Anti-counterfeiting film and preparation method thereof

Abstract

The invention relates to the technical field of anti-counterfeiting, in particular to an anti-counterfeiting film and a preparation method thereof.The anti-counterfeiting film contains Cs2Ag (In1-x-yYbxBiy) Cl6 quantum dots, x is larger than 0 and smaller than or equal to 0.1, y is larger than 0 and smaller than or equal to 0.1, and the anti-counterfeiting film can be widely applied to counterfeiting prevention of various high-grade products.

Description

Technical Field

[0001] The invention relates to the technical field of anti-counterfeiting, and in particular to an anti-counterfeiting film and a preparation method thereof. Background Art

[0002] Anti-counterfeiting technology has great practical significance in combating counterfeit and shoddy products. Anti-counterfeiting technology is an interdisciplinary subject involving optics, chemistry, physics, electromagnetism, computer technology, spectroscopy technology, printing technology, packaging technology and many other fields. Currently, the most widely used anti-counterfeiting technologies include laser holographic anti-counterfeiting technology and chemical material anti-counterfeiting technology.

[0003] Metal halide perovskites have attracted continuous attention in the field of anti-counterfeiting due to their many advantages, such as low cost, high absorption coefficient, high fluorescence quantum yield, narrow fluorescence emission half-width, adjustable Stokes shift, simple liquid phase synthesis, and adjustable band structure. They can be used for anti-counterfeiting identification through the emission of different wavelengths generated by different excitations. Due to the quantum confinement effect, perovskite quantum dots have high fluorescence quantum efficiency, making them a research hotspot in the field of anti-counterfeiting. However, the surface energy of perovskite quantum dots themselves is very large and they are easily affected by environmental factors such as water and oxygen in the air, resulting in poor stability and shortened luminescence lifetime, which limits their application in the field of anti-counterfeiting. Summary of the invention

[0004] Purpose of the invention: In view of the above technical problems, the present invention proposes an anti-counterfeiting film and a preparation method thereof.

[0005] The technical solutions adopted are as follows: An anti-counterfeiting film, the anti-counterfeiting film contains Cs2Ag(In 1-x-y Yb x Bi y )Cl6 quantum dots, 0<x≤0.1, 0<y≤0.1; The Cs2Ag(In 1-x-y Yb x Bi y ) The preparation method of Cl6 quantum dots is as follows: S1: Cs2CO3, 1-octadecene and amino acid ionic liquid are mixed, vacuum degassed at 110-130°C for 30-60min, and then nitrogen is introduced for protection and the temperature is raised to 140-160°C to obtain cesium oleate solution, which is kept warm for later use; S2: AgNO3, InCl3, YbCl3, Bi(NO3)3, 1-octadecene, amino acid ionic liquid and oleylamine were mixed, vacuum degassed at 110-130°C for 30-60min, then nitrogen was introduced and the temperature was raised to 250-270°C, cesium oleate solution was added, and the reaction solution was cooled to room temperature after waiting for 10-30s, centrifuged once, the precipitate was collected and dispersed in n-hexane, centrifuged twice, the supernatant was evenly dispersed in ethyl acetate, and centrifuged three times to obtain Cs2Ag(In 1-x-y Yb x Bi y )Cl6 quantum dots; The amino acid ionic liquid is any one of 1-butyl-3-methylimidazolium threonine salt, 1-butyl-3-methylimidazolium alanine salt, and 1-butyl-3-methylimidazolium arginine salt, or a combination of any two or more thereof.

[0006] Furthermore, 0.01≤x≤0.03, 0.01≤y≤0.03.

[0007] Furthermore, x=0.01, y=0.03.

[0008] Furthermore, the mass ratio of 1-octadecene to the amino acid ionic liquid in S1 is 10-20:1.

[0009] Furthermore, the mass ratio of 1-octadecene, amino acid ionic liquid and oleylamine in S2 is 10-20:1-2:1-2.

[0010] Furthermore, the rotation speed during the first centrifugation is 10000-20000 r / min, the rotation speed during the second centrifugation is 2000-5000 r / min, and the rotation speed during the third centrifugation is 10000-20000 r / min.

[0011] The present invention also provides a method for preparing the anti-counterfeiting film: Cs2Ag(In 1-x-y Yb x Bi y )Cl6 quantum dots are added to the polystyrene solution, and a suspension is obtained after ultrasonic oscillation. The suspension is formed into a film and then dried.

