Copper-based luminescent material with negative heat quenching characteristic and preparation method thereof
By designing the copper-based luminescent material [(bmma)(POPY)CuI]n, the problem of decreased luminescence intensity of organometallic luminescent materials at high temperatures was solved, achieving increased luminescence intensity and color stability at high temperatures, thus promoting applications in lighting, biomedicine, and information security.
Patent Information
- Application Number
- CN202511048025.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-29
- Publication Date
- 2025-11-14
AI Technical Summary
Existing organometallic luminescent materials exhibit decreased photoluminescence intensity and redshifted emission spectra at temperatures above room temperature, limiting their application.
A copper-based luminescent material, [(bmma)(POPY)CuI]n, was developed. Through the design of complexes with specific ligands and metal centers, a zero-dimensional binuclear structure was formed, exhibiting negative thermal quenching characteristics. The luminescence intensity increased in the range of 100K-400K and remained stable at high temperatures.
It achieves a continuous increase in luminescence intensity and stable luminescence color at temperatures above room temperature, making it suitable for temperature sensing and quantum information processing in high-temperature environments.
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Figure CN120944127A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of photoluminescence technology, specifically relating to a copper-based luminescent material with negative thermal quenching properties and its preparation method. Background Technology
[0002] Luminescent metal-organic frameworks (MOFs) and coordination polymers (CPs) are an interesting class of materials because their photoelectric properties can be optimized through molecular design. In particular, improving the photoluminescence quantum yield (PLQY) through ligand engineering has attracted widespread attention. With increased PLQY, luminescent materials can achieve more efficient energy conversion and more stable light emission, thus meeting the urgent need for high-performance luminescent materials in fields such as biolabeling, displays, and light-emitting diodes (LEDs). However, the photoluminescence intensity of existing organometallic organic luminescent materials is affected by thermal quenching. Below room temperature, their luminescence intensity decreases with increasing temperature; above room temperature, not only does the intensity continue to decrease, but the emission spectrum also undergoes a significant redshift, severely hindering applications.
[0003] The choice of ligand molecules in coordination polymers significantly impacts the performance of luminescent crystals. However, after photoexcitation, the multiple vibrational modes and electronically excited states of conjugated organic ligands in coordination polymers can form multiple nonradiative relaxation channels, leading to significant thermal quenching and ultimately causing a decrease in the material's luminescence efficiency at ambient temperatures. Researchers need a detailed understanding of their electronic properties to suppress these nonradiative processes occurring through the ligands.
[0004] In this context, finding novel heat-resistant quenching materials that can reduce energy loss at room temperature and above plays a crucial role in the performance of LEDs. Summary of the Invention
[0005] Against this backdrop, the first objective of this invention is to provide a copper-based luminescent material with negative thermal quenching properties. The copper-based luminescent material with negative thermal quenching properties provided by this invention not only exhibits a significant negative thermal quenching effect, but also shows a continuous increase in luminescence intensity within a temperature range of 100K-400K, and very stable fluorescence intensity in the high-temperature region. Furthermore, the complex exhibits a relatively stable luminescence color with temperature changes.
[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution:
[0007] A copper-based luminescent material with negative thermal quenching properties, wherein the copper-based luminescent material is a complex with the chemical formula [(bmma)(POPY)CuI]. nWhere n = ≥1, the ligand bmma is 1,1′-[[1,1′-biphenyl]-4,4′-dimethylbis(methylene)]bis[2-methyl-1H-imidazolium], the copper-based luminescent material belongs to the triclinic crystal system, space group P-1, and the crystal parameters are as follows. α=79.684(2)°, β=83.443(2)°, γ=69.954(2)°, Z=2,
[0008] Furthermore, the metal center of the crystal consists of two Cu atoms, each of which is coordinated with two P atoms of the POPY ligand and one I atom of CuI. The two Cu atoms are bridged by the bmma ligand to form a zero-dimensional binuclear structure.
[0009] The second objective of this invention is to provide a method for preparing the above-mentioned copper-based luminescent material with negative thermal quenching characteristics. This method uses readily available raw materials, is simple to synthesize, and has a high yield.
[0010] The above-mentioned technical objective of the present invention is achieved by the following technical solution:
[0011] A method for preparing a copper-based luminescent material with negative thermal quenching properties includes the following reaction steps:
[0012] S1. Preparation of organic ligand BMMA: 4,4′-bis(chloromethyl)-1,1′-biphenyl, 2-methylimidazole and potassium carbonate were dissolved in a solvent and heated to reflux. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the solvent was removed by rotary evaporation. After purification, a white powder solid was obtained, which is ligand BMMA.
