Co-assembly method for improving energy transfer efficiency of chromophore, co-assembly and application

Abstract

This invention relates to the field of organic optoelectronic materials technology, specifically to a co-assembly method, co-assembly, and application for improving the energy transfer efficiency of chromophores. The specific method includes the following steps: co-assembling a donor substance and a perfluoroaromatic hydrocarbon (PFAR) in a solvent system to prepare a donor-PFAR complex; co-assembling an acceptor substance and a PFAR in a solvent system to prepare an acceptor-PFAR complex; and co-assembling the donor-PFAR complex and the acceptor-PFAR complex in a solvent system to prepare a crystallization-induced energy transfer (CELT) precise co-assembly. The donor substance is 9,10-bis(phenylethynyl)anthracene, the PFAR is octafluoronaphthalene, and the acceptor substance is 5,12-bis(phenylethynyl)tetraphenyl. This invention solves the problems of high energy dissipation and low FRET efficiency in the fluorescence resonance energy transfer (FRET) process of donor-acceptor pairs with weak aggregated emission.

Description

Technical Field

[0001] This invention relates to the field of organic optoelectronic materials technology, specifically to a co-assembly method, co-assembly, and application for improving the energy transfer efficiency of chromophores. Background Technology

[0002] π-conjugated organic optoelectronic materials are indispensable for the development of advanced electronic information devices and biological diagnostic / therapeutic methods. The properties of these materials are closely related to one or more physical processes, such as electron excitation and emission, upconversion, electron and hole transport, energy transfer, and light trapping.

[0003] Fluorescence resonance energy transfer (FRET) is a nonradiative energy transfer process based on long-range dipole-dipole interactions between energy donors and acceptors. It has attracted considerable attention due to its unique characteristics and broad application prospects. FRET primarily involves energy transfer between two fluorophores: the donor and the acceptor. When the donor fluorophore is excited, if its emission spectrum overlaps with the absorption spectrum of the acceptor fluorophore, the donor can nonradiatively transfer energy to the acceptor, thereby altering the fluorescence intensity and lifetime of both. FRET efficiency is highly dependent on the distance between the donor and acceptor, typically ranging from 1 nm to 10 nm, and decreases rapidly with increasing distance. Furthermore, the degree of spectral overlap between the donor and acceptor, as well as the parallelism of the transition dipole directions, are also key factors affecting FRET efficiency.

[0004] Currently, FRET (Fluorescence Quantum Yield) has been widely applied in various fields, including optoelectronic devices, fluorescence detectors, life sciences, environmental monitoring, nanomaterials, luminescent quantum dots, and functional supramolecular materials. In life sciences, FRET with high fluorescence quantum yield is used as a spectroscopic molecular scale to measure distances and conformational changes between biomolecules, such as protein-protein interactions and DNA hybridization. This is a simple and effective super-resolution optical measurement technique that provides real-time, in-situ detection without any intervention. In optoelectronic devices, FRET is used to modulate and improve the performance of optoelectronic materials, such as solar cells, photodetectors, and LEDs. Therefore, precise control of FRET efficiency is crucial for improving the performance of organic optoelectronic materials, but this remains a key problem that urgently needs to be solved.

[0005] Several methods exist to improve the efficiency of FRET, among which adjusting the distance between the donor and acceptor is one of the most commonly used methods. However, this requires precise nanoscale control and is difficult to implement in practice. Furthermore, controlling the number of acceptors around the donor, altering the degree of spectral overlap between the donor and acceptor, or changing the parallelism of the transition dipole directions of the donor-acceptor pair can also improve FRET efficiency to some extent, but these methods also suffer from operational complexity and time consumption.

[0006] Furthermore, reported FRET is mainly limited to chromophores with high aggregation emission, while effective FRET is difficult to achieve in the weak emission state. This leads to the problem of high energy dissipation and low FRET efficiency in the fluorescence resonance energy transfer process of donor-acceptor pairs with weak aggregation emission. Summary of the Invention

[0007] To address the issues of high energy dissipation and low FRET efficiency in donor-acceptor pairs with weak aggregated emission during fluorescence resonance energy transfer (FRET), this invention aims to provide a co-assembly method, co-assembly, and application for improving chromophore energy transfer efficiency.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows.

[0009] A first aspect of the present invention provides a method for improving FRET efficiency through crystallization-induced precise co-assembly, comprising the following steps:

[0010] A donor-perfluoroaromatic hydrocarbon complex was prepared by co-assembling a donor substance and a perfluoroaromatic hydrocarbon in a solvent system; an acceptor substance and a perfluoroaromatic hydrocarbon were also co-assembled in a solvent system to prepare an acceptor-perfluoroaromatic hydrocarbon complex; the donor-perfluoroaromatic hydrocarbon complex and the acceptor-perfluoroaromatic hydrocarbon complex were then co-assembled in a solvent system, with the perfluoroaromatic hydrocarbon inserting into the crystal lattice of the donor and acceptor substances during the co-assembly process, to obtain a co-assembled compound; the donor substance was 9,10-bis(phenylethynyl)anthracene; the acceptor substance was 5,12-bis(phenylethynyl)tetraphenyl; and the perfluoroaromatic hydrocarbon was octafluoronaphthalene.

[0011] Preferably, the ratio of the total molar amount of the acceptor and donor substances to the molar amount of the perfluoroaromatic hydrocarbon is 1:1. Preferably, the percentage of the molar amount of the acceptor substance to the total molar amount of the donor and acceptor substances is 0.3% to 22.4%.

[0012] Preferably, the solvents used in preparing the donor-perfluoroaromatic complex, the acceptor-perfluoroaromatic complex, and the co-assembled compound are selected from at least one of chloroform, N,N-dimethylformamide, tetrahydrofuran, acetone, and acetonitrile. Preferably, the co-assembly is performed by wet milling in a solvent system or by evaporation in a solvent system to remove the solvent. The co-assembly operation is carried out at room temperature, and octafluoronaphthalene, 9,10-bis(phenylethynyl)anthracene, and 5,12-bis(phenylethynyl)tetraphenyl are all solids at room temperature. Evaporation is carried out at room temperature and atmospheric pressure. Specifically, during wet milling, the ratio of solid to solvent is 10 mg: 0.05 mL; during evaporation, the ratio of solid to solvent is 1 mg: 1 mL.

[0013] Preferably, in the co-assembled assembly, the average distance between the donor material and the acceptor material is 0.69–0.7 nm.

[0014] A second aspect of the present invention provides a co-assembly prepared using the co-assembly method for improving chromophore energy transfer efficiency described in the first aspect.

[0015] Preferably, the co-assembled compound is obtained by co-assembling a donor-perfluoroaromatic compound and an acceptor-perfluoroaromatic compound, and the perfluoroaromatic compounds are inserted into the crystal lattice of the donor and acceptor substances during the co-assembly process, so that the average distance between the donor and acceptor substances is 0.69 nm to 0.7 nm.

