Anti-fake film and preparation method thereof

Abstract

The application relates to the field of anti-counterfeiting technology, in particular to an anti-counterfeiting film and a preparation method thereof. 1‑x‑y Yb x Bi y )Cl6 quantum dots, 0 < x <= 0.1, 0 < y <= 0.1, which can be widely applied to the anti-counterfeiting of various high-grade products.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of anti-counterfeiting technology, in particular to an anti-counterfeiting film and a preparation method thereof. BACKGROUND

[0002] With the development of modern society, counterfeit and inferior products continue to emerge, which causes certain difficulties for people to identify the authenticity and brings immeasurable losses to economic development. Anti-counterfeiting technology has great practical significance for combating counterfeit and inferior products. Anti-counterfeiting technology is a cross-discipline, involving optics, chemistry, physics, electromagnetism, computer technology, spectroscopy, printing technology, packaging technology and many other fields. The currently more commonly used anti-counterfeiting technologies mainly include laser holographic anti-counterfeiting technology and chemical material anti-counterfeiting technology.

[0003] Metal halide perovskite has attracted sustained attention in the field of anti-counterfeiting due to its low cost, high absorption coefficient, high fluorescence quantum yield, narrow fluorescence emission half-width, adjustable Stokes shift, simple liquid-phase synthesis, adjustable energy band structure and many other advantages. It can be used for anti-counterfeiting identification by different wavebands of light generated by different excitation. Due to 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 is very large, which is easily affected by environmental factors such as water and oxygen in the air, resulting in poor stability and shortening of the luminescence lifetime, which limits its application in the field of anti-counterfeiting. SUMMARY

[0004] The present application aims at the above technical problems and provides an anti-counterfeiting film and a preparation method thereof.

[0005] The technical scheme adopted is as follows:

[0006] An anti-counterfeiting film, which contains Cs2Ag(In 1-x-y Yb x Bi y )Cl6 quantum dots, 0 < x ≤ 0.1, 0 < y ≤ 0.1.

[0007] The preparation method of the Cs2Ag(In 1-x-y Yb x Bi y )Cl6 quantum dots is as follows:

[0008] S1: mixing Cs2CO3, 1-octadecene and amino acid ionic liquid, vacuum degassing at a temperature of 110-130℃ for 30-60min, then introducing nitrogen protection and heating to 140-160℃ to obtain a precursor solution, and keeping warm for standby;

[0009] S2: mixing AgNO3, InCl3, YbCl3, Bi(NO3)3, 1-octadecene, amino acid ionic liquid and oleylamine, vacuum degassing at 110-130 DEG C for 30-60 min, then nitrogen protection and heating to 250-270 DEG C, adding precursor solution, waiting for 10-30 s, then cooling the reaction solution to room temperature, once centrifugation, collecting the precipitate and dispersing it in n-hexane, twice centrifugation, uniformly dispersing the obtained supernatant in ethyl acetate, and three times centrifugation to obtain Cs2Ag(In 1-x-y Yb x Bi y )Cl6 quantum dots;

[0010] The amino acid ionic liquid is any one or any two or more combinations of 1-butyl-3-methylimidazole threonine salt, 1-butyl-3-methylimidazole alanine salt and 1-butyl-3-methylimidazole arginine salt.

[0011] Further, 0.01<=x<=0.03, 0.01<=y<=0.03.

[0012] Further, x=0.01, y=0.03.

[0013] Further, the mass ratio of 1-octadecene and amino acid ionic liquid in S1 is 10-20:1.

[0014] Further, the mass ratio of 1-octadecene, amino acid ionic liquid and oleylamine in S2 is 10-20:1-2:1-2.

[0015] Further, the rotation speed is 10000-20000 r / min in the first centrifugation, 2000-5000 r / min in the second centrifugation and 10000-20000 r / min in the third centrifugation.

[0016] The application also provides a preparation method of the above-mentioned anti-fake film.

[0017] The Cs2Ag(In 1-x-y Yb x Bi y )Cl6 quantum dots are added into a polystyrene solution, a suspension is obtained after ultrasonic oscillation, and the suspension is dried after film preparation.