[0013] S2. Preparation of the complex: CuI, bmma, POPY, and solvent A were added to a beaker and stirred to react. After filtering the mixture, solvent A was evaporated at room temperature, forming a colorless crystalline mixture. Solvent B was added to wash away impurities, yielding the complex [(bmma)(POPY)CuI]. n .
[0014] Further, in step S1, the molar ratio of 4,4′-bis(chloromethyl)-1,1′-biphenyl, 2-methylimidazolium and potassium carbonate is (6.9-7.1):(17.4-17.6):(45.4-45.6).
[0015] Further, in step S1, the solvent is acetonitrile, and the mass-to-volume ratio of acetonitrile to 2-methylimidazole is 41-42 ml / g.
[0016] Furthermore, in step S1, the heating and reflux reaction time is 12-15 hours, and the reaction temperature is 81.5℃-82.5℃.
[0017] Further, in step S1, the purification method is as follows: the orange oily crude product generated after rotary evaporation is dissolved in chloroform, washed with water, dried and filtered, and then recrystallized at low temperature with diethyl ether to obtain a white powder solid.
[0018] Further, in step S2, the molar ratio of ligands bmma, POPY and CuI is 0.09–0.11:0.09–0.11:0.09–0.11.
[0019] Further, in step S2, solvent A is a mixture of acetonitrile and dichloromethane, with a volume ratio of acetonitrile to dichloromethane of 1:1, and a mass-volume ratio of solvent A to bmma of 11-12 ml / g; solvent B is acetonitrile.
[0020] Furthermore, in step S2, the static evaporation beaker is a evaporation temperature of room temperature of 15℃~25℃.
[0021] Furthermore, in step S2, the stirring and mixing reaction time is 1 to 2 minutes.
[0022] The beneficial effects of this invention are:
[0023] 1. The copper-based luminescent material [(bmma)(POPY)CuI] with negative thermal quenching properties provided by this invention n The raw materials for synthesis are readily available, the synthesis method is simple, and the yield is high. It exhibits high PLQY efficiency (68.51%) luminescence at room temperature, and the luminescence intensity continuously increases with increasing temperature in the 100K-400K temperature range; however, above 400K, the luminescence intensity gradually decreases with further temperature increases. This invention contributes to the advancement of high-emissivity Cu(I)... - The preparation of organic frameworks has inspired research on functional metal complexes, which are expected to become transformative materials in the fields of lighting, biomedicine, and information security.
[0024] 2. The negative thermal quenching luminescent material [(bmma)(POPY)CuI] provided by this invention n The complex exhibits efficient solid-state emission at room temperature, displaying a strong emission band centered at 495 nm with a lifetime of 2.98 ms at 495 nm. The CIE coordinates remain almost unchanged as the temperature increases from 80 K to 400 K. This indicates that the complex exhibits a relatively stable emission color with varying temperature. This invention overcomes the limitation of traditional materials failing at high temperatures and can be used in precise temperature sensing and quantum information processing under high-temperature conditions. Attached Figure Description
[0025] Figure 1 This is a synthetic route diagram for the ligand.
[0026] Figure 2 This is a synthetic route diagram for the coordination compound.
[0027] Figure 3 This is a zero-dimensional binuclear structure diagram of the copper-based luminescent material of Example 1; Cu, sky blue; N, blue; C, gray; P, green; I, pink; hydrogen atoms have been omitted for clarity.
[0028] Figure 4 This is a powder X-ray diffraction pattern of the copper-based luminescent material in Example 1.
[0029] Figure 5 The image shows the infrared spectrum of the copper-based luminescent material of Example 1.
[0030] Figure 6 Thermogravimetric analysis (TGA) of the copper-based luminescent material in Example 1 is shown.
[0031] Figure 7 At 298 K, the PL excitation and emission spectra (λ) of the copper-based luminescent material in Example 1 are... em =495nm).
[0032] Figure 8 CIE coordinate diagram of the copper-based luminescent material of Example 1 at 298K.
[0033] Figure 9 The temperature-varying PL spectrum of the copper-based luminescent material in Example 1 is shown.
[0034] Figure 10 The temperature-dependent luminescence intensity integral curve of the copper-based luminescent material in Example 1 is shown.
[0035] Figure 11 The temperature-dependent CIE diagram is shown for the copper-based luminescent material in Example 1.
