High-performance narrow-band circularly polarized luminescent material and application thereof

Abstract

The application belongs to the technical field of circularly polarized luminescence, and discloses a high-performance narrow-band circularly polarized luminescent material, which comprises the following components in mass ratio: (97-99):(1-3):(0.05-0.25) of nematic liquid crystal, chiral dopant and rare earth complex. The application utilizes excellent narrow-band emission rare earth complex, matches the chiral structure of liquid crystal with the emission band of the rare earth complex by regulating the proportion of the chiral dopant in the chiral liquid crystal, so that the super-asymmetric CPL is realized, and the high-asymmetric factor |g lum can reach 1.86, which is very close to the maximum theoretical value 2.0. Compared with traditional organic CPL devices, the application has the characteristics of half-gap width and high color purity, and has the potential for advanced display and new anti-counterfeiting technology.

Description

Technical Field

[0001] This invention belongs to the field of circularly polarized light emission technology, specifically relating to a high-performance narrow-band circularly polarized light emission material and its applications. Background Technology

[0002] Circularly polarized luminescence (CPL) refers to the phenomenon where a luminescent system emits light with differentially polarized left-handed and right-handed circular polarization. It holds broad application prospects in fields such as 3D display, biosensing, encryption and anti-counterfeiting, and photocatalytic asymmetric synthesis. Recent advances in CPL research include chiral luminescent materials based on small organic molecules, aggregation-induced emission compounds, supramolecular assemblies, liquid crystals and liquids, polymers, metal ligand coordination complexes and assemblies, metal clusters, and inorganic nanomaterials.

[0003] An important indicator of circularly polarized luminescent materials is the asymmetry factor g. lum Value, defined from a measurement perspective, is: When the asymmetry factor g lum When the value is +2 or -2, it represents purely left-handed or right-handed circularly polarized light, but the actual g of the circularly polarized luminescent material... lum The value is much smaller, usually 10. -5 ~10 -3 Moreover, most CPL materials emit broad-spectral emission with a full width at half maximum (FWHM) greater than 60 nm due to the inherent vibrational coupling between their ground and excited states, which is not conducive to achieving high color purity.

[0004] Rare earth metal-organic complexes (RMCs) possess excellent properties such as high fluorescence quantum efficiency and narrow emission half-maximum width, making them ideal novel CPL materials. However, currently reported rare earth complex CPL materials (such as supramolecular aggregates and chiral metal ligand complexes) exhibit an asymmetry factor (g). lum Its small value and high synthesis difficulty severely limit its practical application. Summary of the Invention

[0005] The purpose of this invention is to overcome at least one deficiency of the prior art and provide a high-performance narrow-band circularly polarized light-emitting material and its applications.

[0006] The technical solution adopted in this invention is:

[0007] In a first aspect, the present invention provides a high-performance narrow-band circularly polarized light-emitting material, the light-emitting material comprising the following mass ratio: nematic liquid crystal, chiral dopant, and rare earth complex in a mass ratio of (97-99):(1-3):(0.05-0.25).

[0008] In some instances, the luminescent material comprises the following mass ratio: nematic liquid crystal, chiral dopant, and rare earth complex in a mass ratio of 98:(1.90–2.00):(0.05–0.25).

[0009] In some instances, the luminescent material comprises the following mass ratio: nematic liquid crystal, chiral dopant, and rare earth complex in a mass ratio of 97:(2.30–2.40):(0.05–0.25).

[0010] In some instances, the luminescent material comprises the following mass fractions: nematic liquid crystal, chiral dopant, and rare earth complex in a mass ratio of 98:(1.00–1.30):(0.05–0.25).

[0011] In some instances, the rare earth complex is selected from any one of tris[4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione]bis(triphenylphosphine oxide) europium, terbium(III) acetylacetonate, neodymium(III) acetylacetonate, (1,10-phenanthroline)tris[4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione] europium(III), tri(acetylacetonate)(1,10-phenanthroline) terbium(III), yronin(III) hexafluorohydrate, and tris(cyclopentadienyl)erbium(III).

[0012] In some instances, the chiral dopant is selected from any one of R5011, S5011, R811, S811, R6N, and S6N.

[0013] In some examples, the method for preparing the luminescent material is as follows: the formula of the luminescent material is added to a solvent in proportion and completely dissolved, stirred and mixed evenly, and the solvent is evaporated to obtain a chiral liquid crystal mixture. The mixture is then heated to the clearing point of the chiral liquid crystal mixture and poured into a liquid crystal cell to obtain the luminescent material.

[0014] Secondly, the high-performance narrow-band circularly polarized light-emitting material provided in the first aspect of this invention is applied in biomedicine, optical information storage and encryption, and optical devices.

[0015] Thirdly, the present invention provides a device made of the high-performance narrow-band circularly polarized light-emitting material described in the first aspect.

[0016] In some instances, the device is at least one of anti-counterfeiting devices, 3D displays, OLEDs, chiral separation membranes, and optoelectronic devices.