[0018] The application has the following beneficial effects:

[0019] The application provides an anti-fake film, which is prepared by using Yb 3+ and Bi 3+The composite doping widens the optical band gap of Cs2AgInCl6, enriches the electronic transition channel, reduces the internal defects, breaks the parity forbidden transition, greatly improves the photoluminescence quantum yield, improves the photoluminescence intensity, and also improves the structure stability of the lead-free double perovskite. The amino acid ionic liquid is used to replace oleic acid as an alkyl ligand to encapsulate the quantum dots in situ. The amino acid ionic liquid is combined with the quantum dot surface through a -COO- group, can control the morphology of the quantum dots and prevent the agglomeration of the quantum dots, significantly reduces the surface defects of the quantum dots, and effectively inhibits the non-radiative recombination caused by defects, so that the prepared perovskite quantum dots have stronger oxygen resistance and moisture resistance. Even if exposed to air for a long time, the decline of the luminescence intensity is small, and the perovskite quantum dots can be widely applied to the anti-counterfeiting of various high-end products. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The PL spectrum of the anti-counterfeiting film prepared in Example 1 and Comparative Examples 1-4. DETAILED DESCRIPTION

[0021] Unless otherwise specified, the specific conditions in the examples are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not specified by the manufacturer, and are all conventional products that can be purchased on the market. The technologies not mentioned in the present application refer to the prior art, and the following examples and comparative examples are parallel tests using the same processing steps and parameters, unless otherwise specified.

[0022] Example 1:

[0023] A preparation method of an anti-counterfeiting film:

[0024] Cs2CO3, 15 g of 1-octadecene and 1 g of 1-butyl-3-methylimidazolium threoninate were added into a flask, stirred and mixed, and then vacuum degassed at 120℃ for 60 min, and then nitrogen was introduced for protection and heated to 160℃ to obtain a precursor solution, which was kept for use. 1 mmol of AgNO3, 0.96 mmol of InCl3, 0.01 mmol of YbCl3, 0.03 mmol of Bi(NO3)3, 40 g of 1-octadecene, 2 g of 1-butyl-3-methylimidazolium threoninate and 2 g of oleylamine were added into a flask, stirred and mixed, and then vacuum degassed at 120℃ for 60 min, and then nitrogen was introduced for protection and heated to 260℃, and the precursor solution was quickly injected, and after 30 s, the flask was cooled to room temperature with an ice water bath, and after the reaction solution was centrifuged at 15000 r / min for 15 min, the precipitate was collected and dispersed in 20 ml of n-hexane, and then centrifuged at 4000 r / min for 15 min, and then the supernatant was uniformly dispersed in 20 ml of ethyl acetate, and finally centrifuged at 15000 r / min for 15 min, and the precipitate was collected and vacuum dried to obtain Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots. 5 g of polystyrene was added into 15 ml of toluene, and then heated to completely dissolve, and then 100 mg of Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots were added, and then ultrasonically oscillated for 10 min, and then 1 ml of the suspension was taken onto a quartz sheet, and then spin-coated into a film using a spin coater, and then the quartz sheet was vacuum dried at 50℃ for 24 h, and the prepared anti-counterfeiting film of the present embodiment had a PL spectrum under 365 nm ultraviolet lamp irradiation as shown in Figure 1 , which had the strongest luminescence intensity.

[0025] Example 2:

[0026] A preparation method of an anti-counterfeiting film:

[0027] Cs2CO3, 15g 1-octadecene and 1g 1-butyl-3-methylimidazolium propionate were added into a flask, stirred and mixed, then the oil bath was heated, vacuum degassing was carried out at 120℃ for 60min, then nitrogen was introduced for protection and heated to 160℃, a precursor solution was obtained and was kept for use, 1mmol AgNO3, 0.96mmol InCl3, 0.01mmol YbCl3, 0.03mmol Bi(NO3)3, 40g 1-octadecene, 2g 1-butyl-3-methylimidazolium propionate and 2g oleylamine were added into a flask, stirred and mixed, then the oil bath was heated, vacuum degassing was carried out at 120℃ for 60min, then nitrogen was introduced for protection and heated to 260℃, the precursor solution was quickly injected, the flask was cooled to room temperature with an ice water bath after 30s, the reaction solution was centrifuged at 15000r / min for 15min, the precipitate was collected and dispersed in 20ml n-hexane, then centrifuged at 4000r / min for 15min, the supernatant was evenly dispersed in 20ml ethyl acetate, finally centrifuged at 15000r / min for 15min, the precipitate was collected and vacuum dried to obtain Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots, 5g polystyrene was added into 15ml toluene, heated appropriately to completely dissolve, then 100mg Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots were added, ultrasonic oscillation was carried out for 10min, 1ml suspension was taken on a quartz sheet, a film was spin-coated by using a spin coater, and the quartz sheet was vacuum dried at 50℃ for 24h.