[0036] Figure 12 The photoluminescence quantum efficiency of the copper-based luminescent material in Example 1 was measured at 298K.
[0037] Figure 13 The image shows the luminescence lifetime decay curve of the copper-based luminescent material in Example 1 at room temperature. Detailed Implementation
[0038] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific implementation methods, features and effects of a copper-based luminescent material with negative thermal quenching characteristics and its preparation method according to the present invention are described in detail below.
[0039] All reagents used in the experiment were purchased from the market, and all instruments used were standard instruments.
[0040] Example 1
[0041] Preparation of BMA (Reference) Figure 1 As shown):
[0042] S1. Dissolve 4,4′-bis(chloromethyl)-1,1′-biphenyl (1.76 g, 7 mmol), 2-methylimidazole (1.44 g, 17.5 mmol), and potassium carbonate (6.30 g, 45.5 mmol) in 60 ml of acetonitrile. Then heat the reactants under reflux for 15 h. During the reaction, the reactants turn orange and eventually form a beige precipitate.
[0043] S2. After the reaction was complete, the mixture was cooled to room temperature and filtered. Orange oil was then extracted by rotary evaporation at 80°C. The extracted orange oil was dissolved in 100 ml of chloroform, and 50 ml of distilled water was added for liquid-liquid extraction. The mixture was separated, and the organic layer was collected. Anhydrous magnesium sulfate (5 g, 41.5 mmol) was added, and the mixture was stirred for 2 hours. The mixture was then filtered and rotary evaporated to the remaining 10 ml of liquid.
[0044] S3. Add 200ml of diethyl ether to the above 10ml liquid, place it in the freezer (-20℃~-10℃) overnight to allow the product to precipitate out, and the final product is a white powder.
[0045] Copper-based luminescent material with negative thermal quenching properties [(bmma)(POPY)CuI] n Preparation (reference) Figure 2 As shown):
[0046] S4. Add CuI (19.0 mg, 0.1 mmol), bmma (34.2 mg, 0.1 mmol), POPY (57.8 mg, 0.1 mmol), acetonitrile (20 mL), and dichloromethane (20 mL) to a flask, stir for 1 minute, filter the resulting mixture, and pour it into a clean 100 mL beaker. Seal the beaker with plastic wrap and poke 5 holes. Allow it to evaporate in a cool, dry place at room temperature for 4 days. After solvent evaporation, a mixture of dry colorless crystals and precipitate is obtained. Wash with 50 mL of acetonitrile and select the colorless crystals [(bmma)(POPY)CuI] suitable for X-ray diffraction analysis. n .
[0047] Example 2
[0048] S1. Dissolve 4,4′-bis(chloromethyl)-1,1′-biphenyl (1.73 g, 6.9 mmol), 2-methylimidazole (1.43 g, 17.4 mmol), and potassium carbonate (6.29 g, 45.4 mmol) in 58 ml of acetonitrile. Then heat the reactants under reflux for 12 h. During the reaction, the reactants turn orange and eventually form a beige precipitate.
[0049] S2. After the reaction was complete, the mixture was cooled to room temperature and filtered. Orange oil was then extracted by rotary evaporation at 80°C. The extracted orange oil was dissolved in 100 ml of chloroform, and 50 ml of distilled water was added for liquid-liquid extraction. The mixture was separated, and the organic layer was collected. Anhydrous magnesium sulfate (5 g, 41.5 mmol) was added, and the mixture was stirred for 2 hours. The mixture was then filtered and rotary evaporated to the remaining 10 ml of liquid.
[0050] S3. Add 200ml of diethyl ether to the above 10ml liquid, place it in the freezer (-20℃~-10℃) overnight to allow the product to precipitate out, and the final product is a white powder.
[0051] S4. Add CuI (17.1 mg, 0.09 mmol), bmma (30.78 mg, 0.09 mmol), POPY (52.02 mg, 0.09 mmol), acetonitrile (18 mL), and dichloromethane (18 mL) to a flask, stir for 1 minute, filter the resulting mixture, and pour it into a clean 100 mL beaker. Seal the beaker with plastic wrap and poke 5 holes. Allow it to evaporate in a cool, dry place at room temperature for 3 days. After solvent evaporation, a mixture of dry colorless crystals and precipitate is obtained. Wash with 50 mL of acetonitrile and select the colorless crystals [(bmma)(POPY)CuI] suitable for X-ray diffraction analysis. n This refers to copper-based luminescent materials with negative thermal quenching properties.