[0016] Preferably, the crystal parameters of the donor-perfluoroaromatic complex are as follows: the crystal parameters of the donor-perfluoroaromatic complex are: monoclinic space group P21 / c, and the unit cell parameters are... α=90°, β=104.471(5)°, γ=90° and Preferably, the crystal parameters of the acceptor-perfluoroaromatic complex are: monoclinic space group P21 / c, and the unit cell parameters are... α=90°, β=100.157(5)°, γ=90°,

[0017] A third aspect of the present invention provides an application of the co-assembled assembly described in the second aspect in the preparation of aqueous luminescent inks.

[0018] The beneficial effects of this invention are:

[0019] 1. This invention mainly uses 9,10-bis(phenylethynyl)anthracene, which has a significant aggregation fluorescence quenching effect, as the donor material for fluorescence resonance energy transfer (FRET), 5,12-bis(phenylethynyl)tetraphenyl as the acceptor material for FRET, and weakly fluorescent octafluoronaphthalene as the molecular brightener. By using a co-assembly method, perfluoroaromatics are inserted into the crystal lattice of the donor and acceptor materials, thereby increasing the FRET efficiency by as much as 180% to 270%, which solves the problems of high energy dissipation and low FRET efficiency in donor-acceptor pairs with weak aggregation emission during FRET.

[0020] 2. This invention enables precise co-assembly through crystallization induction, allowing for the adjustment of color and brightness, transforming monotonous, weakly emitted yellow, orange, and black into colorful, brighter emitted green, yellow-green, yellow, orange, and red. Based on this, this invention successfully fabricates different multi-stimulus-responsive fluorescence modes and highly flexible, strongly luminescent colored flowers, greatly expanding the application fields of the co-assemblies provided by this invention. Attached Figure Description

[0021] Figure 1 Figure a shows the co-assembly principle of BPA-OFN in Example 3; Figure b shows 0.1 mg / mL -1 Photographs of BPA solution, BPA solid, and BPA-OFN eutectic under 365nm ultraviolet light.

[0022] Figure 2 Figure a shows the co-assembly principle of BPN-OFN in Example 4; Figure b shows the 0.1 mg / mL... -1 Photographs of BPN solution, BPN solid, and BPN-OFN eutectic under 365nm ultraviolet light.

[0023] Figure 3 Figure a shows the infrared spectra of OFN, BPA, and BPA-OFN from Example 3; Figure b shows the infrared spectra of OFN, BPN, and BPN-OFN from Example 4.

[0024] Figure 4 In the figure, Figure a shows the Raman spectra of BPA and BPA-OFN of Example 3; Figure b shows the Raman spectra of BPN and BPN-OFN of Example 4.

[0025] Figure 5 Figure a shows the experimental and calculated PXRD spectra of the BPA-OFN eutectic, as well as the experimental PXRD spectra of OFN and BPA; Figure b shows the experimental and calculated PXRD spectra of the BPN-OFN eutectic, as well as the experimental PXRD spectra of OFN and BPN.

[0026] Figure 6Figure a shows the absorption and photoluminescence spectra of BPA solution, BPA solid, and BPA-OFN from Example 3; Figure b shows the absorption and photoluminescence spectra of BPN solution, BPN solid, and BPN-OFN from Example 4.

[0027] Figure 7 In the diagram, Figure C shows the molecular orbital diagram of BPA-OFN; Figure D shows the molecular orbital diagram of BPN-OFN; Figure E shows the molecular hybrid stacking structure of BPA-OFN; Figure F shows the molecular hybrid stacking structure of BPN-OFN; Figure G shows the growth morphology of the BPA-OFN eutectic; and Figure H shows the growth morphology of the BPN-OFN eutectic. The insets in Figures G and H are the corresponding low-magnification transmission electron microscopy images.

[0028] Figure 8 In the figure, a) shows the absorption spectrum of BPN and the photoluminescence spectrum of BPA; b) shows the absorption spectrum of BPA@BPN with different doping ratios; c) shows the photoluminescence spectrum of BPA@BPN with different doping ratios; d) shows the time-resolved fluorescence decay of BPA@BPN with different doping ratios; the inset of figure d is the corresponding photograph under UV light irradiation; e) shows the absorption spectrum of BPN-OFN and the photoluminescence spectrum of BPA-OFN; f) shows the absorption spectrum of BPA-OFN@BPN-OFN with different doping ratios; g) shows the photoluminescence spectrum of BPA-OFN@BPN-OFN with different doping ratios; h) shows the time-resolved fluorescence decay of BPA-OFN@BPN-OFN with different doping ratios; the inset of figure h is the corresponding photograph under UV light irradiation.

[0029] Figure 9 The images show the FM images of BPA-OFN@BPN-OFN microrods under 365 nm excitation. From image a to image e, the doping ratios of BPN-OFN are 0, 0.3, 3.7, 22.4, and 100%, respectively.

[0030] Figure 10 The PXRD spectra are for the five samples.

[0031] Figure 11 These are the CIE coordinate values ​​corresponding to the 5 samples.

[0032] Figure 12 This is a schematic diagram of the energy transfer mechanism.

[0033] Figure 13In the image, Figure a shows the letters FRET and By XJTU, along with a cartoon image of a thumbs-up, drawn with brushes dipped in yellow BPA and black BPN ink, respectively, under visible light; Figure b shows Figure a under ultraviolet light; Figure c shows Figure b after stimulation with OFN solution; Figure d shows Figure c after further stimulation with BPN / OFN solution; Figure e shows a schematic diagram of the preparation of the high-luminescence film and three high-luminescence flowers, along with photographs under sunlight and ultraviolet light. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0035] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Aggregation-Caused Quenching (ACQ) is a fluorescence quenching mechanism. 9,10-Bis(Phenylethynyl)Anthracene (BPA) has the following structural formula: 5,12-Bis(2-Phenylethynyl)-Naphthacene, abbreviated as BPN, has the following structural formula: Octafluoronaphthalene, abbreviated as OFN, has the following structural formula: BPA serves as the donor for fluorescence resonance energy transfer (FRET); BPN serves as the acceptor. Weakly fluorescent octafluoronaphthalene acts as a molecular illuminating agent. Photoluminescence quantum yield, abbreviated as PLQY, is the quantum yield of light emitted by fluorescence.

[0037] Reported FRET has primarily been limited to chromophores with high aggregation emission, while efficient FRET is difficult to achieve in weak emission states. This is because most of the energy is dissipated during the transfer process through non-radiative processes, including intersystem crossing and singlet splitting, resulting in a significant reduction in energy utilization efficiency. Therefore, achieving efficient FRET between donor-acceptor pairs with weak aggregation emission remains a major challenge.

