A composite luminescent material capable of generating circularly polarized light and its preparation

Abstract

The present invention discloses a composite luminescent material capable of generating circularly polarized light and its preparation, belonging to the field of circularly polarized luminescence technology. This composite material, formed by combining a chiral bismuth oxyhalide film doped with ytterbium and erbium rare earth ions with cholesteric liquid crystals, exhibits enhanced chiral light modulation efficiency and higher circular dichroism spectral values ​​than natural materials, resulting in high luminescence efficiency.

Description

Technical Field

[0001] The invention relates to a composite luminescent material capable of generating circularly polarized light and a preparation method thereof, belonging to the technical field of circularly polarized luminescence. Background Art

[0002] Circularly polarized luminescence (CPL) is a type of electromagnetic wave. When two plane-polarized lights with the same propagation direction and mutually perpendicular vibration directions are superimposed, they can synthesize a luminescence phenomenon with regularly changing electric vectors. It is divided into left-handed and right-handed circularly polarized light, reflecting the excited state of the chiral luminescence system. It has a wide range of applications in 3D displays, optoelectronic devices, information storage, photocatalytic asymmetric synthesis, and biological probes.

[0003] Currently, chiral supramolecular self-assembly systems are the primary vehicles for studying the generation, transmission, and amplification of CPLs. Multi-level chiral supramolecular structures with CPL properties can not only impart chirality to achiral chromophores but also significantly amplify the asymmetry factor, glum. However, supramolecular sol / gel systems are soft and have limited order, making it difficult to produce highly ordered and precise microstructures, thus failing to meet the in-depth research needs of chiral luminescent materials.

[0004] Bismuth oxyhalides, as a new type of semiconductor, especially bismuth oxyhalides with sheet structures, have attracted widespread attention in the industry for their excellent physical properties and chemical activity. However, bismuth oxyhalides doped with rare earth ions can only emit natural light, not circularly polarized light. Imparting chirality to two-dimensional materials doped with rare earth ions is expected to create novel nanomaterials that can directly generate circularly polarized light, with enhanced chiral light modulation efficiency and higher circular dichroism spectral values ​​than natural materials, effectively improving the material's luminescence efficiency.

[0005] Chiral two-dimensional materials processed using traditional physical methods have low controllable degrees of freedom, limiting the dimensionality of light regulation. Research has shown that chemical methods, such as solvothermal and hydrothermal methods, offer significant advantages in preparing luminescent rare-earth ion-doped two-dimensional materials. These methods offer a wide range of adjustable experimental factors and facilitate the preparation of two-dimensional luminescent materials with diverse morphologies. Therefore, to address the problem of preparing chiral two-dimensional materials doped with rare-earth ions, we employed chemical methods to design and prepare chiral bismuth oxyhalide films doped with ytterbium and erbium rare-earth ions.

[0006] Based on this, the present invention provides a composite luminescent material capable of generating circularly polarized light and its preparation. By combining a chiral bismuth oxyhalide film doped with rare earth ions with a cholesteric liquid crystal, circularly polarized light can be directly generated and has a higher circular dichroism spectral value than natural materials, and the luminous efficiency of the material can be effectively improved. Summary of the Invention

[0007] To address the deficiencies in the prior art, the present invention provides a composite luminescent material capable of generating circularly polarized light and its preparation method, the specific preparation method of which is as follows:

[0008] (1) Apply a vertical alignment agent on the conductive glass.

[0009] (2) Apply optical adhesive to three sides of the ytterbium and erbium rare earth ion doped chiral bismuth oxyhalide film, and then align and bond it face to face with the conductive glass coated with a vertical orientation agent, forming a gap between the ytterbium and erbium rare earth ion doped chiral bismuth oxyhalide film and the conductive glass coated with a vertical orientation agent, and finally obtain a conductive film glass box.

[0010] (3) Using a capillary tube, injecting cholesteric liquid crystal liquid into the gap of the conductive film glass box obtained in step (2), and finally sealing the injection port with an optical adhesive to obtain a composite luminescent material capable of generating circularly polarized light.

[0011] Preferably, the conductive glass in step (1) is one of fluorine-doped tin oxide transparent conductive glass (FTO glass) and indium tin oxide transparent conductive glass (ITO glass).

[0012] Preferably, the vertical alignment agent (PAPI) in step (1) is purchased from Nanjing Ningcui Optical Technology Co., Ltd.