[0028] Example 3:

[0029] A preparation method of a security film:

[0030] Cs2CO3, 15 g 1-octadecene and 1 g 1-butyl-3-methylimidazolium arginine were added into a flask, stirred and mixed, and then vacuum degassed at 120℃ for 60 min, and then nitrogen was introduced for protection and heated to 160℃ to obtain a precursor solution, which was kept for use. 1 mmol AgNO3, 0.96 mmol InCl3, 0.01 mmol YbCl3, 0.03 mmol Bi(NO3)3, 40 g 1-octadecene, 2 g 1-butyl-3-methylimidazolium arginine and 2 g oleylamine were added into a flask, stirred and mixed, and then vacuum degassed at 120℃ for 60 min, and then nitrogen was introduced for protection and heated to 260℃, and the precursor solution was quickly injected, and the flask was cooled to room temperature with an ice water bath for 30 s, and then the reaction solution was centrifuged at 15000 r / min for 15 min, and the precipitate was collected and dispersed in 20 ml n-hexane, and then centrifuged at 4000 r / min for 15 min, and then the supernatant was evenly dispersed in 20 ml ethyl acetate, and finally centrifuged at 15000 r / min for 15 min, and the precipitate was collected and vacuum dried to obtain Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots. 5 g polystyrene was added into 15 ml toluene, and then appropriately heated to completely dissolve, and then 100 mg Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots were added, and then ultrasonically oscillated for 10 min, and then 1 ml of the suspension was taken onto a quartz sheet, and then spin-coated into a film using a spin coater, and then the quartz sheet was vacuum dried at 50℃ for 24 h.

[0031] Comparative Example 1:

[0032] The same as Example 1, except that Cs2AgInCl6 quantum dots were used instead of Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots.

[0033] A preparation method of a security film:

[0034] Cs2CO3, 15 g 1-octadecene and 1 g 1-butyl-3-methylimidazolium thiocyanate were added into a flask, after stirring and mixing, the oil bath was heated, and the flask was vacuum degassed at 120℃ for 60 min, then nitrogen was introduced for protection and heated to 160℃, to obtain a precursor solution, which was kept for use. AgNO3, InCl3, 40 g 1-octadecene, 2 g 1-butyl-3-methylimidazolium thiocyanate and 2 g oleylamine were added into a flask, after stirring and mixing, the oil bath was heated, and the flask was vacuum degassed at 120℃ for 60 min, then nitrogen was introduced for protection and heated to 260℃, the precursor solution was quickly injected, and the flask was cooled to room temperature with an ice water bath after 30 s, after the reaction solution was centrifuged at 15000 r / min for 15 min, the precipitate was collected and dispersed in 20 ml n-hexane, and then centrifuged at 4000 r / min for 15 min, the supernatant was evenly dispersed in 20 ml ethyl acetate, and finally centrifuged at 15000 r / min for 15 min, the precipitate was collected and vacuum dried to obtain Cs2AgInCl6 quantum dots. 5 g polystyrene was added to 15 ml toluene, and then 100 mg Cs2AgInCl6 quantum dots were added, and the mixture was ultrasonically oscillated for 10 min, 1 ml of the suspension was taken and spin-coated on a quartz plate using a spin coater, and the quartz plate was vacuum dried at 50℃ for 24 h. The PL spectrum of the anti-counterfeiting film prepared in the present example under 365 nm ultraviolet lamp irradiation is shown in Figure 1 .

[0035] Comparative Example 2

[0036] The same as Example 1, except that Cs2Ag(In 0.97 Bi 0.03 )Cl6 quantum dots were used instead of Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots.

