A fluorescent material and its preparation method and application

Abstract

The invention discloses a fluorescent material and a preparation method and application thereof. The fluorescent material comprises the following components: a modifier, perovskite, polyethylene oxide and a solvent; the modifier comprises at least one of methylammonium bromide, cesium bromide and formamide bromide; the molar ratio of the modifier to the perovskite is 0.75 to 0.85:1. The fluorescent film prepared by the fluorescent material of the invention has uniform film quality, good brightness, good fluorescence reversibility and obvious anti-counterfeiting effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of fluorescent materials, and in particular relates to a fluorescent material and a preparation method and application thereof. Background Art

[0002] The mainstream anti-counterfeiting technologies on the market currently include digital anti-counterfeiting technology, laser anti-counterfeiting technology and fluorescent anti-counterfeiting technology. Among them, digital anti-counterfeiting is to use digital identity recognition technology for anti-counterfeiting; laser anti-counterfeiting is to use laser image anti-counterfeiting marks, encrypted laser anti-counterfeiting marks, laser lithography anti-counterfeiting technology for anti-counterfeiting; fluorescent anti-counterfeiting is to use colorless fluorescent ink and colored fluorescent ink for anti-counterfeiting.

[0003] However, the above anti-counterfeiting technologies have the following disadvantages: Among them, digital anti-counterfeiting has the problem of counterfeiting by printing one code multiple times and recycling old codes, and digital anti-counterfeiting is based on the absolute security of the database. Once the data is leaked, the anti-counterfeiting system engineering will collapse across the board; laser anti-counterfeiting technology is expensive and the technology is not mature enough; and fluorescent anti-counterfeiting technology is difficult to overprint because there is no pattern visible in natural light as a mark during overprinting. In addition, fluorescent anti-counterfeiting also has the problem of color shift.

[0004] In summary, the above anti-counterfeiting effects are relatively simple, and their respective shortcomings are more prominent. In order to solve these anti-counterfeiting technical shortcomings, a certain production cost is required, which has a great impact on large-scale, high-efficiency, and high-performance production. Summary of the invention

[0005] The first technical problem to be solved by the present invention is:

[0006] A fluorescent material is provided.

[0007] The second technical problem to be solved by the present invention is:

[0008] A method for preparing the fluorescent material is provided.

[0009] The third technical problem to be solved by the present invention is:

[0010] Application of the above fluorescent materials.

[0011] In order to solve the above-mentioned first technical problem, the technical solution adopted by the present invention is:

[0012] A fluorescent material comprising the following components:

[0013] modifiers, perovskites, polyethylene oxides, and solvents;

[0014] The modifier includes at least one of methylammonium bromide, cesium bromide, and formamide bromide;

[0015] The molar ratio of the modifier to the perovskite is 0.75 to 0.85:1.

[0016] According to one embodiment of the present invention, the molar ratio of the above-mentioned modifier to the perovskite is 0.8:1.

[0017] According to one embodiment of the present invention, the perovskite includes at least one of methylammonium lead bromide and fluoroformamidine lead trihalide.

[0018] The above-mentioned polyethylene oxide increases the stability of the perovskite lattice, so that the fluorescent anti-counterfeiting brightness of the fluorescent anti-counterfeiting film prepared by the fluorescent material of the present invention is more stable.

[0019] The above perovskite materials have good thermal stability and excellent carrier transport properties.

[0020] According to one embodiment of the present invention, the solvent includes a dissolving solvent and a crystallizing solvent.

[0021] According to one embodiment of the present invention, the dissolving solvent includes at least one of N,N-dimethylformamide, isopropanol and dimethyl sulfoxide.

[0022] According to one embodiment of the present invention, the crystallization solvent includes at least one of dichloromethane, chloroform, toluene, acetone and ethanol.

[0023] The dissolving solvent is used to dissolve the modifier and the perovskite.

[0024] The above-mentioned crystallization solvent is used to promote crystallization.

[0025] In order to solve the above second technical problem, the technical solution adopted by the present invention is:

[0026] A method for preparing the above fluorescent material comprises the following steps:

[0027] Mixing the modifier and the perovskite in the solvent to obtain a mixture;

[0028] The mixture is mixed with the polyethylene oxide to obtain the fluorescent material.

[0029] According to one embodiment of the present invention, before the mixture is mixed with the polyethylene oxide, the temperatures of both are 78-82°C.

[0030] According to one embodiment of the present invention, the above mixture is mixed with the polyethylene oxide in a molar ratio of 0.9-1.0:1.0-1.5.

[0031] According to one embodiment of the present invention, the above fluorescent material is taken, a film is spin-coated, and the fluorescent film is placed under ultraviolet light and natural light respectively, and the change in ambient temperature is used to affect the thermal stability of the fluorescent film, causing a phase transition, which is manifested externally as a color change of the film.

[0032] According to one embodiment of the present invention, the ambient temperature varies in the range of 25 to 70°C.

[0033] Another aspect of the present invention provides an application of a fluorescent material in anti-counterfeiting.