[0013] Preferably, the chemical formula of the chiral bismuth oxyhalide film doped with ytterbium and erbium rare earth ions in step (2) is BiEryYbxOX-Y; wherein X is any one or both of Cl and Br, Y is D-sorbitol, x is 0.05 to 0.3, and y is 0.001 to 0.1.

[0014] More preferably, the chemical formula of the chiral bismuth oxyhalide film doped with ytterbium and erbium rare earth ions in step (2) is BiEr 0.08 Yb 0.2 OX-Y; wherein X is Br and Y is D-sorbitol.

[0015] Preferably, the chiral bismuth oxyhalide film doped with ytterbium and erbium rare earth ions in step (2) is specifically prepared as follows:

[0016] a. Using bismuth nitrate, ytterbium oxide, erbium oxide, a halide salt, and D-sorbitol as raw materials, the mixture is prepared in a ratio of Yb ion to Er ion in a molar ratio of x:y, wherein x is 0.05 to 0.3 and y is 0.001 to 0.1; adding concentrated nitric acid to dissolve the mixture, and then adding ethylene glycol or an aqueous solution of ethylene glycol to form a solution with a total concentration of 0.1 to 2 mol / L; stirring the mixture uniformly, adjusting the pH value to 2 to 5, transferring the conductive glass and the prepared total solution into a hydrothermal autoclave with a polytetrafluoroethylene lining, wherein the filling degree of the polytetrafluoroethylene lining is 0.4 to 0.8, and performing a solvothermal reaction at a temperature of 110 to 250° C. and a reaction time of 2 to 25 hours; wherein the halide salt is potassium halide or sodium halide.

[0017] b. Washing and drying the reaction product of step a, and calcining at a high temperature of 300-600° C. for 1-4 hours to obtain a chiral bismuth oxyhalide film doped with ytterbium and erbium rare earth ions.

[0018] Preferably, the conductive glass in step a is one of fluorine-doped tin oxide transparent conductive glass (FTO glass) and indium tin oxide transparent conductive glass (ITO glass).

[0019] More preferably, the chiral bismuth oxyhalide film doped with ytterbium and erbium rare earth ions in step (2) is prepared in the following manner:

[0020] a. Using Bi(NO3)3.5H2O, D-sorbitol (D-SOr), and NaBr as raw materials, the mixture is prepared in a molar ratio of Bi ion:Yb ion:Er ion:D-SOr:Cl ion = 0.945:0.02:0.008:0.1:1. Ytterbium oxide and erbium oxide are first dissolved in concentrated nitric acid, and then all the raw materials are dissolved in ethylene glycol, an organic solvent, to prepare a solution with a total solution concentration of 0.8 mol / L. The above solution is then added to a container and stirred to mix uniformly. The pH value is adjusted to 4 with 1 mol / L hydrochloric acid. The prepared solution and conductive glass are transferred to a hydrothermal autoclave with a polytetrafluoroethylene liner at a filling degree of 0.4, and then the temperature is raised to 160°C and kept at this temperature for 24 hours.

[0021] b. Wash the conductive glass film obtained in step a with deionized water and ethanol three times respectively, dry it in an oven, and heat-treat it at 450°C for 3 hours to obtain a film with the chemical formula Bi 0.945 Er 0.008 Yb 0.02 OBr-0.1D-SOr chiral bismuth oxyhalide thin film material.

[0022] Preferably, the area of ​​the ytterbium and erbium rare earth ion doped chiral bismuth oxyhalide film used in step (2) is the same as the area of ​​the conductive glass used in step (1).

[0023] Preferably, the optical adhesive in step (2) and step (3) is purchased from Nanjing Ningcui Optical Technology Co., Ltd., model number NOA65.

[0024] Preferably, the cholesteric liquid crystal liquid in step (3) is formed by mixing a nematic liquid crystal and a chiral agent, the nematic liquid crystal is purchased from Nanjing Ningcui Optical Technology Co., Ltd., model HTW109100-00, and the chiral agent is purchased from Nanjing Ningcui Optical Technology Co., Ltd., model R5011, wherein the mass of the chiral agent accounts for 1.8 to 2.5% of the total mass of the nematic liquid crystal and the chiral agent.

[0025] Preferably, the amount of cholesteric liquid crystal liquid used in step (3) is not subject to special requirements, and only needs to fill the gaps.

[0026] Unless otherwise specified, all reagents in the present invention are conventional commercially available reagents.

