CN114395394B - Near-infrared fluorescent powder and optical device comprising same - Google Patents
Near-infrared fluorescent powder and optical device comprising same Download PDFInfo
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Abstract
The invention relates to near-infrared fluorescent powder and an optical device containing the same, wherein the emission peak position of the near-infrared fluorescent powder is 1270-1330nm. On one hand, the near-infrared fluorescent powder can be excited by blue light and visible light, particularly can be matched with a blue light chip, can enrich the emission coverage band of the near-infrared fluorescent powder, particularly has a wide emission spectrum in the range of 1270-1330nm at the peak position, has the advantage of higher luminous efficiency, and can be effectively applied to application scenes such as an environmental light source, medical food detection, water quality detection, semiconductor material alignment detection and the like; on the other hand, the near-infrared fluorescent powder has absorption in an infrared region, is suitable for manufacturing ink and is used for anti-counterfeiting materials. In the light-emitting device, on the basis of matching with the near-infrared fluorescent powder, the visible light fluorescent powder with the emission wavelength range of 500-780nm and the near-infrared fluorescent powder with the emission wavelength range of 780-1550nm are simultaneously used, so that the light-emitting device has more efficient near-infrared emission and unique spectrum aiming at the application.
Description
Technical Field
The invention relates to the technical field of luminescent materials, in particular to near-infrared fluorescent powder and an optical device comprising the same.
Background
In recent years, applications of near-infrared light sources in the fields of environmental light sources, medical food detection, water quality detection, semiconductor material alignment detection and the like become an industry focus, and near-infrared LEDs have become an international research focus due to a series of advantages of good directivity, low power consumption, small volume and the like. Currently, only corresponding near-infrared semiconductor chips are available on the market for the above-mentioned applications. However, the near infrared chip has the problems of narrow spectrum (half-height width is less than 40 nm), poor tuning performance, high cost, monopoly of foreign countries and the like. In the application field requiring a broadband near-infrared light source, such as the field of semiconductor material alignment detection, the broadband near-infrared light emission with peak positions at 1300nm and 1500nm wave bands is mainly applied, a plurality of near-infrared chips with different emission wave bands need to be compositely packaged, and the technology has high difficulty coefficient in realization: on one hand, the difference of the driving current of the near-infrared LED chips with different light-emitting wave bands is large, and the great difference of the light attenuation of different chips is easy to cause the sudden drop of the thermal stability, thereby influencing the service life of the whole light-emitting device; on the other hand, the existing long-wave band chip (> 1000 nm) technology is immature, especially the chip technology with the emission peak wavelength position located at the 1270-1330nm wave band is difficult to realize, the luminous efficiency is low, the process of packaging by adopting a plurality of chips is complex and uncontrollable, the cost is high, and the application and popularization of the near-infrared LED optical device are limited.
The fluorescence conversion type near-infrared LED is a new near-infrared light source, is realized by adopting a packaging mode of a blue light/visible light chip and high-efficiency near-infrared fluorescent powder, can avoid a short plate of a chip technology, and has the advantages of simple preparation process, low cost, adjustable spectrum and the like, so that the fluorescence conversion type near-infrared LED is widely concerned by the industry. As one of the core materials of the fluorescence conversion type near-infrared LED, the near-infrared fluorescent powder can directly determine the performances of the near-infrared LED device, such as luminous efficiency, spectral continuity and the like, and the application scene. However, the research on the near-infrared fluorescent powder is just started, the material variety is deficient, the spectrum coverage range is single, the luminous efficiency is low, and especially, the near-infrared fluorescent powder which emits with high efficiency and the emission peak wavelength position of which is located at the 1270-1330nm wave band is lacking.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides the near-infrared fluorescent powder and the optical device containing the fluorescent powder, wherein the emission peak position is positioned in the range of 1270-1330nm. The near-infrared fluorescent powder can be excited by blue light and visible light, and particularly can be matched with a blue light chip, so that the technical problems of the prior art that the near-infrared fluorescent powder is deficient in material types, single in spectrum coverage range, low in luminous efficiency and the like are solved. Another object of the present invention is to provide a light emitting device containing the near-infrared light emitting material, which can realize efficient visible-near-infrared emission under blue light excitation, so as to solve the problems of the existing infrared chip technology that the long near-infrared light emitting efficiency is low, especially the chip technology with the emission peak wavelength position located at the 1270-1330nm band is difficult to realize, the light emitting efficiency is low, and the continuity of the emission spectrum of the light emitting device is poor, and widen the application fields of the light emitting device in semiconductor material alignment detection, metal flaw detection, environmental light source, etc.