[0038] This invention develops a strategy, namely a crystallization-induced precise co-assembly method, to effectively improve the fluorescence resonance energy transfer efficiency (FRET) of ACQ chromophores. This invention selects 9,10-bis(phenylethynyl)anthracene and bis(phenylethynyl)tetraphenyl, which have significant ACQ effects, as the donor and acceptor materials for FRET, respectively, and weakly fluorescent octafluoronaphthalene as a molecular brightener. Through simple grinding or solvent evaporation and precise co-assembly with octafluoronaphthalene, the photoluminescence quantum yield of solid BPA is increased by 107%, and the BPN powder can be illuminated, changing from dark to an unprecedented bright red. More importantly, the monotonous, weak emission of BPA@BPN, such as yellow, orange, and black, can be significantly modulated into colored, brighter emission, such as green, yellow-green, yellow, orange, and red, through crystallization-induced precise co-assembly. The FRET efficiency is improved by as much as 180%–270%, solving the problems of high energy dissipation and low FRET efficiency in the FRET process of donor-acceptor pairs with weak aggregated emission.

[0039] This invention elucidates a deeper understanding of the regulation of fluorescence resonance energy transfer through precise correlation between supramolecular structure and properties. Based on this, the invention successfully fabricates different multi-stimulus-responsive fluorescence modes and highly flexible, strongly luminescent colored flowers.

[0040] The technical solution of the present invention will be further described below through specific embodiments. In the following embodiments, unless otherwise specified, the methods are conventional methods; the reagents and materials, unless otherwise specified, are commercially available. The room temperature is 20–30°C.

[0041] Example 1

[0042] A co-assembly method for improving chromophore energy transfer efficiency includes the following steps:

[0043] Octafluoronaphthalene, exhibiting weak fluorescence emission, was used as the perfluoroaromatic compound (PFAR). 9,10-bis(phenylethynyl)anthracene was used as the donor, and 5,12-bis(phenylethynyl)tetraphenyl was used as the acceptor. The total molar ratio of the acceptor and donor to the PFAR was 1:1. Octafluoronaphthalene, 9,10-bis(phenylethynyl)anthracene, and 5,12-bis(phenylethynyl)tetraphenyl were added to tetrahydrofuran. The total mass ratio of the three compounds to the tetrahydrofuran was 1 mg:1 mL. After thorough mixing, the solvent was removed by evaporation at room temperature and atmospheric pressure, yielding a one-dimensional needle-like co-crystal, i.e., a precise co-assembled supramolecular structure, denoted as BPA / BPN-OFN, with a length reaching tens of micrometers.

[0044] Table 1. Combination of BPA and BPN at different molar percentages

[0045]

[0046]

[0047] Example 2

[0048] A co-assembly method for improving chromophore energy transfer efficiency includes the following steps:

[0049] 0.1 mol of octafluoronaphthalene, 0.08 mol of 9,10-bis(phenylethynyl)anthracene, and 0.02 mol of 5,12-bis(phenylethynyl)tetraphenyl were mixed thoroughly, and then tetrahydrofuran was added. The ratio of the total mass of octafluoronaphthalene, 9,10-bis(phenylethynyl)anthracene, and 5,12-bis(phenylethynyl)tetraphenyl to the amount of tetrahydrofuran was 10 mg: 0.05 mL. The mixture was ground at room temperature for 20-30 seconds until the solvent was completely evaporated, yielding a one-dimensional needle-like co-crystal, i.e., a precise co-assembled supramolecular structure, denoted as BPA / BPN-OFN.

[0050] Example 3

[0051] A co-assembly method for improving chromophore energy transfer efficiency includes the following steps:

[0052] Octafluoronaphthalene, which emits weak fluorescence, was used as a perfluoroaromatic compound, and 9,10-bis(phenylethynyl)anthracene was used as an aromatic donor. Octafluoronaphthalene and 9,10-bis(phenylethynyl)anthracene were added to tetrahydrofuran at a molar ratio of 1:1, with the total mass of octafluoronaphthalene and 9,10-bis(phenylethynyl)anthracene to the amount of tetrahydrofuran being 1 mg: 1 mL. After mixing thoroughly, the solvent was removed by evaporation at room temperature and atmospheric pressure to prepare an aromatic-perfluoroaromatic eutectic, denoted as BPA-OFN.

[0053] Example 4

[0054] A co-assembly method for improving chromophore energy transfer efficiency includes the following steps:

[0055] Octafluoronaphthalene, which emits weak fluorescence, was used as a perfluoroaromatic compound, and 5,12-bis(phenylethynyl)tetraphenyl was used as an aromatic donor. Octafluoronaphthalene and 5,12-bis(phenylethynyl)tetraphenyl were added to tetrahydrofuran at a molar ratio of 1:1, with the total mass ratio of octafluoronaphthalene and 5,12-bis(phenylethynyl)tetraphenyl to tetrahydrofuran being 1 mg: 1 mL. After mixing thoroughly, the solvent was removed by evaporation at room temperature and atmospheric pressure to prepare an aromatic-perfluoroaromatic eutectic, denoted as BPN-OFN.

[0056] Example 5

[0057] A co-assembly method for improving chromophore energy transfer efficiency includes the following steps:

[0058] Octafluoronaphthalene, which emits weak fluorescence, was used as a perfluoroaromatic compound, and 9,10-bis(phenylethynyl)anthracene was used as an aromatic donor. Octafluoronaphthalene and 9,10-bis(phenylethynyl)anthracene were added to tetrahydrofuran at a molar ratio of 1:1, with the total mass of octafluoronaphthalene and 9,10-bis(phenylethynyl)anthracene to the amount of tetrahydrofuran being 10 mg: 0.05 mL. The mixture was ground at room temperature for 20 to 30 seconds until the solvent was completely evaporated, and an aromatic-perfluoroaromatic eutectic was prepared, denoted as BPA-OFN.

[0059] Example 6

[0060] A co-assembly method for improving chromophore energy transfer efficiency includes the following steps:

[0061] Octafluoronaphthalene, which emits weak fluorescence, was used as a perfluoroaromatic compound, and 5,12-bis(phenylethynyl)tetraphenyl was used as an aromatic donor. Octafluoronaphthalene and 5,12-bis(phenylethynyl)tetraphenyl were added to tetrahydrofuran at a molar ratio of 1:1, with the total mass ratio of octafluoronaphthalene and 5,12-bis(phenylethynyl)tetraphenyl to tetrahydrofuran being 10 mg: 0.05 mL. The mixture was ground at room temperature for 20 to 30 seconds until the solvent was completely evaporated, thus preparing an aromatic-perfluoroaromatic eutectic, denoted as BPN-OFN.

