CN114702948A - Infrared quantum dot layer and preparation method thereof, infrared photosensitive element and preparation method thereof - Google Patents

Infrared quantum dot layer and preparation method thereof, infrared photosensitive element and preparation method thereof Download PDF

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CN114702948A
CN114702948A CN202210186406.8A CN202210186406A CN114702948A CN 114702948 A CN114702948 A CN 114702948A CN 202210186406 A CN202210186406 A CN 202210186406A CN 114702948 A CN114702948 A CN 114702948A
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quantum dot
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陈梦璐
郝群
唐鑫
薛晓梦
罗宇宁
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Beijing Institute of Technology BIT
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Abstract

The invention relates to an infrared quantum dot layer and a preparation method thereof, an infrared photosensitive element and a preparation method thereof, wherein the preparation method of the infrared quantum dot layer comprises the steps of preparing a preset quantum dot, a nonpolar long-chain ligand solution, a polar short-chain ligand solution and a solid ligand solution; wherein, the preset quantum dots are dissolved in a non-polar long-chain ligand solution; mixing a nonpolar long-chain ligand solution dissolved with preset quantum dots with a polar short-chain ligand solution to transfer the quantum dots to the polar short-chain ligand to form a preset solution; adopting a preset solution to form a preset film layer; and (3) carrying out solid ligand method treatment on the preset film layer by using solid ligand liquid to passivate the defect state on the surface of the preset film layer so as to form the infrared quantum dot layer. By the technical scheme, the mobility of carriers in the infrared quantum dot layer and the photoelectric response efficiency of the infrared photosensitive element are improved.

Description

Infrared quantum dot layer and preparation method thereof, infrared photosensitive element and preparation method thereof
Technical Field
The disclosure relates to the technical field of photoelectric sensors, in particular to an infrared quantum dot layer and a preparation method thereof, and an infrared photosensitive element and a preparation method thereof.
Background
The high-performance infrared detector can realize the infrared information of objects in a long distance and all weather, and is usually used as a core component in the fields of meteorological remote sensing, military investigation, aerospace detection and the like. The infrared detector sensitive to the waveband is mainly formed on the basis of materials such as single crystal indium antimonide (InSb) and mercury cadmium tellurium (HgCdTe), however, the cost of single crystal epitaxial growth is always high, the process is very complex when the infrared detector is coupled with a silicon-based reading circuit, the cost is further increased, and the application of the detector is limited.
In response to this, people have studied and sought solutions for alternatives such as quantum dot infrared detectors, quantum well infrared detectors, class II superlattices of III-V semiconductors, and the like. Colloidal Quantum dots (Colloidal Quantum dots) are a new generation of photovoltaic materials, which are essentially semiconductor nanocrystals whose surface is covered with ligands and whose size is smaller than the bohr exciton radius, and have been receiving much attention because of their unique properties and photovoltaic characteristics. In the last fifteen years, the colloidal quantum dots have made great progress in the development of photoelectric devices due to the advantages of wide spectrum regulation range, low synthesis and preparation cost of a thermal injection method and direct coating of liquid phase processing on silicon electronic devices.
However, the low mobility of the current carrier in the colloidal quantum dot thin film greatly limits the core performance of devices such as photoresponse rate, internal quantum efficiency and response rate of the photodetector. Ligand exchange in the preparation process of the quantum dots can replace long-chain ligands on the surfaces of the colloidal quantum dots by using short-chain ligands, so that the method is an effective method for improving carrier mobility, and common methods for ligand exchange include a solid ligand exchange method and a traditional liquid phase ligand exchange method. The number of the substituted ligands of the solid ligand exchange method is limited, the degree of the improvement of the carrier mobility is limited, and a large number of cavities can be formed on the surface of the quantum dot film to cause surface defects; the traditional liquid phase ligand exchange method has more substituted ligands, and can effectively improve the carrier mobility, however, the method usually involves annealing, so that the quantum dot part loses the quantum limit, the quantum yield of the material is reduced, and the photoelectric response is lost.
