Organic single crystal intrinsic polarization light emission enhancement structure and preparation method

Abstract

The application discloses an organic single crystal intrinsic polarization light-emitting enhancement structure and a preparation method, and belongs to the technical field of organic photoelectric materials and devices, and comprises an organic single crystal layer and one-dimensional metal nanowires; the organic single crystal layer has intrinsic polarization light-emitting characteristics; the one-dimensional metal nanowires are arranged on at least one surface of the organic single crystal layer to form a single crystal nanowire composite structure by means of spin coating; the one-dimensional metal nanowires are metal nanowires having surface plasmon response characteristics, and the plasmon effect generated by geometric anisotropy modulates the light-emitting dipole radiation behavior of the organic single crystal layer, thereby enhancing the intrinsic polarization light-emitting performance of the organic single crystal layer. The local electromagnetic field and anisotropic regulation of the one-dimensional metal nanowires significantly improve the polarization ratio while keeping the single crystal intrinsic structure unchanged, and the process is simple, the cost is low, and the compatibility is good, thereby solving the technical problems that the polarization performance of the organic single crystal is limited in the prior art, or needs to rely on a complex external structure.

Description

Technical Field

[0001] This invention belongs to the field of organic optoelectronic materials and devices technology, specifically relating to an organic single-crystal intrinsic polarization luminescence enhancement structure and its preparation method, which is particularly suitable for intrinsic polarization luminescence devices with high polarization ratio, low cost, and easy integration. Background Technology

[0002] With the expanding applications of polarized light in polarization displays, information encryption, 3D imaging, and optical detection, light-emitting devices capable of directly generating linearly polarized light have become an important research direction for next-generation optoelectronic devices. Traditional methods for obtaining linearly polarized light typically involve superimposing a polarizer in front of an unpolarized light source, but this results in approximately 50% light energy loss, significantly reducing the device's light utilization efficiency and increasing the complexity of the system structure. Therefore, developing materials and devices capable of directly emitting linearly polarized light has significant application value.

[0003] Organic semiconductor single crystals, due to their long-range ordered molecular arrangement and well-defined crystal axis orientation, typically exhibit molecular transition dipole moments aligned along specific directions. Therefore, their photoluminescence or electroluminescence inherently possesses polarization characteristics, making them ideal candidate materials for achieving intrinsically linearly polarized light sources. However, relying solely on the molecular orientation of organic single crystal materials to achieve high polarization luminescence performance has limitations. The degree of polarization (or polarization ratio) is largely constrained by the intrinsic molecular packing and crystal structure of the material, limiting the potential for improvement. While existing technologies have employed methods such as introducing external optical resonators or grating structures to modulate the polarization of organic material luminescence, these methods either increase the complexity of the device structure or introduce additional optical losses, hindering miniaturization, integration, and low-cost fabrication. Therefore, achieving a significant enhancement of the polarization luminescence performance of organic single crystals without altering the intrinsic structure of the single crystal or significantly increasing its complexity is a pressing technical problem in this field. Summary of the Invention

[0004] Technical problem solved: In view of the technical problems existing in the background technology, the present invention provides an organic single crystal intrinsic polarization luminescence enhancement structure and its preparation method. By controlling the local electromagnetic field and anisotropy of one-dimensional metal nanowires, the polarization ratio is significantly improved while keeping the intrinsic structure of the single crystal unchanged. At the same time, the process is simple, low cost and good compatibility, which solves the technical problem that the improvement of polarization performance of organic single crystals is limited in the prior art or that it requires the reliance on complex external structures.

[0005] Technical solution: The organic single-crystal intrinsic polarization luminescence enhancement structure of the present invention comprises: An organic single-crystal layer, wherein the organic single-crystal layer has intrinsic polarization luminescence characteristics; One-dimensional metal nanowires are formed by spin-coating at least one surface of an organic single-crystal layer to create a single-crystal nanowire composite structure. The one-dimensional metal nanowires are metal nanowires with surface plasmon response characteristics. They modulate the luminescent dipole radiation behavior of the organic single-crystal layer through the plasmon effect generated by geometric anisotropy, thereby enhancing the intrinsic polarization luminescence performance of the organic single-crystal layer.

[0006] Preferably, the organic single crystal layer is an organic semiconductor single crystal material with orientation transition dipole moment.

[0007] Preferably, the organic single crystal layer is a 4,4'-bis(2,2-stilbene)-1,1'-biphenyl single crystal or a 2,6-diphenylanthracene single crystal.

