Cr < 3 + >-based near-infrared emission fluorescent powder as well as preparation method and application thereof

Abstract

The invention discloses Cr < 3 + >-based near-infrared emission fluorescent powder as well as a preparation method and application thereof, and belongs to the technical field of pressure sensing luminescent materials. The molecular formula of the Cr < 3 + >-based near-infrared emission fluorescent powder is CaSc (1-x) Al (1 + x) SiO6: yCr < 3 + >, x is equal to 0-0.4, and y is equal to 0.005-0.02. The preparation method is simple, the quantum efficiency is high, the raw materials are easy to obtain and low in cost, the prepared Cr < 3 + >-based near-infrared emission fluorescent powder has ultra-wideband near-infrared emission, a disordered structure and relatively high structural rigidity, optical sensing performance is remarkably improved, and the Cr < 3 + >-based near-infrared emission fluorescent powder has high luminous intensity and luminous thermal stability and is suitable for industrial production. The material has reversibility as an optical sensor, structural stability and excellent sensitivity.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure sensing luminescent materials, and in particular to a Cr 3+ Based near-infrared emitting phosphor and its preparation method and application. Background Art

[0002] As a very important basic thermodynamic parameter, pressure is the most concerned indicator in industrial production and high-tech fields. In today's rapidly developing science and technology, in order to meet the diversified needs of various industries for pressure monitoring, the research and development of high-sensitivity pressure sensors is imminent. Fluorescence pressure measurement technology uses the photoluminescence properties of materials for non-contact pressure measurement, which has the advantages of high sensitivity and fast response. Its wide measurement range and high spatial resolution enable it to accurately detect small pressure changes. The chemical and physical stability of fluorescent materials makes them suitable for harsh environments and can be easily integrated with other optical systems. In addition, fluorescence pressure measurement is not affected by electromagnetic interference and is suitable for use in strong electromagnetic field environments. These advantages make fluorescence pressure measurement have broad application potential in aerospace, materials science, biomedicine and other fields.

[0003] Pressure sensing luminescent materials have great application potential, but there are few related studies. In addition, due to the limitations of pressure sensing test conditions, the breadth and depth of research need to be strengthened urgently. Pressure sensing rare earth luminescent materials need to collect a variety of signal parameters, mainly: the red shift distance of the spectrum, the movement distance of the central wavelength, and the intensity change of the spectrum. The rate of spectral red shift mainly depends on the change in interaction caused by the expansion and contraction of electron orbits and the change in the distance between ions under pressure changes. At present, there are still many problems in fluorescence pressure measurement technology, such as low resolution, pressure mode (such as shearing, stretching, bending, etc.) greatly affects the accuracy of the experiment, etc., so more in-depth research is needed.

[0004] Ruby is widely used in high-pressure research as a standard pressure system due to its high sensitivity and accuracy. Pressure calibration can be achieved by using the displacement of the R1 and R2 fluorescence peaks of ruby. However, its sensitivity is low, about 0.365nm / GPa, and the measurement error is large in the range below 10GPa. Therefore, in recent years, the focus of researchers has been on continuously improving the sensitivity by developing sensors with different types of doped ions. However, although researchers have continuously improved the pressure sensing performance by looking for different matrix materials, no effective regulation strategy and universal law have been proposed. At the same time, the sensors reported previously are mainly aimed at high-pressure fields (above 10GPa), but higher pressures will damage many organic substances and cause phase changes in the crystal structure. Therefore, it is urgent to develop sensing materials with fast response speed and high measurement accuracy in the low-pressure area (below 10GPa). Summary of the invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a Cr 3+ The invention discloses a near-infrared emitting phosphor and a preparation method and application thereof to solve the problems of low sensitivity, high cost and low accuracy in low pressure area (below 10GPa) of existing pressure sensing luminescent materials.

[0006] The technical solution of the present invention to solve the above technical problems is as follows:

[0007] A Cr 3+ Based on near-infrared emitting phosphor, the molecular formula of near-infrared emitting phosphor is CaSc 1-x Al 1+x SiO6:yCr 3+ , where x=0-0.4, y=0.005-0.02.