Disclosure of Invention
In order to solve the above technical problems or at least partially solve the above technical problems, the present disclosure provides an infrared quantum dot layer and a method for manufacturing the same, an infrared photosensitive element and a method for manufacturing the same, which improve carrier mobility and photoelectric response efficiency.
In a first aspect, the present disclosure provides a method for preparing an infrared quantum dot layer, including:
preparing a preset quantum dot, a nonpolar long-chain ligand solution, a polar short-chain ligand solution and a solid ligand solution; wherein, the preset quantum dots are dissolved in a nonpolar long-chain ligand solution;
mixing a nonpolar long-chain ligand solution dissolved with preset quantum dots with the polar short-chain ligand solution to transfer the quantum dots to the polar short-chain ligand to form a preset solution;
adopting the preset solution to form a preset film layer;
and carrying out solid ligand method treatment on the preset film layer by using the solid ligand liquid to passivate the defect state on the surface of the preset film layer so as to form the infrared quantum dot layer.
Optionally, preparing the pre-set quantum dots comprises performing the following steps in an inert gas environment:
heating a first reactant and a solvent within a first preset temperature range until the first reactant is completely dissolved in the solvent to obtain a clear solution;
diluting the second reactant in the same solvent to obtain a solution to be injected;
injecting the solution to be injected into the clear solution, and heating the solution within a second preset temperature range for a preset time; wherein the first preset temperature range is within the second preset temperature range;
and injecting a coolant, and cooling to room temperature in an environmental condition or a water bath to obtain the preset quantum dots.
Optionally, the quantum dots comprise mercury telluride;
wherein preparing a polar short-chain ligand solution comprises:
providing butylammonium chloride, 2-mercaptoethanol and n-butylamine;
dissolving the butylammonium chloride, the 2-mercaptoethanol and the n-butylamine in dimethyl formamide DMF to form a polar short-chain ligand solution;
wherein the non-polar long chain ligand solution comprises n-hexane;
wherein forming a pre-solution comprises:
adding a normal hexane solution dissolved with mercury telluride into the polar short-chain ligand solution;
continuously adding the anti-solvent, and centrifugally precipitating mercury telluride quantum dots at a preset rotating speed;
after discarding the centrifuged supernatant, the mercury telluride quantum dots were dissolved with DMF to generate colloidally stable quantum dot inks in DMF to form the pre-set solution.
Optionally, forming a pre-set film layer comprises:
forming the preset film layer by spin coating or drop coating the quantum dot ink;
the solid ligand fluid comprises an ethanedithiol/hydrochloric acid solution;
wherein, the treatment of the preset film layer by a solid ligand liquid method comprises the following steps:
carrying out solid ligand method treatment on the preset membrane layer by using ethanedithiol/hydrochloric acid solution; the ethanedithiol uses mercury atoms on the surface of quantum dots to bind and replace 2-mercaptoethanol, surface defect states are passivated, and hydrochloric acid removes surface oxides and stabilizes the Fermi surface.
Optionally, when the preset solution is formed, the method further comprises:
adding mercuric chloride;
wherein the intrinsic or N-doped quantum dots are obtained based on the added amount of mercury chloride.
In a second aspect, the present disclosure provides an infrared quantum dot layer prepared by any one of the methods for preparing an infrared quantum dot layer provided in the first aspect;
the mobility mu of the infrared quantum dot layer is 0.1cm2/Vs≤μ≤10cm2/Vs。
In a third aspect, the present disclosure provides a method for manufacturing an infrared photosensitive element, including: providing a substrate;
forming a multilayer Bragg reflector on the substrate in a stacked arrangement;
forming an optical isolation layer on the multilayer bragg reflector;
forming a transparent electrode layer on the optical isolation layer;
forming an infrared quantum dot layer on the transparent electrode;
forming a total reflection electrode layer on the infrared quantum dot layer;
wherein the infrared quantum dot layer is formed by using any one of the methods for preparing an infrared quantum dot layer provided in the first aspect.
Optionally, the method for preparing the infrared sensitive element further comprises:
forming a doping layer between the infrared quantum dot layer and the full-emission electrode layer;
and the infrared quantum dot layer and the doped layer form a PN junction.