[0017] The beneficial effects of this invention are:

[0018] This invention utilizes excellent narrow-band emission rare-earth complexes and, by controlling the proportion of chiral dopants in the chiral liquid crystal, matches the chiral structure of the liquid crystal with the emission band of the rare-earth complex, thereby achieving a super-asymmetric CPL and a high asymmetry factor |g. lum The contrast ratio reaches 1.86, very close to the maximum theoretical value of 2.0. Compared to traditional organic CPL devices, it features narrow slit width and high color purity. Compared to other rare-earth CPL devices, this formulation achieves high contrast and high asymmetry CPL close to the maximum theoretical value of 2.0, showing potential for use in advanced displays and new anti-counterfeiting technologies. Attached Figure Description

[0019] Figure 1 The images show the circular polarization spectra of Example 2 and Comparative Example 1.

[0020] Figure 2 The images show the circular polarization spectra of Examples 1, 2, 2, and 3 under different europium complex contents.

[0021] Figure 3 The diagram shows the influence of asymmetry factor on different proportions of chiral dopants in Examples 2, 4, and 5.

[0022] Figure 4 The diagram shows the influence of asymmetry factor on different proportions of chiral dopants in Examples 3, 6, and 7.

[0023] Figure 5 The diagram shows the influence of asymmetry factor on different proportions of chiral dopants in Examples 4, 8, and 9. Detailed Implementation

[0024] The following disclosure provides many different implementations or examples for different ways of implementing the present invention.

[0025] The methods for preparing the luminescent materials in the embodiments and comparative examples of this invention are as follows:

[0026] Nematic liquid crystal, chiral dopant, and rare earth complex were dissolved completely in dichloromethane solvent according to a certain ratio. The mixture was then magnetically stirred at 500 rpm for 5 hours to ensure thorough mixing and allow the dichloromethane solvent to evaporate, yielding a chiral liquid crystal mixture. The mixture was heated to 70°C until a clearing point was reached. At 70°C, the chiral liquid crystal mixture was poured into a liquid crystal cell with a thickness of 8 μm to obtain a luminescent material.

[0027] In this invention, the nematic liquid crystal can be changed according to the device's emission color requirements.

[0028] In this invention, the chiral dopant can be replaced according to the device's emission color requirements.

[0029] In some instances, the chiral dopant can be selected from any of the following substances:

[0030]

[0031] In examples of the present invention, the luminescent molecules that can be used are shown below, and the corresponding luminescent molecules, i.e., rare earth complexes, can be replaced according to the emission wavelength requirements:

[0032]

[0033] In the embodiments and comparative examples, the europium rare earth complex used was tris[4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione]bis(triphenylphosphine oxide) europium, the terbium rare earth complex used was terbium acetylacetonate (III), and the neodymium rare earth complex used was neodymium acetylacetonate (III).

[0034] Example 1

[0035] The formulation of this embodiment is: nematic liquid crystal E7, chiral dopant R5011, and europium rare earth complex in a mass ratio of 98:1.95:0.15;

[0036] In this embodiment, the europium rare earth complex selected has a maximum emission wavelength of 615 nm and an emission spectrum half-peak width of 10 nm, which belongs to relatively pure red light emission.

[0037] Example 2

[0038] The formulation of this embodiment is: nematic liquid crystal E7, chiral dopant R5011, and europium rare earth complex in a mass ratio of 98:1.95:0.25;

[0039] In this embodiment, the europium rare earth complex selected has a maximum emission wavelength of 615 nm and an emission spectrum half-peak width of 10 nm, which belongs to relatively pure red light emission.

[0040] Example 3

[0041] The formulation of this embodiment is: nematic liquid crystal E7, chiral dopant R5011, and terbium rare earth complex in a mass ratio of 97:2.35:0.25;

[0042] In this embodiment, the terbium rare earth complex selected has a maximum emission wavelength of 545 nm and an emission spectrum half-peak width of 10 nm, which belongs to relatively pure green light emission.

[0043] Example 4

[0044] The formulation of this embodiment is: nematic liquid crystal E7, chiral dopant R5011, and neodymium rare earth complex in a mass ratio of 98:1.20:0.25;

[0045] In this embodiment, the neodymium rare earth complex selected has a maximum emission wavelength of 1000 nm and an emission spectrum half-width of 10 nm, belonging to near-infrared luminescent molecules.

[0046] Comparative Example 1

[0047] The rare earth complex was replaced with the organic fluorescent molecule Nile Red, and everything else was the same as in Example 2.

[0048] Comparative Example 2

[0049] In this comparative example, the mass ratio of nematic liquid crystal E7, chiral dopant R5011, and europium rare earth complex was 98:1.95:0.35, and all other parameters were the same as in Example 2. The device with this formulation exhibited a CPL signal intensity of 780 nm at the maximum emission wavelength of 615 nm.

[0050] Comparative Example 3

[0051] In this comparative example, the mass ratio of nematic liquid crystal E7, chiral dopant R5011, and europium rare earth complex was 98:1.95:0.45, and all other parameters were the same as in Example 2. The device with this formulation exhibited a CPL signal intensity of 230 nm at the maximum emission wavelength of 615 nm.

