Near-infrared two-region luminescent material with ultra-narrow band emission and tunable wavelength in room-temperature environment and preparation method and application of near-infrared two-region luminescent material

Abstract

The invention provides an ultra-narrow-band emission and wavelength-tunable near-infrared two-region luminescent material in a room temperature environment and a preparation method and application thereof, and belongs to the technical field of luminescent materials. The chemical structural formula of the luminescent material provided by the invention is MIM < II > P < 1-x > O4: xCr < 4 + >, M is Li, Na, K, Rb or Cs, M < II > is Mg, Ca, Sr or Ba, and x is greater than or equal to 0.01 and less than 1. The luminescent material provided by the invention has the characteristic of ultra-narrow band emission in a room temperature environment (the half-peak width is 12-23nm).

Description

Technical Field

[0001] This invention belongs to the field of luminescent materials technology, specifically relating to an ultra-narrowband luminescent material with tunable wavelength in the near-infrared II region at room temperature, its preparation method, and its application. Background Technology

[0002] Near-infrared II (NIIR) light, with wavelengths ranging from 1000 to 1700 nm, possesses characteristics such as non-destructive, real-time, and deep penetration, demonstrating immense application potential in fields like bioimaging, anti-counterfeiting, and material composition analysis. The practical application of NIIR luminescent materials primarily depends on the peak position, intensity, and full width at half maximum (FWHM) of the emission spectrum. The FWHM is a crucial parameter determining whether it can achieve accurate multi-target resolution. In multi-target detection, broadband emission, due to its excessively large spectral coverage, easily leads to severe overlap and crosstalk between the spectral signals of different targets, preventing the instrument from effectively distinguishing and measuring individual targets, resulting in multi-target detection failure and blurred imaging. In contrast, narrowband luminescent materials possess sharp, non-overlapping emission peaks, effectively avoiding signal crosstalk and ensuring the independence of target signals, demonstrating significant application value in multi-target detection and high-resolution imaging. Currently, the activator ions in NIIR narrowband luminescent materials are mainly rare-earth ions (Tm...). 3+ Er 3+ Yb 3+ (etc.), but rare earth ions 4f-4f Intra-configuration transitions suffer from small absorption cross-sections and low excitation efficiency. To address this, current methods commonly employ chemical approaches to construct complex core-shell structures, passivating surface defects in rare-earth luminescent materials and improving their light absorption and excitation efficiency. However, this method involves stringent material preparation conditions and high technical difficulty, hindering its industrial application and widespread adoption. In contrast, transition metal Cr... 4+ It possesses a larger molar extinction coefficient than rare-earth ions, enabling it to produce stronger luminescence intensity and higher imaging signal-to-noise ratio under the same excitation conditions. This holds promise for solving the problem of low quantum yield in rare-earth activated near-infrared II luminescent materials. Numerous research results indicate that Cr... 4+ Activated luminescent materials are difficult to produce near-infrared II emission with narrow-band spectral behavior (half-width at half maximum is less than 30 nm) at room temperature, which seriously restricts their practical application and popularization.

[0003] Therefore, there is an urgent need to develop a Cr24 ... 4+ Activated ultra-narrowband, wavelength-tunable near-infrared II luminescent material. Summary of the Invention

[0004] The purpose of this invention is to provide an ultra-narrowband luminescent material with tunable wavelength near-infrared II emission at room temperature, its preparation method, and its applications. The luminescent material provided by this invention possesses ultra-narrowband near-infrared II emission characteristics at room temperature.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides an ultra-narrowband emitting and wavelength-tunable near-infrared II luminescent material at room temperature, with the chemical structural formula: M Ⅰ M Ⅱ P 1-x O4:xCr 4+ , of which M Ⅰ For Li, Na, K, Rb or Cs, M Ⅱ The elements are Mg, Ca, Sr, or Ba, and 0.01 ≤ x < 1.