[0062] Example 7

[0063] A co-assembly method for improving chromophore energy transfer efficiency includes the following steps:

[0064] The BPA-OFN prepared in Example 3 and the BPN-OFN prepared in Example 4 were added to tetrahydrofuran. The total mass ratio of BPA-OFN and BPN-OFN to the amount of tetrahydrofuran was 1 mg: 1 mL. After mixing evenly, the solvent was removed by evaporation at room temperature and normal pressure to prepare an aromatic-perfluoroaromatic eutectic, denoted as BPA-OFN@BPN-OFN.

[0065] Table 2. The proportions of BPA-OFN and BPN-OFN with different molar percentages.

[0066] Group BPA-OFN BPN-OFN product B1 100％ 0 BPA-OFN B2 99.7％ 0.3％ BPA-OFN@BPN-OFN-0.3% B3 96.3％ 3.7％ BPA-OFN@BPN-OFN-3.7% B4 87.6％ 22.4％ BPA-OFN@BPN-OFN-22.4%

[0067] Test 1: Photophysical property analysis.

[0068] The BPA solid, 0.1 mg / mL BPA solution, and BPA-OFN prepared in Example 3 were observed and analyzed under 365 nm ultraviolet irradiation. The results are shown in the figure. Figure 1 And Table 3. The BPN solid, 0.1 mg / mL BPN solution, and the BPN-OFN prepared in Example 4 were observed and analyzed under 365 nm ultraviolet irradiation. The results are shown in Table 3. Figure 2See Table 3. The BPA solution was prepared by mixing BPA with tetrahydrofuran; the BPN solution was prepared by mixing BPN with tetrahydrofuran.

[0069] Table 3 Results of photophysical property analysis

[0070]

[0071] Depend on Figure 1 and Figure 2 It can be seen that the significantly modulated photophysical properties of BPA-OFN and BPN-OFN can be directly judged by the naked eye. After co-assembly with colorless, weakly emitting OFN, the color of BPA changes from orange-red to green, and the color of BPN changes from black to red. After co-assembly, the photoluminescence quantum yield of BPA-OFN is 29.03%, and that of BPN-OFN is 4.73%, showing brighter luminescence compared to solid BPA and solid BPN. Moreover, the emission color of the cocrystal is consistent with the emission color of its corresponding single-component aromatic hydrocarbon solution. In Examples 5 and 6, through simple solvent-assisted grinding, the dramatic color change indicates that the aromatic hydrocarbon donor and OFN gradually approach each other, eventually forming a green-emitting BPA-OFN cocrystal and a red-emitting BPN-OFN cocrystal.

[0072] The above photophysical property analysis shows that BPA-OFN and BPN-OFN cocrystals are effective tools for illuminating solid-state materials exhibiting the ACQ effect. More importantly, the above preparation method can trigger the interaction between aromatic donors and perfluoroaromatics, rapidly forming aromatic-perfluoroaromatic cocrystals, and the amount of cocrystals prepared reaches the gram level.

[0073] Test 2: Infrared spectroscopy, Raman spectroscopy and powder X-ray diffraction analysis.

[0074] Powder X-ray diffraction, abbreviated as PXRD.

[0075] like Figure 3 The CF key in OFN is 784cm -1 The peak value was reached at 778 cm⁻¹; after co-assembly with BPA, the CF bonds in OFN were redshifted to 778 cm⁻¹. -1 After co-assembly with BPN, the CF bonds in OFN were redshifted to 781 cm⁻¹. -1 Furthermore, for BPA-OFN, the CF bond in OFN is at 1203 cm⁻¹. -1 The stretching peak shifted to 1193 cm⁻¹ -1 For BPN-OFN, the CF bond in OFN is at 1203 cm⁻¹. -1 The stretching peak at that location shifted to 1195 cm⁻¹-1 This migration indicates that the CF bond is weakened and lengthened due to the contribution of n→σ* in the aromatic-perfluoroaromatic eutectic. For BPA-OFN, the peak is at 947 cm⁻¹. -1 The corresponding side-to-side extension of the CF bond in OFN, after assembly, migrated to 944cm. -1 For BPN-OFN, it migrates to 945 cm after assembly. -1 After co-assembly, the characteristic tensile peak of Ar-H in BPA increased from 3053 cm⁻¹. -1 The location moved to 3057cm -1 The characteristic tensile peak of Ar-H in BPN is 3052 cm⁻¹. -1 The location was moved to 3055cm. -1 This change is attributed to the interaction of the halogen bond CF with Ar-H, indicating a successful stacking between electron-deficient OFN and electron-rich aromatics, namely BPA and BPN.

[0076] like Figure 4 In BPA crystals, the peak values ​​are 395 cm⁻¹. -1 1218cm -1 1559cm -1 and 3084cm -1 The Raman spectra of the samples, after OFN co-assembly, were blue-shifted to 396 cm⁻¹. -1 1221cm -1 1560cm -1 and 3090cm -1 In BPN crystals, the peak values ​​are at 1179 cm⁻¹. -1 1324cm -1 1535cm -1 and 2188cm -1 The Raman spectra of the samples, after OFN co-assembly, shifted to 1180 cm⁻¹. -1 1325cm -1 1537cm -1 and 2192cm -1 These results indicate that the electron density of BPA molecules is reduced in the aromatic-perfluoroaromatic eutectic, further confirming the formation of the aromatic-perfluoroaromatic complex.

[0077] Powder X-ray diffraction analysis was used to analyze the BPA-OFN of Example 3, the BPN-OFN of Example 4, the BPA-OFN of Example 5, and the BPN-OFN of Example 6. Figure 5As shown, the samples prepared by simple solvent-assisted grinding in Examples 5 and 6 exhibited sharp diffraction peaks, indicating an ordered crystalline superstructure. Furthermore, the powder X-ray diffraction results of BPA-OFN in Example 5 and BPN-OFN in Example 6 showed a new set of diffraction peaks, distinct from the diffraction peaks of the other individual components, indicating the generation of new species. These results agree well with the simulated curves calculated from the single-crystal structures of the samples prepared by solvent evaporation in Examples 3 and 4, indicating that the molecular packing of the ground samples is identical to that of the aromatic-perfluoroaromatic single crystals. These analyses demonstrate the successful preparation of two aromatic-perfluoroaromatic cocrystals by co-assembling OFN with two different aromatic donors.

[0078] Test 3: UV-Vis absorption and photoluminescence spectroscopy analysis.

[0079] To elucidate the photophysical properties of the aromatic-perfluoroaromatic eutectic, ultraviolet-visible absorption and photoluminescence spectra were recorded and compared with those of the corresponding aromatic solids and diluted aromatic solutions, such as... Figure 6 and Figure 7 The detailed photophysical properties of BPA, BPN, BPA-OFN, and BPN-OFN are shown in Table 4.

