Preparation method and application of single-component white light perovskite material

Abstract

The invention discloses a preparation method and application of a single-component white light perovskite material, and belongs to the field of preparation and application of novel luminescent materials. The chemical formula of the single-component white light perovskite material is CsCdIxCl3-x, x is equal to 1-2, the excitation wavelength is 220-320 nm, the emission wavelength is 350-700 nm, and the fluorescence quantum yield is 70%-90%. The preparation method designed by the invention is green, simple, low in cost and suitable for mass production; the prepared single-component white light perovskite material has the advantages of being high in fluorescence quantum yield, high in crystallinity, wide in emission spectrum, capable of directly generating white light and the like. According to the invention, an aqueous phase synthesis preparation method is adopted, the use of an organic solvent or an acid solution in a traditional solution method is avoided, and the obtained single-component white-light perovskite material can directly generate full-spectrum emission and has great application potential in the field of solid-state illumination.

Description

Technical Field

[0001] The present invention relates to the field of preparation and application of novel luminescent materials, and in particular to a preparation method and application of a single-component white light perovskite material. Background Art

[0002] Compared with traditional light sources (especially incandescent lamps, halogen lamps and fluorescent lamps), LED lighting is extremely cost-effective: compared with incandescent lamps, LED lamps can save 80-90% of energy; compared with halogen lamps, it can save 75-80% of energy; compared with fluorescent lamps, it can save 50-60% of energy. This is because traditional light sources mainly consume energy in the form of thermal radiation, while LED lighting technology can directly and effectively convert electrons into photons. LED light sources also have the advantages of long service life, high integration of lighting control, good optical control, and strong dimming. From the perspective of circular economy, LED light sources have less impact on the environment, so they have become a new generation of solid-state lighting light source technology.

[0003] White light LEDs mainly stimulate yellow phosphors (such as YAG: Ce 3+ ) or by exciting three-primary color phosphors through ultraviolet chips to achieve white light illumination. However, when blue light chips excite yellow phosphors or mixed phosphors, they have large Stokes losses, and self-absorption or reabsorption will lead to reduced light efficiency; under different working conditions, different components of phosphors have different working mechanisms, which may cause the color temperature of white light LEDs to drift, affecting the lighting effect; the narrow-band emission or spectrum loss of phosphors leads to a low color rendering index (CRI) of white light LEDs, which cannot fully present the true color of the illuminated object. Therefore, the development of new and efficient phosphor materials is of great significance to further improve the quality of LED lighting, improve lighting efficiency and reduce energy consumption. Single-component white light fluorescent materials, especially single-component white light emitting perovskite materials based on self-trapped excitons, can effectively reduce the energy loss caused by self-absorption and reabsorption of mixed phosphors due to their large Stokes shift and wide spectrum emission characteristics. In addition, they can directly and efficiently emit full-spectrum white light covering the entire visible light range. Combined with ultraviolet LED chip solid-state lighting technology, it has shown research value and application prospects in current research and application fields. However, the preparation methods of single-component white-light-emitting perovskite materials in this field generally require the use of organic solvents or acid solutions, which is not in line with the concept of green environmental protection; and traditional preparation methods such as gas phase method, mechanical synthesis method, etc. have complicated operation processes, narrow emission spectra, and are difficult to achieve large-scale preparation, and still need further improvement. Summary of the invention

[0004] The purpose of the present invention is to provide a preparation method and application of a single-component white light perovskite material to solve the above-mentioned problems in the background technology. The preparation method designed by the present invention is green, simple, low-cost, and suitable for mass production; the prepared single-component white light perovskite material has the advantages of high fluorescence quantum yield, high crystallinity, wide emission spectrum, and can directly generate white light.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention is to provide a single-component white light perovskite material, wherein the chemical formula of the single-component white light perovskite material is CsCdI x Cl 3-x , x=1~2, the excitation wavelength is 220~320nm, the emission wavelength is 350~700nm, and the fluorescence quantum yield is 70%~90%.