[0006] Preferably, 0.01 ≤ x < 0.5.

[0007] Preferably, 0.01 ≤ x < 0.1.

[0008] Preferably, 0.03 ≤ x ≤ 0.09.

[0009] This invention also provides a method for preparing the ultra-narrowband emitting and wavelength-tunable near-infrared II luminescent material at room temperature as described in the above technical solution, comprising: M Ⅰ Source, M Ⅱ The source, phosphorus source and chromium source are mixed and sintered to obtain a near-infrared II luminescent material with ultra-narrow band emission and tunable wavelength at room temperature.

[0010] Preferably, the M Ⅰ Source, M Ⅱ The sources, phosphorus sources, and chromium sources independently include elements, carbonates, phosphates, nitrates, or oxides.

[0011] Preferably, the M Ⅰ M in the source Ⅰ M Ⅱ M in the source Ⅱ The molar ratio of phosphorus in the phosphorus source to chromium in the chromium source is 1:1:(1-x):x.

[0012] Preferably, the sintering holding temperature is 1000~1500℃, and the sintering holding time is 2~4h.

[0013] Preferably, the sintering holding temperature is 1000~1300℃, and the sintering holding time is 3~4h.

[0014] This invention also provides the application of the ultra-narrowband emitting and wavelength-tunable near-infrared II luminescent material at room temperature as described in the above technical solution, or the ultra-narrowband emitting and wavelength-tunable near-infrared II luminescent material at room temperature prepared by the preparation method described in the above technical solution, in the fields of luminescence, laser, bioimaging, anti-counterfeiting, and material composition detection and analysis.

[0015] This invention provides an ultra-narrowband emitting and wavelength-tunable near-infrared II luminescent material at room temperature, with the chemical structural formula: M Ⅰ M Ⅱ P 1-x O4:xCr 4+ , of which M Ⅰ For Li, Na, K, Rb or Cs, M Ⅱ The elements are Mg, Ca, Sr, or Ba, and 0.01 ≤ x < 1. This invention uses M... Ⅰ M Ⅱ P 1-x Using an O4-configured compound as the matrix, this matrix possesses advantages such as a wide band gap, structural diversity, and flexible tunable chemical composition. By controlling the matrix's chemical composition, near-infrared emitting region II materials with continuously tunable emission peak positions and full width at half maximum (FWHM) were obtained. The results of the examples show that this invention, by doping different proportions of Cr... 4+ The obtained near-infrared II luminescent materials all exhibit ultra-narrow band emission characteristics at room temperature (half-width at half maximum 12~23nm). Attached Figure Description

[0016] Figure 1 A comparison of the XRD spectrum of the near-infrared II luminescent material provided in Example 1 and the standard PDF card (76-1456) of NaCaPO4; Figure 2 The photoluminescence spectrum of the near-infrared II luminescent material provided in Example 1 under red light (λ=628nm) excitation; Figure 3 The excitation spectrum corresponding to the 1175nm emission peak of the near-infrared II luminescent material provided in Example 1; Figure 4 A comparison of the XRD spectrum of the near-infrared II luminescent material provided in Example 2 and the standard PDF card (33-1282) of NaSrPO4; Figure 5 The photoluminescence spectrum of the near-infrared II luminescent material provided in Example 2 under red light (λ=616nm) excitation; Figure 6 The excitation spectrum corresponding to the 1163nm emission peak of the near-infrared II luminescent material provided in Example 2 is shown. Detailed Implementation

[0017] This invention provides an ultra-narrowband emitting and wavelength-tunable near-infrared II luminescent material at room temperature, with the chemical structural formula: M Ⅰ M Ⅱ P 1-x O4:xCr 4+ .

[0018] In this invention, the M Ⅰ The elements are Li, Na, K, Rb, or Cs; the M Ⅱ The elements are Mg, Ca, Sr, or Ba; and 0.01 ≤ x < 1.