[0080] Table 4 Key information on aromatic hydrocarbons and the prepared eutectic

[0081]

[0082]

[0083] Note: a The concentrations of the BPA and BPN solutions were 0.1 mg / mL. b Both BPA solid and BPN solid are powdered solids. c Compared to BPA solid, the absorption wavelength of BPA-OFN changes; compared to BPN solid, the absorption wavelength of BPN-OFN changes. d Compared to BPA solid-state, the emission wavelength of BPA-OFN is shifted; compared to BPN solid-state, the emission wavelength of BPN-OFN is shifted. e It is the absolute quantum yield obtained through the integrating sphere method, the average of three trials. f Compared with BPA solid, BPA-OFN exhibits enhanced photoluminescence quantum yield; compared with BPN solid, BPN-OFN exhibits enhanced photoluminescence quantum yield.

[0084] like Figure 6When co-assembled with OFN molecules (with a high band gap of ~3.78 eV), the BPA-OFN cocrystal exhibited a significant blue shift, with a blue shift value as high as ~35 nm; the BPN-OFN cocrystal also showed a significant blue shift, with a blue shift value as high as ~66 nm. The optical band gap of the BPA solid is 2.16 eV, that of the BPN solid is 1.72 eV, that of the BPA-OFN cocrystal is 2.48 eV, and that of the BPB-OFN cocrystal is 1.91 eV. When co-crystallized with OFN, the aromatic-perfluoroaromatic complexes exhibited a significant blue shift emission, with the BPA-OFN cocrystal shifting significantly from 567 nm to 487 nm, and the BPN-OFN cocrystal shifting significantly from 684 nm to 612 nm.

[0085] Notably, the absorption and emission of the eutectic largely approximate those of the aromatic hydrocarbon solution, indicating that OFN molecules subtly act as a solid solvent and are precisely and periodically inserted into the aromatic hydrocarbon lattice through aromatic-perfluoroaromatic interactions. These observations are consistent with... Figure 1 and Figure 2 The observations shown are in excellent agreement. The aforementioned blue shift is due to the periodic insertion of electron-deficient OFN molecules between two adjacent aromatic molecules via π-π and CH···F interactions, which further blocks the formation of BPA and BPN dimers. This conclusion has been confirmed by density functional theory calculations. The blue shift in emission originates from the inserted OFN molecules screening the π-π interactions between two adjacent aromatic molecules, which can effectively reduce the photoluminescence redshift caused by exciton delocalization.

[0086] Importantly, the photoluminescence quantum yield of the aromatic-perfluoroaromatic eutectic is much higher than that of the pure aromatic crystals mentioned above. Specifically, the photoluminescence quantum yields of BPA-OFN and BPN-OFN are increased by 105% (14.18%–29.03%) and 141% (0.02%–4.73%), respectively, and even higher than the photoluminescence quantum yields of the corresponding BPA solutions, as shown in Table 4.

[0087] The above results demonstrate that periodically inserted OFN molecules can effectively disrupt the close-packed structure and aromatic-aromatic dimers in pure aromatic solids through π-π and CH···F interactions. Undoubtedly, the weakly fluorescent OFN with a high band gap of ~3.78 eV can interrupt intermolecular interactions and electron exchange between adjacent aromatics, further blocking the SF process and the transition of ISC from singlet to triplet states. Therefore, the crystallization-induced precise co-assembly strategy can easily suppress the nonradiative energy loss of the fluorescence resonance energy transfer (FRET) donor BPA and acceptor BPN molecules, paving the way for improving the FRET efficiency between donors and acceptors.

[0088] To better understand the modulation of photophysical properties, based on the packing structures of BPA-OFN and BPN-OFN complexes, the leading molecular orbitals were calculated using density functional theory, such as... Figure 7 .

[0089] In the BPA-OFN and BPN-OFN cocrystals, the small atom charges of the aromatic moiety are +0.166 and +0.142, respectively. These values ​​are similar and small, indicating that there is almost no charge transfer interaction between OFN and BPA / BPN in these cocrystal structures, which is consistent with the UV absorption results after co-assembly. Furthermore, the highest and lowest occupied molecular orbitals were calculated, namely HOMO and LUMO, further verifying this. After co-assembly with OFN, both HOMO and LUMO orbitals are dominated by the aromatic moiety, confirming the conclusion that there is no charge transfer interaction between OFN and the aromatic moiety.

[0090] Importantly, single-crystal X-ray diffraction analysis further confirmed the aforementioned filling mode and intermolecular interactions, and revealed the structure-photophysical relationship. As expected, both aromatic-perfluoroaromatic superstructures exhibited the same mixed-stacking crystal structure, with aromatic and OFN molecules alternately stacked along the

[001] direction, as shown below. Figure 7 The E and F plots show that the molar ratio of the two molecules is 1:1. Specifically, BPA-OFN belongs to the monoclinic space group P21 / c, and its unit cell parameters are... α=90°, β=104.471(5)°, γ=90° and The average distance between BPA and OFN is After co-crystallization with OFN, the distance between two adjacent BPAs increases to Similarly, the BPN-OFNs adopt a face-to-face pattern along their

[001] direction, and the average distance between the BPN-OFNs is The average distance between BPN and BPN is like Figure 7 BPN-BPN also belongs to the monoclinic space group P21 / c, and its cell parameters are... α=90°, β=100.157(5)°, γ=90°,

[0091] The average distance between aromatic hydrocarbons and OFN in the aromatic hydrocarbon-perfluoroaromatic eutectic indicates a π-π interaction between the aromatic hydrocarbons and OFN. Furthermore, numerous F···HC bonds are formed between OFN and adjacent aromatic hydrocarbons, creating a pseudo-two-dimensional network in the (001) plane. Therefore, various intermolecular interactions, including π-π and halogen bond interactions, stabilize the aromatic hydrocarbon-perfluoroaromatic eutectic. These structural analyses further confirm the above conclusions, namely that OFN molecules are completely inserted into the aromatic hydrocarbon lattice during co-crystallization, effectively separating the aromatic hydrocarbon molecules and hindering the interaction and electron exchange between adjacent BPA or BPN molecules. As a result, the triplet state becomes nonexistent, such as... Figure 1 Figure b shows that ACQ aromatic molecules exhibit high luminescence efficiency in their aggregated state. Furthermore, the π-π interactions and halogen bonds between aromatics and OFN lead to the preferential growth of the AP eutectic along the

[100] direction, which is the axial direction. This is beneficial for the formation of a one-dimensional aromatic-OFN superstructure, such as... Figure 7 The G-graph and H-graph.