[0027] Principle of the present invention:

[0028] While cholesteric liquid crystals are non-luminescent, they are tunable. When combined with a chiral bismuth oxyhalide film doped with ytterbium and erbium rare earth ions, the resulting luminescent composite exhibits variable luminescence intensity as the cholesteric liquid crystal changes direction. The resulting composite exhibits dual chirality, resulting in higher circular dichroism values ​​and higher luminescence efficiency than natural materials.

[0029] Beneficial effects of the present invention

[0030] (1) The material of the present invention, which combines the ytterbium and erbium rare earth ion chiral bismuth oxyhalide film with cholesteric liquid crystal, has good light response characteristics, can directly generate circularly polarized light, has stronger chiral light modulation efficiency and higher circular dichroism spectrum value than natural materials, and has high luminous efficiency.

[0031] (2) The chiral halide bismuth oxide film doped with ytterbium and erbium rare earth ions of the present invention can be prepared by using different halogens as a matrix and a composite of chiral materials with different concentrations. The cholesteric liquid crystal can be prepared by combining a nematic liquid crystal material with a chiral agent. The preparation method is easy to operate, the operating conditions are easy to control, and various liquid crystal materials can be easily prepared.

[0032] (3) The chiral bismuth halide oxide thin film material doped with ytterbium and erbium rare earth ions in the present invention can be combined with cholesteric liquid crystal to serve as an information functional material. It is expected to be used as a novel luminescent material for scientific research in the fields of luminescence enhancement and direct generation of circularly polarized light, thereby expanding the scope of exploration in the field of chiral material research. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 BiEr prepared in Example 1 0.08 Yb0.2 Absorption spectrum of the material composed of OBr-D-SOr film and 1.8wt% cholesteric liquid crystal.

[0034] Figure 2 BiEr prepared in Example 2 0.08 Yb 0.2 Absorption spectrum of the material composed of OBr-D-SOr film and 2.1wt% cholesteric liquid crystal.

[0035] Figure 3 BiEr prepared in Example 3 0.08 Yb 0.2 Absorption spectrum of the material composed of OBr-D-SOr film and 2.5wt% cholesteric liquid crystal.

[0036] Figure 4 BiEr prepared in Example 1 0.08 Yb 0.2 SEM image of OBr-D-SOr thin film material.

[0037] Figure 5 BiEr prepared in Example 1 0.08 Yb 0.2 SEM image of OBr-D-SOr thin film material.

[0038] Figure 6 BiEr under 980nm laser excitation 0.08 Yb 0.2 OBr-D-SOr film-1.8wt% cholesteric liquid crystal combined with BiEr 0.08 Yb 0.2 OBr-D-SOr film-2.1wt% cholesteric liquid crystal combined with BiEr 0.08 Yb 0.2 Comparative luminescence intensity spectrum of materials composed of OBr-D-SOr film and 2.5wt% cholesteric liquid crystal.

[0039] Figure 7 BiEr under 980nm laser excitation 0.08 Yb 0.2 Luminescence intensity spectrum of OBr-D-SOr thin film material and BiEr 0.08 Yb 0.2 OBr-D-SOr film-1.8wt% cholesteric liquid crystal combination material, BiEr 0.08 Yb 0.2 OBr-D-SOr film-2.1wt% cholesteric liquid crystal combined with BiEr 0.08 Yb 0.2Combined comparison of the transmission spectra of the materials composed of OBr-D-SOr film and 2.5wt% cholesteric liquid crystal.

[0040] Figure 8 For BiEr 0.08 Yb 0.2 Luminescence spectrum of OBr-D-SOr film under 980nm laser excitation.

[0041] Figure 9 BiEr prepared in Example 1 0.08 Yb 0.2 The material composed of OBr-D-SOr film and 1.8wt% cholesteric liquid crystal produces a circularly polarized light spectrum under 980nm excitation.

[0042] Figure 10 BiEr prepared in Example 1 0.08 Yb 0.2 The material composed of OBr-D-SOr film and 1.8wt% cholesteric liquid crystal produces a circularly polarized light spectrum under 980nm excitation.

[0043] Figure 11 BiEr prepared in Example 2 0.08 Yb 0.2 The material composed of OBr-D-SOr film and 2.1wt% cholesteric liquid crystal generates a circularly polarized light spectrum under 980nm excitation.

[0044] Figure 12 BiEr prepared in Example 2 0.08 Yb 0.2 The material composed of OBr-D-SOr film and 2.1wt% cholesteric liquid crystal generates a circularly polarized light spectrum under 980nm excitation.