[0012] Beneficial effects of the present invention: The present invention provides an anti-counterfeiting film, through Yb 3+ and Bi 3+Composite doping broadens the optical band gap of Cs2AgInCl6, enriches the electron transition channels, reduces internal defects, breaks the parity forbidden transition, greatly improves its photoluminescence quantum yield, improves the photoluminescence intensity, and also improves the structural stability of lead-free double perovskite. The present invention also uses amino acid ionic liquid instead of oleic acid as an alkyl ligand to in-situ encapsulate quantum dots. The amino acid ionic liquid is bound to the surface of the quantum dots through the -COO- group, which can control the morphology of the quantum dots and prevent their agglomeration, significantly reduce the surface defects of the quantum dots, and effectively inhibit the non-radiative recombination caused by the defects, so that the prepared perovskite quantum dots have stronger antioxidant and moisture resistance. Even if exposed to the air for a long time, the luminescence intensity decreases very little, and can be widely used in the anti-counterfeiting of various high-end products. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 PL spectra of the anti-counterfeiting films prepared in Example 1 and Comparative Examples 1-4. DETAILED DESCRIPTION

[0014] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially. The techniques not mentioned in the present invention are all referenced to the prior art. Unless otherwise specified, the following examples and comparative examples are parallel experiments, using the same processing steps and parameters.

[0015] Embodiment 1: A method for preparing an anti-counterfeiting film: 1mmol Cs2CO3, 15g 1-octadecene and 1g 1-butyl-3-methylimidazolium threonate were added to a flask, stirred and mixed, and then heated in an oil bath. Vacuum degassing was performed at 120°C for 60min, and then nitrogen was introduced for protection and the temperature was raised to 160°C to obtain a cesium oleate solution, which was kept warm for use. 1mmol AgNO3, 0.96mmol InCl3, 0.01mmol YbCl3, 0.03mmol Bi(NO3)3, 40g 1-octadecene, 2g 1-Butyl-3-methylimidazole threonine salt and 2g oleylamine were added to the flask, stirred and mixed, and the oil bath was heated. The vacuum degassing was carried out at 120°C for 60min, and then nitrogen was introduced and the temperature was raised to 260°C. The cesium oleate solution was quickly injected. After waiting for 30s, the flask was cooled to room temperature with an ice water bath. After returning to room temperature, the reaction solution was centrifuged at 15000r / min for 15min, the precipitate was collected and dispersed in 20ml of n-hexane, and the reaction solution was centrifuged at 4000r / min for 15min. The supernatant was evenly dispersed in 20ml of ethyl acetate, and finally centrifuged at 15000r / min for 15min for three times. The precipitate was collected and dried in vacuum to obtain Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots, add 5g polystyrene to 15ml toluene, heat until completely dissolved, then add 100mg Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots, after ultrasonic oscillation for 10 minutes, take 1 ml of the suspension on a quartz plate and use a spin coater to spin coat it into a film, and then dry the quartz plate in vacuum at 50°C for 24 hours. The PL spectrum of the anti-counterfeiting film prepared in this example under 365nm ultraviolet light is as shown in the figure Figure 1 As shown, it has the strongest luminous intensity.

[0016] Embodiment 2: A method for preparing an anti-counterfeiting film: 1mmol Cs2CO3, 15g 1-octadecene and 1g 1-butyl-3-methylimidazolium alanine salt were added to a flask, stirred and mixed, and then the oil bath was heated. Vacuum degassing was performed at 120°C for 60min, and then nitrogen was introduced and the temperature was raised to 160°C to obtain cesium oleate solution, which was kept warm for use. 1mmol AgNO3, 0.96mmol InCl3, 0.01mmol YbCl3, 0.03mmol Bi(NO3)3, 40g 1-octadecene, 2g 1-Butyl-3-methylimidazole alanine salt and 2g oleylamine were added to the flask, stirred and mixed, and the oil bath was heated. Vacuum degassing was performed at 120°C for 60min, and then nitrogen was introduced and the temperature was raised to 260°C. The cesium oleate solution was quickly injected. After waiting for 30s, the flask was cooled to room temperature with an ice water bath. After returning to room temperature, the reaction solution was centrifuged at 15000r / min for 15min, the precipitate was collected and dispersed in 20ml of n-hexane, and the reaction solution was centrifuged at 4000r / min for 15min. The supernatant was evenly dispersed in 20ml of ethyl acetate, and finally centrifuged at 15000r / min for 15min for three times. The precipitate was collected and dried in vacuum to obtain Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots, add 5g polystyrene to 15ml toluene, heat until completely dissolved, then add 100mg Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots, after ultrasonic oscillation for 10 minutes, take 1 ml of the suspension and use a spin coater to spin-coat it into a film on a quartz slide, and then dry the quartz slide in a vacuum at 50°C for 24 hours.