To achieve the above object, according to one aspect of the present invention, there is provided a near-infrared phosphor, a near-infrared phosphor comprising a composition formula A 2-x-d-m Sr x D d E 1-g-y G g O z yCr, and mM inorganic compound, wherein, the A element is one or two of Ca, ba, mg and Zn; d element is one or two of La, gd, tb, Y and Lu; the element E is one or two of Hf, ge and Si; g element is one or two of Ga, in, sc, al, ce and Bi; m element is one or two of Li, na and K; wherein 0<x≤0.2，0<d≤0.2，0≤g≤0.1，3.7≤z≤4.3，0<y is less than or equal to 0.1, m is less than or equal to 0.2, and the near-infrared fluorescent powder has a cubic crystal systemCa of (2) 2 GeO 4 A crystal structure. Wherein "comma" indicates an element also contained in the material.
Furthermore, in the molecular formula, the element A is Ca and Ba, the mole percentage of Ba occupying the element A is i, and 0% < i is less than or equal to 10%.
Furthermore, in the molecular formula, 0< -x is less than or equal to 0.12.
Furthermore, in the molecular formula, the E element is Hf and Ge element, the mole percentage of Hf occupying the E element is j, and 0% < j is less than or equal to 8%.
Furthermore, the molecular formula is characterized in that G element is one of Ce and Bi, and 0< -G is less than or equal to 0.1.
Further, in the formula, g =4/3y.
Furthermore, in the molecular formula, the element D is one of Y, gd and Lu, and 0-less-than-0D is less than or equal to 0.07.
Further, in the formula, the M element is one of Li, na and K, and M = d.
The invention provides near-infrared fluorescent powder with an emission peak wavelength position located in the range of 1270-1330nm, which can be excited by blue light and visible light, so that the technical problems that the longer near-infrared luminous efficiency is low in the existing infrared chip technology, especially the chip technology with the emission peak wavelength position located in the 1270-1330nm band is difficult to realize and the luminous efficiency is low, the existing near-infrared fluorescent powder material is deficient in variety, single in spectrum coverage range, low in luminous efficiency and the like are solved, and the near-infrared fluorescent powder can be effectively applied to application scenes such as an environmental light source, medical food detection, water quality detection, semiconductor material alignment detection and the like; on the other hand, the near-infrared fluorescent powder has absorption in an infrared region, is suitable for manufacturing ink and is used for anti-counterfeiting materials.
According to another aspect of the present invention, there is provided a light emitting device comprising a light source and a luminescent material comprising a near infrared phosphor as provided hereinbefore in the first aspect of the invention.
Further, the light source is a semiconductor chip with an emission peak wavelength range of 400-460nm or 600-660 nm.
Further, the luminescent material also comprises visible light fluorescent powder with the emission wavelength range of 500-780nm and near infrared fluorescent powder with the emission wavelength range of 780-1550 nm.
Further, the visible light phosphor is a phosphor with an emission wavelength range of 500-780nm, including but not limited to (Mg, zn) (Ca, sr, ba) 3 Si 2 O 8 :Eu 2+ 、(Ca,Sr,Ba)Si 2 N 2 O 2 :Eu 2+ 、β-SiAlON:Eu 2+ 、(Lu,Y,Gd) 3 (Al,Ga) 5 O 12 :Ce 3+ ,Tb 3+ 、(Lu,Y,Gd) 3 (Al,Ga) 5 O 12 :Ce 3+ 、(La,Y,Lu) 3 Si 6 N 11 :Ce 3+ 、(Ca,Sr,Ba) 2 Si 5 N 8 :Eu 2+ 、(Ca,Sr)AlSiN 3 :Eu 2+ 、K 2 (Si,Ge)F 6 :Mn 4+ 、(Sr,Ca,Ba) 4 (Al,Sc,Ga,In) 14 O 25 :Mn 4+ 、(La,Y,Gd,Lu) 3 (Al,Ga)(Ge,Si) 5 O 16 :Mn 4+ 、CaO·Al 2 O 3 ·Ga 2 O 3 ·ZnO·MnO 2 ·Li 2 O、(Lu,Y,Gd) 3 (Al,Ga) 5 O 12 :Mn 4+ One or more of.