[0008] The beneficial effects of the present invention are as follows: the present invention realizes Cr by designing a disordered structure and improving structural rigidity. 3+ The ultra-sensitive optical sensing performance of the Cr-based near-infrared emitting phosphor is significantly improved. 3+ The base near-infrared emitting phosphor has ultra-wide near-infrared emission, the center of mass of the emission spectrum is located at 950nm, the emission range is 700-1400nm, the luminous intensity and thermal stability are high, the sensing performance is 40 times higher than that of traditional commercial ruby ​​sensors, and the sensitivity is high, reaching 15.08nm / GPa.

[0009] Furthermore, the molecular formula of the near-infrared emitting phosphor is CaScAlSiO6:0.01Cr 3+ or CaSc 0.6 Al 1.4 SiO6:0.01Cr 3+ .

[0010] The above Cr 3+ A method for preparing near-infrared emitting phosphor comprises the following steps:

[0011] (1) Weigh CaCO3, Sc2O3, SiO2, Al2O3 and Cr2O3 according to the molecular formula stoichiometric ratio, mix them evenly with alcohol, and grind them;

[0012] (2) The grinding product of step (1) is sintered, cooled, and ground into powder.

[0013] The beneficial effects of the present invention are as follows: the present invention adopts the traditional high-temperature solid-state reaction synthesis method for preparation, the raw materials are easily available, the cost is low, the production efficiency is high, and it is easy to industrialize production, and it can provide a variety of Cr 3+ This provides new ideas for the preparation of optical sensors.

[0014] Furthermore, in step (1), 4-6% of the mass of the total solid raw material is additionally added to AlF3.

[0015] Furthermore, the grinding time in step (1) is 5-20 min.

[0016] Furthermore, in step (2), the sintering temperature is 1275-1400° C., the sintering time is 3-5 hours each time, and the sintering is repeated 2-4 times.

[0017] The above Cr 3+ Application of near-infrared emitting phosphors in the preparation of optical sensors.

[0018] An optical sensor comprising the above-mentioned Cr 3+ Based near-infrared emitting phosphors.

[0019] The present invention has the following beneficial effects:

[0020] The present invention provides a Cr 3+ Near-infrared emitting phosphor CaSc based 1-x Al 1+x SiO6:yCr 3+ The preparation method thereof has the advantages of simple preparation method, high production efficiency, easy availability of raw materials, low cost, and the prepared Cr 3+ The base near-infrared emitting phosphor has ultra-wide near-infrared emission, a disordered structure and high structural rigidity, which achieves a significant improvement in optical sensing performance. It has high luminous intensity and thermal stability, and has reversibility, structural stability and excellent sensitivity as an optical sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Cr was prepared for Examples 1-2 and Comparative Example 1 3+ Raman spectrum of near-infrared emitting phosphor;

[0022] Figure 2 Cr was prepared for Example 1 and Comparative Example 1 3+ Schematic diagram of the structure of near-infrared emitting phosphor;

[0023] Figure 3 Cr was prepared for Example 1 and Comparative Example 1 3+ Crystal field parameter diagram of near-infrared emitting phosphor;

[0024] Figure 4 Cr was prepared in Example 1 3+ Near infrared spectra of near infrared emitting phosphors under different pressures;

[0025] Figure 5 Cr was prepared for Example 1 and Comparative Example 1 3+The graph of the monotonic movement of the spectral centroid of the near-infrared emitting phosphor when the pressure increases from normal pressure to 7.43 GPa;

[0026] Figure 6 It is the monotonic movement rate of the spectral center of mass of different samples when the pressure increases from normal pressure to 7.43 GPa. DETAILED DESCRIPTION

[0027] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples are only used to explain the present invention and are not used to limit the scope of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0028] Embodiment 1:

[0029] A Cr 3+ A method for preparing near-infrared emitting phosphor comprises the following steps:

[0030] (1) According to the molecular formula CaScAlSiO6:0.01Cr 3+ Weigh CaCO3, Sc2O3, SiO2, Al2O3 and Cr2O3 in a stoichiometric ratio and mix them evenly with alcohol (the mass ratio of solid raw materials to alcohol is 1:3), and add AlF3 with a mass fraction of 5% of the total mass of the solid raw materials, and grind for 10 minutes;

[0031] (2) The ground product of step (1) was placed in a tube furnace and sintered at 1350°C for 4 hours and then cooled. The sintering was repeated twice at the same temperature to ensure sufficient reaction. After natural cooling, the sample was ground into powder to obtain Cr 3+ Based on near infrared emitting phosphor CaScAlSiO6:Cr 3+ .

