Chiral selective optical filter and use thereof

Abstract

The application discloses a preparation and application of a chiral selective optical filter. The chiral selective optical filter is a chiral film obtained by spin coating of chiral silver clusters; the chiral silver clusters are obtained by coordination reaction of chiral molecules containing mercapto and silver ions; the chiral molecules containing mercapto can be obtained by breaking disulfide bonds of L / D-cystine derivatives. The optical filter has important applications in biological medicine, optical information storage and encryption, optical devices and CP-LED. The corresponding circularly polarized signals can be obtained by using the optical filter, i.e. exciting a light emitting unit and then obtaining the circularly polarized signals through the chiral selective optical filter. The light emitting unit is a non-chiral organic dye molecule, inorganic phosphor material or fluorescent polymer microsphere. The optical filter is located at the rear side of the light emitting unit. The application can obtain the corresponding better circularly polarized signals by using the non-chiral light emitting unit through the chiral selective optical filter, and the preparation method is simple and has strong operability.

Description

A chirality-selective optical filter and its application Technical Field

[0001] This invention relates to a chiral selective optical filter and its application, belonging to the field of luminescent materials. Background Technology

[0002] Optical filters are instruments used to select the emission wavelength. They can select the desired wavelength from a large number of emission wavelengths, while rejecting light of other wavelengths. Such optical filters can be used for wavelength selection, noise filtering in optical amplifiers, gain equalization, and optical multiplexing / demultiplexing. Optical filters with chiral selection can also function as polarization filters, not only filtering light but also chirally selecting the corresponding circularly polarized light.

[0003] Polarization is one of the essential properties of light, playing a crucial role in target recognition, display, information storage, and remote sensing. Unlike intensity and wavelength, polarization possesses the ability to distinguish information about light in three-dimensional space. Circularly polarized light (CP) is a special type of elliptically polarized light, which can be viewed as the superposition of two linearly polarized lights (LPLs) with the same frequency and perpendicular polarization direction. The path traced by the end of the electric field direction or light vector in a plane perpendicular to the propagation direction is a circle. Due to its rich optical information and angle-independent properties, circularly polarized light is widely used in various devices and technologies, including 3D optical displays, optical data storage, anti-counterfeiting, information encryption, and optical devices.

[0004] In recent years, circularly polarized luminescent (CPL) materials with both left-handed and right-handed polarization have attracted much attention from researchers, making their design and fabrication crucial. Chirality-selective optical filters offer a highly efficient and useful new method for preparing CPL materials, applicable to various non-chiral luminescent systems. The prepared CPL material systems have potential applications in 3D optical displays, optical data storage, anti-counterfeiting, organic light-emitting diodes (OLEDs), and biomedicine. Therefore, providing a chirality-selective optical filter is of great significance. Summary of the Invention

[0005] The purpose of this invention is to provide a chirality-selective optical filter that is applicable not only to chiral fluorescent systems but also to chiral phosphorescent systems, effectively solving the dilemma of difficulty in preparing circularly polarized phosphorescent (CPP) materials due to triplet instability.

[0006] The chiral selective optical filter provided by this invention is a chiral thin film obtained by spin coating of chiral silver clusters;

[0007] The chiral silver cluster is obtained by coordination reaction between a chiral molecule containing a thiol group and silver ions;

[0008] The structural formula of the chiral molecule containing a thiol group is shown in Formula I or Formula II:

[0009]

[0010] Formula I

[0011]

[0012] Formula II.

[0013] The chiral molecule containing a thiol group can be obtained from an L / D-cysteine ​​derivative by breaking disulfide bonds;

[0014] The reaction equation is shown below:

[0015]

[0016]

[0017] The specific steps are as follows:

[0018] Dissolve L / D-Cys-18NCO in DMSO, add D / L-dithiothreitol, and stir at 80-130℃ for 1-4 hours. After cooling to room temperature, add H2O, and a large amount of white precipitate will form. Filter to obtain the final product.

[0019] In this invention, the chiral silver clusters are dispersed in a solvent and then spin-coated onto a chiral film substrate to obtain the chiral film;

[0020] The solvent may be ethanol, methanol or acetone, preferably ethanol;

[0021] The chiral thin film substrate is a permeable glass substrate, such as a glass slide or a quartz sheet;

[0022] The spin coating conditions are as follows: low speed rotation speed is 50 rpm to 500 rpm, spin coating time is 10 to 60 seconds; high speed rotation speed is 800 rpm to 2000 rpm, spin coating time is 20 to 90 seconds. The dispersion of the chiral silver cluster is added dropwise at low speed, and then the spin coating is switched to high speed. This process is one spin coating cycle.

