Blue-light-excited broadband near-infrared sulfide luminescent material and preparation method thereof

Abstract

The invention is applicable to the technical field of fluorescent materials, and provides a blue-light-excited broadband near-infrared sulfide luminescent material, the chemical general formula of the luminescent material is SrSc2-2xCrxS4, and x is greater than or equal to 0.0025 and less than or equal to 0.015. The invention also provides a preparation method of the blue light excited broadband near-infrared sulfide luminescent material. The invention also provides an application of the blue light excited broadband near-infrared sulfide luminescent material. Sc < 3 + > ions are replaced by Cr < 3 + > ions, the emission intensity changes along with the process that the Cr < 3 + > ions replace the Sc < 3 + > ions, the Sc < 3 + > ions can be effectively excited by blue light, the optimal emission wavelength is 1030 nm, and efficient near-infrared broadband emission with the half-peak width of 225 nm is generated under excitation of 468 nm blue light through electron transition from 4T2 to 4A2 of Cr < 3 + >; the adopted raw material resources are rich in reserves, the preparation method is simple and feasible, the physical and chemical stability is good, the fluorescence lifetime is ideal, the material is green and pollution-free, the applicability is very high, the emission bandwidth is wide, the emission wavelength is long, and the material can be widely applied to the technical field of near infrared spectroscopy.

Description

Technical Field

[0001] The invention belongs to the technical field of fluorescent materials, and in particular relates to a broadband near-infrared sulfide luminescent material excited by blue light and a preparation method thereof. Background Art

[0002] Near-infrared light has the advantages of low energy and strong penetration. Near-infrared spectroscopy technology combines the characteristics of fast detection speed, non-destructiveness, and real-time, and has received more and more attention. Among them, the wide spectrum of near-infrared light from 650 to 1050 nm covers the frequency doubling and summing characteristic information of the vibration of hydrogen-containing groups (OH, NH, CH). By scanning the near-infrared wide spectrum of the sample, the characteristic information of the hydrogen-containing groups of organic molecules in the sample can be obtained, which can be widely used in the field of food detection and environmental pollution detection. The wide spectrum or multi-spectrum of 850 to 1200 nm and 1400 to 1800 nm can be applied to medical detection, biometrics, and security monitoring. Therefore, near-infrared light has great application prospects in detection and analysis, biological imaging, night vision lighting, modern agriculture, machine vision and other fields.

[0003] Commonly used near-infrared light sources on the market mainly include incandescent lamps, halogen lamps, fluorescent lamps, short-wave infrared lasers and infrared light-emitting diodes, all of which have inherent defects. Incandescent lamps and halogen lamps are large in size, high in energy consumption, low in efficiency and short in service life; fluorescent lamps are inefficient, contain heavy metal elements and are prone to flickering; short-wave infrared lasers have a small divergence angle, high power consumption and relatively high cost; infrared light-emitting diodes have a narrow emission band, poor thermal stability and high production equipment costs, and cannot be widely used in the field of near-infrared spectroscopy technology. In recent years, due to the invention of the blue light chip InGaN, the research on near-infrared fluorescence conversion light-emitting diodes (NIRpc-LEDs) has developed rapidly. The near-infrared light-emitting diodes obtained by combining blue light LED chips with excellent near-infrared phosphors have the advantages of low cost, adjustable spectrum, long life, high luminous efficiency, high thermal stability, miniaturization, and rapid response, and have gradually become the mainstream light source of near-infrared.

[0004] In NIR pc-LEDs technology, near-infrared luminescent phosphors, as key components, play a vital role in determining the overall optical performance. However, the emission of existing near-infrared emission systems is mainly concentrated in the band less than 1000nm, and there is still a lack of long-wave emission near-infrared phosphor systems; in addition, some existing near-infrared phosphors also have deficiencies such as low luminescence quantum efficiency and poor thermal stability, which limits their application in some fields.

[0005] Therefore, there is an urgent need to develop a near-infrared luminescent material that is excited by blue light and has a long emission wavelength, wide emission bandwidth, high luminous intensity and good stability. Summary of the invention

[0006] The purpose of the embodiments of the present invention is to provide a broadband near-infrared sulfide luminescent material excited by blue light, aiming to solve the problems raised in the above background technology.

[0007] The embodiment of the present invention is implemented as follows: a broadband near-infrared sulfide luminescent material excited by blue light, the chemical formula of the luminescent material is SrSc 2-2x Cr x S4, where 0.0025≤x≤0.015.