[0007] The second technical solution of the present invention is to provide a method for preparing the above-mentioned single-component white light perovskite material, comprising the following steps:

[0008] Weighing an I source and a Cl source according to a stoichiometric ratio, dissolving them in a solvent, and heating them to obtain the single-component white light perovskite material;

[0009] The I source is CsI and / or CdI2, the Cl source is CsCl and / or CdCl2, and the I source and the Cl source are not Cs salt or Cd salt at the same time.

[0010] Preferably, the solvent is water.

[0011] Preferably, the heating temperature is 150° C. and the heating time is 20-30 min.

[0012] Preferably, the heating is performed under stirring conditions.

[0013] The third technical solution of the present invention is to provide an application of the above-mentioned single-component white light perovskite material in the preparation of white light LED devices.

[0014] Technical solution 4 of the present invention: provides a white light LED device, using the above-mentioned single-component white light perovskite material as phosphor.

[0015] Preferably, the ultraviolet pump chip of the white light LED device has a wavelength range of 260-290 nm and a color rendering index of 82-95.

[0016] Preferably, after heating, excess water is sucked out using a rubber-tipped dropper, and the remaining solid is collected in a drying oven and dried at 50° C. for 3 h to obtain the single-component white light perovskite material.

[0017] The fifth technical solution of the present invention: provides a method for preparing the above-mentioned white light LED device, mixing a single-component white light perovskite material with a packaging material, and coating it on an ultraviolet light-emitting diode chip to obtain a white light LED device pumped by the ultraviolet chip.

[0018] The beneficial technical effects of the present invention are as follows:

[0019] The preparation method designed by the present invention is green, simple, low-cost, and suitable for mass production; the prepared single-component white light perovskite material has the advantages of high fluorescence quantum yield, high crystallinity, wide emission spectrum, and can directly generate white light.

[0020] The application mode of the UV chip-pumped white light LED device proposed in the present invention avoids the disadvantages of traditional fluorescent color shift, spectrum loss, etc. The color rendering index (CRI) of the directly generated white light exceeds 90. The prepared white light LED device has good working stability and has excellent application prospects in the field of solid-state lighting.

[0021] The present invention adopts a water-phase synthesis preparation method, avoiding the use of organic solvents or acid solutions in the traditional solution method. Compared with other preparation methods such as gas phase method and mechanical synthesis method, the operation process is simple and efficient, can be prepared in large quantities, the reaction conditions are mild, and it is more environmentally friendly. The obtained single-component white light perovskite material can directly produce full-spectrum emission and shows great application potential in the field of solid-state lighting. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is the X-ray diffraction comparison diagram of the products of Examples 1 to 4.

[0024] Figure 2 It is a comparison chart of the fluorescence excitation spectrum and emission spectrum of the products of Examples 1 to 3.

[0025] Figure 3 The fluorescence quantum yield spectra of the products of Examples 1 to 3 are compared.

[0026] Figure 4 It is a comparison diagram of the life attenuation curves of the products of Examples 1 to 3.

[0027] Figure 5 This is the emission spectrum response diagram of the product of Example 1 under different working currents.

[0028] Figure 6 This is the emission spectrum response diagram of the product of Effect Example 2 under different working currents. DETAILED DESCRIPTION

[0029] Now, various exemplary embodiments of the present invention are described in detail, and this detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present invention. It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention.

[0030] In addition, for the numerical range in the present invention, it is understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0031] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the invention pertains. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention.

[0032] The words “include,” “including,” “have,” “contain,” etc. used in the present invention are open-ended terms, meaning including but not limited to.

[0033] The specifications of cesium iodide used in the following embodiments of the present invention are: item number C105364-25g, Cas number 7789-17-5, purity 99.9%, brand name Aladdin. The specifications of cadmium iodide are: item number C104460-25g, Cas number 7790-80-9, purity 99.5%, brand name Aladdin. The specifications of cadmium chloride are: item number C116344-10g, Cas number 10108-64-2, purity 99.99%, brand name Aladdin. The specifications of cesium chloride are: item number C105367-25g, Cas number 7647-17-8, purity 99.99%, brand name Aladdin.