[0019] In one implementation, x may specifically be 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.5, or 0.8.

[0020] Cr 4+ The spectral behavior depends on the crystal field strength of its lattice site; the shorter the average bond length between the ligand and the chromium ion, the stronger the crystal field, resulting in Cr... 4+ This invention readily generates narrowband near-infrared emission and employs M... Ⅰ M Ⅱ P 1-x Using O4-configured compounds as the matrix, this matrix possesses advantages such as a wide band gap, structural diversity, and flexible tunable chemical composition, effectively inducing Cr... 4+ It generates ultra-narrowband near-infrared II emission; by controlling the matrix chemical composition, the near-infrared emission wavelength (1064~1175nm) and half-width at half maximum (12~23nm) can be continuously adjusted, thereby meeting the different requirements of various application scenarios for the luminescence characteristics of near-infrared II luminescent materials.

[0021] This invention also provides a method for preparing the ultra-narrowband emitting and wavelength-tunable near-infrared II luminescent material at room temperature as described in the above technical solution, comprising: M Ⅰ Source, M Ⅱ The source, phosphorus source and chromium source are mixed and sintered to obtain a near-infrared II luminescent material with ultra-narrow band emission and tunable wavelength at room temperature.

[0022] Unless otherwise specified, the present invention does not impose any special restrictions on the source of the raw materials, and commercially available products well known to those skilled in the art can be used.

[0023] In this invention, the M Ⅰ Source, M Ⅱ The phosphorus source and chromium source preferably independently comprise elements, carbonates, phosphates, nitrates, or oxides. As one embodiment, the M... ⅠThe source can specifically be Li2CO3, Na2CO3, K2CO3, Rb2CO3, or Cs2CO3; the M Ⅱ The source can be specifically MgO, CaCO3, SrCO3 or BaCO3; the phosphorus source can be specifically NH6PO4; the chromium source can be specifically Cr2O3.

[0024] In this invention, the M Ⅰ M in the source Ⅰ M Ⅱ M in the source Ⅱ The preferred molar ratio of phosphorus in the phosphorus source to chromium in the chromium source is 1:1:(1-x):x; wherein 0.01≤x<1.

[0025] The present invention relates to the M Ⅰ Source, M Ⅱ There are no special limitations on the particle size of the phosphorus source and chromium source; any powder material well known to those skilled in the art can be used.

[0026] The present invention relates to the M Ⅰ Source, M Ⅱ There are no particular limitations on the mixing method of the phosphorus source and chromium source; any technical solution well known to those skilled in the art can be used to mix the raw materials evenly. As one embodiment, the mixing can be ball milling or grinding; the mixing time can be 20-25 minutes.

[0027] In this invention, the sintering holding temperature is preferably 1000~1500℃; the sintering holding time is preferably 2~4h. As one embodiment, the sintering holding temperature can specifically be 1000℃, 1050℃, 1100℃, 1150℃, 1200℃, 1250℃, 1300℃, 1350℃, 1400℃, 1450℃, or 1500℃; the sintering holding time can specifically be 2h, 2.5h, 3h, 3.5h, or 4h.

[0028] After sintering, the present invention preferably cools and grinds the sintered product in sequence to obtain an ultra-narrowband emitting material with tunable wavelength in the near-infrared II region at room temperature.

[0029] The present invention does not impose any special limitations on the cooling operation; any cooling technique known to those skilled in the art can be used to cool the material to room temperature.

[0030] The present invention does not impose any special limitations on the grinding operation, and any grinding technique known to those skilled in the art can be used.

[0031] The preparation method of the present invention is simple and easy to operate. It only requires mixing the raw materials in proportion and sintering them. No new equipment is needed, which reduces the production cost of enterprises and is conducive to large-scale industrial promotion.

