Synthesis method of infrared light excited Na5Lu (MoO4) 4 matrix green light emitting fluorescent powder

Abstract

The invention provides a synthesis method of infrared light excited Na5Lu (MoO4) 4 matrix green light emitting fluorescent powder. The synthesis method is characterized in that the Na5Lu (MoO4) 4 matrix green light emitting fluorescent powder is light pink powder. The preparation method comprises the following steps: firstly, weighing corresponding oxides, molybdate and the like, mixing the weighed substances, uniformly grinding in an agate mortar, putting into a corundum crucible, putting into a muffle furnace, calcining for 4 hours at 600 DEG C in an air atmosphere, cooling to room temperature, taking out and grinding; according to the green light emitting fluorescent powder prepared by the method, the up-conversion luminous efficiency is improved to a great extent, and the energy consumption is reduced; the fluorescent powder has potential application in the aspects of laser anti-counterfeiting, LED devices and imaging. Er < 3 + > / Yb < 3 + > is doped with a Na5Lu (MoO4) 4 matrix, and molybdate green light emitting fluorescent powder is prepared in an infrared excitation range through energy transfer between ions.

Description

Technical Field

[0001] The present invention belongs to the field of powder material synthesis, and particularly relates to a method for synthesizing phosphor by high-temperature solid-phase reaction in a reducing atmosphere.

Background Art

[0002] In rare-earth ion-doped upconversion inorganic luminescent materials, rare-earth ions act as activators and sensitizers, converting low-frequency photons into high-frequency photons through a multi-photon process, and have received increasing attention due to their wide applications in fields such as fluorescent biological probes, indoor lighting, photocatalysis, bioimaging, and optical temperature measurement. Compared with other trivalent lanthanide ions, since Er 3+ ions can emit bright green light in the green light region, Er 3+ is usually used as the green-light-emitting activator of upconversion materials and has thus been widely studied. However, due to the lack of strong absorption of Er 3+ in the near-infrared (NIR) region, the upconversion materials doped with Er 3+ alone generally have a phenomenon of low luminescence efficiency. To make up for this deficiency, Yb 3+ ions are introduced. Yb 3+ has an appreciable absorption cross-section near 980 nm and can efficiently and accurately transfer the obtained energy to Er 3+ ions, thereby improving the luminescence efficiency of Er 3+ / Yb 3+ co-doped upconversion luminescent materials.

[0003] With the development of technology, rapid and accurate temperature measurement plays an important role in biology and medicine. However, traditional temperature measurement is not suitable for harsh conditions because of the long reaction time and low sensitivity. Nowadays, a new type of temperature measurement method has been widely studied in the field of temperature monitoring - non-contact temperature measurement method. Fluorescence intensity ratio (FIR) is one of the non-contact temperature measurement methods and has been deeply studied in this field. Non-contact optical temperature sensors have the characteristics of high precision, convenient use, fast response, safety and reliability, etc. Different excitation powers have little influence on the FIR technology based on rare-earth ion thermally coupled energy levels (TCEL), so it is considered to be an optical temperature measurement technology with great potential.

[0004] The selection of the host matrix, different doped ions and the change of concentration will all affect the luminescence efficiency, among which the selection of the host matrix plays a primary role. Since molybdate is an oxide with relatively low acoustic field energy and has excellent physical and chemical stability, it has been widely studied in recent years. Molybdate with scheelite structure, A 5 M(MoO 4 ) 4(A = Na, Li, K; M = La, Y, Gd, Dy, Yb, Er), featuring long lifespan, excellent luminescence intensity, good stability, etc.

Summary of the Invention

[0005] The present invention discovers a molybdate matrix with relatively low phonon energy, which can efficiently transfer the energy of Yb 3+ ions to Er 3+ ions, enabling the Er 3+ ions to emit intense green light, and to a large extent, improving the upconversion energy transfer efficiency.

[0006] To achieve the object of the present invention, the present invention provides a method for synthesizing an infrared light-excited Na 5 Lu(MoO 4 ) 4 matrix green light-emitting phosphor, characterized in that the method comprises the following steps:

[0007] Weigh a certain amount of analytical pure Na 2 CO 3 , Lu 2 O 3 , Yb 2 O 3 , (NH 4 ) 6 Mo 7 O 24 ·4H 2 O, Er 2 O 3 , mix the medicines evenly in an agate mortar, and grind for 10 min; put the evenly ground sample into a corundum crucible, place the crucible in a muffle furnace, and calcine at 600 °C for 4 hours in an air atmosphere, then cool to room temperature; take out the sample and grind it evenly to obtain the Na 5 Lu(MoO 4 ) 4 matrix green light-emitting phosphor.

[0008] The certain amount of analytical pure Na 2 CO 3 , (NH 4 ) 6 Mo 7 O 24 ·4H 2 O, Yb 2 O 3 , Lu 2 O 3 , Er 2 O 3The mass ratio is: 0.2650:0.7062:0.0394:(0.1990 - 0.1194):(0 - 0.0383).