[0032] Embodiment 2:

[0033] A Cr 3+ A method for preparing near-infrared emitting phosphor comprises the following steps:

[0034] (1) According to the molecular formula CaSc 0.6 Al 1.4 SiO6:0.01Cr 3+ Weigh CaCO3, Sc2O3, SiO2, Al2O3 and Cr2O3 in a stoichiometric ratio and mix them evenly with alcohol (the mass ratio of solid raw materials to alcohol is 1:3), and add AlF3 with a mass fraction of 5% of the total mass of the solid raw materials, and grind for 10 minutes;

[0035] (2) The ground product of step (1) was placed in a tube furnace and sintered at 1350°C for 4 hours and then cooled. The sintering was repeated twice at the same temperature to ensure sufficient reaction. After natural cooling, the sample was ground into powder to obtain Cr 3+ Near-infrared emitting phosphor CaSc based 0.6 Al 1.4 SiO6:Cr 3+ .

[0036] Embodiment 3:

[0037] A Cr 3+ A method for preparing near-infrared emitting phosphor comprises the following steps:

[0038] (1) According to the molecular formula CaSc 0.2 Al 1.2 SiO6:0.01Cr 3+ Weigh CaCO3, Sc2O3, SiO2, Al2O3 and Cr2O3 in a stoichiometric ratio and mix them evenly with alcohol (the mass ratio of solid raw materials to alcohol is 1:3), and add AlF3 with a mass fraction of 5% of the total mass of the solid raw materials, and grind for 10 minutes;

[0039] (2) The ground product of step (1) was placed in a tube furnace and sintered at 1350°C for 4 hours and then cooled. The sintering was repeated twice at the same temperature to ensure sufficient reaction. After natural cooling, the sample was ground into powder to obtain Cr 3+ Near-infrared emitting phosphor CaSc based 0.2 Al 1.2 SiO6:Cr 3+ .

[0040] Comparative Example 1:

[0041] A Cr 3+ A method for preparing near-infrared emitting phosphor comprises the following steps:

[0042] (1) According to the molecular formula CaMgSi2O6:0.01Cr 3+ Weigh CaCO3, SiO2, MgO and Cr2O3 in a stoichiometric ratio and mix them with alcohol (the mass ratio of solid raw materials to alcohol is 1:3) evenly, and add AlF3 with a mass fraction of 5% of the total mass of the solid raw materials, and grind for 10 minutes;

[0043] (2) The ground product of step (1) was placed in a tube furnace and sintered at 1350°C for 4 hours and then cooled. The sintering was repeated twice at the same temperature to ensure sufficient reaction. After natural cooling, the sample was ground into powder to obtain Cr 3+ Based on near infrared emitting phosphor CaMgSi2O6:Cr 3+ .

[0044] Test example:

[0045] Take the Cr prepared in Examples 1-2 and Comparative Example 1 3+ The near-infrared emitting phosphors were characterized. The crystal structure was analyzed by X-ray Rietveld refinement and Raman spectroscopy, and the optical properties of the samples were studied by emission spectra, fluorescence lifetime and pressure-dependent emission spectra.