[0092] This was verified by using the minimum energy principle of the materials workshop and by making predictions based on the minimum energy principle. Figure 7 The calculation results shown in the G and H diagrams indicate that both aromatic-perfluoroaromatic eutectics grow along the

[100] direction, resulting in the formation of a one-dimensional component. The morphology of the eutectics observed by transmission electron microscopy is consistent with the above calculation results. Furthermore, an attempt was made to further confirm the eutectic structure using selected region electron diffraction. However, no lattice was observed, likely because the high energy of electron beam irradiation can destroy the organic crystal structure.

[0093] Test 4: Absorption spectrum and photoluminescence spectrum.

[0094] Under the premise of satisfying the three elements of fluorescence resonance energy transfer (FRET): sufficient spectral overlap, DA distance <10 nm, and well-oriented DA dipoles, the lattice parameters of BPA-OFN and BPN-OFN crystal units lay the foundation for the FRET process between BPN-OFN doping into the BPA-OFN host and the energy DA pair. Specifically, green-emitting BPA-OFN and red-emitting BPN-OFN can act as energy donor and energy acceptor, respectively. These properties, coupled with the unique function of OFN in suppressing non-radiative energy dissipation, suggest that the strategy of crystallization-induced precise co-assembly to improve the FRET efficiency between BPA and BPN is highly feasible.

[0095] To achieve this goal, a small amount of BPN-OFN was introduced into BPA-OFN through simple grinding or solvent evaporation. For comparison, fluorescence resonance energy transfer experiments were also performed on BPA-BPN pairs without OFN by adding a small amount of BPA to BPN. The absorption spectra of BPN and BPN-OFN, and the emission spectra of BPA and BPA-OFN are shown below. Figure 8 As shown, the fluorescence spectrum of BPA and the absorption spectrum of BPN clearly overlap well in the wavelength range of 490 nm to 650 nm. Similarly, the emission spectrum of BPA-OFN and the absorption spectrum of BPN-OFN also overlap well in the wavelength range of 450 nm to 700 nm. These results indicate that fluorescence resonance energy transfer may occur from BPA donor to BPN acceptor, or from BPA-OFN to BPN-OFN. This verifies the strategy of the above embodiments of the present invention. Figure 8 As shown in Tables 1 and 2, at low doping ratios of 0.3% and 3.7%, the absorption bands of BPA-OFN@BPN-OFN show almost no change compared to the pure donor BPA and BPA-OFN. However, at a doping ratio of 22.4%, a new weak absorption peak is observed, which clearly originates from the pure acceptor BPN and BPN-OFN. Furthermore, compared to the OFN-free BPA@BPN system, the absorption spectrum of the BPA-OFN@BPN-OFN system exhibits a blue shift of approximately 35 nm due to the periodic insertion of OFN.

[0096] Steady-state emission spectra of BPA@BPN or BPA-OFN@BPN-OFN microrod films were analyzed. For BPA@BPN, the emission peak of BPA at 537 nm redshifted to 596 nm. Furthermore, corresponding images of the BPA@BPN films under 365 nm UV irradiation showed a monotonic emission from yellow to red to dark with increasing BPN doping concentration. The photoluminescence quantum yields of BPA@BPN-0.3%, BPA@BPN-3.7%, BPA@BPN-22.4%, and BPN were 14.18%, 10.65%, 8.88%, 1.87%, and 0.02%, respectively, indicating significant modulation of fluorescence emission.

[0097] In stark contrast, BPA-OFN@BPN-OFN exhibits tunable fluorescence and emits a brighter, broader spectral range by using OFNs involved in crystallization-induced precise co-assembly. In such a fluorescence resonance energy transfer system, when a small amount of BPN-OFN is used as a dopant, BPN-OFN pairs can replace π-π similar crystal structures and complex halogen bonds in BPA-OFN pairs. Increasing the doping rate to 22.4% gradually suppresses the emission band at 487 nm from the BPA-OFN components, while those at 553 nm are greatly enhanced, indicating effective isomorphic emission from the BPA-OFN donor to the BPN-OFN acceptor. Furthermore, BPA-OFN@BPN-OFN exhibits a blue shift at 553 nm compared to the 612 nm emission band of pure BPN-OFN crystals, likely due to the solid-state dispersion effect of the large amount of BPA-OFN in the BPN-OFN pair.

[0098] Under ultraviolet light excitation, as the doping rate of BPN-OFN increases, the corresponding microrod films can achieve emission colors ranging from green to yellow to orange to red. The quantum yields of BPA-OFN microrods and BPA-OFN@BPN-OFN microrods with different doping amounts are 29.03%, 32.46%, 34.77%, 31.80%, and 4.73%, respectively, which are much higher than those of pure BPA and BPA / BPN-OFN with different doping amounts.

[0099] The high fluorescence efficiency of BPA-OFN@BPN-OFN is attributed to the milder effect of the OFN component.

[0100] Table 5 Key Information of Fluorescence Resonance Energy Transfer Complex

[0101] name t / ns <![CDATA[Absolute quantum yield / % a > <![CDATA[E / % b ]]> <![CDATA[Improvement / % c > BPA solids 10.00 14.18 - - BPA / BPN-OFN-0.3% 9.68 10.65 3.2 0 BPA / BPN-OFN-3.7% 9.44 8.88 5.6 0 BPA / BPN-OFN-22.4% 8.70 1.87 13.0 0 BPN solid 7.45 0.02 - - BPA-OFN 16.61 29.03 - - BPA-OFN@BPN-OFN-0.3% 15.11 32.46 9.0 181 BPA-OFN@BPN-OFN-3.7% 13.24 34.77 20.3 263 BPA-OFN@BPN-OFN-22.4% 9.26 31.80 44.3 241 BPN-OFN 1.34 4.73 - -

[0102] Note: a The absolute quantum yield obtained by the integrating sphere method is the average of three trials. b Fluorescence resonance energy transfer efficiency, according to Calculate, where E is the FRET efficiency, a value between 0 and 1; t DA The fluorescence lifetime when the donor and acceptor substances coexist; t D The fluorescence lifetime is the fluorescence lifetime when the donor substance exists alone. c Compared with the fluorescence resonance energy transfer (FRET) without OFN, the FRET efficiency of the OFN-containing FRET complex is improved.

[0103] Furthermore, to investigate the effect of OFN doping on fluorescence resonance energy transfer efficiency, time-resolved fluorescence decay spectra of BPA@BPN and BPA-OFN@BPN-OFN fluorescence resonance energy transfer systems deposited on quartz substrates were measured. Figure 8 As shown, the fluorescence lifetime of pure BPA microrods is approximately 10.00 ns. With BPN doping ratios of 0.3%, 3.7%, and 22.4%, the fluorescence lifetime decreases to 9.68 ns, 9.44 ns, and 8.70 ns, respectively. Since fluorescence resonance energy transfer provides an additional de-excitation pathway, it enhances the decay of the excited state of the donor, thereby shortening its fluorescence lifetime. In contrast, the fluorescence lifetimes of BPA-OFN and BPN-OFN complexes are 16.61 and 1.34 ns, respectively. Figure 8 When BPN-OFN was doped with different proportions of 0.3%, 3.7%, and 22.4%, the lifetime of BPA-OFN gradually decreased to 15.11, 13.24, and 9.26 ns, respectively. These results provide strong additional evidence to support the direct energy transfer process from BPA to BPN, as well as the FRET process between BPA-OFN and BPN-OFN via nonradiative dipole-dipole interactions.