[0037] A method for preparing an anti-counterfeiting film

[0038] Cs2CO3, 15 g of 1-octadecene and 1 g of 1-butyl-3-methylimidazolium thiocyanate were added into a flask, stirred and mixed, and then vacuum degassed at 120℃ for 60 min, and then nitrogen was introduced for protection and heated to 160℃ to obtain a precursor solution, which was kept for use. 1 mmol of AgNO3, 0.97 mmol of InCl3, 0.03 mmol of Bi(NO3)3, 40 g of 1-octadecene, 2 g of 1-butyl-3-methylimidazolium thiocyanate and 2 g of oleylamine were added into a flask, stirred and mixed, and then vacuum degassed at 120℃ for 60 min, and then nitrogen was introduced for protection and heated to 260℃, and the precursor solution was quickly injected, and after 30 s, the flask was cooled to room temperature with an ice water bath, and after the reaction solution was centrifuged at 15000 r / min for 15 min, the precipitate was collected and dispersed in 20 ml of n-hexane, and then centrifuged at 4000 r / min for 15 min, and then the supernatant was uniformly dispersed in 20 ml of ethyl acetate, and finally centrifuged at 15000 r / min for 15 min, and the precipitate was collected and vacuum dried to obtain Cs2Ag(In 0.97 Bi 0.03 )Cl6 quantum dots. 5 g of polystyrene was added into 15 ml of toluene, and then heated to completely dissolve, and then 100 mg of Cs2Ag(In 0.97 Bi 0.03 )Cl6 quantum dots were added, and then ultrasonically oscillated for 10 min, and then 1 ml of the suspension was taken onto a quartz plate and spin-coated into a film using a spin coater, and then the quartz plate was vacuum dried at 50℃ for 24 h to obtain a security film. The PL spectrum of the security film prepared in the present comparative example under irradiation of a 365 nm ultraviolet lamp is shown in FIG. 4, and the luminescence intensity is reduced to a certain extent compared with that of Example 1. Figure 1

[0039] Comparative Example 3:

[0040] The present example is basically the same as Example 1, except that Cs2Ag(In 0.99 Yb 0.01 )Cl6 quantum dots were used instead of Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots.

[0041] A method for preparing a security film:

[0042] ​Cs2CO3, 15 g 1-octadecene and 1 g 1-butyl-3-methylimidazolium threoninate were added into a flask, stirred and mixed, and then vacuum degassed at 120℃ for 60 min, and then nitrogen was introduced for protection and heated to 160℃ to obtain a precursor solution, which was kept for use. 1 mmol AgNO3, 0.99 mmol InCl3, 0.01 mmol YbCl3, 40 g 1-octadecene, 2 g 1-butyl-3-methylimidazolium threoninate and 2 g oleylamine were added into a flask, stirred and mixed, and then vacuum degassed at 120℃ for 60 min, and then nitrogen was introduced for protection and heated to 260℃, and the precursor solution was quickly injected, and after 30 s, the flask was cooled to room temperature with an ice water bath, and after the reaction solution was centrifuged at 15000 r / min for 15 min, the precipitate was collected and dispersed in 20 ml n-hexane, and then centrifuged at 4000 r / min for 15 min, and then the supernatant was evenly dispersed in 20 ml ethyl acetate, and finally centrifuged at 15000 r / min for 15 min, and the precipitate was collected and vacuum dried to obtain Cs2Ag(In 0.99 Yb 0.01 )Cl6 quantum dots. 5 g polystyrene was added into 15 ml toluene, and then heated to completely dissolve, and then 100 mg Cs2Ag(In 0.99 Yb 0.01 )Cl6 quantum dots were added, and then ultrasonic oscillation was performed for 10 min, and then 1 ml of the suspension was taken and spin-coated on a quartz plate using a spin coater to form a film, and then the quartz plate was vacuum dried at 50℃ for 24 h. The PL spectrum of the anti-counterfeiting film prepared in the present example under irradiation of a 365 nm ultraviolet lamp is shown in Figure 1 , and the luminescence intensity was reduced to a certain extent compared with that of Example 1.

[0043] Comparative Example 4:

[0044] The present example was basically the same as Example 1, except that 1-butyl-3-methylimidazolium threoninate was replaced by oleic acid.