[0008] Preferably, the one-dimensional metal nanowire is a silver nanowire or a gold nanowire.

[0009] Preferably, the one-dimensional metal nanowire has a diameter of 10-200 nm and a length of 5-50 μm.

[0010] Preferably, the one-dimensional metal nanowires are distributed in a dispersed or network-like manner on the surface of the organic single crystal layer.

[0011] This invention also discloses a method for preparing an organic single-crystal intrinsic polarization luminescence enhancement structure, comprising the following steps: Step 1: Prepare an organic single crystal layer, wherein the organic single crystal layer has intrinsic polarization emission characteristics; Step 2: Prepare a one-dimensional metal nanowire dispersion; Step 3: Apply the one-dimensional metal nanowire dispersion to at least one surface of the organic single crystal layer by spin coating to form a one-dimensional metal nanowire structure, thereby obtaining an organic single crystal intrinsic polarization luminescence enhancement structure.

[0012] Preferably, in step 1, an epitaxial growth method using liquid surface nucleation or liquid interface nucleation is used to prepare the organic single crystal layer.

[0013] Preferably, the one-dimensional metal nanowire dispersion is a silver nanowire aqueous dispersion with a concentration of 0.1 mg / mL; the spin coating process adopts a two-stage procedure, including a first stage of low-speed spreading and a second stage of high-speed film formation.

[0014] Preferably, the rotation speed of the first low-speed spreading stage is 500-1000 rpm, and the spin coating time is 5-15s; the rotation speed of the second high-speed film forming stage is 2000-4000 rpm, and the spin coating time is 20-40s.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. Significant enhancement effect: By introducing one-dimensional metal nanowires onto the surface of organic single crystals, the polarization emission performance can be greatly improved by utilizing the plasmon effect; for example, experiments have shown that after introducing silver nanowires, the polarization emission ratio of DBTVB single crystal can be increased from about 41.3 to 279.4, which is a significant improvement effect. 2. Simple process and good compatibility: This invention uses spin coating to construct nanowire structures. The process is mature and simple to operate. It is fully compatible with the existing organic optoelectronic device fabrication process. There is no need to perform additional processing on organic single crystals or introduce complex optical components. It is easy to realize and integrate. 3. Does not change the intrinsic structure of the material: This method is a purely physical modulation process that does not involve chemical reactions and does not change the molecular structure, stacking mode and crystal morphology of organic single crystals, thus ensuring the stability and other excellent properties of the material itself. 4. High versatility and low cost: This enhancement strategy can be applied to various organic single-crystal light-emitting materials with orientation transition dipole moments (such as DBTVB, DPA, etc.) as well as various metal nanowires with excellent plasmon properties (such as silver wires, gold wires). The raw materials and process costs are both low, and it has good prospects for promotion and application. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the epitaxial growth of organic polarized light-emitting single crystals via nucleation on a liquid surface, as described in an embodiment of the present invention. Figure 2 This is a schematic diagram of the process of spin-coating silver nanowires onto an organic single crystal in an embodiment of the present invention; Figure 3 This is a polar coordinate diagram of the intrinsic polarization emission spectrum of DBTVB single crystal at different polarization angles and the intensity of its 502nm emission peak in an embodiment of the present invention. Figure 4 The polarization-induced emission spectra of DBTVB single crystal after spin-coating silver nanowires in this embodiment of the invention and the polar coordinate diagram of the intensity of its 502nm emission peak at different polarization angles are shown. Figure 5 This is a box plot showing the photoluminescence polarization ratio distribution before and after spin-coating silver nanowires with DPA single crystals in an embodiment of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will be described in conjunction with the accompanying drawings. Figures 1-5 The technical solutions of this embodiment are clearly and completely described. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the described embodiments of this invention are within the scope of protection of this invention.

[0018] This invention discloses an organic single-crystal intrinsic polarization luminescence enhancement structure, comprising an organic single-crystal layer and a one-dimensional metal nanowire. The organic single-crystal layer is an organic semiconductor single-crystal material with orientation transition dipole moments, exhibiting intrinsic polarization luminescence characteristics; the organic single-crystal layer can be made of 4,4'-bis(2,2-stilbene)-1,1'-biphenyl single crystal or 2,6-diphenylanthracene single crystal.

[0019] The one-dimensional metal nanowires are spin-coated onto at least one surface of an organic single-crystal layer to form a single-crystal nanowire composite structure; the one-dimensional metal nanowires are metal nanowires with surface plasmon response characteristics; the one-dimensional metal nanowires can be silver nanowires or gold nanowires; the diameter of the one-dimensional metal nanowires is 10-200 nm and the length is 5-50 μm.