[0046] According to the Raman spectrum ( Figure 1 ) shows that only CaMgSi2O6:Cr was observed in the three samples. 3+ Located at 670cm -1 The narrow band Raman peak at 1000 nm is the Raman signal generated by the ordered [SiO4] in its structure, and only the stretching vibration of Si-O-Si exists. At the same time, the broad peaks of high-frequency Si-O bonds and low-frequency Al-O bonds are observed to exist in CaScAlSiO6:Cr 3+ and CaSc 0.6 Al 1.4 SiO6:Cr 3+ In phosphors, this is due to the coexistence of three stretching bonds: Al-O-Al, Al-O-Si, and Si-O-Si. The positions of these three bonds are at 625, 650, and 670 cm-1, respectively. -1 The main reason for this is the disordered distribution of Al and Si ions. Low frequency (0-400cm -1 ) are attributed to the vibrations of Ca-O, Sc-O and Mg-O bonds, while the medium frequencies (400-900cm -1 ) corresponds to the vibration of Si-O and Al-O bonds. In addition, only in CaMgSi2O6:Cr 3+ High frequency area (950-1100cm -1 ) observed a unique Si-O-Si vibration. The above results confirm that the CaScAlSiO6:Cr 3+ and CaSc 0.6 Al 1.4 SiO6:Cr 3+ There is a disordered structure in the phosphor.

[0047] according to Figure 2-Figure 6 It can be seen that in the structure of Comparative Example 1, Cr 3+ Ions are usually in a highly symmetrical coordination environment, resulting in a fixed d orbital energy level splitting and a narrow emission spectrum; while the CaScAlSiO6:Cr prepared in Example 1 3+The phosphor structure creates an asymmetric and variable coordination environment, resulting in a more diverse d orbital energy level splitting and a wider emission spectrum. The diversity of the local environment and the change of the field strength in the disordered structure lead to the 3+ The change of ion energy level splitting leads to the broadening of emission spectrum, and the change of intensity and peak position. 3+ The phosphor is in a weak crystal field environment (Dq / B=2.01), which results in ultra-wide near-infrared emission. The centroid of the emission spectrum is located at 950nm, and the emission range is 700-1400nm. Compared with Comparative Example 1, the CaScAlSiO6:Cr 3+ The structural rigidity of the phosphor is improved, thereby suppressing its non-radiative transition and significantly improving the luminous intensity and thermal stability of the luminescent material. Figure 4 and Figure 5 It can be seen that the CaScAlSiO6:Cr prepared in Example 1 3+ The emission spectrum of the phosphor significantly blue-shifts after being subjected to high pressure. When the pressure increases from normal pressure to 7.43 GPa, the center of mass of the spectrum moves monotonically at a rate of 15.08 nm / GPa, which is three times that of comparative example 1 and 40 times higher than the performance of conventional commercial ruby ​​sensors.

[0048] 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, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A Cr 3+ Based on near-infrared emitting phosphors, It is characterized in that The molecular formula of near-infrared emitting phosphor is CaSc 1- x Al 1+x SiO 6 :yCr 3+ , where x=0-0.4, y=0.005-0.

02.

2. The Cr according to claim 1 3+ Based on near-infrared emitting phosphors, It is characterized in that The molecular formula of near-infrared emitting phosphor is CaScAlSiO 6 :0.01Cr 3+ or CaSc 0.6 Al 1.4 SiO 6 :0.01Cr 3+ .

3. Cr according to claim 1 or 2 3+ A method for preparing near-infrared emitting phosphors, It is characterized in that The following steps are involved: (1) Weigh CaCO according to the molecular formula stoichiometric ratio 3 Sc 2 O 3 、SiO 2 、Al 2 O 3 and Cr 2 O 3 Mix well with alcohol and grind; (2) The grinding product of step (1) is sintered, cooled, and ground into powder.

4. Cr according to claim 3 3+ A method for preparing near-infrared emitting phosphors, It is characterized in that In the step (1), 4-6% of the total solid raw material mass of AlF 3 .

5. The Cr according to claim 3 3+ A method for preparing near-infrared emitting phosphors, It is characterized in that The grinding time in step (1) is 5-20 min.

6. The Cr according to claim 3 3+ A method for preparing near-infrared emitting phosphors, It is characterized in that The sintering temperature in step (2) is 1275-1400° C., the sintering time is 3-5 hours each time, and the sintering is repeated 2-4 times.

7. The Cr according to claim 1 or 2 3+ Application of near-infrared emitting phosphors in the preparation of optical sensors.

8. An optical sensor, It is characterized in that Comprising the Cr according to claim 1 or 2 3+ Based near-infrared emitting phosphors.

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