In a fourth aspect, the present disclosure also provides an infrared photosensitive element formed by using any one of the methods for manufacturing an infrared photosensitive element provided in the third aspect.
Compared with the prior art, the technical scheme provided by the embodiment of the disclosure has the following advantages:
the preparation method of the infrared quantum dot layer provided by the embodiment of the disclosure comprises the following steps: preparing a preset quantum dot, a nonpolar long-chain ligand solution, a polar short-chain ligand solution and a solid ligand solution; wherein, the preset quantum dots are dissolved in a non-polar long-chain ligand solution; mixing a nonpolar long-chain ligand solution dissolved with preset quantum dots with a polar short-chain ligand solution to transfer the quantum dots to the polar short-chain ligand to form a preset solution; adopting a preset solution to form a preset film layer; and (3) carrying out solid ligand method treatment on the preset film layer by using solid ligand liquid to passivate the defect state on the surface of the preset film layer so as to form the infrared quantum dot layer. Therefore, the nonpolar long-chain ligand solution in which the preset quantum dots are dissolved is mixed with the polar short-chain ligand solution, so that the polar short-chain ligand replaces the nonpolar long-chain ligand on the surface of the quantum dots, the transfer of the quantum dots from the nonpolar long-chain ligand to the polar short-chain ligand is realized, the stable preset solution is formed, and after a preset film layer is formed by using the preset solution, the preset film layer is treated by a solid ligand method to form an infrared quantum dot layer, wherein the annealing process is not needed, so that the quantum dots all keep quantum limit, the quantum yield is high, and the photoelectric response is good; meanwhile, the length of the ligand chain is short, and the surface of the preset film layer is treated by using a solid ligand method, so that the carrier mobility is further improved.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and together with the description, serve to explain the principles of the disclosure.
In order to more clearly illustrate the embodiments or technical solutions in the prior art of the present disclosure, the drawings used in the description of the embodiments or prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.
Fig. 1 is a schematic flow chart of a method for manufacturing an infrared quantum dot layer according to an embodiment of the present disclosure;
fig. 2 is a statistical diagram of a particle size distribution of quantum dots provided in an embodiment of the present disclosure;
fig. 3 is a transmission electron microscope image of quantum dots before and after ligand exchange provided by an embodiment of the present disclosure;
fig. 4 is a graph illustrating characteristics of field effect transistor tests of photosensitive layers of infrared quantum dots with different doping types according to an embodiment of the disclosure.
Fig. 5 is a schematic view of mobility of a field effect transistor prepared by using a photosensitive layer of an infrared quantum dot according to an embodiment of the present disclosure;
fig. 6 is a schematic flow chart of a method for manufacturing an infrared photosensitive element according to an embodiment of the present disclosure.
In the embodiment of the present disclosure, the correspondence between the reference number and the structure name: s101, S102, S103, S104, S601, S602, S603, S604, S605, and S606 represent each step in the method flow diagram.
Detailed Description
In order that the above objects, features and advantages of the present disclosure may be more clearly understood, aspects of the present disclosure will be further described below. It should be noted that the embodiments and features of the embodiments of the present disclosure may be combined with each other without conflict.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure, but the present disclosure may be practiced in other ways than those described herein; it is to be understood that the embodiments disclosed in the specification are only a few embodiments of the present disclosure, and not all embodiments.
Fig. 1 is a schematic flow chart of a method for manufacturing an infrared quantum dot layer according to an embodiment of the present disclosure. As shown in fig. 1, the method for preparing the infrared quantum dot layer may include:
s101, preparing preset quantum dots, a nonpolar long-chain ligand solution, a polar short-chain ligand solution and a solid ligand solution; wherein, the preset quantum dots are dissolved in the nonpolar long-chain ligand solution.