[0104] Furthermore, to further understand the impact of OFN insertion on the fluorescence resonance energy transfer process between BPA-BPN pairs, the FRET efficiencies of BPA@BPN and BPA-OFN@BPN-OFN systems with different doping ratios were calculated using the FRET efficiency calculation formula, as shown in Table 5. Compared with BPA@BPN, the FRET efficiency of the OFN-containing fluorescence resonance energy transfer system can be significantly improved. For example, doping ratios of 0.3%, 3.7%, and 22.4%, 3.2%, 13.0%, 9.0%, 20.3%, and 44.3% represent FRET efficiency improvements of 181%, 263%, and 241%, respectively.

[0105] When excited by ultraviolet light, pure BPA-OFN microrods emit a strong green light, while doped BPA-OFN microrods exhibit a uniform and tunable emission color ranging from green to yellow to orange, and then to red. As the doping ratio of BPA-OFN increases from 0.3% to 22.4%, the emission color changes. Figure 9 This is consistent with the emission color of the corresponding microrod film. Furthermore, regardless of the BPN-OFN doping ratio, this observation shows uniform emission, indicating that BPN molecules are uniformly dispersed within the BPA-OFN host, a fact also confirmed by PXRD. Figure 10After introducing a small amount of BPN as a dopant, the PXRD patterns of the fluorescence resonance energy transfer complexes showed that they remained highly crystalline, primarily derived from the BPA-OFN component. In fact, even at a doping ratio of 3.7%, no XRD peaks were observed in the BPN-OFN component; only when the doping concentration increased to 22.4% were very weak characteristics revealed.

[0106] Therefore, it can be inferred that the high doping ratio of BPN-OFN does not cause phase separation in the fluorescence resonance energy transfer system, indicating that each fluorescence resonance energy transfer microrod is composed of an almost uniform composition and a precise mixed-stacking structure. Furthermore, to more accurately compare emission colors, Figure 11 CIE chromaticity diagrams of the prepared samples are provided. The color coordinates of BPA-OFN, the three doped fluorescence resonance energy transfer complexes, and BPN-OFN calculated from their PL spectra are (0.36, 0.53), (0.42, 0.53), (0.46, 0.52), (0.50, 0.49), and (0.63, 0.37), respectively. The corresponding colors in the CIE are consistent with the experimental results above.

[0107] The energy transfer mechanism of doped BPA-OFN, such as Figure 12 As shown, energy transfer from excited BPA-OFN to BPN-OFN occurs due to the following prerequisites. First, the donor-acceptor pair of BPA-OFN / BPN-OFN satisfies the structural requirements, namely, a well-matched stacking mode as indicated by structural analysis. Second, the emission spectrum of BPA-OFN shows good overlap with the absorption spectrum of BPN-OFN, providing another condition for fluorescence resonance energy transfer. Furthermore, due to the good dispersion of BPN molecules in the BPA-OFN matrix, a suitable distance can be achieved between BPA-OFN and BPN-OFN.

[0108] In addition to the three prerequisites mentioned above, the fluorescence resonance energy transfer efficiency (FRET) also depends on other parameters, such as the fluorescence lifetime and photoluminescence quantum yield of the donor, and the quenching efficiency of the acceptor. Therefore, compared to the OFN-free BPA@BPN system, a significant improvement in FRET efficiency can be achieved in BPA-OFN@BPN-OFN, due to the substantial increase in OFN-induced photoluminescence quantum yield.

[0109] The physical processes involved in fluorescence resonance energy transfer (FRET) are as follows: First, the energy absorption of the donors leads to their excitation from the ground state to the excited singlet state. Second, possible FRETs from the excited donors include spontaneous emission and nonradiative processes. Simultaneously, if a proximal energy acceptor is available, a nonradiative FRET from the energy donor to the energy acceptor can occur, such as... Figure 12Under non-radiative photoexcitation, the electron energy of the excited-state donor can be transferred to the ground-state acceptor. Therefore, the donor emission is quenched by the acceptor. By adjusting the dopant ratio, the green emission of BPA-OFN is partially quenched, while the red emission of BPN-OFN is correspondingly enhanced, resulting in tunable emission. Notably, this simple method of improving fluorescence resonance energy transfer efficiency and reducing energy loss during FRET has not been previously reported, and it could serve as an advanced strategy for developing high-emission organic supramolecular light-collecting systems with high fluorescence resonance energy transfer efficiency. This can be easily achieved by precisely doping OFN into commercially available donor-acceptor pairs with the ACQ effect through simple grinding or solvent evaporation.

[0110] Application Examples

[0111] The aforementioned tunable excited-state OFN insertion and energy acceptor doping strategy achieves high efficiency and strong fluorescence emission, while the fluorescence color is controllable, such as... Figures 8-12 As shown, this strategy combines a simple preparation method, making it possible to explore the application of the corresponding crystals in advanced fluorescent inks and multi-stimulus responsive fluorescent systems, such as... Figure 13 This demonstrates its potential application value in multiple fields.

[0112] First, by using a water / surfactant-mediated milling process with polyvinyl alcohol (PVA) surfactant, these materials were easily dispersed in water, resulting in a uniformly dispersed, fully water-dispersed fluorescent ink with the same luminescence as the solid sample. Subsequently, based on the strong intermolecular interactions and similar lattices of BPA-OFN and BPN-OFN, a multi-stimulus responsive fluorescent system was successfully prepared.

[0113] like Figure 13 Using two brushes dipped in yellow BPA and black BPN ink, the letters FRET and By XJTU, as well as a cartoon thumbs-up, were drawn respectively. Under ultraviolet light, the letters FRET were easily distinguishable due to the yellow fluorescence of BPA, while the letters By XJTU and the cartoon thumbs-up disappeared due to the dark emission of BPN.

[0114] When drawn on the canvas with OFN solution, the weakly yellow-emitting letters FRET immediately turned into strong green emission, while the non-luminescent black letters By XJTU and the cartoon image of a thumbs-up were successfully illuminated and visualized. This observation is similar to the fluorescence changes after BPA and BPN are co-assembled with OFN, indicating that BPA-OFN and BPN-OFN eutectics were generated under the stimulation of OFN solution.

