. In addition, in this test example, the wavelength of the highest luminous intensity in the main peak of the emission spectrum of the test object is recorded: at the beginning of the test, the wavelength of the highest luminous intensity in the main peak of the emission spectrum of the test object is recorded (recorded as X1); after the test is carried out for 3 hours, the wavelength of the highest luminous intensity in the main peak of the emission spectrum of the test object is recorded (recorded as X2).

[0079] 3. Test results The test results are shown in Table 10.

[0080] Table 10. Test result statistics of this test case

[0081] 4. Result analysis: In the light conversion elements provided by treatment groups 1E~2E and comparison group 5-1E, the quantum dot solution includes multiple quantum dots. Since different types of quantum dots may have different light decay rates, in a light conversion system involving multiple quantum dots, if the difference in light decay rates of different types of quantum dots is greater, the wavelength difference of the highest luminous intensity in the main peak of the emission spectrum measured by the light conversion element before and after the light decay experiment is greater, which is not conducive to maintaining good working stability of the light conversion element. It can be seen from the test data in Table 10 that the X1-X2 values ​​measured by the light conversion elements provided by treatment groups 1E and 2E are significantly smaller than those of comparison group 5-1E, indicating that the light conversion elements provided by treatment groups 1E and 2E have better luminous stability.

[0082] From the test results of this test example, it can be seen that when using multiple quantum dots, by matching the type of ligand and the type of near-infrared conversion quantum dots, the light decay rate of different types of quantum dots can be reduced to close to 0 as much as possible, or the light decay conditions of different types of quantum dots can be made similar, so that the wavelength of light emitted by the conversion element can maintain good stability.

[0083] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A near-infrared light-emitting device based on a quantum dot solution, characterized in that: The near-infrared light-emitting device comprises an excitation light source, a light conversion element and a light guide structure, wherein the light conversion element comprises a containing container and a quantum dot solution contained in the containing container; On one side of the light emitting surface of the excitation light source, the light conversion element and the light guide structure are sequentially arranged in a direction away from the excitation light source; the quantum dot solution contains near-infrared light conversion quantum dots and a solvent, the content of the near-infrared light conversion quantum dots in the quantum dot solution is 0.001-5wt%, and the near-infrared light conversion quantum dots contain ligands; The ligand includes at least one of a water-soluble ligand and a fat-soluble ligand. The water-soluble ligand includes at least one of a thiol ligand, an amine ligand, a vinyl alcohol ligand, and a carboxyl ligand. The fat-soluble ligand includes at least one of an alkylamine ligand, an alkylammonium salt ligand, and a fatty acid ligand.

2. The near-infrared light-emitting device based on a quantum dot solution according to claim 1, characterized in that: The ligand includes a water-soluble ligand, and the solvent of the quantum dot solution includes at least one of water, alcohol compounds, amide compounds, ether compounds, and sulfoxide compounds.

3. The near-infrared light-emitting device based on a quantum dot solution as claimed in claim 1, characterized in that: The ligand includes a fat-soluble ligand, and the solvent of the quantum dot solution includes at least one of a benzene compound, an alkane compound, a halogenated hydrocarbon compound, and an organosilicon compound.

4. The near-infrared light-emitting device based on a quantum dot solution according to claim 1, characterized in that: The near-infrared light-converting quantum dots contain at least one of the elements lead, silver, mercury, indium, sulfur, selenium, arsenic, and tellurium.

5. The near-infrared light-emitting device based on a quantum dot solution as claimed in claim 4, characterized in that: The near-infrared light conversion quantum dots include at least one of PbS quantum dots, PbSe quantum dots, PbTe quantum dots, Ag2S quantum dots, HgTe quantum dots, and InAs quantum dots.

6. The near-infrared light-emitting device based on a quantum dot solution according to claim 1, characterized in that: The number of carbon atoms in the main carbon chain of the ligand is 10 to 18.

7. The near-infrared light-emitting device based on a quantum dot solution as claimed in claim 6, characterized in that: When the ligand includes the water-soluble ligand, the water-soluble ligand includes at least one of a thiol ligand and a carboxyl ligand, When the ligand includes the fat-soluble ligand, the fat-soluble ligand includes at least one of oleic acid and oleylamine.

8. The near-infrared light-emitting device based on a quantum dot solution as claimed in claim 1, characterized in that: The emission wavelength range of the light conversion element covers 900-1700 nm.

9. The near-infrared light-emitting device based on a quantum dot solution as claimed in claim 1, characterized in that: The quantum dot solution also includes a light diffusion material, which includes at least one of silicone microspheres, silica microspheres, polystyrene microspheres, polymethyl methacrylate microspheres, titanium dioxide particles, zinc oxide particles, barium sulfate particles, glass microspheres, aluminum oxide particles, and zirconium oxide particles.

10. The near-infrared light-emitting device based on a quantum dot solution according to claim 1, characterized in that: A filter element is also provided between the light conversion element and the light guide structure; the filter element satisfies that the infrared light transmittance is ≥50% and the visible light transmittance is ≤80%.

11. The near-infrared light-emitting device based on a quantum dot solution as claimed in claim 1, characterized in that The near-infrared light-emitting device based on quantum dot solution also includes a refrigeration system, which is arranged on the outside of the light conversion element.

12. A near infrared light device, characterized in that: It comprises a near-infrared light-emitting device based on a quantum dot solution as described in any one of claims 1 to 11, wherein the near-infrared light device is an imager, a diagnostic instrument, a physical therapy instrument, a beauty instrument, or a hair growth instrument.

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