[0023] In this invention, the silver ions are added in the form of an aqueous solution of silver nitrate;

[0024] The concentration of the silver nitrate aqueous solution is 0.023~0.46 mol / L;

[0025] The molar ratio of the chiral molecule containing thiol to the silver ion is 4:1 to 2:5, preferably 1:1.

[0026] In this invention, the solvent used in the coordination reaction is a DMSO-H2O system, and the volume ratio of the two is 1:1 to 9:1, preferably 7:3.

[0027] The optical filter provided by this invention has important applications in biomedicine, optical information storage and encryption, optical devices, and CP-LED.

[0028] The optical filter of this invention can obtain a corresponding circularly polarized signal, including the following steps:

[0029] The light-emitting unit is excited, and a circularly polarized signal is obtained through the optical filter of this invention;

[0030] The light-emitting unit is a non-chiral organic dye molecule, an inorganic phosphorescent material, or a fluorescent polymer microsphere;

[0031] The optical filter is located behind the light-emitting unit, that is, it is placed after the light-emitting unit.

[0032] The organic dye molecules exist in a solution state, while the inorganic phosphorescent material exists in a solid state.

[0033] Preferably, the organic dye molecules include pyrene, aminopyrene, rhodamine 110, rhodamine B, and modulated white light dyes;

[0034] The inorganic phosphorescent materials include alkaline earth metal aluminate-type yellow-green phosphors (specifically, SrAl2O4:Eu,Dy), purple phosphors (specifically, CaAl2O4:Eu,Nd), and blue-green phosphors (specifically, Sr4Al4O4:Eu,Nd). 25 Phosphors include Eu, Dy, silicate-type sky blue phosphors (such as Sr2MgSi2O7), and sulfide-type red phosphors (such as Y2O2S:Eu.Mg:Ti).

[0035] The fluorescent polymer microspheres can be polystyrene microspheres with a particle size of 1 μm to 50 μm.

[0036] The present invention has the following beneficial technical effects:

[0037] (1) The present invention obtains chiral long alkyl chain molecules containing thiol groups through simple synthesis, and obtains chiral helical nanofibers through metal coordination.

[0038] (2) The present invention prepares the obtained chiral helical nanofibers into a chiral thin film with circularly polarized phosphorescence properties by spin coating, which has potential applications in application devices, anti-counterfeiting, 3D display and other fields.

[0039] (3) The chiral thin film prepared by the present invention can be used as a chiral selective optical filter, thereby enabling non-chiral fluorescent or phosphorescent units to obtain circularly polarized signals.

[0040] (4) The chiral selective optical filter prepared by the present invention has a simple operation method, strong applicability, small environmental influence factors, and low cost, which is of great significance for the preparation of various circularly polarized light-emitting materials.

[0041] This invention develops the fabrication and application of a chiral selective optical filter, and explores its chiral optical properties and application expansion. Attached Figure Description

[0042] Figure 1a shows the 1H NMR spectrum of L-Cys-18NCO prepared in a specific embodiment of the present invention;

[0043] Figure 1b shows the 1H NMR spectrum of D-Cys-18NCO prepared in a specific embodiment of the present invention;

[0044] Figure 2a shows the 1H NMR spectrum of SH-(L-Cys-18NCO) prepared in Example 1 of this invention;

[0045] Figure 2b shows the 1H NMR spectrum of SH-(D-Cys-18NCO) prepared in Example 1 of this invention;

[0046] Figure 3 shows the CPL spectrum of the non-chiral organic dye pyrenecarboxylic acid obtained by passing it through a chiral optical filter in Example 2 of the present invention.

[0047] Figure 4 shows the CPL spectrum of the achiral organic dye Rhodamine 110 obtained through a chiral optical filter in Example 3 of the present invention.

[0048] Figure 5 shows the CPL spectrum of the non-chiral organic dye Rhodamine B obtained through a chiral optical filter in Example 4 of the present invention.

[0049] Figure 6 shows the CPL spectrum obtained by passing white light of a mixture of three non-chiral organic dyes through a chiral optical filter in Example 5 of the present invention.