[0045] Figure 13 BiEr prepared in Example 3 0.08 Yb 0.2 The material composed of OBr-D-SOr film and 2.5wt% cholesteric liquid crystal produces a circularly polarized light spectrum under 980nm excitation;

[0046] Figure 14 BiEr prepared in Example 3 0.08 Yb 0.2 The material composed of OBr-D-SOr film and 2.5wt% cholesteric liquid crystal generates a circularly polarized light spectrum under 980nm excitation.

[0047] Figure 15 Schematic diagram of the experimental setup for generating circularly polarized light under 980nm excitation.

[0048] Figure 16BiEr prepared in Example 1 0.08 Yb 0.2 The luminescence spectrum of the material composed of OBr-D-SOr film and 1.8wt% cholesteric liquid crystal under 980nm excitation.

[0049] Figure 17 BiEr prepared in Example 2 0.08 Yb 0.2 The luminescence spectrum of the material composed of OBr-D-SOr film and 2.1wt% cholesteric liquid crystal under 980nm excitation.

[0050] Figure 18 BiEr prepared in Example 3 0.08 Yb 0.2 The luminescence spectrum of the material composed of OBr-D-SOr film and 2.5wt% cholesteric liquid crystal under 980nm excitation. DETAILED DESCRIPTION

[0051] The present invention will be further described in detail below with reference to specific embodiments, but the protection scope of the present invention is not limited to the contents described above.

[0052] Example 1

[0053] A composite luminescent material capable of generating circularly polarized light, the specific preparation steps of which are as follows:

[0054] (1) Bi(NO3)3·5H2O, Yb2O3, Er2O3, D-sorbitol (D-SOr) and NaBr were prepared as raw materials at a molar ratio of Bi ion: Yb ion: Er ion: D-SOr: Cl ion = 1:0.02:0.008:1:1. Ytterbium oxide and erbium oxide were first dissolved in concentrated nitric acid, and then all the raw materials were dissolved in an organic solvent ethylene glycol to prepare a solution with a total solution concentration of 0.8 mol / L. The above solution was then added to a container and stirred to mix evenly, and the pH value was adjusted to 4 with hydrochloric acid at a concentration of 1 mol / L. The prepared solution and FTO glass were transferred together into a hydrothermal autoclave with a polytetrafluoroethylene liner, with a filling degree of 0.4, and then heated to 160°C and kept warm for 24 hours.

[0055] (2) The FTO film obtained in step (1) was washed three times with deionized water and ethanol respectively, dried in an oven, and heat-treated at 450°C for 3 hours to obtain a film with a chemical composition of BiEr 0.08 Yb 0.2 OBr-D-SOr chiral bismuth oxyhalide thin film material.

[0056] (3) BiEr prepared in step (2) 0.08 Yb 0.2The three sides of the OBr-D-SOr chiral bismuth oxyhalide film are coated with optical adhesive NOA65 and then bonded to a FTO glass plate coated with a vertical alignment agent. 0.08 Yb 0.2 A gap is formed between the OBr-D-SOr chiral bismuth oxyhalide film and the FTO plate coated with a vertical alignment agent, and finally an FTO box is obtained.

[0057] (4) Using a capillary tube, a cholesteric liquid crystal mixed with a nematic liquid crystal and a chiral agent is injected into the gap of the FTO box obtained in step (3), wherein the mass of the chiral agent accounts for 1.8% of the total mass of the nematic liquid crystal and the chiral agent. Finally, an optical adhesive is used to seal the injection port to obtain a composite luminescent material BiEr capable of generating circularly polarized light. 0.08 Yb 0.2 OBr-D-SOr film-1.8wt% cholesteric liquid crystal.

[0058] Example 2

[0059] A composite luminescent material capable of generating circularly polarized light, the specific preparation steps of which are as follows:

[0060] (1) Bi(NO3)3·5H2O, Yb2O3, Er2O3, D-sorbitol (D-SOr) and NaBr were prepared as raw materials at a molar ratio of Bi ion: Yb ion: Er ion: D-SOr: Cl ion of 1:0.02:0.008:1:1. Ytterbium oxide and erbium oxide were first dissolved in concentrated nitric acid, and then all the raw materials were dissolved in an organic solvent ethylene glycol to prepare a solution with a total solution concentration of 0.8 mol / L. The above solution was then added to a container and stirred to mix evenly. The pH value was adjusted to 4 with hydrochloric acid at a concentration of 1 mol / L. The prepared solution and ITO glass were transferred into a hydrothermal autoclave with a polytetrafluoroethylene liner with a filling degree of 0.4, and then the temperature was raised to 160°C and kept warm for 24 hours.