[0017] Embodiment 3: A method for preparing an anti-counterfeiting film: 1mmol Cs2CO3, 15g 1-octadecene and 1g 1-butyl-3-methylimidazole arginine salt were added to a flask, stirred and mixed, and then the oil bath was heated. Vacuum degassing was performed at 120°C for 60min, and then nitrogen was introduced and the temperature was raised to 160°C to obtain cesium oleate solution, which was kept warm for use. 1mmol AgNO3, 0.96mmol InCl3, 0.01mmol YbCl3, 0.03mmol Bi(NO3)3, 40g 1-octadecene, 2g 1-Butyl-3-methylimidazole arginine salt and 2g oleylamine were added to the flask, stirred and mixed, and the oil bath was heated. Vacuum degassing was performed at 120°C for 60min, and then nitrogen was introduced and the temperature was raised to 260°C. The cesium oleate solution was quickly injected. After waiting for 30s, the flask was cooled to room temperature with an ice water bath. After returning to room temperature, the reaction solution was centrifuged at 15000r / min for 15min, the precipitate was collected and dispersed in 20ml of n-hexane, and the reaction solution was centrifuged at 4000r / min for 15min. The supernatant was evenly dispersed in 20ml of ethyl acetate, and the reaction solution was centrifuged at 15000r / min for 15min. The precipitate was collected and dried in vacuum to obtain Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots, add 5g polystyrene to 15ml toluene, heat until completely dissolved, then add 100mg Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots, after ultrasonic oscillation for 10 minutes, take 1 ml of the suspension and use a spin coater to spin-coat it into a film on a quartz slide, and then dry the quartz slide in a vacuum at 50°C for 24 hours.

[0018] Comparative Example 1: The same as Example 1, except that Cs2AgInCl6 quantum dots are used instead of Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots.

[0019] A method for preparing an anti-counterfeiting film: 1mmol Cs2CO3, 15g 1-octadecene and 1g 1-butyl-3-methylimidazolium threonate were added to the flask, stirred and mixed, and then the oil bath was heated. Vacuum degassing was performed at 120°C for 60min, and then nitrogen was introduced and the temperature was raised to 160°C to obtain cesium oleate solution. The solution was kept warm for use. 1mmol AgNO3, 1mmol InCl3, 40g 1-octadecene, 2g 1-Butyl-3-methylimidazole threonine salt and 2g oleylamine were added to the flask, stirred and mixed, and the oil bath was heated. Vacuum degassing was performed at 120°C for 60min, and then nitrogen was introduced for protection and the temperature was raised to 260°C. The cesium oleate solution was quickly injected, and the flask was cooled to room temperature with an ice water bath after waiting for 30s. After returning to room temperature, the reaction solution was centrifuged at 15000r / min for 15min, the precipitate was collected and dispersed in 20ml of n-hexane, and centrifuged at 4000r / min for 15min. The supernatant was evenly dispersed in 20ml of ethyl acetate, and finally centrifuged at 15000r / min for three times for 15min. The precipitate was collected and vacuum dried to obtain Cs2AgInCl6 quantum dots. 5g of polystyrene was added to 15ml of toluene, heated appropriately until completely dissolved, and then 100mg of Cs2AgInCl6 quantum dots, after ultrasonic oscillation for 10 minutes, take 1 ml of the suspension on a quartz plate and use a spin coater to spin coat it into a film, and then dry the quartz plate in vacuum at 50°C for 24 hours. The PL spectrum of the anti-counterfeiting film prepared in this comparative example under 365nm ultraviolet light irradiation is as follows Figure 1 As shown, it has the lowest luminous intensity.

[0020] Comparative Example 2: The same as Example 1, except that Cs2Ag(In 0.97 Bi 0.03 )Cl6 quantum dots replace Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots.