[0020] One-dimensional metallic nanowires modulate the luminescent dipole radiation behavior of organic single-crystal layers through the plasmon effect generated by geometric anisotropy. Specifically, this modulation can enhance dipole radiation parallel to the long axis of the nanowires or suppress radiation components perpendicular to them, thereby significantly enhancing the luminescent polarization ratio of the organic single crystal on a macroscopic scale. The one-dimensional metallic nanowires are distributed in a dispersed or network-like manner on the surface of the organic single-crystal layer.

[0021] This invention also discloses a method for preparing an organic single-crystal intrinsic polarization luminescence enhancement structure, comprising the following steps: Step 1: Prepare an organic single crystal layer, which has intrinsic polarization luminescence characteristics; the organic single crystal layer is prepared by epitaxial growth method of liquid surface nucleation or liquid interface nucleation.

[0022] Step 2: Prepare a one-dimensional metal nanowire dispersion; the one-dimensional metal nanowire dispersion is a silver nanowire aqueous dispersion with a concentration of 0.1 mg / mL; the spin coating process adopts a two-stage procedure, including a first low-speed spreading stage and a second high-speed film formation stage; the rotation speed of the first low-speed spreading stage is 500-1000 rpm, and the spin coating time is 5-15 s; the rotation speed of the second high-speed film formation stage is 2000-4000 rpm, and the spin coating time is 20-40 s.

[0023] Step 3: Apply the one-dimensional metal nanowire dispersion to at least one surface of the organic single crystal layer by spin coating to form a dispersed or network-like one-dimensional metal nanowire structure, thereby obtaining an organic single crystal intrinsic polarization luminescence enhancement structure.

[0024] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0025] Example 1: In this embodiment of the invention, a DBTVB single-crystal-Ag nanowire-reinforced structure was prepared using 4,4'-bis(2,2-stilbene)-1,1'-biphenyl single-crystal material. The specific preparation steps are as follows: (I) Preparation of DBTVB organic single crystal layer: like Figure 1 As shown, the liquid surface nucleation method was employed: First, DBTVB powder was dissolved in chlorobenzene to prepare a supersaturated solution with a concentration of 0.1 mg / mL, and then slowly heated to 90°C to ensure complete dissolution. Next, 0.2 mL of the hot solution was pipetted onto a clean ITO substrate placed in a petri dish. The petri dish was then transferred to a 70°C oven to allow the chlorobenzene solvent to slowly evaporate over 6 hours. Finally, after the solvent had completely evaporated, uniformly sized, flat-surfaced sheet-like DBTVB single crystals were obtained on the ITO substrate, serving as the substrate and luminescent layer for subsequent steps.

[0026] (II) Construction of silver nanowire structures: like Figure 2 As shown, commercially available silver nanowires (200 nm in diameter and 50 μm in length) were selected. First, the original silver nanowire dispersion was diluted with ultrapure water to a concentration of 0.1 mg / mL and thoroughly shaken to ensure uniform dispersion. Then, the silver nanowires were deposited onto the prepared DBTVB single crystal surface using spin coating. The specific spin coating procedure was a two-stage process: first, the rotation was carried out at a low speed of 800 rpm for 10 seconds to allow the nanowire solution to spread fully on the crystal surface; then, the rotation speed was rapidly increased to 3000 rpm and held for 30 seconds to remove excess solvent and form a uniformly dispersed silver nanowire network. This yielded an organic single-crystal intrinsic polarization luminescence enhancement structure.

[0027] (III) Performance Characterization and Effect Verification: Photoluminescence testing of the prepared samples was performed using a confocal Raman spectroscopy system. A 405 nm wavelength laser was used as the excitation source. A rotatable linear polarizer was introduced into the detection optical path. The emission intensity in different polarization directions was detected by rotating the polarizer angle (from 0° to 360°), and a polar coordinate graph of the intensity of the characteristic emission peak at 502 nm was plotted (e.g., ...). Figure 3 and Figure 4 (As shown).

[0028] Test results show that pure DBTVB single crystals exhibit significant intrinsic polarization luminescence characteristics, with a polarization ratio (the ratio of maximum intensity to minimum intensity) of approximately 41.3. After introducing silver nanowires, the polarization luminescence anisotropy of this composite structure is significantly enhanced, with a polarization ratio of 279.4, an improvement of approximately 6.8 times compared to the pure single crystal. This clearly demonstrates that the silver nanowire structure can extremely effectively enhance the intrinsic polarization luminescence performance of organic single crystals.