[0050] Figure 7 shows the CPP spectra obtained by passing the non-chiral inorganic phosphors of Examples 6-10 of the present invention through a chiral optical filter. Spectrum 1 is the CPP spectrum obtained by the purple phosphor CaAl₂O₄:Eu,Nd; spectrum 2 is the CPP spectrum obtained by the sky-blue phosphor Sr₂MgSi₂O₇; and spectrum 3 is the CPP spectrum obtained by the blue-green phosphor Sr₄Al₄O₇. 25 CPP spectra obtained from Eu and Dy, spectrum 4 is the CPP spectrum obtained from green phosphor SrAl2O4:Eu and Dy, and spectrum 5 is the CPP spectrum obtained from red phosphor Y2O2S:Eu.Mg:Ti;

[0051] Figure 8 shows the CPL spectrum of the non-chiral fluorescent polymer microspheres (polystyrene red light microspheres) of Example 11 of the present invention obtained through a chiral light filter. Detailed Implementation

[0052] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0053] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0054] The L / D-cystine derivative (L / D-Cys-18NCO) used in the following examples is prepared as follows:

[0055] 1 mmol of L / D-cystine methyl ester dihydrochloride (purchased from Inokai) and 2.4 mmol of octadecyl isocyanate (purchased from Inokai) were reacted at a molar ratio of 1:2.4 in 100 mL of CH₂Cl₂ (dichloromethane, purchased from Sinopharm Group). 2.4 mmol of TEA (triethylamine, purchased from Sinopharm Group) was added, and the reaction was carried out at room temperature for 48 hours. After the reaction was complete, the mixture was washed three times with dichloromethane and filtered to obtain L / D-Cys-18NCO (95% yield), which was then set aside for use. Structural confirmation data are shown in Figures 1a and 1b.

[0056]

[0057] or

[0058]

[0059] The preparation method of SH-(L / D-Cys-18NCO) used in the following examples is as follows:

[0060] 0.46 mmol of L / D-Cys-18NCO was dissolved in 50 mL of DMSO (dimethyl sulfoxide, purchased from Sinopharm Group), and 0.36 mmol of DL-dithiothreitol (purchased from Inocare) was added. The mixture was stirred at 120 °C for 3 hours. After cooling to room temperature, 20 mL of H2O was added, resulting in a large amount of white precipitate. This precipitate was filtered to obtain SH-(L / D-Cys-18NCO), which was then set aside for use. The structural confirmation data are shown in Figures 2a and 2b.

[0061]

[0062] or

[0063]

[0064] Example 1: Fabrication of a chiral-selective optical filter

[0065] 1. Preparation of chiral silver clusters

[0066] 0.46 mmol of chiral molecule SH-(L / D-Cys-18NCO) was heated and dissolved in 1.4 mL of DMSO, followed by the addition of 0.6 mL of AgNO3 aqueous solution (0.046 mmol), resulting in the precipitation of a large amount of pale yellow suspension. The suspension was filtered and washed three times with ethanol to obtain a pale yellow solid, which was then ultrasonically dispersed in an ethanol solution.

[0067] 2. Fabrication of chiral-selective optical filters

[0068] Five mg of the chiral silver clusters were ultrasonically and uniformly dispersed in 1 mL of ethanol solution. The solution was added dropwise at a low speed (50 μL at a time) using a spin coater (KW-4B benchtop spin coater, purchased from Beijing Saidekais Electronics Co., Ltd.), followed by high-speed spin coating. Repeating the spin coating process a few times yielded light yellow uniform films with different circularly polarized phosphorescence (CPP) signals. Optical filters with varying degrees of chirality selectivity can be obtained based on different film thicknesses.

[0069] The chiral thin film obtained by spin coating 200 rpm for 20 seconds at a low speed and 1000 rpm for 35 seconds at a high speed, and spin coating 20 times, was used as a chiral selective optical filter in the following application experiments.

[0070] Example 2: Application of chiral selective optical filters

[0071] (1) Pyrenecarboxylic acid (purchased from Inokai Reagent Company), a non-chiral organic dye fluorescent molecule, was dissolved in DMSO solution as a luminescent unit;

[0072] (2) The chiral selective optical filter prepared in Example 1 is placed on the rear side of the light-emitting unit;

[0073] (3) Use light with a wavelength of 320 nm as the excitation wavelength to excite the light-emitting unit, and obtain the corresponding CPL signal through an L-type or D-type optical filter, as shown in Figure 3.

[0074] Example 3: Application of chiral-selective optical filters

[0075] (1) Rhodamine 110 (purchased from Inokai Reagent Company), a non-chiral organic dye fluorescent molecule, was dissolved in methanol solution as a luminescent unit;

[0076] (2) The chiral selective optical filter prepared in Example 1 is placed on the rear side of the light-emitting unit;

[0077] (3) Use light with a wavelength of 360 nm as the excitation wavelength to excite the light-emitting unit, and obtain the corresponding CPL signal through an L-type or D-type optical filter, as shown in Figure 4.