[0061] (2) The ITO film obtained in step (1) was washed three times with deionized water and ethanol respectively, dried in an oven, and heat-treated at 450° C. for 3 h to obtain a film with a chemical composition of BiEr 0.08 Yb 0.2 OBr-D-SOr chiral bismuth oxyhalide thin film material.

[0062] (3) BiEr prepared in step (2) 0.08 Yb 0.2 The three sides of the OBr-D-SOr chiral bismuth oxyhalide film are coated with optical adhesive and then bonded to an ITO glass plate coated with a vertical alignment agent. 0.08 Yb 0.2A gap is formed between the OBr-D-SOr chiral bismuth oxyhalide film and the ITO plate coated with a vertical alignment agent, and an ITO box is finally obtained.

[0063] (4) Using a capillary tube, a cholesteric liquid crystal formed by mixing a nematic liquid crystal and a chiral agent is injected into the gap of the ITO box obtained in step (3), wherein the mass of the chiral agent accounts for 2.1% of the total mass of the nematic liquid crystal and the chiral agent. Finally, an optical adhesive is used to seal the injection port to obtain a composite luminescent material BiEr capable of generating circularly polarized light. 0.08 Yb 0.2 OBr-D-SOr film-2.1wt% cholesteric liquid crystal.

[0064] Example 3

[0065] A composite luminescent material capable of generating circularly polarized light, the specific preparation steps of which are as follows:

[0066] (1) Bi(NO3)3.5H2O, Yb2O3, Er2O3, D-sorbitol (D-SOr) and NaBr were used as raw materials and prepared according to the molar ratio of Bi ion: Yb ion: Er ion: D-SOr: Cl ion = 1:0.02:0.008:1:1. Ytterbium oxide and erbium oxide were first dissolved in concentrated nitric acid, and then all the raw materials were dissolved in organic solvent ethylene glycol to prepare a solution with a total solution concentration of 0.8 mol / L; then the above solution was added to a container and stirred to mix evenly, and the pH value was adjusted to 4 with hydrochloric acid with a concentration of 1 mol / L. The prepared solution and ITO glass were transferred into a hydrothermal autoclave with a polytetrafluoroethylene lining with a filling degree of 0.4, and then the temperature was raised to 160°C and kept warm for 24 hours.

[0067] (2) The ITO film obtained in step (1) was washed three times with deionized water and ethanol respectively, dried in an oven, and heat-treated at 450° C. for 3 h to obtain a film with a chemical composition of BiEr 0.08 Yb 0.2 OBr-D-SOr chiral bismuth oxyhalide thin film material.

[0068] (3) BiEr prepared in step (2) 0.08 Yb 0.2 The three sides of the OBr-D-SOr chiral bismuth oxyhalide film are coated with optical adhesive NOA65 and then bonded to a FTO glass plate coated with a vertical alignment agent. 0.08 Yb 0.2 A gap is formed between the OBr-D-SOr chiral bismuth oxyhalide film and the FTO plate coated with a vertical alignment agent, and finally an FTO box is obtained.

[0069] (4) Using a capillary tube, a cholesteric liquid crystal mixed with a nematic liquid crystal and a chiral agent is injected into the gap of the FTO box obtained in step (3), wherein the mass of the chiral agent accounts for 2.5% of the total mass of the nematic liquid crystal and the chiral agent. Finally, the injection port is sealed with an optical adhesive NOA65 to obtain a composite luminescent material BiEr capable of generating circularly polarized light. 0.08 Yb 0.2 OBr-D-SOr film-2.5wt% cholesteric liquid crystal.

[0070] The materials obtained in Examples 1 to 3 were subjected to relevant tests.

[0071] The BiEr obtained in Example 1 0.08 Yb 0.2 Absorption spectrum of the material composed of OBr-D-SOr film-1.8wt% cholesteric liquid crystal; Figure 1 As shown; according to the absorption peak of its absorption spectrum, its band gap width is approximately 2.58eV.

[0072] BiEr obtained in Example 2 0.08 Yb 0.2 Absorption spectrum of the material composed of OBr-D-SOr film-2.1wt% cholesteric liquid crystal; Figure 2 As shown; according to the two absorption peaks in its absorption spectrum, its band gap width can be obtained to be approximately 1.75eV and 2.58eV respectively.