[0052] Example 3
[0053] S1. Dissolve 4,4′-bis(chloromethyl)-1,1′-biphenyl (1.73 g, 6.9 mmol), 2-methylimidazole (1.43 g, 17.4 mmol), and potassium carbonate (6.29 g, 45.4 mmol) in 58 ml of acetonitrile. Then heat the reactants under reflux for 12 h. During the reaction, the reactants turn orange and eventually form a beige precipitate.
[0054] S2. After the reaction was complete, the mixture was cooled to room temperature and filtered. Orange oil was then extracted by rotary evaporation at 80°C. The extracted orange oil was dissolved in 100 ml of chloroform, and 50 ml of distilled water was added for liquid-liquid extraction. The mixture was separated, and the organic layer was collected. Anhydrous magnesium sulfate (5 g, 41.5 mmol) was added, and the mixture was stirred for 2 hours. The mixture was then filtered and rotary evaporated to the remaining 10 ml of liquid.
[0055] S3. Add 200ml of diethyl ether to the above 10ml liquid, place it in the freezer (-20℃~-10℃) overnight to allow the product to precipitate out, and the final product is a white powder.
[0056] S4. Add CuI (20.9 mg, 0.11 mmol), bmma (37.62 mg, 0.11 mmol), POPY (63.58 mg, 0.11 mmol), acetonitrile (22 mL), and dichloromethane (22 mL) to a flask, stir for 1 minute, filter the resulting mixture, and pour it into a clean 100 mL beaker. Seal the beaker with plastic wrap and poke 5 holes. Allow it to evaporate in a cool, dry place at room temperature for 4 days. After solvent evaporation, a mixture of dry colorless crystals and precipitate is obtained. Wash with 50 mL of acetonitrile and select the colorless crystals [(bmma)(POPY)CuI] suitable for X-ray diffraction analysis. n This refers to copper-based luminescent materials with negative thermal quenching properties.
[0057] The copper-based luminescent material [(bmma)(POPY)CuI] obtained in Examples 1-3 n Data collection, data reduction, and cell optimization were performed using the Iuker InstrumentService v4.2.2 and SAINT V8.34 A packages. The SHELXS package was used for coordination compound structure analysis, and the crystal data was optimized using the full matrix least squares method via the SHELXL package. Absorption correction was performed using the SADABS multi-scan package. Hydrogen atoms of the organic ligands were anisotropically optimized in F2 using the riding mode on the SHELXTL package. The final crystallographic data of the coordination compound are shown in Table 1, along with some bond lengths. The bond angle (°) data are shown in Table 2.
[0058] Table 1. Crystallographic parameters of the coordination compounds:
[0059]
[0060]
[0061] a R1=Σ(||F0|-|Fc||) / Σ|F0|; b wR2=[Σw(|F0 2 |-|Fc 2 |) 2 / Σw|F0 2 | 2 ] 1 / 2 ; c GOF=[∑[w(F0 2 -Fc 2 ) 2 ] / (Nobs-Nparams)] 1 / 2 ,
[0062] Based on the data I>2σ(I).
[0063] Table 2. Important bond lengths in the crystal structure of coordination compounds. Bond angle (°):
[0064]
[0065] The crystal obtained in Example 1 was analyzed by powder X-ray diffraction: as shown Figure 4 As shown, the red spectral lines were plotted based on experimental data, while the black spectral lines were obtained through computer simulation based on the crystal structure. Figure 4 It can be seen that the experimental and simulated values of the complex are in very good agreement, indicating that the complex is a pure phase.
[0066] The infrared spectrum of the crystal obtained in Example 1 is as follows: Figure 5 As shown, the black spectral lines are plotted using data obtained from the crystal, while the red lines are plotted using data obtained from the ligands. Figure 5 It can be seen that the vibrational contraction peaks of the ligand and the complex are almost the same, indicating that there are organic ligands in the complex.
[0067] Thermogravimetric analysis was performed on the crystal obtained in Example 1: as follows Figure 6 As shown, the thermal stability of the complex was investigated from room temperature to 800 °C. The TGA curves reveal that the complex exhibits good thermal stability, with its mass loss occurring in two steps. The first weight loss of approximately 68-69% was observed between 100 and 484 °C due to the removal of halogens and some ligands. The second weight loss between 484 and 800 °C can be attributed to the complete removal of the remaining ligands.
