CsPbX3 / HgTe quantum dot material, and preparation method and application thereof

Abstract

The application relates to the technical field of photoelectric detection, in particular to a CsPbX3 / HgTe quantum dot material and a preparation method and application thereof. The CsPbX3 / HgTe quantum dot material prepared by the application utilizes methyl to connect CsPbX3 quantum dots and HgTe quantum dots to form a nanoscale heterojunction, and the CsPbX3 quantum dots are coated with a silicon layer, so that the carriers of the two are effectively isolated to form a depletion layer, and then an electric field is formed between the two quantum dot materials, the carrier separation of the mercury telluride quantum dots is promoted, and the response speed of the light detector is effectively improved. Moreover, the CsPbX3 / HgTe quantum dot material provided by the application has response capability in the infrared light, visible light, ultraviolet and X-ray wave bands, and effectively widens the detection spectral range.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of photoelectric detection, in particular to a CsPbX3 / HgTe quantum dot material and a preparation method and application thereof. BACKGROUND

[0002] Photoelectric imaging plays an important role in the fields of military reconnaissance, remote sensing surveying and mapping, spaceflight and aviation, etc. Existing photoelectric detectors mainly adopt bulk semiconductor materials such as mercury cadmium telluride, type II superlattice, indium antimonide, silicon and indium gallium arsenide, which have excellent performance and high stability. However, the complex material preparation and flip-chip bonding process limit the batch production and low-cost application of bulk semiconductor focal plane arrays.

[0003] As a new liquid semiconductor material, the colloidal quantum dot has a tunable energy band gap, and the absorption spectrum and response spectrum can be adjusted by adjusting the size and shape. Under the surface effect, the quantum dot has the advantages of large specific surface area, high quantum efficiency and carrier lifetime. The advantages of the colloidal quantum dot, such as wide spectral control range, large synthesis scale, low preparation cost and easy processing technology, bring a lot of design and control freedom to quantum dot devices, and provide a new idea for the research and development of new infrared focal plane arrays. The current research hot emerging materials have wide applications in photoelectricity, sensing, biological medicine, display, energy, photocatalysis, electronics, communication and many other fields.

[0004] The CMOS (complementary metal-oxide-semiconductor) silicon-based compatible quantum dot technology has always been a research hotspot. The unique liquid synthesis characteristics of the colloidal quantum dot can realize silicon-based monolithic integration, avoiding the complex alignment and flip-chip bonding process in the flip-chip bonding process, and thus preparing high-performance optical detection devices. However, the current quantum dot colloids have a narrow response band, which limits the detection spectral range of the optical detector.

[0005] Therefore, it is desirable to provide a new hybrid quantum dot material. SUMMARY

[0006] To solve the above technical problems, the application provides a CsPbX3 / HgTe quantum dot material and a preparation method and application thereof. The CsPbX3 / HgTe quantum dot material prepared by the application utilizes methyl to connect the CsPbX3 quantum dot and the HgTe quantum dot to form a nanoscale heterojunction, and the CsPbX3 quantum dot is coated with a silicon layer, effectively isolating the carriers of the two to form a depletion layer, and then forming an electric field between the two quantum dot materials, promoting the carrier separation of the mercury telluride quantum dot, and effectively improving the response speed of the optical detector. Moreover, the CsPbX3 / HgTe quantum dot material provided by the application has response capabilities in the infrared light, visible light, ultraviolet light and X-ray wave bands, effectively widening the detection spectral range.

[0007] In a first aspect, the present application provides a preparation method of a CsPbX3 / HgTe quantum dot material, the preparation method comprising:

[0008] (1) reacting CsPbX3 quantum dots with silicate in an organic solvent to obtain CsPbX3 quantum dots coated with a silicon layer;

[0009] (2) mixing HgTe quantum dots in a mixed solvent of butanediol and ethanol, centrifuging to obtain a subsidence precipitate, dissolving the subsidence precipitate in a mixed solution of chlorobenzene, mercaptoethanol and ethanol to perform liquid ligand exchange, and centrifuging to obtain ligand-exchanged HgTe quantum dots;

[0010] (3) mixing the ligand-exchanged HgTe quantum dots, the CsPbX3 quantum dots coated with a silicon layer, and a monohalogenated methane in a nonpolar solvent, adding a polar solvent to perform extraction, and obtaining the CsPbX3 / HgTe quantum dot material;

[0011] wherein X is selected from Br, Cl or I, and steps (1) and (2) are not in a specific order.