[0073] The BiEr obtained in Example 3 0.08 Yb 0.2 Absorption spectrum of the material composed of OBr-D-SOr film-2.5wt% cholesteric liquid crystal; Figure 3 As shown; according to the two absorption peaks in its absorption spectrum, its band gap width can be obtained to be approximately 1.55eV and 2.58eV respectively.

[0074] The Yb-Er rare earth ion doped chiral bismuth oxyhalide film prepared in Example 1 was tested under SEM scanning electron microscope. The SEM morphology of the material was as follows: Figure 4 、 Figure 5 As shown, it presents a dextral ball-like morphology.

[0075] BiEr under 980nm laser excitation 0.08 Yb 0.2 OBr-D-SOr film-1.8wt% cholesteric liquid crystal combined with BiEr 0.08 Yb 0.2 OBr-D-SOr film-2.1wt% cholesteric liquid crystal combined with BiEr 0.08 Yb0.2 Comparison of luminescence intensity of materials composed of OBr-D-SOr film-2.5wt% cholesteric liquid crystal, such as Figure 6 As shown, it can be clearly observed that BiEr 0.08 Yb 0.2 OBr-D-SOr film-2.1wt% cholesteric liquid crystal combined with BiEr 0.08 Yb 0.2 The luminescence intensity of the material composed of OBr-D-SOr film-2.5wt% cholesteric liquid crystal is higher than that of BiEr 0.08 Yb 0.2 The material is composed of OBr-D-SOr film and 1.8wt% cholesteric liquid crystal.

[0076] BiEr under 980nm laser excitation 0.08 Yb 0.2 The luminescence intensity spectrum of OBr-D-SOr film is similar to that of BiEr 0.08 Yb 0.2 OBr-D-SOr film-1.8wt% cholesteric liquid crystal combined with BiEr 0.08 Yb 0.2 OBr-D-SOr film-2.1wt% cholesteric liquid crystal combined with BiEr 0.08 Yb 0.2 The transmission spectrum of the material composed of OBr-D-SOr film-2.5wt% cholesteric liquid crystal is combined with the comparison chart, such as Figure 7 As shown, it can be seen that BiEr 0.08 Yb 0.2 OBr-D-SOr film-1.8wt% cholesteric liquid crystal combined with BiEr 0.08 Yb 0.2 The transmission spectrum of the material composed of OBr-D-SOr film-2.5wt% cholesteric liquid crystal is similar to that of BiEr under 980nm laser excitation. 0.08 Yb 0.2 The luminescence intensity spectra of OBr-D-SOr films have overlapping parts, which indicates that the photonic band gap of liquid crystals may overlap with the luminescence band gap of the film.

[0077] BiEr under 980nm laser excitation 0.08 Yb 0.2 The luminescence spectrum of OBr-D-SOr film, such as Figure 8 As shown, it can be seen that BiEr 0.08 Yb 0.2 The OBr-D-SOr film emits obvious red light under 980nm laser excitation.

[0078] BiEr under 980nm laser excitation 0.08 Yb 0.2 For a material composed of OBr-D-SOr film and 1.8wt% cholesteric liquid crystal, α is defined as the angle between the polarizer and the quarter wave plate (QWP) optical axis, and β is defined as the angle between the analyzer and the quarter wave plate (QWP) optical axis. When the angle between the polarizer and the quarter wave plate (QWP) optical axis is α=β=45°(LL) or α=β=-45°(RR), as Figure 9 As shown, the luminescence intensity of RR is significantly lower than that of LL, and the luminescence intensity of LL is lower than that of BiEr 0.08 Yb 0.2 The material is composed of OBr-D-SOr film and 1.8wt% cholesteric liquid crystal.

[0079] BiEr under 980nm laser excitation 0.08 Yb 0.2 For a material composed of an OBr-D-SOr film and 1.8 wt% cholesteric liquid crystal, when the angle between the optical axis of the polarizer and the quarter wave plate (QWP) is α=45°, and the angle between the optical axis of the analyzer and the quarter wave plate (QWP) is β=-45° (LR), or when the angle between the optical axis of the polarizer and the quarter wave plate (QWP) is α=-45°, and the angle between the optical axis of the analyzer and the quarter wave plate (QWP) is β=45° (RL), as Figure 10 As shown, the luminous intensity of LR is significantly lower than that of RL, and the luminous intensity of RL is lower than that of BiEr 0.08 Yb 0.2 The material is composed of OBr-D-SOr film and 1.8wt% cholesteric liquid crystal.