Specifically, the method comprises the steps of dissolving preset quantum dots in a nonpolar long-chain ligand solution, mixing the dissolved preset quantum dots with a polar short-chain ligand solution, replacing nonpolar long-chain ligands on the surfaces of the quantum dots with the polar short-chain ligands, transferring the quantum dots from the nonpolar solution to the polar solution to form stable short-chain ligand quantum dots, and treating the surfaces of the quantum dots with solid ligands at night, so that an infrared quantum dot layer is prepared by using a normal-temperature liquid ligand exchange method and a solid exchange method, the carrier mobility is improved, the surface defects of the quantum dots are avoided, and the quantum yield and the photoelectric response efficiency are improved.
In some embodiments, preparing the pre-set quantum dots comprises performing the following steps in an inert gas environment:
heating a first reactant and a solvent within a first preset temperature range until the first reactant is completely dissolved in the solvent to obtain a clear solution; diluting the second reactant in the same solvent to obtain a solution to be injected; injecting the solution to be injected into the clear solution, and heating the solution within a second preset temperature range for a preset time; wherein the first preset temperature range is within a second preset temperature range; and (3) injecting a coolant, and cooling to room temperature in an environmental condition or a water bath to obtain the preset quantum dots.
Exemplarily, under a nitrogen environment, taking 135mg of mercuric chloride as a first reactant and 16ml of oleylamine as a solvent, 0.5mmol of mercuric chloride and 16ml of oleylamine as solvents are heated at 100 ℃ until the mercuric chloride is completely dissolved to obtain a clear solution. Taking bis (trimethylsilyl) telluride as a second reactant, taking 68mg of 0.25mmol of bis (trimethylsilyl) telluride and diluting 5ml of the bis (trimethylsilyl) telluride in oleylamine to obtain a solution to be injected, injecting the solution to be injected into a clear solution, and heating the solution at the synthesis temperature of 80-110 ℃ for 5 minutes. Anhydrous tetrachloroethylene is used as a coolant, 20mL of anhydrous tetrachloroethylene is injected into the heated solution for rapid cooling reaction, and the solution is cooled to room temperature under an environmental condition or in a water bath, the absorption wavelength of the spectral center depends on the synthesis temperature, and the preset quantum dot with the absorption wavelength of the spectral center being 2um-6um is obtained in the embodiment of the disclosure. It should be noted that the synthesis temperature may be within a first preset temperature range and a second preset temperature range, and the specific temperature may be set according to actual synthesis needs, which is not limited in the embodiments of the present disclosure.
S102, mixing the nonpolar long-chain ligand solution dissolved with the preset quantum dots with the polar short-chain ligand solution to transfer the quantum dots to the polar short-chain ligand to form the preset solution.
In some embodiments, the quantum dots comprise mercury telluride; wherein preparing a polar short-chain ligand solution comprises: providing butylammonium chloride, 2-mercaptoethanol and n-butylamine; dissolving butylammonium chloride, 2-mercaptoethanol and n-butylamine in dimethyl formamide DMF to form a polar short-chain ligand solution; wherein the nonpolar long-chain ligand solution comprises n-hexane; wherein forming a pre-solution comprises: adding a normal hexane solution dissolved with mercury telluride into the polar short-chain ligand solution; continuously adding the anti-solvent, and centrifugally precipitating mercury telluride quantum dots at a preset rotating speed; after discarding the centrifuged supernatant, the mercury telluride quantum dots were dissolved in dimethylformamide DMF to form colloidally stable quantum dot inks in dimethylformamide DMF to form the pre-set solutions.
Illustratively, in a liquid ligand exchange process, 0.5mmol of butylammonium chloride, 140. mu.L of 2-mercaptoethanol, and 400. mu.L of n-butylamine were dissolved in 5mL of dimethylformamide DMF to form a polar short-chain ligand solution. Dissolving preset quantum dots in n-hexane with the concentration of about 80mg/mL to form a nonpolar long-chain ligand solution, adding 400 mu L of the nonpolar long-chain ligand solution into the polar short-chain ligand solution to form a mixed solution, slightly shaking the mixed solution to transfer the quantum dots from the nonpolar long-chain ligand to the polar short-chain ligand, adding toluene as an anti-solvent, centrifuging at the speed of 4000rpm (revolutions per minute) for 30 seconds to precipitate mercury telluride quantum dots, discarding the centrifuged supernatant, dissolving the mercury telluride quantum dots with 40 microliter of dimethylformamide DMF, and generating colloidally stable quantum dot ink in the dimethylformamide DMF, thereby forming the preset solution.