[0009] The single - matrix molybdate green - light - emitting phosphor obtained by calcining at 600°C for 4 hours has a heating regime of 80min → 600°C → 240min → 600°C → 180min → 200°C → 120min → 60°C → end.

[0010] An infrared - light - excited Na 5 Lu(MoO 4 ) 4 Synthesis method of a matrix green - light - emitting phosphor, characterized in that the Na 5 Lu(MoO 4 ) 4 Matrix green - light - emitting phosphor is a light - pink powder.

[0011] The beneficial effect of the present invention is that the green - light - emitting phosphor prepared by this method can efficiently transfer the energy of Yb 3+ ions to Er 3+ ions, enabling the Er 3+ ions to emit strong green light visible to the naked eye, greatly improving the up - conversion energy transfer efficiency. When the infrared light with a wavelength of 980nm is used as the excitation wavelength to irradiate Na 5 Lu(MoO 4 ) 4 :Yb 3+ / Er 3+ phosphor, its emission spectrum is obtained, which consists of two spectral bands with significantly different intensities centered at 530nm, 552nm and 669nm, respectively attributed to the 3+ of Er 2 H 11 / 2 → 4 I 15 / 2 , 4 S 3 / 2 → 4 I 15 / 2 , 4 F 9 / 2 → 4 I 15 / 2 energy - level transitions. Yb 3+ acts as a sensitizer, absorbs the energy of the infrared light in the ground state to the excited state, and then effectively transfers it to the 3+ of the activator Er 4 F 7 / 2 energy level. The up - conversion emission intensity increases significantly with the increase of the Er 3+ ion concentration and reaches a peak when x = 0.1. Due to Yb 3+The ions have a large absorption cross-section at 980 nm, and there is a large energy overlap between Yb 3+ and Er 3+ ions. Therefore, energy can be easily transferred from Yb 3+ ions to Er 3+ ions, thereby improving the upconversion emission performance.

Description of the Drawings

[0012] Figure 1 is the emission spectrum of Na 5 Lu(MoO 4 ) 4 :Yb 3+ / Er 3+ phosphor.

[0013] Figure 2 is the XRD pattern of Na 5 Lu(MoO 4 ) 4 :Yb 3+ / Er 3+ .

[0014] Figure 3 is the logarithmic spectrum of different powers of Na 5 Lu(MoO 4 ) 4 :Yb 3+ / Er 3+ .

[0015] Figure 4 is the CIE diagram of Na 5 Lu(MoO 4 ) 4 :Yb 3+ / Er 3+ .

Detailed Embodiments

[0016] The following embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The embodiments of the present invention described and illustrated herein can generally be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0017] Examples 1 to 6

[0018] Weigh the drugs according to the raw material ratio in Table 1, mix the drugs evenly in an agate mortar, and grind for 10 minutes; put the evenly ground sample into a corundum crucible, place the crucible in a muffle furnace, and calcine at 600 °C for 4 hours in an air atmosphere to obtain the phosphor. Its heating regime is 80 min → 600 °C → 240 min → 600 °C → 180 min → 200 °C → 120 min → 60 °C → end, take out and grind evenly to obtain Na 5 Lu(MoO 4 ) 4 matrix green light-emitting phosphor.

[0019] Table 1 Raw material ratio

[0020]

[0021] Place the samples of Example 1 and 2 in the solid sample cell of the FLS980 fluorescence spectrometer, flatten them and then test the fluorescence properties. The excitation wavelength of the sample doped with Er 3+ / Yb 3+ is 980 nm, and the emission wavelengths are 530 nm, 552 nm and 669 nm. As Figure 1 shown, the emission peaks at 530 nm, 552 nm and 669 nm correspond to the 3+ H 2 → 11 / 2 I 4 、 15 / 2 S 4 → 3 / 2 I 4 、 15 / 2 F 4 → 9 / 2 I 4 energy level transitions.

[0022] Perform XRD tests on the samples of Examples 1 to 6 respectively, set the scanning 2θ angle range to be from 10° to 80°, and the scanning step size to be 10° / min. Compare the data obtained from the test with the standard spectrum using MDI Jade 6.0 software. Test the influence of different doping amounts on the crystal structure. The XRD patterns of the samples with different doping amounts are shown in Figure 2 .

[0023] Figure 2 From Figure 2 it can be seen that the XRD pattern of the prepared Na 5 Lu(MoO 4 ) 4 :xEr 3+ / 0.2Yb 3+ is the same as that of the pure phase Na 5 Lu(MoO 4 ) 4Match, the unit cell parameters of the crystal Z = 4, Er 3+ / Yb 3+ Occupy the lattice sites of Lu 3+ Doped Er 3+ / Yb 3+ The phosphor under the excitation of 980 nm infrared light, the up-conversion emission spectrum consists of two strong green emissions (530 and 552 nm) and a relatively weak red emission (669 nm), corresponding to Er 3+ 's 2 H 11 / 2 → 4 I 15 / 2 , 4 S 3 / 2 → 4 I 15 / 2 , 4 F 9 / 2 → 4 I 15 / 2 energy level transitions. When emitting the green light with the strongest peak at 530 nm, it corresponds to the 4f→4f transition of Er 3+ .