[0012] The preparation method provided by the present application is simple in process, suitable for large-scale preparation, and greatly reduces the material processing cost. On the one hand, a silicon layer is coated on the surface of the CsPbX3 quantum dots to block the carrier from falling off from the CsPbX3 quantum dots, thereby avoiding the carrier from forming crosstalk with the HgTe quantum dots. On the other hand, long-chain ligands on the surface of the HgTe quantum dots are replaced by short-chain ligands through liquid ligand exchange, thereby realizing the accumulation and transfer of charges. Then, the two are connected by methyl to form a nanoscale heterojunction, so that the prepared CsPbX3 / HgTe quantum dot material can effectively improve the response speed of the photodetector. In addition, the CsPbX3 quantum dots emit visible light of 540 nm after being irradiated by ultraviolet light and X-ray, and the HgTe quantum dots can absorb and respond to visible light. Therefore, the response band of the HgTe quantum dots can be widened to the ultraviolet and X-ray bands, so that the CsPbX3 / HgTe quantum dot material has the response ability of the infrared, visible, ultraviolet and X-ray bands, effectively widening the detection spectral range.

[0013] As a preferred technical solution of the present application, the preparation method of the CsPbX3 quantum dots comprises mixing PbX2, octadecene, oleic acid and oleylamine, adding a cesium source to react, and obtaining CsPbX3 quantum dots.

[0014] As a preferred technical solution of the present application, the preparation method of the CsPbBr3 quantum dots comprises mixing lead bromide, octadecene, oleic acid and oleylamine, adding a cesium source to react, and obtaining CsPbBr3 quantum dots.

[0015] As a preferred technical solution of the present application, the preparation method of the CsPbX3 quantum dots comprises: mixing PbX2, octadecene, oleic acid and oleylamine at 120°C, then heating to 140°C for 30 min, adding a cesium source for reaction for 5s, cooling to obtain CsPbX3 quantum dots.

[0016] As a preferred technical solution of the present application, the ratio of the molar amount of PbX2 to the volume of octadecene, oleic acid and oleylamine is 0.752 mmol:20 mL:2 mL:2 mL.

[0017] As a preferred technical solution of the present application, the cesium source is selected from cesium carbonate.

[0018] As a preferred technical solution of the present application, the molar ratio of cesium in the cesium source to lead in PbX2 is 1:1.

[0019] As a preferred technical solution of the present application, the molar ratio of CsPbX3 quantum dots to silicate is 1:8.

[0020] When the ratio of CsPbX3 quantum dots to silicate is within the above range, a uniform silicon layer can be coated on the surface of each CsPbX3 quantum dot, and the thickness is about 5 nm.

[0021] As a preferred technical solution of the present application, the silicate comprises methyl orthosilicate.

[0022] As a preferred technical solution of the present application, the organic solvent in step (1) is a mixed solvent of cyclohexane and toluene. Since the obtained CsPbX3 quantum dots coated with a silicon layer have poor solubility, the present application selects a mixed solvent of cyclohexane and toluene, so that the CsPbX3 quantum dots coated with a silicon layer can be better dissolved.

[0023] As a preferred technical solution of the present application, the reaction in step (1) is carried out under the protection of an inert gas atmosphere. The inert gas is selected from nitrogen and / or argon.

[0024] As a preferred technical solution of the present application, the temperature of the reaction in step (1) is 140-160°C, for example 140°C, 145°C, 150°C, 155°C, 160°C, etc.

[0025] As a preferred technical solution of the present application, the reaction time in step (1) is 120 min.

[0026] As a preferred technical solution of the present application, after the reaction in step (1), centrifugation is further carried out to obtain the upper layer of CsPbX3 quantum dots coated with a silicon layer.