Fig. 2 is a statistical graph of particle size distribution of quantum dots provided in an embodiment of the present disclosure, where the abscissa in fig. 2 is a diameter, and the unit is nm, and the ordinate is a size distribution, and represents the number of quantum dots with corresponding diameters, an image above fig. 2 represents a particle size distribution of quantum dots with diameters of 7.6 ± 0.8nm, an image in the middle represents a particle size distribution of quantum dots with diameters of 10.0 ± 1.1nm, an image below represents a particle size distribution of quantum dots with diameters of 13.1 ± 1.1nm, two curves in each image respectively represent size changes of quantum dots before and after ligand exchange, and the two curves almost coincide, which indicates that a liquid ligand exchange process has no significant influence on the size of quantum dots, and that a modified ligand exchange method has universality on mercury telluride quantum dots with different diameters.
Fig. 3 is a transmission electron microscope image of quantum dots before and after ligand exchange provided in an embodiment of the present disclosure. As shown in FIG. 3, due to the high binding energy of mercury and sulfur, the mercapto group in 2-mercaptoethanol is connected with the mercury atom on the surface of the quantum dot to replace long-chain oleylamine on the surface of the quantum dot, and the quantum dot gap in the quantum dot film is reduced from 1 nanometer to 0.1 nanometer. The alcohol group in the 2-mercaptoethanol has polarity, so that the quantum dot is transferred from a non-polar solution to a polar solution, and the electromotive potential of the quantum dot is regulated and controlled by matching with the butylammonium chloride and the n-butylamine, so that the stability of the quantum dot in the polar solution is improved. Meanwhile, in the process, the gaps of the quantum dots are greatly reduced, the electrical coupling of the quantum dots is enhanced, and the carrier mobility is greatly improved.
In some embodiments, in forming the pre-set solution, further comprising: adding mercuric chloride; wherein the intrinsic or N-doped quantum dots are obtained based on the added amount of mercury chloride.
Specifically, in order to adjust the doping type of the quantum dot, a certain amount of mercuric chloride can be added during the formation of the preset solution, after mercury ions are attached to the surface of the quantum dot, the surface dipole of the mercuric chloride can stabilize electrons in the quantum dot, and the intrinsic type or N type doped quantum dot can be obtained according to different addition amounts of the mercuric chloride. Illustratively, when a small amount of mercuric chloride is added into the preset liquid, intrinsic quantum dots can be obtained, when a large amount of mercuric chloride is added into the preset liquid, N-type doped quantum dots can be obtained, and when the mercuric chloride is not added into the preset liquid, P-type doped quantum dots are obtained.
Fig. 4 is a graph illustrating test characteristics of field effect transistors on photosensitive layers of infrared quantum dots with different doping types according to an embodiment of the disclosure. In fig. 4, the abscissa source voltage is in volts (V), the ordinate source current is in amperes (a), and four field effect transistor test curves are obtained exemplarily according to the content of mercury chloride added when the preset solution is formed, where curve i represents a stronger N-type doped quantum dot curve, curve ii represents a weaker N-type doped curve, curve iii represents a more intrinsic doped quantum dot curve, curve iv represents a weaker P-type doped curve, and curve V represents a stronger P-type doped curve.
And S103, forming a preset film layer by adopting a preset solution.
In some embodiments, forming the pre-set film layer comprises: and forming a preset film layer by spin coating or drop coating the quantum dot ink.
Specifically, a mercury telluride quantum dot solution dissolved in dimethyl formamide DMF is formed into a uniform preset film layer in a spin coating, drop coating or spray coating mode.
And S104, carrying out solid ligand method treatment on the preset film layer by using the solid ligand liquid to passivate the defect state on the surface of the preset film layer to form the infrared quantum dot layer.