[0021] A method for preparing an anti-counterfeiting film: 1mmol Cs2CO3, 15g 1-octadecene and 1g 1-butyl-3-methylimidazolium threonate were added to a flask, stirred and mixed, and then heated in an oil bath. Vacuum degassing was performed at 120°C for 60min, and then nitrogen was introduced and the temperature was raised to 160°C to obtain a cesium oleate solution. The solution was kept warm for use. 1mmol AgNO3, 0.97mmol InCl3, 0.03mmol Bi(NO3)3, 40g 1-octadecene, 2g 1-Butyl-3-methylimidazole threonine salt and 2g oleylamine were added to the flask, stirred and mixed, and the oil bath was heated. The vacuum degassing was carried out at 120°C for 60min, and then nitrogen was introduced and the temperature was raised to 260°C. The cesium oleate solution was quickly injected. After waiting for 30s, the flask was cooled to room temperature with an ice water bath. After returning to room temperature, the reaction solution was centrifuged at 15000r / min for 15min, the precipitate was collected and dispersed in 20ml of n-hexane, and the reaction solution was centrifuged at 4000r / min for 15min. The supernatant was evenly dispersed in 20ml of ethyl acetate, and finally centrifuged at 15000r / min for 15min for three times. The precipitate was collected and dried in vacuum to obtain Cs2Ag(In 0.97 Bi 0.03 )Cl6 quantum dots, add 5g polystyrene to 15ml toluene, heat until completely dissolved, then add 100mg Cs2Ag(In 0.97 Bi 0.03 )Cl6 quantum dots, after ultrasonic oscillation for 10 minutes, take 1 ml of the suspension on a quartz plate and use a spin coater to spin coat it into a film, and then dry the quartz plate in vacuum at 50°C for 24 hours. The PL spectrum of the anti-counterfeiting film prepared in this comparative example under 365nm ultraviolet light irradiation is as follows Figure 1 As shown, the luminous intensity is reduced to a certain extent compared with Example 1.

[0022] Comparative Example 3: The same as Example 1, except that Cs2Ag(In 0.99 Yb 0.01 )Cl6 quantum dots replace Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots.

[0023] A method for preparing an anti-counterfeiting film: 1mmol Cs2CO3, 15g 1-octadecene and 1g 1-butyl-3-methylimidazolium threonate were added to a flask, stirred and mixed, and then the oil bath was heated. Vacuum degassing was performed at 120°C for 60min, and then nitrogen was introduced and the temperature was raised to 160°C to obtain a cesium oleate solution. The solution was kept warm for use. 1mmol AgNO3, 0.99mmol InCl3, 0.01mmol YbCl3, 40g 1-octadecene, 2g 1-Butyl-3-methylimidazole threonine salt and 2g oleylamine were added to the flask, stirred and mixed, and the oil bath was heated. The vacuum degassing was carried out at 120°C for 60min, and then nitrogen was introduced and the temperature was raised to 260°C. The cesium oleate solution was quickly injected. After waiting for 30s, the flask was cooled to room temperature with an ice water bath. After returning to room temperature, the reaction solution was centrifuged at 15000r / min for 15min, the precipitate was collected and dispersed in 20ml of n-hexane, and the reaction solution was centrifuged at 4000r / min for 15min. The supernatant was evenly dispersed in 20ml of ethyl acetate, and finally centrifuged at 15000r / min for 15min for three times. The precipitate was collected and dried in vacuum to obtain Cs2Ag(In 0.99 Yb 0.01 )Cl6 quantum dots, add 5g polystyrene to 15ml toluene, heat until completely dissolved, then add 100mg Cs2Ag(In 0.99 Yb 0.01 )Cl6 quantum dots, after ultrasonic oscillation for 10 minutes, take 1 ml of the suspension on a quartz plate and use a spin coater to spin coat it into a film, and then dry the quartz plate in vacuum at 50°C for 24 hours. The PL spectrum of the anti-counterfeiting film prepared in this comparative example under 365nm ultraviolet light irradiation is as follows Figure 1 As shown, the luminous intensity is reduced to a certain extent compared with Example 1.

[0024] Comparative Example 4: The method is substantially the same as Example 1, except that oleic acid is used instead of 1-butyl-3-methylimidazolium threonate.