[0052] Comparative Example 4

[0053] In this comparative example, the mass ratio of nematic liquid crystal E7, chiral dopant R5011, and europium rare earth complex was 98:1.70:0.25, and all other parameters were the same as in Example 2. Under this formulation, the device exhibited an asymmetry factor |g| at the maximum emission wavelength of 615 nm. lum |=0.39.

[0054] Comparative Example 5

[0055] In this comparative example, the mass ratio of nematic liquid crystal E7, chiral dopant R5011, and europium rare earth complex was 97:2.50:0.25, and all other parameters were the same as in Example 2. Under this formulation, the device exhibited an asymmetry factor |g| at the maximum emission wavelength of 615 nm. lum |=0.30.

[0056] Comparative Example 6

[0057] In this comparative example, the mass ratio of nematic liquid crystal E7, chiral dopant R5011, and terbium rare earth complex was 98:1.50:0.25, and all other parameters were the same as in Example 3. Under this formulation, the device exhibited an asymmetry factor |g| at the maximum emission wavelength of 615 nm. lum |=0.26.

[0058] Comparative Example 7

[0059] In this comparative example, the mass ratio of nematic liquid crystal E7, chiral dopant R5011, and terbium rare earth complex was 97:2.60:0.25, and all other parameters were the same as in Example 3. Under this formulation, the device exhibited an asymmetry factor |g| at the maximum emission wavelength of 545 nm. lum |=0.33.

[0060] Comparative Example 8

[0061] In this comparative example, the mass ratio of the chiral dopant R5011 to the neodymium rare earth complex in the nematic liquid crystal E7 was 99:0.70:0.25, and all other parameters were the same as in Example 4. Under this formulation, the device exhibited an asymmetry factor |g| at the maximum emission wavelength of 545 nm. lum |=0.28.

[0062] Comparative Example 9

[0063] In this comparative example, the mass ratio of the chiral dopant R5011 to the neodymium rare earth complex in the nematic liquid crystal E7 was 98:2.00:0.25, and all other parameters were the same as in Example 4. Under this formulation, the device exhibited an asymmetry factor |g| at the maximum emission wavelength of 1000 nm. lum | = 0.25.

[0064] Analysis and Conclusion

[0065] from Figure 1 As can be seen, the intensity of circularly polarized luminescent materials using rare-earth complexes is significantly stronger than that of Nile Red. As luminescent molecules, rare-earth complexes have a much narrower emission bandwidth than organic fluorescent molecules.

[0066] from Figure 2 As can be seen, the CPL signal intensity of the material using the formulation of this invention increases from 300 (mdge) to 1600 (mdge) at the maximum emission wavelength of 615 nm with the increase of europium complex.

[0067] At the same time from Figures 3-5 It can be seen from this that the chiral signal asymmetry factor |g lum The value of |glum| first increases and then decreases with the amount of chiral dopant, and a high asymmetry factor |glum| can be achieved to 1.86, which is very close to the maximum theoretical value of 2.0. This indicates that by adjusting the chiral scale to match the emission wavelength of the luminescent molecules, high color purity and high asymmetry circularly polarized light-emitting devices can only be obtained within the range defined by this invention.

[0068] The above is a further detailed description of the present invention and should not be considered as a limitation on the specific implementation of the present invention. For those skilled in the art, simple deductions or substitutions without departing from the concept of the present invention are all within the protection scope of the present invention.

Claims

1. A high-performance narrow-band circularly polarized luminescent material, characterized in that, The luminescent material comprises the following mass ratio: a nematic liquid crystal in a mass ratio of (97-99):(1-3):(0.05-0.25), a chiral dopant, and a rare earth complex, wherein the rare earth complex is selected from tris[4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione]bis(triphenylphosphine oxide) europium, terbium acetylacetonate (III), and neodymium acetylacetonate (III).

2. The luminescent material according to claim 1, characterized in that, The luminescent material comprises the following mass ratio: nematic liquid crystal, chiral dopant, and rare earth complex in a mass ratio of 98:(1.90~2.00):(0.05~0.25).

3. The luminescent material according to claim 1, characterized in that, The luminescent material comprises the following mass ratio: nematic liquid crystal, chiral dopant, and rare earth complex in a mass ratio of 97:(2.30~2.40):(0.05~0.25).

4. The luminescent material according to claim 1, characterized in that, The luminescent material comprises the following mass fractions: nematic liquid crystal, chiral dopant, and rare earth complex in a mass ratio of 98:(1.00~1.30):(0.05~0.25).

5. The luminescent material according to claim 1, characterized in that, The chiral dopant is selected from any one of R5011, S5011, R811, S811, R6N, and S6N.

6. The luminescent material according to claim 1, characterized in that, The method for preparing the luminescent material is as follows: the formula of the luminescent material is added to a solvent in proportion and completely dissolved, stirred and mixed evenly, and the solvent is evaporated to obtain a chiral liquid crystal mixture; the mixture is heated to the clearing point of the chiral liquid crystal mixture, and then poured into a liquid crystal cell to obtain the luminescent material.

Images