In some embodiments, the solid ligand fluid comprises a ethanedithiol/hydrochloric acid solution; the method for treating the preset membrane layer by a solid ligand liquid method comprises the following steps: carrying out solid ligand method treatment on the preset membrane layer by using ethanedithiol/hydrochloric acid solution; the ethanedithiol uses mercury atoms on the surface of quantum dots to bind and replace 2-mercaptoethanol, surface defect states are passivated, and hydrochloric acid removes surface oxides and stabilizes the Fermi surface.
Specifically, the preset film layer is treated by a solid ligand method by using ethanedithiol/hydrochloric acid with the concentration of 2%, for example, the ethanedithiol is bound by mercury atoms on the surface of quantum dots to replace 2-mercaptoethanol, the hydrophilicity of the material is reduced, the defect state of the surface is passivated, and meanwhile, the hydrochloric acid can remove oxides on the surface of the film and stabilize the Fermi surface of the film. Therefore, when the solid ligand exchange method is used, the surface defect caused by a large number of holes on the film surface of the infrared quantum dot layer is avoided, and the carrier mobility is improved.
The disclosed embodiment also provides an infrared quantum dot layer, which has the technical effect of the manufacturing method of the infrared quantum dot layer, and the mobility mu of the infrared quantum dot layer is 0.1cm2/Vs≤μ≤10cm2/Vs。
FIG. 5 shows a field effect of a photosensitive layer of an infrared quantum dot prepared according to an embodiment of the present disclosureMobility of the transistor is schematically shown in fig. 5, in which the abscissa represents the source voltage in volts (V) and the ordinate represents the source current in amperes (a), and as shown in fig. 5, the mobility μ of the infrared quantum dot layer provided by the embodiment of the present disclosure is 3.4cm2Vs, and the doping characteristic curve shows that the infrared quantum dot layer is doped in an N type. As is known to those skilled in the art, the carrier mobility is generally 10 when only oleylamine is used as a ligand-7-10-5cm2the/Vs shows that the carrier mobility of the photosensitive layer of the infrared quantum dot prepared by the embodiment of the disclosure is greatly improved.
The embodiment of the present disclosure further provides a method for manufacturing an infrared photosensitive element, and fig. 6 is a schematic flow chart of the method for manufacturing an infrared photosensitive element provided by the embodiment of the present disclosure, as shown in fig. 6, the method for manufacturing an infrared photosensitive element includes:
s601, providing a substrate.
Specifically, sapphire, silicon or silicon carbide and the like can be selected as a substrate, and the substrate material has high transmittance and low absorptivity for the selected infrared light wave. Preferably, a sapphire material can be selected as a substrate, the production technology of the sapphire substrate is mature, the device quality is good, and the sapphire has good stability and high mechanical strength.
And S602, forming a multilayer Bragg reflector stacked on the substrate.
Specifically, a high-reflectivity layer of the Bragg reflector is manufactured by using methods such as mask evaporation, molecular epitaxial growth and the like, the high-reflectivity layer can be made of materials such as titanium pentoxide, silicon, calcium fluoride, magnesium fluoride and the like, the thickness of the high-reflectivity layer is determined by the determined central wavelength of the light wave to be detected, and the thickness of the high-reflectivity layer is 3-5 micrometers according to the sensitivity of mercury telluride quantum dots to the medium wave infrared. After the high-reflectivity layer is prepared, a low-reflectivity layer is prepared on the high-reflectivity layer, the refractive index of the material forming the low-reflectivity layer is higher than that of the material forming the high-reflectivity layer, the low-reflectivity layer can be made of silicon dioxide or zinc selenide, for example, and the thickness of the low-reflectivity layer is also determined by the determined central wavelength of the light wave to be detected.
The bragg reflector layers are repeatedly manufactured, namely the layers are laminated according to the mode of high-reflectivity layer-low-reflectivity layer-high-reflectivity layer, the high-reflectivity layer and the low-reflectivity layer are regarded as one bragg reflector, the number of the bragg reflector layers is generally 1-4, the bragg reflector layers can be adjusted during manufacturing according to the central frequency required to be detected through actual simulation, and the number of the bragg reflector layers is set to be 3 in the embodiment of the disclosure.
And S603, forming an optical isolation layer on the multilayer Bragg reflector.