[0027] As a preferred technical solution of the present application, the volume ratio of HgTe quantum dots to butanedithiol to ethanol in step (2) is 1:1:(2-10).

[0028] As a preferred technical solution of the present application, the temperature for mixing in step (2) is 30℃, and the mixing time is 30 min.

[0029] As a preferred technical solution of the present application, the volume ratio of HgTe quantum dots to chlorobenzene to mercaptoethanol to ethanol in step (2) is 1:1:1:(2-10).

[0030] As a preferred technical solution of the present application, the temperature for liquid phase ligand exchange in step (2) is 30℃, and the time is 30 min.

[0031] As a preferred technical solution of the present application, the molar ratio of HgTe quantum dots to CsPbX3 quantum dots coated with a silicon layer to monohalogenated methane after ligand exchange is 1:1:1.

[0032] As a preferred technical solution of the present application, the monohalogenated methane is selected from any one or more of methyl bromide, methyl chloride, methyl fluoride or methyl iodide, and is preferably methyl bromide.

[0033] As a preferred technical solution of the present application, the temperature for reaction in step (3) is 30℃.

[0034] As a preferred technical solution of the present application, the time for reaction in step (3) is 60 min.

[0035] As a preferred technical solution of the present application, the non-polar solvent in step (3) is selected from cyclohexane.

[0036] As a preferred technical solution of the present application, the polar solvent in step (3) is selected from dimethylacetamide.

[0037] In a second aspect, the present application provides a CsPbX3 / HgTe quantum dot material prepared by the preparation method of the first aspect, wherein X is selected from Br, Cl or I.

[0038] The CsPbX3 / HgTe quantum dot material provided by the application connects the CsPbX3 quantum dot and the HgTe quantum dot by using a methyl to form a nanoscale heterojunction, and the CsPbX3 quantum dot is coated with a silicon layer with a thickness of about 5 nm, which effectively isolates the carriers of the two to form a depletion layer, and further forms an electric field between the two quantum dot materials, promotes the carrier separation of the mercury telluride quantum dot, and effectively improves the response speed of the photodetector.

[0039] In a third aspect, the application provides a CsPbX3 / HgTe quantum dot film, which is prepared from the CsPbX3 / HgTe quantum dot material of the second aspect.

[0040] In a fourth aspect, the application provides a single-layer multicolor detector, which comprises the CsPbX3 / HgTe quantum dot film of the third aspect.

[0041] As a preferred technical solution of the application, the single-layer multicolor detector further comprises a CMOS substrate, and the CsPbX3 / HgTe quantum dot film is located on the surface of the CMOS substrate.

[0042] As a preferred technical solution of the application, the preparation method of the single-layer multicolor detector comprises:

[0043] After the CsPbX3 / HgTe quantum dot material is dissolved in a solvent and then drop-coated on the CMOS substrate, the single-layer multicolor detector is obtained after standing.

[0044] The preparation of the single-layer multicolor detector of the application can effectively save the preparation time and process of the device.

[0045] The technical solution provided by the embodiments of the application has the following advantages compared with the prior art:

[0046] 1. The preparation method provided by the application is simple in process and suitable for large-scale preparation, which greatly reduces the material processing cost.

[0047] 2、The CsPbX3 / HgTe quantum dot material provided by the application connects the CsPbX3 quantum dot and the HgTe quantum dot by using methyl to form a nanoscale heterojunction, and the CsPbX3 quantum dot is coated with a silicon layer with a thickness of about 5 nm, so that the carriers of the two are effectively isolated to form a depletion layer, and then an electric field is formed between the two quantum dot materials, so that the carrier separation of the mercury telluride quantum dot is promoted, and the response speed of the light detector is effectively improved; in addition, the CsPbX3 / HgTe quantum dot material has response capabilities for infrared light, visible light, ultraviolet light and X-ray wave bands, and effectively widens the detection spectral range. DETAILED DESCRIPTION

[0048] In order to enable more clear understanding of the above-mentioned purposes, features and advantages of the application, the schemes of the application will be further described below. It should be noted that the embodiments of the application and the features in the embodiments can be combined with each other without conflict.