[0008] Another object of the present invention is to provide a method for preparing a broadband near-infrared sulfide luminescent material excited by blue light, comprising the following steps: According to the chemical formula SrSc 2-2x Cr x S4, weighing raw materials according to the molar ratio of each element in the raw material Sr:Sc:Cr=1:2-2x:x, wherein 0.0025≤x≤0.015, and the raw materials are compounds containing Sr, Sc, and Cr elements respectively; The weighed raw materials are added with a dispersant and ground thoroughly until the dispersant evaporates to obtain a uniform powder, the ground powder is pre-calcined at 750-850°C for 2-3h, and then a sulfiding gas is introduced, and the powder is fired at 950-1100°C for 2-4h, and then the temperature is slowly lowered to room temperature until it cools, thereby obtaining the blue light-excited broadband near-infrared sulfide luminescent material.

[0009] Preferably, the compound containing the Sr element is one of SrO, SrCO3, Sr(OH)2, SrCl2, and SrSO4.

[0010] Preferably, the compound of the Sc element is one of Sc2O3, Sc(OH)3, Sc2(CO3)3, and Sc2S3.

[0011] Preferably, the compound containing Cr element is one of Cr2O3, CrCl3, and Cr2(CO3)3.

[0012] Preferably, the dispersant is anhydrous ethanol.

[0013] Another object of an embodiment of the present invention is to provide a blue light-excited broadband near-infrared sulfide luminescent material for use in the fields of nondestructive testing, food and agricultural product testing, biomedicine, and environmental pollution detection.

[0014] The embodiment of the present invention provides a blue light excited broadband near-infrared sulfide luminescent material, the chemical formula of which is SrSc 2-2x Cr x S4, Sc in the chemical formula 3+ Cr3+ Ion substitution, with Cr 3+ Ion substitution Sc 3+ The emission intensity of the ions changes accordingly and can be effectively excited by blue light. The optimal emission wavelength is at 1030nm, which comes from Cr 3+ of 4 T2→ 4 The electronic transition of A2 produces efficient near-infrared broadband emission with a half-peak width of 225nm under 468nm blue light excitation; The preparation method provided in the embodiment of the present invention uses abundant raw material resources, is simple and easy to prepare, has good physicochemical stability, ideal fluorescence lifetime, is green and pollution-free, has strong applicability, and has a wide emission bandwidth and long emission wavelength, and can be widely used in the field of near-infrared spectroscopy technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 XRD diagrams of samples prepared in Examples 1-6 and Comparative Example 1 of the present invention; Figure 2 The excitation spectra of the samples prepared in Examples 1-6 of the present invention; Figure 3 This is the emission spectrum of the samples prepared in Examples 1-6 of the present invention under 468nm excitation; Figure 4 This is the emission spectrum of the sample prepared in Example 3 of the present invention under 468nm excitation; Figure 5 This is the variable temperature emission spectrum of the sample prepared in Example 3 of the present invention under 468nm excitation; Figure 6 This is the normalized intensity spectrum of the sample prepared in Example 3 of the present invention under 468nm excitation at variable temperature; Figure 7 The emission spectra of the pc-LED device packaged with the sample prepared in Example 3 of the present invention and the blue LED chip at different currents. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0017] A blue light-excited broadband near-infrared sulfide luminescent material, the preparation method of which comprises the following steps: (1) According to the chemical formula SrSc 2-2x Cr xS4, accurately weigh the corresponding raw materials using an electronic balance according to the molar ratio of each element Sr:Sc:Cr=1:2-2x:x, x is 0.0025≤x≤0.015, wherein the raw materials are Sr source, Sc source, and Cr source respectively; The Sr source is an oxide containing Sr or a compound that can be converted into the oxide; The Sc source is an oxide containing Sc or a compound that can be converted into the oxide; The Cr source is an oxide containing Cr or a compound that can be converted into the oxide; (2) The weighed raw materials are placed in an agate mortar, anhydrous ethanol is added as a dispersant, and the raw materials are fully ground until the alcohol evaporates to obtain a uniform powder. The ground powder is placed in an alumina crucible, and the crucible is placed in a tube furnace at 750-850°C for pre-burning for 2-3 hours. The crucible is then moved into a tube furnace at 950-1100°C and sulfiding gas CS2 is introduced. The crucible is fired in a sulfiding environment for 2-4 hours, and then slowly cooled to room temperature until cooled to obtain the high-efficiency near-infrared luminescent material.

[0018] The specific implementation of the present invention is described in detail below in conjunction with specific embodiments.

[0019] Embodiment 1: A blue light-excited broadband near-infrared sulfide luminescent material, the preparation method of which comprises the following steps: (1) According to the chemical formula SrSc 2-2x Cr x S4 (x=0.0025), the initial raw materials are SrCO3, Sc2O3, Cr2O3, accurately weighed according to the molar ratio of each element, adding an appropriate amount of anhydrous ethanol as a dispersant and grinding for 30 minutes to make the raw materials evenly mixed to obtain a mixed powder; (2) Place the mixed powder into an alumina crucible, pre-sinter the crucible in a 900°C tubular furnace for 2 h, then move the crucible to a 1100°C tubular furnace and introduce sulfide gas CS2 for 3 h, then slowly cool to room temperature until cooled.