[0025] A method for preparing an anti-counterfeiting film: 1mmol Cs2CO3, 15g 1-octadecene and 1g oleic acid were added into the flask, stirred and mixed, and then the oil bath was heated. Vacuum degassing was carried out at 120℃ for 60min, and then nitrogen was introduced and the temperature was raised to 160℃ to obtain cesium oleate solution. The solution was kept warm for use. 1mmol AgNO3, 0.96mmol InCl3, 0.01mmol YbCl3, 0.03mmol Bi(NO3)3, 40g 1-octadecene, 2g oleic acid and 2g oleylamine were added to the flask, stirred and mixed, and then the oil bath was heated. Vacuum degassing was performed at 120°C for 60min, and then nitrogen was introduced for protection and the temperature was raised to 260°C. The cesium oleate solution was quickly injected, and the flask was cooled to room temperature with an ice water bath after waiting for 30s. After returning to room temperature, the reaction solution was centrifuged at 15000r / min for 15min, the precipitate was collected and dispersed in 20ml n-hexane, and centrifuged at 4000r / min for 15min. The supernatant was evenly dispersed in 20ml ethyl acetate, and finally centrifuged at 15000r / min for three times for 15min, the precipitate was collected, and vacuum dried to obtain Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots, add 5g polystyrene to 15ml toluene, heat until completely dissolved, then add 100mg Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots, after ultrasonic oscillation for 10 minutes, take 1 ml of the suspension on a quartz plate and use a spin coater to spin coat it into a film, and then dry the quartz plate in vacuum at 50°C for 24 hours. The PL spectrum of the anti-counterfeiting film prepared in this comparative example under 365nm ultraviolet light irradiation is as follows Figure 1 As shown, the luminous intensity is slightly reduced compared with Example 1.

[0026] Performance Testing: The fluorescence intensity changes of the anti-counterfeiting films prepared in Examples 1-3 and Comparative Examples 1-4 under 365 nm ultraviolet light irradiation at 0 d and 90 d in a room temperature environment with a humidity of 65±5% were measured by a fluorescence spectrophotometer (Edinburgh FLS1000), and the results are shown in Table 1 below: ; It can be seen from Table 1 above that the fluorescence intensity of the anti-counterfeiting films prepared in Examples 1-3 of the present invention only decreases slightly after being placed in a high humidity room temperature environment for 90 days, while the fluorescence intensity of the anti-counterfeiting films prepared in Comparative Examples 1-4 decreases significantly.

[0027] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An anti-counterfeiting film, characterized in that: The anti-counterfeiting film contains Cs2Ag(In 1-x-y Yb x Bi y )Cl6 quantum dots, 0<x≤0.1, 0<y≤0.1; The Cs2Ag(In 1-x-y Yb x Bi y ) The preparation method of Cl6 quantum dots is as follows: S1: Cs2CO3, 1-octadecene and amino acid ionic liquid are mixed, vacuum degassed at 110-130°C for 30-60min, and then nitrogen is introduced for protection and the temperature is raised to 140-160°C to obtain cesium oleate solution, which is kept warm for later use; S2: AgNO3, InCl3, YbCl3, Bi(NO3)3, 1-octadecene, amino acid ionic liquid and oleylamine were mixed, vacuum degassed at 110-130°C for 30-60min, then nitrogen was introduced and the temperature was raised to 250-270°C, cesium oleate solution was added, and the reaction solution was cooled to room temperature after waiting for 10-30s, centrifuged once, the precipitate was collected and dispersed in n-hexane, centrifuged twice, the supernatant was evenly dispersed in ethyl acetate, and centrifuged three times to obtain Cs2Ag(In 1-x-y Yb x Bi y )Cl6 quantum dots; The amino acid ionic liquid is any one of 1-butyl-3-methylimidazolium threonine salt, 1-butyl-3-methylimidazolium alanine salt, and 1-butyl-3-methylimidazolium arginine salt, or a combination of any two or more thereof.

2. The anti-counterfeiting film according to claim 1, characterized in that: 0.01≤x≤0.03, 0.01≤y≤0.

03.

3. The anti-counterfeiting film according to claim 1, characterized in that: x=0.01,y=0.

03.

4. The anti-counterfeiting film according to claim 1, characterized in that: The mass ratio of 1-octadecene to amino acid ionic liquid in S1 is 10-20:

1.

5. The anti-counterfeiting film according to claim 1, characterized in that: The mass ratio of 1-octadecene, amino acid ionic liquid and oleylamine in S2 is 10-20:1-2:1-2.

6. The anti-counterfeiting film according to claim 1, characterized in that: The speed during the first centrifugation is 10000-20000 r / min, the speed during the second centrifugation is 2000-5000 r / min, and the speed during the third centrifugation is 10000-20000 r / min.

7. A method for preparing the anti-counterfeiting film according to any one of claims 1 to 6, characterized in that: Cs2Ag(In 1-x-y Yb x Bi y )Cl6 quantum dots are added to the polystyrene solution, and a suspension is obtained after ultrasonic oscillation. The suspension is formed into a film and then dried.

Images