Cesium lead bromide / silicon dioxide quantum dot and preparation method thereof

Abstract

The invention discloses a cesium-lead-bromine / silicon dioxide quantum dot and a preparation method thereof, and belongs to the technical field of quantum dot luminescent materials.The preparation method comprises the steps that at the temperature of 75-95 DEG C, cesium bromide, lead bromide and water are mixed and then magnetically stirred, and a cesium-lead-bromine precursor solution is obtained; at the temperature of 75-95 DEG C, mixing aminopropyltriethoxysilane with the cesium-lead-bromine precursor solution, and then carrying out magnetic stirring to obtain a cesium-lead-bromine / silicon dioxide solution; and drying the cesium lead bromide / silicon dioxide solution at the temperature of 75-95 DEG C to obtain the cesium lead bromide / silicon dioxide quantum dots. The cesium-lead-bromine / silicon dioxide quantum dot has the characteristics of structural stability, acid resistance, 800 DEG C high temperature resistance, water resistance and the like, is long in luminescence life, high in quantum yield and non-toxic, and meets the preparation requirements of flexible wearable devices, light-emitting gratings and other optical devices.

Description

Technical Field

[0001] The invention belongs to the technical field of quantum dot luminescent materials, and in particular relates to cesium lead bromine / silicon dioxide quantum dots and a preparation method thereof. Background Art

[0002] Perovskite nanocrystals have flourished in the past decade and stand out for their superior optoelectronic properties, such as high defect tolerance, widely tunable emission wavelength, and narrow emission linewidth. These extraordinary properties make them have great application prospects in the fields of photovoltaics, light-emitting diodes (LEDs), anti-counterfeiting, and photodetectors.

[0003] So far, many state-of-the-art methods have been used to synthesize perovskites with excellent emission properties. Unfortunately, the intrinsic instability of perovskites due to the high dynamics of their ionic structures and surface ligands towards humidity, polar solvents, heat, and light irradiation has become a major obstacle on the road to commercial application. Summary of the invention

[0004] One of the purposes of the present invention is to provide a method for preparing cesium lead bromine / silicon dioxide quantum dots. The cesium lead bromine / silicon dioxide quantum dots prepared by the method have the characteristics of structural stability, acid resistance, 800-degree high temperature resistance and water resistance, long luminescence lifetime, high quantum yield, and are non-toxic, meeting the preparation requirements of optical devices such as flexible wearable devices and luminescent gratings.

[0005] A second object of the present invention is to provide a cesium lead bromine / silicon dioxide quantum dot.

[0006] In order to achieve one of the above purposes, the present invention adopts the following technical solutions:

[0007] A method for preparing cesium lead bromine / silicon dioxide quantum dots, the preparation method comprising the following steps:

[0008] Step S1, mixing cesium bromide, lead bromide and water at a temperature of 75 to 95° C. and then stirring them magnetically to obtain a cesium lead bromine precursor solution;

[0009] Step S2, at a temperature of 75-95° C., mixing aminopropyltriethoxysilane with the cesium lead bromine precursor solution and then stirring magnetically to obtain a cesium lead bromine / silicon dioxide solution;

[0010] Step S3, drying the cesium lead bromine / silicon dioxide solution at a temperature of 75-95° C. to obtain cesium lead bromine / silicon dioxide quantum dots.

[0011] Furthermore, in the step S1, in the cesium lead bromine precursor solution, 0.004 to 0.01875 mmol of cesium bromide and 0.004 to 0.01875 mmol of lead bromide are dissolved in each liter of water.

[0012] Furthermore, in the step S1, the magnetic stirring time is 0.5 to 1 h, and the speed is 950 to 1050 rpm / min.

[0013] Furthermore, in step S2, the volume ratio of the aminopropyltriethoxysilane to the cesium lead bromide precursor solution is 0.1-1:30-50.

[0014] Furthermore, in step S2, the magnetic stirring time is 1 to 4 hours, and the speed is 950 to 1050 rpm / min.

[0015] Furthermore, in step S3, the drying time is 11 to 13 hours.

[0016] In order to achieve the second objective above, the present invention adopts the following technical solution:

[0017] A cesium lead bromine / silicon dioxide quantum dot is prepared by the above-mentioned preparation method.

[0018] Furthermore, the cesium lead bromine / silicon dioxide quantum dots include an inner layer of cesium lead bromine and silicon dioxide wrapped outside the cesium lead bromine.

[0019] Furthermore, the morphology of the cesium lead bromine / silicon dioxide quantum dots is nanocube, nanosphere, nanohexagonal sheet or nanoflower.