[0020] Embodiment 2: A blue light-excited broadband near-infrared sulfide luminescent material, the preparation method of which comprises the following steps: (1) According to the chemical formula SrSc 2-2x Cr x S4 (x=0.005), the initial raw materials are SrCO3, Sc2O3, Cr2O3, accurately weighed according to the molar ratio of each element, and an appropriate amount of anhydrous ethanol is added as a dispersant to fully grind for 30 minutes to mix the raw materials evenly to obtain a mixed powder; (2) Place the mixed powder into an alumina crucible, pre-sinter the crucible in a 900°C tubular furnace for 2 h, then move the crucible to a 1100°C tubular furnace and introduce sulfide gas CS2 for 3 h, then slowly cool to room temperature until cooled.

[0021] Embodiment 3: A blue light-excited broadband near-infrared sulfide luminescent material, the preparation method of which comprises the following steps: (1) According to the chemical formula SrSc 2-2x Cr x S4 (x=0.0075), the initial raw materials are SrCO3, Sc2O3, Cr2O3, accurately weighed according to the molar ratio of each element, adding an appropriate amount of anhydrous ethanol as a dispersant and grinding for 30 minutes to make the raw materials evenly mixed to obtain a mixed powder; (2) Place the mixed powder into an alumina crucible, pre-sinter the crucible in a 900°C tubular furnace for 2 h, then move the crucible to a 1100°C tubular furnace and introduce sulfide gas CS2 for 3 h, then slowly cool to room temperature until cooled.

[0022] Embodiment 4: A blue light-excited broadband near-infrared sulfide luminescent material, the preparation method of which comprises the following steps: (1) According to the chemical formula SrSc 2-2x Cr x S4 (x=0.01), the initial raw materials are SrCO3, Sc2O3, Cr2O3, accurately weighed according to the molar ratio of each element, and an appropriate amount of anhydrous ethanol is added as a dispersant to fully grind for 30 minutes to mix the raw materials evenly to obtain a mixed powder; (2) Place the mixed powder into an alumina crucible, pre-sinter the crucible in a 900°C tubular furnace for 2 h, then move the crucible to a 1100°C tubular furnace and introduce sulfide gas CS2 for 3 h, then slowly cool to room temperature until cooled.

[0023] Embodiment 5: A blue light-excited broadband near-infrared sulfide luminescent material, the preparation method of which comprises the following steps: (1) According to the chemical formula SrSc 2-2x Cr x S4 (x=0.0125), the initial raw materials are SrCO3, Sc2O3, Cr2O3, accurately weighed according to the molar ratio of each element, adding an appropriate amount of anhydrous ethanol as a dispersant and grinding for 30 minutes to make the raw materials evenly mixed to obtain a mixed powder; (2) Place the mixed powder into an alumina crucible, pre-sinter the crucible in a 900°C tubular furnace for 2 h, then move the crucible to a 1100°C tubular furnace and introduce sulfide gas CS2 for 3 h, then slowly cool to room temperature until cooled.

[0024] Embodiment 6: A near-infrared luminescent material, the preparation method of which comprises the following steps: (1) According to the chemical formula SrSc 2-2x Cr x S4 (x=0.015), the initial raw materials are SrCO3, Sc2O3, Cr2O3, accurately weighed according to the molar ratio of each element, adding an appropriate amount of anhydrous ethanol as a dispersant and grinding for 30 minutes to make the raw materials evenly mixed to obtain a mixed powder; (2) Place the mixed powder into an alumina crucible, pre-sinter the crucible in a 900°C tubular furnace for 2 h, then move the crucible to a 1100°C tubular furnace and introduce sulfide gas CS2 for 3 h, then slowly cool to room temperature until cooled.

[0025] Comparative Example 1: A high-efficiency near-infrared luminescent material, the preparation method of which comprises the following steps: (1) According to the chemical formula SrSc 2-2x Cr x S4 (x=0), the initial raw materials are SrCO3 and Sc2O3, accurately weighed according to the molar ratio of each element, adding an appropriate amount of anhydrous ethanol as a dispersant and fully grinding for 30 minutes to make the raw materials evenly mixed to obtain a mixed powder; (2) Place the mixed powder into an alumina crucible, pre-sinter the crucible in a 900°C tubular furnace for 2 h, then move the crucible to a 1100°C tubular furnace and introduce sulfide gas CS2 for 4 h, then slowly cool to room temperature until cooled.