Specifically, an optical isolation layer is further prepared on the multilayer bragg reflector, the optical isolation layer is preferably made of silicon dioxide or low-refractive-index materials, the thickness of the optical isolation layer can be determined according to the detected central wavelength of the light wave and the thickness of the infrared quantum dot layer, and the embodiment of the disclosure does not limit the thickness.
And S604, forming a transparent electrode layer on the optical isolation layer.
Specifically, a transparent electrode layer is prepared on the optical isolation layer, the transparent electrode layer can be made of conductive materials such as indium tin oxide and the like with high conductivity, strong stability and high infrared light transmittance, the thickness of the transparent electrode layer can be set to be 20-100nm, and the transparent electrode layer is used for reducing the absorption rate of infrared light waves and improving the transmittance and the conductivity of the infrared light waves.
And S605, forming an infrared quantum dot layer on the transparent electrode.
Specifically, preparing an infrared quantum dot layer on a transparent electrode by a normal-temperature liquid ligand exchange method and a solid exchange method, wherein the thickness of the infrared quantum dot layer is 20-1000nm, coating a mercury telluride quantum dot solution dissolved in dimethyl formamide DMF on a substrate, treating with solid ligand liquid ethanedithiol/hydrochloric acid, and repeating the step for 2-3 times.
S606, forming a total reflection electrode layer on the infrared quantum dot layer; in which the infrared quantum dot layer is formed by any one of the methods for preparing an infrared quantum dot layer as in the above embodiments.
Specifically, the total reflection electrode layer may be made of a metal material such as gold, silver, aluminum, copper, and the like, and preferably, gold may be selected as a constituent material of the total reflection electrode layer, the thickness of the total reflection electrode layer is generally between 100nm and 1000nm, the total reflection electrode layer has a high reflectivity for infrared light waves, and the infrared quantum dot layer may be prepared according to S101 to S104, which is not described herein again.
In some embodiments, the method of manufacturing an infrared sensitive element further comprises: the transparent electrode layer and the total reflection electrode layer are externally connected with a power supply.
Specifically, the basic working principle of the photoconductive element is that when the element absorbs photons radiated by a target or a background, electrons of an outermost shell layer of an element material are transited to form free electrons in a crystal, and a photoelectric effect is generated.
In some embodiments, the method of manufacturing an infrared sensitive element further comprises: forming a doping layer between the infrared quantum dot layer and the total reflection electrode layer; wherein, the infrared quantum dot layer and the doped layer form a PN junction.
In the existing photovoltaic element preparation process, a heterogeneous material is generally required to realize doping characteristics, and difficulties of energy band matching, lattice matching, doping drift, interface transmission matching, carrier mobility matching and the like exist. According to the embodiment of the disclosure, when the preset solution is formed in the preparation process of the infrared quantum dot layer, more mercury chloride is added to obtain the N-type doped quantum dot, meanwhile, the P-type doped layer is prepared between the total reflection electrode layer and the photosensitive layer of the infrared quantum dot by utilizing silver telluride, and the P-type doped layer and the N-type doped quantum dot in the photosensitive layer of the infrared quantum dot form the PN junction, so that the self-doping can be realized through the surface dipole, and the manufacturing difficulty of the PN junction is greatly reduced.
The embodiment of the present disclosure further provides an infrared photosensitive element, which is formed by using any one of the above methods for manufacturing an infrared photosensitive element, so that the infrared photosensitive element also has the technical effects of the above method for manufacturing an infrared photosensitive element, which can be understood with reference to the above description and is not described herein again.
It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The foregoing are merely exemplary embodiments of the present disclosure, which enable those skilled in the art to understand or practice the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A method for preparing an infrared quantum dot layer, comprising:
preparing a preset quantum dot, a nonpolar long-chain ligand solution, a polar short-chain ligand solution and a solid ligand solution; wherein, the preset quantum dots are dissolved in a nonpolar long-chain ligand solution;
mixing a nonpolar long-chain ligand solution dissolved with preset quantum dots with the polar short-chain ligand solution to transfer the quantum dots to the polar short-chain ligand to form a preset solution;
forming a preset film layer by adopting the preset solution;
and carrying out solid ligand method treatment on the preset film layer by using the solid ligand liquid to passivate the defect state on the surface of the preset film layer so as to form the infrared quantum dot layer.