[0034] One of the above technical solutions has at least one of the following advantages or beneficial effects:

[0035] The adaptability of the fluorescent material to the environment is effectively improved, and the fluorescent material of the present invention can be prepared without isolating the air;

[0036] The fluorescent film prepared from the fluorescent material of the present invention can achieve rapid temperature response and can achieve thermochromic fluorescent anti-counterfeiting effect under ultraviolet or natural light;

[0037] The fluorescent film prepared from the fluorescent material of the present invention is colorless and transparent at room temperature, and the color of the fluorescent film will change significantly at a higher temperature.

[0038] The fluorescent film prepared by the fluorescent material of the present invention has uniform film quality, good brightness, good fluorescence reversibility, and obvious anti-counterfeiting effect;

[0039] The fluorescent material of the present invention has low cost and short processing flow, and does not require post-processing of the material and process. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0041] Figure 1 Schematic diagram of fluorescent anti-counterfeiting film under natural light / ultraviolet light.

[0042] Figure 2 The fluorescence intensity comparison of the fluorescent material of the present invention at 25°C and 45°C was tested by a fluorescence spectrometer. DETAILED DESCRIPTION

[0043] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in conjunction with the implementation modes.

[0044] Example 1

[0045] The methylammonium bromide and the methylamine lead bromide are mixed in the solvent at a molar ratio of 0.8:1 to obtain a mixture, wherein the solvent is 1 mL of dimethylformamide and 0.5 mL of dichloromethane, and the molar concentration of the mixture is 1.9 mol / L;

[0046] The mixture is heated to 80° C., and then mixed with the polyethylene oxide at 80° C. at a molar ratio of 0.9:1.2 to obtain a fluorescent material.

[0047] Example 2

[0048] The methylammonium bromide and the methylamine lead bromide are mixed in the solvent at a molar ratio of 0.8:1 to obtain a mixture, wherein the solvent is 1 mL of isopropanol and 0.5 mL of dichloromethane, and the molar concentration of the mixture is 1.9 mol / L;

[0049] The mixture is heated to 80° C., and then mixed with the polyethylene oxide at 80° C. at a molar ratio of 0.9:1.2 to obtain a fluorescent material.

[0050] Example 3

[0051] The methylammonium bromide and the methylamine lead bromide are mixed in the solvent at a molar ratio of 0.8:1 to obtain a mixture, wherein the solvent is 1 mL of isopropanol and 0.5 mL of ethanol, and the molar concentration of the mixture is 1.9 mol / L;

[0052] The mixture is heated to 80° C., and then mixed with the polyethylene oxide at 80° C. at a molar ratio of 0.9:1.2 to obtain a fluorescent material.

[0053] Example 4

[0054] The methylammonium bromide and the methylamine lead bromide are mixed in the solvent at a molar ratio of 0.8:1 to obtain a mixture, wherein the solvent is 1 mL of dimethylformamide and 0.5 mL of toluene, and the molar concentration of the mixture is 1.9 mol / L;

[0055] The mixture is heated to 80° C., and then mixed with the polyethylene oxide at 80° C. at a molar ratio of 0.9:1.2 to obtain a fluorescent material.

[0056] Performance Testing:

[0057] Take the fluorescent material of Example 1, spin-coat the film, and test the anti-counterfeiting effect of the fluorescent film under ultraviolet light and natural light respectively by using the change of ambient temperature. The test results are as follows: Figure 1 .

[0058] 1) Figure 1a-1b is a schematic diagram of the fluorescent film under natural light. Figure 1 a is room temperature, Figure 1 b is heating to 45°C. It can be seen that the heating causes the color of the film to change from colorless and transparent to yellow, which is the anti-counterfeiting effect under natural light.

[0059] 2) Figure 1 c-1d is a schematic diagram of the fluorescent film under ultraviolet light. Figure 1 c is room temperature, Figure 1 d is when the temperature is raised to 45°C. It can be seen that the temperature increase causes the color of the film to change from colorless and transparent to green, which is the anti-counterfeiting effect under ultraviolet light.

[0060] When the general Figure 1 b and Figure 1 When the fluorescent film of d is cooled to room temperature, the colors of both fluorescent films are reversed to colorless and transparent.

[0061] Take the fluorescent material of Example 1, spin-coat the film, and test the fluorescence intensity of the fluorescent film at 25°C and 45°C in a fluorescence spectrometer. The test results are as follows: Figure 2 .

[0062] from Figure 2 It can be seen that the temperature increase causes the fluorescence intensity of the fluorescent material of the present invention to rise sharply, indicating that the anti-counterfeiting effect of the fluorescent material of the present invention is obvious.

[0063] The above are only embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention specification, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A fluorescent material used in anti-counterfeiting, characterized in that: Includes the following components: modifiers, perovskites, polyethylene oxides, and solvents; The modifier is methylammonium bromide; The perovskite is methylamine lead bromide; The method for preparing the fluorescent material comprises the following steps: Methylammonium bromide and methylamine lead bromide are mixed in a solvent at a molar ratio of 0.8:1 to obtain a mixture, wherein the solvent is 1 mL of dimethylformamide and 0.5 mL of dichloromethane; The mixture is heated to 80° C., and then mixed with polyethylene oxide at a temperature of 80° C. at a molar ratio of 0.9:1.2 to obtain a fluorescent material.

Images