[0032] This invention also provides the application of the ultra-narrowband emitting and wavelength-tunable near-infrared II luminescent material at room temperature as described in the above technical solution, or the ultra-narrowband emitting and wavelength-tunable near-infrared II luminescent material at room temperature prepared by the preparation method described in the above technical solution, in the fields of luminescence, laser, bioimaging, anti-counterfeiting, and material composition detection and analysis.

[0033] The present invention does not impose any special limitations on the operation of the application, and any technical solution known to those skilled in the art can be used.

[0034] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0035] Example 1 A near-infrared II luminescent material with ultra-narrowband emission and tunable wavelength at room temperature has the chemical formula: NaCaP 0.97 O4: 0.03Cr 4+ The near-infrared II luminescent material belongs to the orthorhombic crystal system and has the space group Pnma; The preparation method of the ultra-narrowband emission and wavelength-tunable near-infrared II luminescent material at room temperature is as follows: 0.3970g of Na2CO3, 0.7499g of CaCO3, 0.8360g of NH6PO4 and 0.0171g of Cr2O3 are mixed and ground for 20min, then placed in a high-temperature furnace and sintered at 1250℃ for 4h. After cooling to room temperature with the furnace, the mixture is ground again to obtain the ultra-narrowband emission and wavelength-tunable near-infrared II luminescent material at room temperature.

[0036] Figure 1 A comparison image of the XRD pattern of the near-infrared II luminescent material provided in Example 1 and the standard PDF card (76-1456) of NaCaPO4. Figure 1 It can be seen that the near-infrared II luminescent material provided by this invention belongs to the orthorhombic crystal system with space group Pnma.

[0037] Figure 2 The photoluminescence spectrum of the near-infrared II luminescent material provided in Example 1 under red light (λ=628nm) excitation is shown. Figure 2It can be seen that the emission wavelength of the near-infrared II luminescent material provided by the present invention covers the wavelength range of 1050~1350nm.

[0038] Figure 3 The excitation spectrum corresponding to the 1175 nm emission peak of the near-infrared II luminescent material provided in Example 1 is shown. Figure 3 It can be seen that the excitation wavelength of the near-infrared II luminescent material provided by the present invention is in the range of 500~1000nm, and it can be effectively excited by red light or near-infrared I light source.

[0039] Example 2 A near-infrared II luminescent material with ultra-narrowband emission and tunable wavelength at room temperature has the chemical formula: NaSrP 0.95 O4: 0.05Cr 4+ The near-infrared II luminescent material belongs to the triclinic crystal system and has a space group of P-1. The preparation method of the ultra-narrowband emission and wavelength-tunable near-infrared II luminescent material at room temperature is as follows: 0.3379g of Na2CO3, 0.9412g of SrCO3, 0.6967g of NH6PO4 and 0.0242g of Cr2O3 are mixed and ground for 20min, then placed in a high-temperature furnace and sintered at 1050℃ for 4h. After cooling to room temperature with the furnace, the mixture is ground again to obtain the ultra-narrowband emission and wavelength-tunable near-infrared II luminescent material at room temperature.

[0040] Figure 4 A comparison image of the XRD pattern of the near-infrared II luminescent material provided in Example 2 and the standard PDF card (33-1282) of NaSrPO4. Figure 4 It can be seen that the near-infrared II luminescent material provided by this invention belongs to the triclinic crystal system and has a space group of P-1.

[0041] Figure 5 The photoluminescence spectrum of the near-infrared II luminescent material provided in Example 2 under red light (λ=616nm) excitation is shown. Figure 5 It can be seen that the emission wavelength of the near-infrared II luminescent material provided by the present invention covers the wavelength range of 1050~1350nm.

[0042] Figure 6 The excitation spectrum corresponding to the 1163 nm emission peak of the near-infrared II luminescent material provided in Example 2 is shown. Figure 6 It can be seen that the excitation wavelength of the near-infrared II luminescent material provided by the present invention is in the range of 500~1000nm, and it can be effectively excited by red light or near-infrared I light source.