[0115] Subsequently, with increasing concentration, the letters R, E, and T were sequentially plotted using BPN-OFN solution. As expected, the three green-emitting letters turned yellow, orange, and orange-red, respectively, indicating that BPA-OFN@BPN-OFN formed a highly efficient fluorescence resonance energy transfer complex. Therefore, the letter F with green emission, the letter R with yellow emission, the letters E and T with orange emission, and the letter By XJTU with orange-red emission are easily distinguishable, as shown below. Figure 13 The d-image ultimately forms a brightly colored painting. This stimulus-fluorescence color-changing result demonstrates the material's promising potential in advanced fully water-dispersible fluorescent inks and anti-fake fluorescence recording.

[0116] Even more impressively, aqueous luminescent inks can also be used to prepare high-emission films through a simple doctor-blade coating technique, such as... Figure 13 The image shows an e-graph. It is noteworthy that the synthesized luminescent film possesses ultra-flexible properties, facilitating free bending, folding, and cutting. Combined with its high emission characteristics, this promotes the application of such materials in advanced manufacturing and packaging. Based on these advantages, three high-emission flowers were successfully prepared using yellow-emitting BPA-OFN@BPN-OFN-0.3%, orange-emitting BPA-OFN@BPN-OFN-3.7%, and red-emitting BPN-OFN film as petals, and green-emitting BPA-OFN film as leaves, as shown. Figure 13 The e-image shows that BPA-OFN, BPA-OFN@BPN-OFN-0.3%, BPA-OFN@BPN-OFN-3.7%, and BPN-OFN exhibit green, yellow, orange, and red colors, respectively. This experiment demonstrates the enormous application potential of aqueous luminescent inks in advanced luminescent art techniques. Combined with the aforementioned research on stimulus-responsive fluorescent paintings, this highlights the versatility of such aqueous luminescent inks.

[0117] In summary, this invention presents a novel and simple method—crystallization-induced precise co-assembly—to significantly improve the fluorescence resonance energy transfer efficiency (FRET) of donor-acceptor pairs with ACQ effects, such as BPA as the donor and BPN as the acceptor. In this strategy, weakly fluorescent OFN is cleverly used as a molecular brightener to promote the precise co-assembly of BPA and BPN during crystallization. Since BPA and BPN have high spectral overlap but each exhibits significant ACQ effects, this co-assembly method effectively overcomes this challenge, achieving a highly efficient FRET process.

[0118] This invention achieves precise co-assembly of BPA and BPN mediated by weakly fluorescent OFN through simple grinding or solvent evaporation methods. This innovative strategy significantly improves the photoluminescence quantum yield of BPA solids to as high as 107%, and for the first time illuminates the previously dim BPN solids, exhibiting bright red fluorescence. Most importantly, the previously monotonous and weak FRET emission of BPA@BPN, such as yellow, orange, and dark colors, is significantly modulated into more colorful and brighter emission, such as green, yellow-green, yellow, orange, and red, after this co-assembly process, with FRET efficiency improved by 180%–270%.

[0119] By delving into the precise relationship between supramolecular structure and properties, this invention reveals the underlying mechanism for enhancing FRET efficiency, providing a new perspective for understanding and regulating the FRET process. Furthermore, this strategy endows BPA / BPN with excellent anti-counterfeiting properties and artistic application potential, and has been successfully applied to create unique multi-stimulus responsive fluorescent patterns and highly flexible, high-emission-intensity colored flowers. The embodiments of this invention not only provide a rare and crucial solution for improving the FRET efficiency of ACQ donor-acceptor pairs, but also greatly broaden the research and application fields of ACQ molecules, providing important references and inspiration for FRET regulation strategies in other organic systems.

[0120] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A co-assembly method for improving the energy transfer efficiency of chromophores, characterized in that, Includes the following steps: Donor substances and perfluoroaromatic hydrocarbons were co-assembled in a solvent system to prepare donor-perfluoroaromatic hydrocarbon complexes; acceptor substances and perfluoroaromatic hydrocarbons were co-assembled in a solvent system to prepare acceptor-perfluoroaromatic hydrocarbon complexes. The donor-perfluoroaromatic complex and the acceptor-perfluoroaromatic complex were co-assembled in a solvent system, and the perfluoroaromatic compounds were inserted into the crystal lattices of the donor and acceptor substances during the co-assembly process to prepare the co-assembled complex. The donor substance is 9,10-bis(phenylethynyl)anthracene; the acceptor substance is 5,12-bis(phenylethynyl)tetraphenyl; and the perfluoroaromatic hydrocarbon is octafluoronaphthalene.

2. The co-assembly method for improving chromophore energy transfer efficiency according to claim 1, characterized in that, The ratio of the total molar amount of the acceptor and donor substances to the molar amount of the perfluoroaromatic hydrocarbon is 1:

1.

3. The co-assembly method for improving chromophore energy transfer efficiency according to claim 1, characterized in that, The percentage of the molar amount of the acceptor substance to the total molar amount of the donor and acceptor substances is 0.3% to 22.4%.

4. The co-assembly method for improving chromophore energy transfer efficiency according to claim 1, characterized in that, The solvents used to prepare the donor-perfluoroaromatic complex, the acceptor-perfluoroaromatic complex, and the co-assembly are selected from at least one of chloroform, N,N-dimethylformamide, tetrahydrofuran, acetone, and acetonitrile.

5. The co-assembly method for improving chromophore energy transfer efficiency according to claim 4, characterized in that, The co-assembly is performed by wet milling in a solvent system or by evaporation in a solvent system to remove the solvent.

6. The co-assembly method for improving chromophore energy transfer efficiency according to claim 1, characterized in that, In the co-assembled assembly, the average distance between the donor and acceptor substances is 0.69~0.7 nm.

7. A co-assembled assembly, characterized in that, The co-assembled assembly was prepared using the co-assembly method for improving chromophore energy transfer efficiency as described in any one of claims 1 to 6.

8. The co-assembled assembly according to claim 7, characterized in that, The crystal parameters of the donor-perfluoroaromatic complex are: monoclinic space group P21 / c, cell parameters a = 13.6066(13) Å, b = 18.6373(17) Å, c = 13.8665(13) Å, α = 90°, β = 104.471(5)°, γ = 90° and V = 3404.8(6) Å. 3 .

9. The co-assembled assembly according to claim 7, characterized in that, The crystal parameters of the acceptor-perfluoroaromatic complex are: monoclinic space group P21 / c, cell parameters a = 13.9229(8) Å, b = 17.5453(8) Å, c = 13.5469(6) Å, α = 90°, β = 100.157(5)°, γ = 90°, V = 3257.4(3) Å. 3 .

10. The application of the co-assembled assembly according to claim 7 in the preparation of aqueous luminescent ink.

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