[0020] In summary, the technical solution of the present invention has the following technical effects:

[0021] 1. The present invention avoids the use of traditional oleylamine and oleic acid by synthesizing cesium bromide and lead bromide in water, reduces the toxicity of organic solvents, and lays a foundation for the preparation of wearable devices;

[0022] 2. The present invention uses the hydrolysis product of aminopropyltriethoxysilane (APTES) which can be used as a surface ligand and a silica precursor at the same time, thereby isolating the toxicity of cesium lead bromine and physical and chemical factors such as water, thereby improving the quantum yield and luminescence lifetime; the luminescence lifetime of the cesium lead bromine / silicon dioxide quantum dots of the present invention is 53.98792~67.20816ns, and the yield of cesium lead bromine / silicon dioxide quantum dots is 24.65~70.86%, which meets the preparation requirements of optical devices such as flexible wearable devices and luminescent gratings.

[0023] 3. The present invention adopts a hydrothermal method to synthesize cesium lead bromine, and wraps silicon dioxide on the cesium lead bromine, giving the cesium lead bromine the morphology of nanospheres, nanocubes, nanohexagonal sheets, and nanoflowers, thereby increasing the reaction area of ​​photocatalysis, which is beneficial to the carrier separation of light detection, and at the same time is isolated from the anion exchange reaction of cesium lead bromine and the outside world, ensuring that the cesium lead bromine / silicon dioxide quantum dots have the characteristics of structural stability, acid resistance, resistance to high temperature of 800 degrees, and water resistance, and improving the intrinsic stability of the ionic structure and surface ligands of cesium lead bromine / silicon dioxide quantum dots to humidity, polar solvents, heat and light irradiation, meeting the preparation requirements of optical devices such as flexible wearable devices and light-emitting gratings.

[0024] 4. The luminescent wavelength of the cesium lead bromine / silicon dioxide quantum dots in the present invention is uniformly adjustable from ultraviolet to visible light (435nm to 535nm), and can be used to prepare optical devices such as flexible wearable devices and luminescent gratings.

[0025] 5. The present invention adopts a hydrothermal method to synthesize cesium lead bromine. The method at room temperature and pressure is simple and easy to operate. It provides a certain reference for the preparation of high-performance luminescent materials and flexible wearable devices and optical devices such as luminescent gratings. It has broad market prospects and is suitable for large-scale promotion and application. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention is clearly and completely described below. 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 are within the scope of protection of the present invention.

[0027] This embodiment provides a method for preparing cesium lead bromine / silicon dioxide quantum dots, which comprises the following steps:

[0028] Step S1, at a temperature of 75-95° C., cesium bromide, lead bromide and water are mixed and magnetically stirred to obtain a cesium lead bromine precursor solution.

[0029] This embodiment uses cesium bromide and lead bromide to synthesize in water to obtain a cesium lead bromine precursor solution, thereby realizing the synthesis of perovskite (i.e., cesium lead bromine precursor) in an aqueous phase, avoiding the use of traditional oleylamine and oleic acid, reducing the toxicity of organic solvents, and laying a foundation for the preparation of wearable devices.

[0030] In the cesium lead bromine precursor solution of this embodiment, 0.004-0.01875 mmol of cesium bromide and 0.004-0.01875 mmol of lead bromide are dissolved in each liter of water. The magnetic stirring time is 0.5-1 hour, and the speed is 950-1050 rpm / min.

[0031] Step S2: at a temperature of 75-95° C., aminopropyltriethoxysilane is mixed with the cesium lead bromine precursor solution and then magnetically stirred to obtain a cesium lead bromine / silicon dioxide solution.

[0032] The aminopropyltriethoxysilane (APTES) in this embodiment can hydrolyze to form amino groups and silicon dioxide at a temperature of 75 to 95° C. The amino groups can be used as surface ligands to reduce the defect state density of cesium lead bromine. Silicon dioxide can be used as a precursor, and the toxicity of cesium lead bromine and physical and chemical factors such as water can be isolated through silicon dioxide, which can improve the quantum yield and luminescence intensity of cesium lead bromine / silicon dioxide quantum dots on the basis of reducing the toxicity of cesium lead bromine / silicon dioxide quantum dots. At the same time, silicon dioxide is used to wrap cesium lead bromine, giving it the morphology of cesium lead bromine nanospheres, nanocubes, nanohexagonal sheets, and nanoflowers, thereby increasing the reaction area of ​​photocatalysis, which is beneficial to the carrier separation of light detection, and at the same time isolating the cesium lead bromine from the external anion exchange reaction, ensuring that the cesium lead bromine / silicon dioxide quantum dots have structural stability, acid resistance, resistance to 800 degrees high temperature, and water resistance. It improves the intrinsic stability of the ionic structure and surface ligands of cesium lead bromine / silicon dioxide quantum dots to humidity, polar solvents, heat, and light irradiation, and meets the preparation requirements of optical devices such as flexible wearable devices and luminescent gratings.