[0049] In the following description, many specific details are set forth in order to provide a thorough understanding of the application, but the application can also be implemented in other manners different from those described herein; obviously, the embodiments in the description are only some embodiments of the application, not all embodiments.

[0050] Preparation Example 1

[0051] The present preparation example provides a CsPbBr3 quantum dot and a preparation method thereof, and the preparation method is as follows:

[0052] (1) Preparation of cesium oleate: the whole process is carried out in an inert gas glove box, a 100 mL glass bottle is placed on a magnetic stirring hot plate, 0.36 g of Cs2CO3, 15 mL of ODE (octadecene) and 1.5 mL of OA (oleic acid) are added to the 100 mL glass bottle, the hot plate is heated to 120 DEG C and stirred, and after 30 min, the temperature is increased to 150 DEG C until all Cs2CO3 reacts with OA to obtain a clear solution, which is cesium oleate.

[0053] (2) Synthesis of CsPbBr3 quantum dots: the whole process is carried out in an inert gas glove box

[0054] Into a 100 mL glass bottle, 0.276 g of PbBr2, 20 mL of ODE, 2 mL of OA and 2 mL of Oam (oleyl amine) were added, the hot plate was heated to 120°C and stirred to degas for 30 min, after the PbBr2 salt was completely dissolved, the temperature was raised to 140°C. After the heat balance for 30 min, 2 mL of preheated cesium oleate solution was quickly injected for 5 seconds, the reaction product was cooled using an ice water bath, and cooled for 20 min. After that, the reaction product was divided into centrifuge tubes, ethyl acetate and toluene were added for centrifugation, centrifugation was performed at 8000 rpm for 2 min, the supernatant was taken, and the purification operation was repeated 3 times, and the last supernatant 4 mL was obtained, which was the CsPbBr3 quantum dot solution.

[0055] Example 1

[0056] The present embodiment provides a CsPbBr3 / HgTe quantum dot material and a preparation method thereof, and the preparation method comprises the following steps:

[0057] (1) Preparation of CsPbBr3 quantum dots coated with a silicon layer:

[0058] In an inert gas glove box, 4 mL of purified CsPbBr3 quantum dots were taken, 4 mL of cyclohexane and 20 mL of toluene were added, stirring was performed at 160°C for 30 min, 200 μL of tetramethyl orthosilicate was quickly injected into the solution, and stirring was performed at 160°C for 120 min. After that, the water bath was cooled for 30 min, centrifugation was performed at 8000 rpm for 2 min, and the supernatant was taken, which was the CsPbBr3 quantum dot solution coated with a silicon layer, ready for use.

[0059] (2) Ligand exchange of HgTe quantum dots in a liquid phase:

[0060] Into a 20 mL glass bottle, 10 mL of HgTe quantum dots, 10 mL of butanedithiol and 20 mL of ethanol were added, stirring was performed on a hot plate at 30°C for 30 min, centrifugation was performed at 8000 rpm for 2 min, and the precipitate was taken. The precipitate was dissolved with 10 mL of chlorobenzene, 10 mL of mercaptoethanol and 20 mL of ethanol were added, stirring was performed on a hot plate at 30°C for 30 min, centrifugation was performed at 8000 rpm for 2 min, and the precipitate was dissolved with cyclohexane, and the HgTe quantum dots were obtained.

[0061] (3) Preparation of CsPbBr3 / HgTe quantum dot material:

[0062] Take 100 mL of glass bottle to join the cyclohexane dissolved HgTe quantum dots 10 mL obtained in step (2), join 20 mL of the silicon layer coated CsPbBr3 quantum dot solution obtained in step (3), join 20 mL of methyl bromide, stir on the hot plate at 30 DEG C for 60 min, join 30 mL of dimethylacetamide for ultrasonic, because the polarity of cyclohexane and dimethylacetamide is different, the material can be layered, and the upper layer is discarded using a rubber head dropper, and the lower layer is the CsPbBr3 / HgTe quantum dot material.