[0068] The luminescence of the crystal obtained in Example 1 was tested: as follows Figure 7 As shown, the complex exhibits a strong emission band centered at 495 nm, with a full width at half maximum (FWHM) of approximately 107 nm and CIE coordinates of (0.2241, 0.3665). Figure 8 ),like Figure 12 As shown, the photoluminescence quantum yield (PLQY) of the complex in the solid state is 68.51%, as... Figure 13 As shown, the PL lifetime is 2.98ms.
[0069] The PL quenching properties of the crystal obtained in Example 1 were tested: Figure 9 and Figure 10 As shown, the luminescence intensity continuously increases with increasing temperature within the range of 100K-400K; however, when the temperature exceeds 400K, the luminescence intensity gradually decreases with further increases in temperature. Correspondingly, as... Figure 11As shown, the CIE coordinates remain almost unchanged in the range of 100-400K, indicating the stability of the emitted color.
[0070] The photoluminescence quantum efficiency and photoluminescence lifetime of the crystal obtained in Example 1 were tested: the photoluminescence quantum efficiency curve is shown below. Figure 12 As shown, the photoluminescence quantum yield (PLQY) of the complex in the solid state is 68.51%, and this invention belongs to the category of high-efficiency luminescent materials; Figure 13 As shown, the PL lifetime is 2.98ms at 298K, and this invention belongs to long-lifetime luminescent materials.
Claims
1. A copper-based luminescent material with negative thermal quenching properties, characterized in that: The copper-based luminescent material is a complex with the chemical formula [(bmma)(POPY)CuI]. n Where n = ≥1, the ligand bmma is 1,1′-[[1,1′-biphenyl]-4,4′-dimethylbis(methylene)]bis[2-methyl-1H-imidazolium], the copper-based luminescent material belongs to the triclinic crystal system, space group P-1, and the crystal parameters are as follows. α=79.684(2)°, β=83.443(2)°, γ=69.954(2)°, 2. The copper-based luminescent material with negative thermal quenching characteristics according to claim 1, characterized in that: The crystal's metallic center consists of two Cu atoms. Each Cu atom is coordinated with two P atoms of the POPY ligand and one I atom of CuI. The two Cu atoms are bridged by the bmma ligand, forming a zero-dimensional binuclear structure.
3. A method for preparing a copper-based luminescent material with negative thermal quenching characteristics as described in claim 1 or 2, characterized in that: The reaction steps include the following; S1. Dissolve 4,4′-bis(chloromethyl)-1,1′-biphenyl, 2-methylimidazole and potassium carbonate in a solvent, heat to reflux and react. After the reaction is complete, cool to room temperature, filter, remove the solvent by rotary evaporation, and obtain a white powder solid, i.e. ligand bmma, after purification. S2. CuI, bmma, POPY, and solvent A are added to a beaker and stirred to react. After filtering the mixture, solvent A is evaporated at room temperature, forming a colorless crystalline mixture. Solvent B is added to wash away impurities, yielding the complex [(bmma)(POPY)CuI]. n .
4. The preparation method according to claim 3, characterized in that: In step S1, the molar ratio of 4,4′-bis(chloromethyl)-1,1′-biphenyl, 2-methylimidazole and potassium carbonate is (6.9-7.1):(17.4-17.6):(45.4-45.6).
5. The preparation method according to claim 3, characterized in that: In step S1, the solvent is acetonitrile, and the mass-to-volume ratio of acetonitrile to 2-methylimidazole is 41-42 ml / g.
6. The preparation method according to claim 3, characterized in that: In step S1, the heating and reflux reaction time is 12-15 hours, and the reaction temperature is 81.5℃-82.5℃.
7. The preparation method according to claim 3, characterized in that: In step S1, the purification method is as follows: the orange oily crude product generated after rotary evaporation is dissolved in chloroform, washed with water, dried and filtered, and then recrystallized at low temperature with diethyl ether to obtain a white powder solid.
8. The preparation method according to claim 3, characterized in that: In step S2, the molar ratio of ligands bmma, POPY and CuI is 0.09–0.11:0.09–0.11:0.09–0.
11.
9. The method for preparing the copper-based luminescent material with negative thermal quenching characteristics according to claim 3, characterized in that: In step S2, solvent A is a mixture of acetonitrile and dichloromethane, with a volume ratio of acetonitrile to dichloromethane of 1:1, and a mass-volume ratio of solvent A to bmma of 11-12 ml / g; solvent B is acetonitrile.
10. The preparation method according to claim 3, characterized in that: In step S2, the stirring and mixing reaction time is 1 to 2 minutes.