[0029] Example 2: In this example, a DPA single-crystal-Ag nanowire-reinforced structure was prepared using 2,6-diphenylanthracene single-crystal material to verify the universality of the method of this invention.

[0030] DPA single crystals were prepared using suitable methods such as physical vapor transport or liquid surface nucleation, similar to those used in Example 1. Subsequently, using the exact same process parameters and steps as in Example 1, a diluted silver nanowire dispersion (0.1 mg / mL) was spin-coated onto the surface of the DPA single crystal to form a composite reinforced structure.

[0031] Polarization luminescence tests were performed on DPA single crystals before and after spin-coating silver nanowires, and statistical analysis was conducted on multiple samples (results are shown in the figure). Figure 5 (As shown). Statistical results show that the intrinsic polarization ratio of untreated DPA single crystals is mainly distributed at around 7. After introducing silver nanowires onto the surface, although the enhancement range varies depending on the material system, the polarization ratio is generally increased to the range of 8-9, showing a statistically significant enhancement effect. This comparative experiment confirms that the enhancement method of the present invention is applicable to different types of organic single-crystal polarized luminescent materials.

[0032] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An organic single-crystal intrinsic polarization luminescence enhancement structure, characterized in that, include: An organic single-crystal layer, wherein the organic single-crystal layer has intrinsic polarization luminescence characteristics; One-dimensional metal nanowires are formed by spin-coating at least one surface of an organic single-crystal layer to create a single-crystal nanowire composite structure. The one-dimensional metal nanowires are metal nanowires with surface plasmon response characteristics. They modulate the luminescent dipole radiation behavior of organic single crystal layers through the plasmon effect generated by geometric anisotropy, thereby enhancing the intrinsic polarization luminescence performance of organic single crystal layers.

2. The organic single-crystal intrinsic polarization luminescence enhancement structure according to claim 1, characterized in that, The organic single crystal layer is an organic semiconductor single crystal material with orientation transition dipole moment.

3. The organic single-crystal intrinsic polarization luminescence enhancement structure according to claim 2, characterized in that, The organic single crystal layer is 4,4'-bis(2,2-stilbene)-1,1'-biphenyl single crystal or 2,6-diphenylanthracene single crystal.

4. The organic single-crystal intrinsic polarization luminescence enhancement structure according to claim 1, characterized in that, The one-dimensional metal nanowires are silver nanowires or gold nanowires.

5. The organic single-crystal intrinsic polarization luminescence enhancement structure according to claim 4, characterized in that, The one-dimensional metal nanowires have a diameter of 10-200 nm and a length of 5-50 μm.

6. The organic single-crystal intrinsic polarization luminescence enhancement structure according to claim 1, characterized in that, The one-dimensional metal nanowires are distributed in a dispersed or network-like manner on the surface of the organic single crystal layer.

7. A method for preparing an organic single-crystal intrinsic polarization luminescence enhancement structure as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Prepare an organic single crystal layer, wherein the organic single crystal layer has intrinsic polarization emission characteristics; Step 2: Prepare a one-dimensional metal nanowire dispersion; Step 3: Apply the one-dimensional metal nanowire dispersion to at least one surface of the organic single crystal layer by spin coating to form a one-dimensional metal nanowire structure, thereby obtaining an organic single crystal intrinsic polarization luminescence enhancement structure.

8. The method for preparing the organic single-crystal intrinsic polarization luminescence enhancement structure according to claim 7, characterized in that, In step 1, an organic single crystal layer is prepared using an epitaxial growth method with either a liquid surface nucleation method or a liquid interface nucleation method.

9. The method for preparing the organic single-crystal intrinsic polarization luminescence enhancement structure according to claim 7, characterized in that, The one-dimensional metal nanowire dispersion is a silver nanowire aqueous dispersion with a concentration of 0.1 mg / mL to the original concentration; the spin coating process adopts a two-stage procedure, including a first stage of low-speed spreading and a second stage of high-speed film formation.

10. The method for preparing the organic single-crystal intrinsic polarization luminescence enhancement structure according to claim 9, characterized in that, The first low-speed spreading stage has a rotation speed of 500-1000 rpm and a spin coating time of 5-15s; the second high-speed film forming stage has a rotation speed of 2000-4000 rpm and a spin coating time of 20-40s.

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