[0063] Application Example 1

[0064] The application example provides a single-layer multi-color detector and a preparation method thereof, and the preparation method comprises the following steps:

[0065] The CsPbBr3 / HgTe quantum dots prepared in Example 1 are dropped on a CMOS substrate, and then placed on a hot plate at 45 DEG C to volatilize the quantum dots, so as to leave a quantum dot film layer, thereby obtaining the single-layer multi-color detector.

[0066] It should be noted that, in this document, relational terms such as "first" and "second", and the like can 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. Moreover, the terms "comprises", "comprising", or any other variations 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 can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without more limitations, an element defined by the phrase "comprising a..." does not exclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0067] The above description is only a specific implementation of the present application, which enables those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a CsPbX 3 / HgTe quantum dot material, characterized in that, The preparation method comprises: (1) reacting CsPbX3 quantum dots with silicate in an organic solvent to obtain CsPbX3 quantum dots coated with a silicon layer; (2) mixing HgTe quantum dots in a mixed solvent of butanediol and ethanol, centrifuging to obtain a precipitate, dissolving the precipitate in a mixed solution of chlorobenzene, mercaptoethanol and ethanol to perform liquid phase ligand exchange, and centrifuging to obtain ligand-exchanged HgTe quantum dots; (3) mixing the ligand-exchanged HgTe quantum dots, CsPbX3 quantum dots coated with a silicon layer and monohalogenated methane in a nonpolar solvent, and adding a polar solvent to perform extraction to obtain the CsPbX3 / HgTe quantum dot material; wherein X is selected from Br, Cl or I, and steps (1) and (2) are not in a specific order; the molar ratio of the CsPbX3 quantum dots to the silicate is 1:8; the molar ratio of the ligand-exchanged HgTe quantum dots, CsPbX3 quantum dots coated with a silicon layer and monohalogenated methane is 1:1:

1.

2. The production method according to claim 1, characterized by, The preparation method of the CsPbX3 quantum dots comprises mixing PbX2, octadecene, oleic acid and oleylamine, adding a cesium source to perform reaction to obtain CsPbX3 quantum dots.

3. The production method according to claim 1 or 2, characterized by, The silicate comprises methyl orthosilicate; and / or, the organic solvent in step (1) is selected from a mixed solvent of cyclohexane and toluene; and / or, the reaction in step (1) is performed under protection of an inert gas atmosphere; and / or, the temperature of the reaction in step (1) is 140-160℃; and / or, the time of the reaction in step (1) is 120 min; and / or, after the reaction in step (1), centrifugation is further performed to obtain CsPbX3 quantum dots coated with a silicon layer in the upper layer.

4. The production method according to claim 1 or 2, characterized by, In step (2), the volume ratio of the HgTe quantum dots to butanediol and ethanol is 1:1:(2-10); and / or, the mixing temperature in step (2) is 30℃, and the mixing time is 30 min; and / or, in step (2), the volume ratio of the HgTe quantum dots to chlorobenzene, mercaptoethanol and ethanol is 1:1:1:(2-10); and / or, the temperature of the liquid phase ligand exchange in step (2) is 30℃, and the time is 30 min.

5. The production method according to claim 1 or 2, characterized by, The monohalogenated methane is selected from any one or more of methyl bromide, methyl chloride, methyl fluoride or methyl iodide.

6. The production method according to claim 1 or 2, characterized by, In step (3), the reaction temperature is 30℃; and / or, the reaction time in step (3) is 60 min; and / or, the nonpolar solvent in step (3) is selected from cyclohexane; and / or, the polar solvent in step (3) is selected from dimethylacetamide.

7. The CsPbX3 / HgTe quantum dot material prepared by the preparation method according to any one of claims 1-6, wherein, X is selected from Br, Cl or I.

8. A CsPbX3 / HgTe quantum dot film, characterized in that, The CsPbX3 / HgTe quantum dot film is prepared from the CsPbX3 / HgTe quantum dot material of claim 7.

9. A single layer multicolor detector, characterized by, The single-layer multi-color detector comprises the CsPbX3 / HgTe quantum dot film of claim 8.

10. The single layer multi-color detector of claim 9, wherein, The single-layer multi-color detector further comprises a CMOS substrate, and the CsPbX3 / HgTe quantum dot film is located on the surface of the CMOS substrate.