[0045] A method for preparing an anti-counterfeiting film:

[0046] Cs2CO3, 15 g of 1-octadecene and 1 g of oleic acid were added into a flask, after stirring and mixing, the oil bath was heated, and the flask was vacuum degassed at 120℃ for 60 min, then nitrogen was introduced for protection and heated to 160℃, to obtain a precursor solution, which was kept for use. 1 mmol of AgNO3, 0.96 mmol of InCl3, 0.01 mmol of YbCl3, 0.03 mmol of Bi(NO3)3, 40 g of 1-octadecene, 2 g of oleic acid and 2 g of oleylamine were added into a flask, after stirring and mixing, the oil bath was heated, and the flask was vacuum degassed at 120℃ for 60 min, then nitrogen was introduced for protection and heated to 260℃, the precursor solution was quickly injected, and after 30 s, the flask was cooled to room temperature with an ice water bath, after the temperature returned to room temperature, the reaction solution was centrifuged at 15000 r / min for 15 min, the precipitate was collected and dispersed in 20 ml of n-hexane, and then centrifuged at 4000 r / min for 15 min, the supernatant was evenly dispersed in 20 ml of ethyl acetate, and finally centrifuged at 15000 r / min for 15 min, and the precipitate was collected and vacuum dried to obtain Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots, 5 g of polystyrene was added to 15 ml of toluene, and then 100 mg of Cs2Ag(In 0.96 Yb 0.01 Bi 0.03 )Cl6 quantum dots were added, and after ultrasonic oscillation for 10 min, 1 ml of the suspension was taken onto a quartz plate and spin-coated into a film using a spin coater, and the quartz plate was vacuum dried at 50℃ for 24 h, to obtain the anti-counterfeiting film. The PL spectrum of the anti-counterfeiting film prepared in the pair of examples under 365 nm ultraviolet lamp irradiation is shown in Figure 1 , and the luminescence intensity is slightly reduced compared with example 1.

[0047] Performance test:

[0048] The fluorescence intensity changes of the anti-counterfeiting films prepared in examples 1-3 and pair of examples 1-4 under 365 nm ultraviolet lamp irradiation at 0 d and after being placed in a room temperature environment with a humidity of 65±5% for 90 d were measured by a fluorescence spectrophotometer (Edinburgh FLS1000), and the results are shown in Table 1 below (“-” represents a decrease):

[0049]

[0050] As can be seen from Table 1 above, the fluorescence intensity of the anti-counterfeiting films prepared in examples 1-3 of the present application only has a small decrease after being placed in a high humidity room temperature environment for 90 d, while the fluorescence intensity of the anti-counterfeiting films prepared in pair of examples 1-4 has a large decrease.

[0051] The above examples are only used to illustrate the technical solutions of the present application, but not to limit the present application; although the present application has been described in detail with reference to the foregoing examples, those ordinarily skilled in the art should understand: the technical solutions recorded in the foregoing examples can still be modified, or some technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A security film, characterized in that, The anti-fake film contains Cs2Ag(In 1-x-y Yb x Bi y )Cl6 quantum dots, x=0.01, y=0.03; The Cs2Ag(In 1-x-y Yb x Bi y The preparation method of the Cs2Ag(In 1-x-y Yb x Bi y quantum dots is as follows: S1: mixing Cs2CO3, 1-octadecene and amino acid ionic liquid, vacuum degassing at 110-130 DEG C for 30-60 min, then nitrogen protection and heating to 140-160 DEG C, to obtain a precursor solution, and standby; S2: mixing AgNO3, InCl3, YbCl3, Bi(NO3)3, 1-octadecene, amino acid ionic liquid and oleylamine, vacuum degassing at 110-130℃ for 30-60min, then nitrogen protection and heating to 250-270℃, adding precursor solution, waiting for 10-30s, then cooling the reaction solution to room temperature, centrifuging once, collecting the precipitate and dispersing it in n-hexane, centrifuging twice, uniformly dispersing the obtained supernatant in ethyl acetate, and centrifuging thrice to obtain Cs2Ag(In 1-x-y Yb x Bi y )Cl6 quantum dots; The amino acid ionic liquid is any one or any two or more combinations of 1-butyl-3-methylimidazole threonine salt, 1-butyl-3-methylimidazole alanine salt and 1-butyl-3-methylimidazole arginine salt; The mass ratio of 1-octadecene to the amino acid ionic liquid in S1 is 10-20:1; The mass ratio of 1-octadecene, the amino acid ionic liquid and oleylamine in S2 is 10-20:1-2:1-2; The rotation speed in the first centrifugation is 10000-20000 r / min, the rotation speed in the second centrifugation is 2000-5000 r / min, and the rotation speed in the third centrifugation is 10000-20000 r / min.

2. A method of producing the security film according to claim 1, characterized by, Cs2Ag(In 1-x-y Yb x Bi y )Cl6 quantum dots into a polystyrene solution, and a suspension is obtained after ultrasonic oscillation. The suspension is made into a film and dried.

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