[0024] Different powers and emission intensities are as Figure 3 shown. For the three emission peaks (530 nm, 552 nm, 669 nm) of the Na 5 Lu 0.7 (MoO 4 ) 4 :0.10Er 3+ / 0.2Yb 3+ sample, the calculated slopes of the linear fitting are 2.49, 2.59, and 2.15 respectively, all close to 2. It shows that the luminescence processes at 530 nm, 552 nm, and 669 nm are all two-photon absorption processes, further clarifying that the green and red up-conversion emissions of Na 5 Lu 0.8-x (MoO 4 ) 4 :xEr 3+ / 0.2Yb 3+ are all related to the two-photon process.

[0025] The prepared Er 3+ / Yb 3+ doped Na 5 Lu(MoO 4 ) 4 phosphor, with 980 nm as the excitation wavelength, the emission spectra of the co-doped series of phosphors were measured. Na 5 Lu 0.8-x (MoO 4 )4 : xEr 3+ / 0.2Yb 3+ The emission spectrum of Figure 4 is shown as follows. The obtained fluorescence emission spectrum data was imported into the 1931 CIE color coordinate software, and the CIE values of the phosphor are shown in Table 3. Na 5 Lu 0.8-x (MoO 4 ) 4 : xEr 3+ / 0.2Yb 3+ The CIE diagram of Figure 4 is shown as follows.

[0026] Table 2 CIE values of the phosphor

[0027]

[0028]

[0029] Figure 3 shows the variation of the spectral diagram of the Na 5 Lu 0.7 (MoO 4 ) 4 : 0.10Er 3+ / 0.2Yb 3+ sample with the pump power. The UC luminescence intensity (I UC ) increases with the increase of the pump power (P), while the positions of the emission band and emission peak remain unchanged, indicating that there is a correlation between I UC and P. Linear fitting was performed on the three emission peaks (530 nm, 552 nm, 669 nm) of the K 5 Yb 0.9 (MoO 4 ) 4 : 0.10Er sample, and the calculated slopes are 2.49, 2.59, and 2.15 respectively, all of which are close to 2. This indicates that the luminescence processes at 530 nm, 552 nm, and 669 nm are all two-photon absorption processes, and further shows that the green and red upconversion emissions of Na 5 Lu 0.8-x (MoO 4 ) 4 : xEr 3+ / 0.2Yb 3+ are both related to the two-photon process.

[0030] As can be seen from Table 2 and Figure 4 , with the increase of the Er 3+ doping amount, the chromaticity values of the samples gradually deviate from the standard green chromaticity value (0.333, 0.333), indicating that under the excitation of 980 nm infrared light, by doping Er3+ / Yb 3+ A phosphor emitting green light can be prepared.

Claims

1. A method for synthesizing infrared light excited Na5Lu(MoO4)4 matrix green light emitting phosphor, characterized in that: The method comprises the following steps: weighing a certain amount of analytically pure Na2CO3, Lu2O3, Yb2O3, (NH4)6Mo7O 24 ·4H2O, Er2O3, mix the raw materials evenly in an agate mortar and grind for 10 minutes; put the evenly ground sample into a corundum crucible, place the crucible in a muffle furnace, calcine at 600℃ in an air atmosphere for 4 hours, and cool to room temperature; take out the sample and grind it evenly to obtain Na5Lu(MoO4)4 molybdate-based green light emitting phosphor.

2. The method for synthesizing an infrared light excited Na5Lu(MoO4)4 matrix green light emitting phosphor as claimed in claim 1, characterized in that: A certain amount of analytically pure Na2CO3, (NH4)6Mo7O 24 The mass ratio of 4H2O, Yb2O3, Lu2O3 and Er2O3 is: 0.2650: 0.7062: 0.0394: (0.1990~0.1194): (0~0.0383).

3. The method for synthesizing an infrared light excited Na5Lu(MoO4)4 matrix green light emitting phosphor as claimed in claim 1, characterized in that: The calcination at 600°C for 4h described in step a obtains Na5Lu(MoO4)4 molybdate-based green light-emitting phosphor, and the heating regime is 80min→600°C→240min→600°C→180min→200°C→120min→60°C→end.

4. The method for synthesizing an infrared light excited Na5Lu(MoO4)4 matrix green light emitting phosphor as claimed in claim 1, characterized in that The Na5Lu(MoO4)4 molybdate-based green light emitting phosphor is a light pink powder.

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