[0033] In this embodiment, the volume ratio of aminopropyltriethoxysilane to cesium lead bromide precursor solution is 0.1-1:30-50, preferably 0.3-0.8:35-45. The magnetic stirring time is 1-4 hours, and the speed is 950-1050 rpm / min.

[0034] Step S3, drying the cesium lead bromine / silicon dioxide solution at a temperature of 75-95° C. to obtain cesium lead bromine / silicon dioxide quantum dots.

[0035] The drying time in this embodiment is 11 to 13 hours.

[0036] Another embodiment provides a cesium lead bromine / silicon dioxide quantum dot, which is prepared by the preparation method provided in the embodiment.

[0037] The cesium lead bromine / silicon dioxide quantum dots of this embodiment include an inner layer of cesium lead bromine and silicon dioxide wrapped outside the cesium lead bromine. The morphology of the cesium lead bromine / silicon dioxide quantum dots is nanocube, nanosphere, nanohexagonal sheet or nanoflower.

[0038] Embodiment 1:

[0039] Step S1, at a temperature of 90° C., 0.012 mmol of cesium bromide and 0.012 mmol of lead bromide are dissolved in each liter of water, cesium bromide, lead bromide and water are mixed, and magnetic stirring is performed at a rate of 1000 rpm / min for 40 minutes to obtain a cesium lead bromine precursor solution.

[0040] Step S2, at a temperature of 90° C., according to a volume ratio of 0.3:45, aminopropyltriethoxysilane is mixed with the cesium lead bromine precursor solution, and magnetically stirred at a rate of 1000 rpm / min for 4 hours to obtain a cesium lead bromine / silicon dioxide solution.

[0041] Step S3, drying the cesium lead bromine / silicon dioxide solution at 90° C. for 12 hours to obtain cesium lead bromine / silicon dioxide quantum dots.

[0042] The morphology of the cesium lead bromine / silicon dioxide quantum dots in this embodiment is nanocube, and its emission wavelength is uniformly adjustable from 435nm to 535nm. The excitation light of 280 to 424nm of the cesium lead bromine / silicon dioxide quantum dots can excite the cesium lead bromine / silicon dioxide, which is a wide spectrum excitation material, 1540cm -1 and 2930cm -1 The wave number is derived from NH vibration, 1393 cm -1 The wave number is derived from Si-CH2 vibration, 1138 cm -1 and 1128cm -1 The wave number originates from Si-O-Si vibration, the luminescence lifetime is 67.20816ns, and the yield of cesium lead bromine / silicon dioxide quantum dots is 24.65%.

[0043] Embodiment 2:

[0044] Step S1, at a temperature of 90° C., 0.008 mmol of cesium bromide and 0.008 mmol of lead bromide are dissolved in each liter of water, cesium bromide, lead bromide and water are mixed, and magnetic stirring is performed at a rate of 950 rpm / min for 30 minutes to obtain a cesium lead bromine precursor solution.

[0045] Step S2, at a temperature of 90° C., according to a volume ratio of 0.8:35, aminopropyltriethoxysilane is mixed with the cesium lead bromide precursor solution, and magnetic stirring is performed at a rate of 950 rpm / min for 2 hours to obtain a cesium lead bromide / silicon dioxide solution.

[0046] Step S3, drying the cesium lead bromine / silicon dioxide solution at a temperature of 90° C. for 11 hours to obtain cesium lead bromine / silicon dioxide quantum dots.

[0047] The morphology of the cesium lead bromine / silicon dioxide quantum dots in this embodiment is a nano hexagonal plate, and its emission wavelength is uniformly adjustable from 435nm to 535nm. The cesium lead bromine / silicon dioxide quantum dots can be excited by the excitation light of 280 to 424nm, which is a wide spectrum excitation material, 1540cm -1 and 2930cm -1 The wave number is derived from NH vibration, 1393 cm -1 The wave number is derived from Si-CH2 vibration, 1138 cm -1 and 1128cm -1 The wave number originates from Si-O-Si vibration, the luminescence lifetime is 62.54847ns, and the yield of cesium lead bromine / silicon dioxide quantum dots is 38.07%.

[0048] Embodiment 3:

[0049] Step S1, at a temperature of 75° C., 0.016 mmol of cesium bromide and 0.016 mmol of lead bromide are dissolved in each liter of water, cesium bromide, lead bromide and water are mixed, and magnetic stirring is performed at a rate of 950 rpm / min for 30 minutes to obtain a cesium lead bromine precursor solution.

[0050] Step S2, at a temperature of 75° C., aminopropyltriethoxysilane is mixed with the cesium lead bromide precursor solution in a volume ratio of 0.7:40, and magnetically stirred at a rate of 950 rpm / min for 4 hours to obtain a cesium lead bromide / silicon dioxide solution.

[0051] Step S3, drying the cesium lead bromine / silicon dioxide solution at a temperature of 75° C. for 11 hours to obtain cesium lead bromine / silicon dioxide quantum dots.