[0080] BiEr under 980nm laser excitation 0.08 Yb 0.2 For a material composed of OBr-D-SOr film and 2.1wt% cholesteric liquid crystal, when the angle between the polarizer and the quarter wave plate (QWP) optical axis is α=β=45°(LL) or α=β=-45°(RR), Figure 11 As shown, the luminescence intensity of LL is significantly lower than that of RR, and the luminescence intensity of RR is lower than that of BiEr 0.08 Yb 0.2 The material is composed of OBr-D-SOr film and 2.1wt% cholesteric liquid crystal.

[0081] BiEr under 980nm laser excitation 0.08 Yb 0.2For a material composed of an OBr-D-SOr film and 2.1 wt% cholesteric liquid crystal, when the angle between the optical axis of the polarizer and the quarter wave plate (QWP) is α=45°, and the angle between the optical axis of the analyzer and the quarter wave plate (QWP) is β=-45° (LR), or when the angle between the optical axis of the polarizer and the quarter wave plate (QWP) is α=-45°, and the angle between the optical axis of the analyzer and the quarter wave plate (QWP) is β=45° (RL), as Figure 12 As shown, the luminous intensity of RL is significantly lower than that of LR, and the luminous intensity of LR is lower than that of BiEr 0.08 Yb 0.2 The material is composed of OBr-D-SOr film and 2.1wt% cholesteric liquid crystal.

[0082] BiEr under 980nm laser excitation 0.08 Yb 0.2 For a material composed of OBr-D-SOr film and 2.5wt% cholesteric liquid crystal, when the angle between the polarizer and the quarter wave plate (QWP) optical axis is α=β=45°(LL) or α=β=-45°(RR), Figure 13 As shown, the luminescence intensity of LL is significantly lower than that of RR, and the luminescence intensity of LL is lower than that of BiEr 0.08 Yb 0.2 The material is composed of OBr-D-SOr film and 2.5wt% cholesteric liquid crystal.

[0083] BiEr under 980nm laser excitation 0.08 Yb 0.2 For a material composed of an OBr-D-SOr film and 2.5 wt% cholesteric liquid crystal, when the angle between the optical axis of the polarizer and the quarter wave plate (QWP) is α=45°, and the angle between the optical axis of the analyzer and the quarter wave plate (QWP) is β=-45° (LR), or when the angle between the optical axis of the polarizer and the quarter wave plate (QWP) is α=-45°, and the angle between the optical axis of the analyzer and the quarter wave plate (QWP) is β=45° (RL), as Figure 14 As shown, the luminous intensity of LR is significantly lower than that of RL, and the luminous intensity of RL is lower than that of BiEr 0.08 Yb 0.2 The material is composed of OBr-D-SOr film and 2.5wt% cholesteric liquid crystal.

[0084] Schematic diagram of the experimental setup Figure 15As shown, a 980nm laser passes through a polarizer and a quarter-wave plate (QWP), is focused by a lens, and then strikes the sample. The light emitted by the sample is first focused by the lens, then passes through the quarter-wave plate (QWP) and analyzer before being received by the spectrometer. We adjust the angle between the polarizer and the QWP optical axis to α = 45°, generating left-handed polarization (L) excitation light; α = -45° generates right-handed polarization (R) excitation light.

[0085] BiEr under 980nm laser excitation 0.08 Yb 0.2 The luminescence spectrum of the material composed of OBr-D-SOr film-1.8wt% cholesteric liquid crystal is as follows: Figure 16 As shown, according to the spectrum, the material emits obvious red light under 980nm excitation.

[0086] BiEr under 980nm laser excitation 0.08 Yb 0.2 The luminescence spectrum of the material composed of OBr-D-SOr film-2.1wt% cholesteric liquid crystal is as follows: Figure 17 As shown, according to the spectrum, the material emits obvious red light under 980nm excitation.

[0087] BiEr under 980nm laser excitation 0.08 Yb 0.2 The luminescence spectrum of the material composed of OBr-D-SOr film-2.5wt% cholesteric liquid crystal is as follows: Figure 18 As shown, according to the spectrum, the material emits obvious red light under 980nm excitation.

[0088] In summary, the present invention prepares and synthesizes a composite luminescent material capable of generating circularly polarized light. The composite luminescent material has the following advantages:

[0089] First, build Figure 15 The device is capable of generating upconverted circularly polarized light, such as Figures 9-14 As shown;

[0090] Second, the liquid crystal material itself does not emit light, and the rare earth ion (Yb 3+ , Er 3+ ) of the chiral BiErYbOBr-D-SOr film to emit light, and the luminescence intensity increases with the increase of the chiral doping amount in the liquid crystal material, such as Figure 6 shown.