[0034] All raw materials used in the following embodiments of the present invention are commercially available products.

[0035] Example 1

[0036] A method for preparing a single-component white light perovskite material:

[0037] (1) Weigh 0.6734 g CsCl powder (0.004 mol) and 0.7333 g CdCl2 powder (0.004 mol) and dissolve them in a 20 mL glass sample bottle filled with 14 mL deionized water;

[0038] (2) Stirring and heating at 150°C for 20 minutes and cooling naturally to room temperature;

[0039] (3) Use a 5 mL rubber-tipped pipette to suck out excess deionized water, collect the remaining solid in a drying oven, and dry it at 50 °C for 3 h to obtain a single-component white light perovskite material (denoted as CsCdCl3).

[0040] Figure 1 It is the X-ray diffraction comparison diagram of the products of Examples 1 to 4.

[0041] Figure 2 It is a comparison chart of the fluorescence excitation spectrum and emission spectrum of the products of Examples 1 to 3.

[0042] Figure 3 The fluorescence quantum yield spectra of the products of Examples 1 to 3 are compared.

[0043] Figure 4 It is a comparison diagram of the life attenuation curves of the products of Examples 1 to 3.

[0044] Figure 1-4 In the figure, x=0 represents CsCdCl3, x=1 represents CsCdICl2, and x=2 represents CsCdI2Cl. Figure 1 In this example, CsCdI3(H2O) represents the product of Example 4.

[0045] from Figure 1 It can be seen that CsCdCl3 has good crystallinity and a pure phase crystal structure.

[0046] like Figure 2 As shown, the excitation peak of CsCdCl3 is 294nm, the emission peak is 413nm, the half-peak width is 96nm, and it has a large Stokes shift.

[0047] from Figure 3 It can be seen that the photoluminescence quantum yield of CsCdCl3 reaches 15.1%.

[0048] from Figure 4 It can be seen that the lifetime of CsCdCl3 is 4.63ms.

[0049] Example 2

[0050] A method for preparing a single-component white light perovskite material:

[0051] (1) Weigh 1.0392 g CsI powder (0.004 mol) and 0.7333 g CdCl2 powder (0.004 mol) and dissolve them in a 10 mL glass sample bottle filled with 7.5 mL deionized water;

[0052] (2) Stirring and heating at 150°C for 20 minutes and cooling naturally to room temperature;

[0053] (3) Use a 5 mL rubber-tipped pipette to suck out excess deionized water, collect the remaining solid in a drying oven, and dry it at 50 °C for 3 h to obtain a single-component white light perovskite material (denoted as CsCdICl2).

[0054] from Figure 1 It can be seen that CsCdICl2 has good crystallinity and a pure phase crystal structure.

[0055] like Figure 2 As shown, the excitation peak of CsCdICl2 is 288nm, the emission peak is 403nm, the half-peak width is 98nm, and it has a large Stokes shift.

[0056] from Figure 3 It can be seen that the photoluminescence quantum yield of CsCdICl2 reaches 86.3%.

[0057] from Figure 4 It can be seen that the lifetime of CsCdICl2 is 2.67ms.

[0058] Example 3

[0059] A method for preparing a single-component white light perovskite material:

[0060] (1) Weigh 0.6734 g CsCl powder (0.004 mol) and 1.4649 g CdI2 powder (0.004 mol) and dissolve them in a 10 mL glass sample bottle filled with 2.5 mL deionized water;

[0061] (2) Stirring and heating at 150°C for 20 minutes and cooling naturally to room temperature;

[0062] (3) Use a 5 mL rubber-tipped pipette to suck out excess deionized water, collect the remaining solid in a drying oven, and dry it at 50 °C for 3 h to obtain a single-component white light perovskite material (denoted as CsCdI2Cl).

[0063] from Figure 1 It can be seen that CsCdI2Cl has good crystallinity and a pure phase crystal structure.

[0064] like Figure 2As shown, the excitation peak of CsCdI2Cl is 285 nm, the emission peak is 418 nm, the half-peak width is 96 nm, and it has a large Stokes shift.