[0026] Performance Test: The samples prepared in Examples 1-6 and Comparative Example 1 were analyzed using powder X-ray diffraction (XRD) technology to obtain XRD patterns as shown in Figure 1 As shown; it can be seen that the samples prepared in Examples 1-6 of the present invention and Comparative Example 1 can all match well with the standard card mp-17678, indicating that the prepared fluorescent materials are all pure phase; through spectral testing, the SrSc prepared in Comparative Example 1 2-2x Cr x S4 (x=0), i.e., SrSc2S4, has no emission signal response under 468nm excitation, indicating that the sample has no near-infrared luminescence; Figure 2 and Figure 3The emission and excitation spectra of the samples prepared in Examples 1-6 are given; it can be seen that the excitation spectra of the samples under 1030nm near-infrared monitoring show a broadband excitation peak in the range of 200 to 750nm, and there is strong excitation near 468nm, indicating that it can be applied to pc-LED excited by blue light LED chips. Under 468nm excitation, the samples show broadband near-infrared emission, ranging from 800nm ​​to around 1600nm, and the main emission peak wavelength is located near 1030nm; Figure 4 The optimal emission wavelength and half-peak width of the emission spectrum of the sample prepared in Example 3 are given; it can be seen that the sample exhibits broadband emission in the near-infrared region under 468nm excitation, with a half-peak width of 225nm and an optimal emission wavelength of 1030nm; the emission wavelength almost covers the entire near-infrared region I and part of the region II, and can be widely used in the field of near-infrared spectroscopy technology; Figure 5 The temperature-dependent luminescence spectrum of the sample prepared in Example 3 is given; it can be seen that the emission intensity of the sample steadily decreases as the temperature increases due to the thermal quenching effect, and the sample exhibits relatively good thermal stability; Figure 6 The normalized intensity spectrum of the sample prepared in Example 3 is given. It can be seen that when the sample is excited at 468nm, when the temperature rises to 423K (150°C), its emission intensity still maintains about 61.8% of the initial intensity. Figure 7 The emission spectra of the LED device prepared by the sample prepared in Example 3 and the commercial blue light chip under different current driving conditions are shown, indicating that the phosphor prepared in the embodiment of the present invention can be successfully prepared into a near-infrared LED device with the commercial blue light chip, and the luminous intensity increases with the increase of current, proving that the near-infrared LED device has good luminous performance.

[0027] In summary, the materials prepared in the embodiments of the present invention have the advantages of broadband emission and emission wavelength, and have great application potential in the fields of biometrics, non-invasive monitoring, food analysis, and environmental testing.

[0028] The above description is only a preferred embodiment of the present invention and is 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 in the protection scope of the present invention.

Claims

1. A broadband near-infrared sulfide luminescent material excited by blue light, characterized in that: The chemical formula of the luminescent material is SrSc 2-2x Cr x S4, where 0.0025≤x≤0.

015.

2. A method for preparing a blue light excited broadband near-infrared sulfide luminescent material as claimed in claim 1, characterized in that: The following steps are involved: According to the chemical formula SrSc 2-2x Cr x S4, weighing raw materials according to the molar ratio of each element in the raw material Sr:Sc:Cr=1:2-2x:x, wherein 0.0025≤x≤0.015, and the raw materials are compounds containing Sr, Sc, and Cr elements respectively; The weighed raw materials are added with a dispersant and ground thoroughly until the dispersant evaporates to obtain a uniform powder, the ground powder is pre-calcined at 750-850°C for 2-3h, and then a sulfiding gas is introduced, and the powder is fired at 950-1100°C for 2-4h, and then the temperature is slowly lowered to room temperature until it cools, thereby obtaining the blue light-excited broadband near-infrared sulfide luminescent material.

3. The method for preparing a blue light excited broadband near-infrared sulfide luminescent material according to claim 2, characterized in that: The compound containing the Sr element is one of SrO, SrCO3, Sr(OH)2, SrCl2, and SrSO4.

4. The method for preparing a blue light excited broadband near-infrared sulfide luminescent material according to claim 2, characterized in that: The compound of the Sc element is one of Sc2O3, Sc(OH)3, Sc2(CO3)3, and Sc2S3.

5. The method for preparing a blue light excited broadband near-infrared sulfide luminescent material according to claim 2, characterized in that: The compound containing Cr element is one of Cr2O3, CrCl3, and Cr2(CO3)3.

6. The method for preparing a blue light excited broadband near-infrared sulfide luminescent material according to claim 2, characterized in that: The dispersant is anhydrous ethanol.

7. An application of the blue light excited broadband near-infrared sulfide luminescent material as claimed in claim 1 in the fields of non-destructive testing, food and agricultural product testing, biomedicine, and environmental pollution detection.

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