[0091] Third, doping with rare earth ions (Yb 3+ , Er 3+The material is made of a chiral BiErYbOBr-D-SOr film combined with liquid crystal. As the chiral agent in the liquid crystal material changes, its band gap will also change. Figure 1-Figure 3 shown.

[0092] The above implementation examples have been used to explain in detail the different implementation processes of the present invention. However, the implementation methods of the present invention are not limited to these. Ordinary technicians in the relevant technical field can achieve the purpose of the present invention based on the contents disclosed in the present invention. Any improvements and modifications based on the concept of the present invention fall within the scope of protection of the present invention. The specific scope of protection shall be subject to the claims.

Claims

1. Preparation of a composite luminescent material capable of generating circularly polarized light, characterized in that: The composite luminescent material is formed by combining a chiral bismuth oxyhalide film doped with ytterbium and erbium rare earth ions with a cholesteric liquid crystal. The specific preparation method is as follows: (1) Applying vertical alignment agent on the conductive glass; (2) applying an optical adhesive on three sides of the ytterbium- and erbium-doped rare earth ion chiral bismuth oxyhalide film, and then aligning and bonding it face-to-face with the conductive glass coated with a vertical alignment agent, forming a gap between the ytterbium- and erbium-doped rare earth ion chiral bismuth oxyhalide film and the conductive glass coated with the vertical alignment agent, and finally obtaining a conductive film glass box; (3) injecting cholesteric liquid crystal liquid into the gap of the conductive film glass box obtained in step (2) using a capillary tube, and finally sealing the injection port with an optical adhesive to obtain a composite luminescent material capable of generating circularly polarized light; The chemical formula of the chiral bismuth oxyhalide film doped with ytterbium and erbium rare earth ions in step (2) is BiEryYbxOX-Y; wherein X is any one or two of Cl and Br, Y is D-sorbitol, x is 0.05 to 0.3, and y is 0.001 to 0.

1.

2. The preparation of the composite luminescent material capable of generating circularly polarized light according to claim 1, characterized in that: The conductive glass in step (1) is one of fluorine-doped tin oxide transparent conductive glass and indium tin oxide transparent conductive glass.

3. The preparation of the composite luminescent material capable of generating circularly polarized light according to claim 1, characterized in that: The chiral bismuth oxide halide film doped with ytterbium and erbium rare earth ions in step (2) is specifically prepared as follows: a. Using bismuth nitrate, ytterbium oxide, erbium oxide, a halide salt, and D-sorbitol as raw materials, the mixture is prepared according to the molar ratio of Yb ion:Er ion:x:y, wherein x is 0.05-0.3 and y is 0.001-0.1; adding concentrated nitric acid to dissolve the mixture, and then adding ethylene glycol or an aqueous solution of ethylene glycol to form a solution with a total concentration of 0.1-2 mol / L, stirring the mixture evenly, adjusting the pH value to 2-5, transferring the conductive glass and the prepared total solution into a hydrothermal autoclave with a polytetrafluoroethylene lining, wherein the filling degree of the hydrothermal autoclave is 0.4-0.8, and performing a solvothermal reaction at a temperature of 110-250°C and a reaction time of 2-25 hours; wherein the halide salt is potassium halide or sodium halide; b. Washing and drying the reaction product of step a, and calcining at a high temperature of 300-600° C. for 1-4 hours to obtain a chiral bismuth oxyhalide film doped with ytterbium and erbium rare earth ions.

4. The preparation of the composite luminescent material capable of generating circularly polarized light according to claim 3, characterized in that: The conductive glass in step a is one of fluorine-doped tin oxide transparent conductive glass and indium tin oxide transparent conductive glass.

5. The preparation of the composite luminescent material capable of generating circularly polarized light according to claim 1, characterized in that: The area of ​​the ytterbium and erbium rare earth ion doped chiral bismuth oxyhalide film used in step (2) is the same as the area of ​​the conductive glass used in step (1).

6. The preparation of the composite luminescent material capable of generating circularly polarized light according to claim 1, characterized in that: In step (3), the cholesteric liquid crystal liquid is formed by mixing a nematic liquid crystal and a chiral agent, wherein the mass of the chiral agent accounts for 1.8-2.5% of the total mass of the nematic liquid crystal and the chiral agent.

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