[0078] Example 4: Application of chiral selective optical filters

[0079] (1) Rhodamine B (purchased from Inokai Reagent Company), a non-chiral organic dye fluorescent molecule, was dissolved in methanol solution as a luminescent unit;

[0080] (2) The chiral selective optical filter prepared in Example 1 is placed on the rear side of the light-emitting unit;

[0081] (3) Use light with a wavelength of 360 nm as the excitation wavelength to excite the light-emitting unit, and obtain the corresponding CPL signal through an L-type or D-type optical filter, as shown in Figure 5.

[0082] Example 5: Application of chiral-selective optical filters

[0083] (1) White light was prepared by mixing three luminescent molecules, namely pyrene carboxylic acid, rhodamine 110 and rhodamine B, which are non-chiral organic dye fluorescent molecules;

[0084] (2) The chiral selective optical filter prepared in Example 1 is placed on the rear side of the light-emitting unit;

[0085] (3) Use light with a wavelength of 340 nm as the excitation wavelength to excite the light-emitting unit, and obtain the corresponding CPL signal through an L-type or D-type optical filter, as shown in Figure 6.

[0086] Example 6: Application of chiral-selective optical filters

[0087] (1) A non-chiral inorganic phosphor, alkaline earth metal aluminate type purple phosphor (CaAl2O4:Eu,Nd) (commercially purchased from Shenzhen Yaodesheng Technology Co., Ltd., product model KYD-12, particle size 45~55 μm) was used as the luminescent unit;

[0088] (2) The chiral selective optical filter prepared in Example 1 is placed on the rear side of the light-emitting unit;

[0089] (3) Use light with a wavelength of 320 nm as the excitation wavelength to excite the light-emitting unit, and obtain the corresponding CPP signal through an L-type or D-type optical filter, as shown in CPP spectrum No. 1 in Figure 7.

[0090] Example 7: Application of chiral-selective optical filters

[0091] (1) A non-chiral inorganic phosphor silicate-type sky blue phosphor (Sr2MgSi2O7) (commercially purchased from Shenzhen Yaodesheng Technology Co., Ltd., product model KYD-7, particle size 65~75μm) was used as the light-emitting unit;

[0092] (2) The chiral selective optical filter prepared in Example 1 is placed on the rear side of the light-emitting unit;

[0093] (3) Use light with a wavelength of 365 nm as the excitation wavelength to excite the light-emitting unit, and obtain the corresponding CPP signal by passing through an L-type or D-type optical filter, as shown in CPP spectrum No. 2 in Figure 7.

[0094] Example 8: Application of chiral selective optical filters

[0095] (1) Non-chiral inorganic phosphorescent material, alkaline earth metal aluminate type blue-green phosphor (Sr4Al4O) 25 Eu, Dy) (purchased from Shenzhen Yaodesheng Technology Co., Ltd., product model KYD-9, particle size 40~45 μm) as the luminescent unit;

[0096] (2) The chiral selective optical filter prepared in Example 1 is placed on the rear side of the light-emitting unit;

[0097] (3) Use light with a wavelength of 360 nm as the excitation wavelength to excite the light-emitting unit, and obtain the corresponding CPP signal through an L-type or D-type optical filter, as shown in CPP spectrum No. 3 in Figure 7.

[0098] Example 9: Application of chiral-selective optical filters

[0099] (1) The non-chiral inorganic phosphor, alkaline earth metal aluminate type yellow-green phosphor (SrAl2O4:Eu,Dy) (commercially purchased from Shenzhen Yaodesheng Technology Co., Ltd., product model KYD-7, particle size 65~75 μm) was used as the luminescent unit;

[0100] (2) The chiral selective optical filter prepared in Example 1 is placed on the rear side of the light-emitting unit;

[0101] (3) Use light with a wavelength of 365 nm as the excitation wavelength to excite the light-emitting unit, and obtain the corresponding CPP signal through an L-type or D-type optical filter, as shown in CPP spectrum No. 4 in Figure 7.

[0102] Example 10: Application of chiral-selective optical filters

[0103] (1) A non-chiral inorganic phosphor sulfide type red phosphor (Y2O2S:Eu.Mg:Ti) (commercially purchased from Shenzhen Yaodesheng Technology Co., Ltd., KYD-15, particle size 15~25 μm) was used as the luminescent unit;

[0104] (2) The chiral selective optical filter prepared above is placed on the rear side of the light-emitting unit;

[0105] (3) Use light with a wavelength of 340 nm as the excitation wavelength to excite the light-emitting unit, and obtain the corresponding CPP signal through an L-type or D-type optical filter, as shown in CPP spectrum No. 5 in Figure 7.