[0052] The morphology of the cesium lead bromine / silicon dioxide quantum dots in this embodiment is a nano hexagonal plate, and its emission wavelength is uniformly adjustable from 435nm to 535nm. The cesium lead bromine / silicon dioxide quantum dots can be excited by the excitation light of 280 to 424nm, which is a wide spectrum excitation material, 1540cm -1 and 2930cm -1 The wave number is derived from NH vibration, 1393 cm -1 The wave number is derived from Si-CH2 vibration, 1138 cm -1 and 1128cm -1 The wave number originates from Si-O-Si vibration, the luminescence lifetime is 58.49367ns, and the yield of cesium lead bromine / silicon dioxide quantum dots is 70.86%.

[0053] Embodiment 4:

[0054] Step S1, at a temperature of 95° C., 0.004 mmol of cesium bromide and 0.004 mmol of lead bromide are dissolved in each liter of water, cesium bromide, lead bromide and water are mixed, and magnetic stirring is performed at a rate of 1050 rpm / min for 60 min to obtain a cesium lead bromine precursor solution.

[0055] Step S2, at a temperature of 95° C., aminopropyltriethoxysilane is mixed with the cesium lead bromine precursor solution in a volume ratio of 0.1:30, and magnetically stirred at a rate of 1050 rpm / min for 1 hour to obtain a cesium lead bromine / silicon dioxide solution.

[0056] Step S3, drying the cesium lead bromine / silicon dioxide solution at a temperature of 95° C. for 13 hours to obtain cesium lead bromine / silicon dioxide quantum dots.

[0057] The morphology of the cesium lead bromine / silicon dioxide quantum dots in this embodiment is a nanoflower, and its emission wavelength is uniformly adjustable from 435nm to 535nm. The excitation light of 280 to 424nm of the cesium lead bromine / silicon dioxide quantum dots can excite the cesium lead bromine / silicon dioxide, which is a wide spectrum excitation material, 1540cm -1 and 2930cm -1 The wave number is derived from NH vibration, 1393 cm -1 The wave number is derived from Si-CH2 vibration, 1138 cm -1 and 1128cm -1 The wave number originates from Si-O-Si vibration, the luminescence lifetime is 53.98792ns, and the yield of cesium lead bromine / silicon dioxide quantum dots is 34.45%.

[0058] Please note that the technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. The above embodiments only express several implementation methods of the present application, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several variations and improvements can be made, which all belong to the scope of protection of the present application. Therefore, the scope of protection of the patent in this application shall be based on the attached claims.

Claims

1. A method for preparing cesium lead bromine / silicon dioxide quantum dots, characterized in that: The preparation method comprises the following steps: Step S1, mixing cesium bromide, lead bromide and water at a temperature of 75 to 95° C. and then stirring them magnetically to obtain a cesium lead bromine precursor solution; Step S2, at a temperature of 75-95° C., mixing aminopropyltriethoxysilane with the cesium lead bromine precursor solution and then performing magnetic stirring to obtain a cesium lead bromine / silicon dioxide solution; Step S3, drying the cesium lead bromine / silicon dioxide solution at a temperature of 75-95° C. to obtain cesium lead bromine / silicon dioxide quantum dots.

2. The preparation method according to claim 1, characterized in that: In the step S1, in the cesium lead bromine precursor solution, 0.004-0.01875 mmol of cesium bromide and 0.004-0.01875 mmol of lead bromide are dissolved in each liter of water.

3. The preparation method according to claim 2, characterized in that: In the step S1, the magnetic stirring time is 0.5 to 1 h, and the speed is 950 to 1050 rpm / min.

4. The preparation method according to any one of claims 1 to 3, characterized in that: In the step S2, the volume ratio of the aminopropyltriethoxysilane to the cesium lead bromide precursor solution is 0.1-1:30-50.

5. The preparation method according to claim 4, characterized in that: In the step S2, the magnetic stirring time is 1 to 4 hours, and the speed is 950 to 1050 rpm / min.

6. The preparation method according to claim 5, characterized in that: In the step S3, the drying time is 11 to 13 hours.

7. A cesium lead bromine / silicon dioxide quantum dot, characterized in that: The cesium lead bromine / silicon dioxide quantum dots are prepared by the preparation method described in any one of claims 1 to 6.

8. The cesium lead bromine / silicon dioxide quantum dots according to claim 7, characterized in that: The cesium lead bromine / silicon dioxide quantum dots include an inner layer of cesium lead bromine and silicon dioxide wrapped outside the cesium lead bromine.

9. The cesium lead bromine / silicon dioxide quantum dots according to claim 8, characterized in that: The morphology of the cesium lead bromine / silicon dioxide quantum dots is nanocube, nanosphere, nanohexagonal sheet or nanoflower.