[0043] Example 3 A near-infrared II luminescent material with ultra-narrowband emission and tunable wavelength at room temperature has the chemical formula: NaCaP 0.95 O4: 0.05Cr 4+ The near-infrared II luminescent material belongs to the orthorhombic crystal system and has the space group Pnma; The preparation method of the ultra-narrowband emission and wavelength-tunable near-infrared II luminescent material at room temperature is as follows: 0.3982g of Na2CO3, 0.7521g of CaCO3, 0.8211g of NH6PO4 and 0.0286g of Cr2O3 are mixed and ground for 20min, then placed in a high-temperature furnace and sintered at 1250℃ for 4h. After cooling to room temperature with the furnace, the mixture is ground again to obtain the ultra-narrowband emission and wavelength-tunable near-infrared II luminescent material at room temperature.

[0044] Example 4 A near-infrared II luminescent material with ultra-narrowband emission and tunable wavelength at room temperature has the chemical formula: NaCaP 0.93 O4: 0.07Cr 4+ The near-infrared II luminescent material belongs to the orthorhombic crystal system and has the space group Pnma; The preparation method of the ultra-narrowband emission and wavelength-tunable near-infrared II luminescent material at room temperature is as follows: 0.3994g of Na2CO3, 0.7543g of CaCO3, 0.8062g of NH6PO4 and 0.0401g of Cr2O3 are mixed and ground for 20min, then placed in a high-temperature furnace and sintered at 1250℃ for 4h. After cooling to room temperature with the furnace, the mixture is ground again to obtain the ultra-narrowband emission and wavelength-tunable near-infrared II luminescent material at room temperature.

[0045] Example 5 A near-infrared II luminescent material with ultra-narrowband emission and tunable wavelength at room temperature has the chemical formula: NaCaP 0.91 O4: 0.09Cr 4+ The near-infrared II luminescent material belongs to the orthorhombic crystal system and has the space group Pnma; The preparation method of the ultra-narrowband emission and wavelength-tunable near-infrared II luminescent material at room temperature is as follows: 0.4006g of Na2CO3, 0.7565g of CaCO3, 0.7912g of NH6PO4 and 0.0517g of Cr2O3 are mixed and ground for 20min, then placed in a high-temperature furnace and sintered at 1250℃ for 4h. After cooling to room temperature with the furnace, the mixture is ground again to obtain the ultra-narrowband emission and wavelength-tunable near-infrared II luminescent material at room temperature.

[0046] The full width at half maximum (FWHM) of the near-infrared II luminescent materials provided in Examples 1-5 was tested, and the results are shown in Table 1.

[0047] Table 1. Full width at half maximum (FWHM) of the near-infrared II luminescent materials provided in Examples 1-5

[0048] As can be seen from Table 1, this invention uses different proportions of Cr doping. 4+ The obtained near-infrared II luminescent materials all exhibit ultra-narrow band emission (half-width at half maximum ≤ 23 nm).

[0049] Comparative Example 1 A near-infrared II luminescent material, chemically characterized as: CaYGaO4:Cr 4+ From Laser & Photonics Reviews, 2024, Vol. 18, No. 1.

[0050] The near-infrared II luminescent material has a full width at half maximum (FWHM) of 233 nm at room temperature (298 K) and 193 nm at a low temperature (81 K).

[0051] Comparative Example 2 A near-infrared phosphor, chemically characterized as: LiAlO2:Cr 4+ From Inorganic Chemistry, 2024, Vol. 63, No. 29.

[0052] The near-infrared II luminescent material has a full width at half maximum (FWHM) of 257 nm at room temperature (298 K).

[0053] Comparative Example 3 A near-infrared phosphor, chemically characterized as: SrLaGa3O7:Cr 4+ From Laser & Photonics Reviews, 2025, Vol. 19, No. 3.