[0106] Example 11: Application of chiral-selective optical filters

[0107] (1) Non-chiral polystyrene red light microspheres (purchased from Shanghai Yiyuan Biotechnology Co., Ltd., particle size 20 μm) were used as the luminescent unit;

[0108] (2) The chiral selective optical filter prepared in Example 1 is placed on the rear side of the light-emitting unit;

[0109] (3) Use light with a wavelength of 360 nm as the excitation wavelength to excite the light-emitting unit, and obtain the corresponding CPL signal through an L-type or D-type optical filter, as shown in Figure 8.

[0110] Comparative Example 1

[0111] (1) Pyrenecarboxylic acid (purchased from Inokai Reagent Company), a non-chiral fluorescent molecule, was dissolved in DMSO solution as a luminescent unit;

[0112] (2) The chiral selective optical filter prepared in Example 1 is placed in front of the light-emitting unit;

[0113] (3) Using light with a wavelength of 320 nm as the excitation wavelength, the excitation unit cannot obtain the corresponding CPL signal.

[0114] Comparative Example 2

[0115] (1) The non-chiral inorganic phosphor, alkaline earth metal aluminate type yellow-green phosphor (SrAl2O4:Eu,Dy) (commercially purchased from Shenzhen Yaodesheng Technology Co., Ltd., product model KYD-7, particle size 65~75 μm) was used as the luminescent unit;

[0116] (2) The chiral selective optical filter prepared in Example 1 is placed in front of the light-emitting unit;

[0117] (3) Use light with a wavelength of 365 nm as the excitation wavelength to excite the light-emitting unit, and obtain the corresponding CPP signal through a chiral-selective optical filter.

[0118] As can be seen from Comparative Examples 1-2, the chiral-selective optical filter needs to be placed behind the light-emitting unit, and chiral selection is required to obtain the corresponding CPL / CPP signal.

Claims

1. A chiral selective optical filter, comprising a chiral thin film obtained by spin-coating a chiral silver cluster; wherein the chiral silver cluster is obtained by coordination reaction between a chiral molecule containing a thiol group and silver ions; the optical filter is located behind a light-emitting unit; the structural formula of the chiral molecule containing the thiol group is shown in Formula I or Formula II: Formula I Formula II.

2. The optical filter according to claim 1, characterized in that: The chiral silver clusters are dispersed in a solvent and then spin-coated onto a chiral film substrate to obtain the chiral film; the solvent is ethanol, methanol, or acetone; the chiral film substrate is a glass substrate; the spin-coating conditions are: low speed of 50 rpm to 500 rpm for 10 s to 60 s, and high speed of 800 rpm to 2000 rpm for 20 s to 90 s.

3. The optical filter according to claim 1 or 2, characterized in that: The silver ions are added in the form of an aqueous solution of silver nitrate; the concentration of the aqueous solution of silver nitrate is 0.023~0.46 mol / L; the molar ratio of the chiral molecule containing thiol to the silver ions is 4:1~2:

5.

4. The optical filter according to claim 1 or 2, characterized in that: The coordination reaction uses a DMSO-H2O system as the solvent, with a volume ratio of 1:1 to 9:

1.

5. The application of the optical filter according to any one of claims 1-4 in biomedicine, optical information storage and encryption, optical devices, and CP-LED.

6. A method for obtaining a circularly polarized signal, comprising the following steps: exciting a light-emitting unit, and obtaining a circularly polarized signal through an optical filter as described in any one of claims 1-4; wherein the light-emitting unit is a non-chiral organic dye molecule, an inorganic phosphorescent material, or a fluorescent polymer microsphere.

7. The method according to claim 6, characterized in that: The optical filter is located behind the light-emitting unit.

8. The method according to claim 6 or 7, characterized in that: The organic dye molecules exist in a solution state, while the inorganic phosphorescent material exists in a solid state.

9. The method according to claim 6 or 7, characterized in that: The organic dye molecules include pyrene, aminopyrene, rhodamine 110, rhodamine B, and modulated white light dyes; the inorganic phosphorescent materials include alkaline earth metal aluminate type yellow-green phosphor, purple phosphor, and blue-green phosphor, silicate type sky-blue phosphor, and sulfide type red phosphor; the fluorescent polymer microspheres are polystyrene microspheres.

10. A circularly polarized signal obtained by the method of any one of claims 6-8 and its application in 3D displays, CP-LEDs or optoelectronic devices.

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