[0065] from Figure 3 It can be seen that the photoluminescence quantum yield of CsCdI2Cl reaches 74.5%.

[0066] from Figure 4 It can be seen that the lifetime of CsCdI2Cl is 3.19ms.

[0067] Example 4

[0068] A method for preparing a single-component white light perovskite material:

[0069] (1) Weigh 1.0392 g CsI powder (0.004 mol) and 1.4649 g CdI2 powder (0.004 mol) and dissolve them in a 20 mL glass sample bottle containing 1 mL deionized water;

[0070] (2) Stirring and heating at 150°C for 20 minutes and cooling naturally to room temperature;

[0071] (3) Use a 5 mL rubber-tipped pipette to suck out excess deionized water, collect the remaining solid in a drying oven, and dry it at 50 °C for 3 h to obtain a single-component white light perovskite material (denoted as CsCdI3).

[0072] The prepared CsCdI3 does not have fluorescence phenomenon, so it is impossible to characterize the excitation spectrum, emission spectrum, fluorescence quantum efficiency and lifetime.

[0073] from Figure 1 It can be seen that CsCdI3 has good crystallinity and a pure phase crystal structure.

[0074] Effect Example 1

[0075] A method for preparing a white light LED device:

[0076] The product of Example 2 was mixed with silicone potting glue (the silicone potting glue used was Dow Jones Corning OE-6550, with A glue and B glue mixed at a mass ratio of 1:1) at a mass ratio of 1:6, and coated on a UV light-emitting diode chip with a UV pump chip range of 270-280nm to obtain a white light LED device. The emission spectrum response was as follows when tested at a working current of 20-120mA. Figure 5 .

[0077] Effect Example 2

[0078] The only difference from Example 1 is that the product of Example 2 is replaced by the product of Example 3 of equal mass. The emission spectrum response is as follows when the working current is 20-120 mA. Figure 6 .

[0079] Figure 5 This is the emission spectrum response diagram of the product of Example 1 under different working currents.

[0080] Figure 6 This is the emission spectrum response diagram of the product of Effect Example 2 under different working currents.

[0081] Depend on Figure 5 and Figure 6 It can be seen that under the working current of 120mA, the single-component white light perovskite materials obtained in Examples 2 and 3 work stably in integrated devices. In addition, Example 1 has the best color rendering index of 92.2 when the working current is 120mA; Example 2 has the best color rendering index of 87.2 when the working current is 60mA. It can be seen that the perovskite phosphors prepared in Examples 2 and 3 can be pumped by ultraviolet chips and integrated into LED devices that directly emit white light, among which the white light LED device based on CsCdICl2 phosphor has the best color rendering performance.

[0082] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A single-component white light perovskite material, characterized in that: The chemical formula of the single-component white light perovskite material is CsCdI x Cl 3-x , x=1~2, the excitation wavelength is 220~320nm, the emission wavelength is 350~700nm, and the fluorescence quantum yield is 70%~90%.

2. A method for preparing the single-component white light perovskite material according to claim 1, characterized in that: The following steps are involved: Weighing an I source and a Cl source according to a stoichiometric ratio, dissolving them in a solvent, and heating them to obtain the single-component white light perovskite material; The I source is CsI and / or CdI2, the Cl source is CsCl and / or CdCl2, and the I source and the Cl source are not Cs salt or Cd salt at the same time.

3. The preparation method according to claim 2, characterized in that: The solvent is water.

4. The preparation method according to claim 2, characterized in that: The heating temperature is 150° C. and the heating time is 20-30 minutes.

5. The preparation method according to claim 2, characterized in that: The heating is carried out under stirring conditions.

6. Use of the single-component white light perovskite material according to claim 1 in preparing a white light LED device.

7. A white light LED device, characterized in that: The single-component white light perovskite material according to claim 1 is used as phosphor.

8. The white light LED device according to claim 7, characterized in that: The ultraviolet pump chip range of the white light LED device is 260-290nm, and the color rendering index is 82-95.

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