[0054] The near-infrared II luminescent material has a full width at half maximum (FWHM) of 305 nm at room temperature (298 K).

[0055] Comparative Example 4 A near-infrared phosphor, chemically characterized as: Li4SrCa(SiO4)2:Cr 4+ This article is from the Journal of Materials Chemistry C, 2024, Volume 12, Issue 36.

[0056] The near-infrared II phosphor has a full width at half maximum (FWHM) of 233 nm at room temperature (300 K). No specific FWHM data was given at a low temperature (100 K), but it exhibits broadband emission, suggesting that its FWHM is approximately 195 nm.

[0057] Comparative Example 5 A near-infrared phosphor, chemically characterized as: Ca2GeO4:Cr 4+ From Dalton Transactions, 2022, Vol. 51, No. 35.

[0058] The near-infrared II phosphor has a full width at half maximum (FWHM) of 215 nm at room temperature (300 K). No specific FWHM data was given at a low temperature (4 K), but it exhibits narrow-band emission, suggesting that its FWHM is approximately 15 nm.

[0059] A comparison of Examples 1-5 and Comparative Examples 1-5 shows that, compared to previously reported Cr... 4+ The Cr-doped near-infrared phosphor provided by this invention 4+ Doped near-infrared II luminescent materials are currently the only near-infrared II phosphors that can achieve ultra-narrowband emission at room temperature and have tunable wavelengths through solid-state reactions.

[0060] The above description is only a preferred embodiment 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. A near-infrared II luminescent material with ultra-narrowband emission and tunable wavelength at room temperature, the chemical structural formula of which is: M Ⅰ M Ⅱ P 1-x O4:xCr 4+ ,in, M Ⅰ For Li, Na, K, Rb or Cs, M Ⅱ The elements are Mg, Ca, Sr, or Ba, and 0.01 ≤ x < 1.

2. The ultra-narrowband emitting and wavelength-tunable near-infrared II luminescent material at room temperature according to claim 1, characterized in that, The condition is 0.01 ≤ x < 0.

5.

3. The ultra-narrowband emitting and wavelength-tunable near-infrared II luminescent material at room temperature according to claim 2, characterized in that, The condition is 0.01 ≤ x < 0.

1.

4. The ultra-narrowband emitting and wavelength-tunable near-infrared II luminescent material at room temperature according to claim 3, characterized in that, The condition is 0.03≤x≤0.

09.

5. A method for preparing the ultra-narrowband emitting and wavelength-tunable near-infrared II luminescent material at room temperature as described in any one of claims 1 to 4, comprising: M Ⅰ Source, M Ⅱ The source, phosphorus source and chromium source are mixed and sintered to obtain a near-infrared II luminescent material with ultra-narrow band emission and tunable wavelength at room temperature.

6. The preparation method according to claim 5, characterized in that, The M Ⅰ Source, M Ⅱ The sources, phosphorus sources, and chromium sources independently include elements, carbonates, phosphates, nitrates, or oxides.

7. The preparation method according to claim 5, characterized in that, The M Ⅰ M in the source Ⅰ M Ⅱ M in the source Ⅱ The molar ratio of phosphorus in the phosphorus source to chromium in the chromium source is 1:1:(1-x):x.

8. The preparation method according to claim 5, characterized in that, The sintering holding temperature is 1000~1500℃, and the sintering holding time is 2~4h.

9. The preparation method according to claim 8, characterized in that, The sintering holding temperature is 1000~1300℃, and the sintering holding time is 3~4h.

10. The application of the ultra-narrowband emitting and wavelength-tunable near-infrared II luminescent material at room temperature as described in any one of claims 1 to 4, or the ultra-narrowband emitting and wavelength-tunable near-infrared II luminescent material at room temperature prepared by the preparation method described in any one of claims 5 to 9, in the fields of luminescence, laser, bioimaging, anti-counterfeiting, and material composition detection and analysis.

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