2. The method of preparing an infrared quantum dot layer according to claim 1, wherein the preparing of the pre-set quantum dots comprises performing the following steps in an inert gas atmosphere:
heating a first reactant and a solvent within a first preset temperature range until the first reactant is completely dissolved in the solvent to obtain a clear solution;
diluting a second reactant to be injected in the same solvent to obtain a solution to be injected;
injecting the solution to be injected into the clear solution, and heating the solution within a second preset temperature range for a preset time; wherein the first preset temperature range is within the second preset temperature range;
and injecting a coolant, and cooling to room temperature in an environmental condition or a water bath to obtain the preset quantum dots.
3. The method of preparing an infrared quantum dot layer according to claim 1 or 2, wherein the quantum dots comprise mercury telluride;
wherein preparing a polar short-chain ligand solution comprises:
providing butylammonium chloride, 2-mercaptoethanol and n-butylamine;
dissolving the butylammonium chloride, 2-mercaptoethanol and n-butylamine in dimethyl formamide DMF to form a polar short-chain ligand solution;
wherein the non-polar long chain ligand solution comprises n-hexane;
wherein forming a pre-set solution comprises:
adding a normal hexane solution dissolved with mercury telluride into the polar short-chain ligand solution;
continuously adding the anti-solvent, and centrifugally precipitating mercury telluride quantum dots at a preset rotating speed;
after discarding the centrifuged supernatant, the mercury telluride quantum dots were dissolved with DMF to generate colloidally stable quantum dot inks in DMF to form the pre-set solution.
4. The method of preparing an infrared quantum dot layer according to claim 3, wherein forming a pre-set film layer comprises:
forming the preset film layer by spin coating or drop coating the quantum dot ink;
the solid ligand fluid comprises an ethanedithiol/hydrochloric acid solution;
wherein, carry out solid ligand liquid method to the preset rete and handle, include:
carrying out solid ligand method treatment on the preset membrane layer by using ethanedithiol/hydrochloric acid solution; the ethanedithiol uses mercury atoms on the surface of quantum dots to bind and replace 2-mercaptoethanol, surface defect states are passivated, and hydrochloric acid removes surface oxides and stabilizes the Fermi surface.
5. The method of preparing an infrared quantum dot layer according to claim 3, further comprising, in forming the preliminary solution:
adding mercuric chloride;
wherein the intrinsic or N-doped quantum dots are obtained based on the added amount of mercury chloride.
6. An infrared quantum dot layer, which is produced by the method for producing an infrared quantum dot layer according to any one of claims 1 to 5;
the mobility mu of the infrared quantum dot layer is 0.1cm2/Vs≤μ≤10cm2/Vs。
7. A preparation method of an infrared photosensitive element is characterized by comprising the following steps:
providing a substrate;
forming a multilayer Bragg reflector on the substrate in a stacked arrangement;
forming an optical isolation layer on the multilayer Bragg reflector;
forming a transparent electrode layer on the optical isolation layer;
forming an infrared quantum dot layer on the transparent electrode;
forming a total reflection electrode layer on the infrared quantum dot layer;
wherein the infrared quantum dot layer is formed by the method of manufacturing an infrared quantum dot layer according to any one of claims 1 to 5.
8. The method for producing an infrared photosensitive element according to claim 7, further comprising:
the transparent electrode layer and the total reflection electrode layer are externally connected with a power supply.
9. The method for producing an infrared photosensitive element according to claim 7, further comprising:
forming a doping layer between the infrared quantum dot layer and the full-emission electrode layer;
and the infrared quantum dot layer and the doped layer form a PN junction.
10. An infrared photosensitive element, characterized by being formed by the method for producing an infrared photosensitive element according to any one of claims 7 to 9.
CN202210186406.8A 2022-02-28 2022-02-28 Infrared quantum dot layer and preparation method thereof, infrared photosensitive element and preparation method thereof Pending CN114702948A (en)

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