Further, the near infrared phosphor is a phosphor with an emission wavelength ranging from 780nm to 1550nm, including but not limited to (La, Y, gd, lu) 3 (Al,Ga) 5 (Ge,Si)O 14 :Cr 3+ ,Yb 3+ ,Er 3+ 、Sc 2 O 3 ·Ga 2 O 3 ·(Cr,Yb,Nd,Er) 2 O 3 、(La,Lu,Y,Gd)(Sc,Ga,Al,In) 3 B 4 O 12 :Cr 3+ ,Yb 3+ ,Er 3+ One or more of.
Wherein, in each substance, the term "indicates that the element in parentheses may be a single component or a solid solution containing more than one element, for example: (Ca, sr) AlSiN 3 :Eu 2+ Is represented as CaAlSiN 3 :Eu 2+ 、SrAlSiN 3 :Eu 2+ And Ca 1-α Sr α AlSiN 3 :Eu 2+ (0<α<1) One or more of them. The near-infrared fluorescent powder disclosed by the invention is matched with the fluorescent powder for use, so that a light-emitting device emits light with high luminous efficiency and excellent spectrum continuity, the problems that a longer near-infrared light-emitting efficiency is low in the existing infrared chip technology, especially the chip technology with the emission peak wavelength position located at the 1270-1330nm waveband is difficult to realize, the light-emitting efficiency is low, and the light-emitting device has poor spectrum continuity are solved, and the application requirements of various traditional and novel fields including application fields of semiconductor material alignment detection, metal flaw detection, environmental light source, medical food detection, water quality detection and the like are met.
The technical scheme of the invention has the following beneficial technical effects:
the invention provides near-infrared fluorescent powder with an emission peak wavelength position located in the range of 1270-1330nm, which can be excited by blue light and visible light, so that the technical problems that the longer near-infrared luminous efficiency is low in the existing infrared chip technology, especially the chip technology with the emission peak wavelength position located in the 1270-1330nm band is difficult to realize and the luminous efficiency is low, the existing near-infrared fluorescent powder material is deficient in variety, single in spectrum coverage range, low in luminous efficiency and the like are solved, and the near-infrared fluorescent powder can be effectively applied to application scenes such as an environmental light source, medical food detection, water quality detection, semiconductor material alignment detection and the like; on the other hand, the near-infrared fluorescent powder has absorption in an infrared region, is suitable for manufacturing ink and is used for anti-counterfeiting materials. The near-infrared fluorescent powder can be used for preparing a light-emitting device, the light-emitting device can obtain near-infrared emission with the emission peak wavelength position located at 1270-1330nm under the excitation of blue light/visible light, particularly under the excitation of the blue light, has the advantage of high luminous efficiency, and can be widely applied to various traditional and novel fields in the application fields of semiconductor material alignment detection, metal flaw detection, environmental light sources, medical food detection, water quality detection and the like. In addition, on the basis of matching with the near-infrared fluorescent powder, the light-emitting device simultaneously uses the visible light fluorescent powder with the emission wavelength range of 500-780nm and the near-infrared fluorescent powder with the emission wavelength range of 780-1550nm, so that the light-emitting device has more efficient near-infrared emission and unique spectrum aiming at the application, and the application field of the light-emitting device is further widened.
Drawings
FIG. 1 is a graph showing the absorption spectrum of a near-infrared phosphor sample prepared in example 1;
FIG. 2 is a graph showing an emission spectrum of a near-infrared phosphor sample prepared in example 1;
FIG. 3 is an XRD pattern of a sample of the near infrared phosphor prepared in example 1;
FIG. 4 (a) is an SEM photograph of a comparative example; FIG. 4 (b) is an SEM photograph of example 1; FIG. 4 (c) is an SEM photograph of example 5; FIG. 4 (d) is an SEM photograph of example 47;
FIG. 5 is a schematic view of a light-emitting device; wherein 1-luminescent material, 2-semiconductor chip, 3-pin, 4-heat sink, 5-base, 6-glass cover.
Detailed Description
It should be noted that, in the present application, the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail with reference to examples.
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the accompanying drawings in combination with the embodiments. It is to be understood that these descriptions are only illustrative and are not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.
As described in the background art, the near infrared chip technology of longer wavelength band in the existing infrared chip technology is immature, the light emitting efficiency is low, especially the chip technology of which the emission peak wavelength position is located at the 1270-1330nm band is difficult to realize, the light emitting efficiency is low, and the research of the near infrared fluorescent powder is just started at present, the material variety is deficient, the spectrum coverage range is single, the light emitting efficiency is low, especially the high-efficiency near infrared fluorescent powder of which the emission peak wavelength position is located at the 1270-1330nm band is absent, so that the application of the fluorescent conversion type near infrared LED device is limited, and in order to solve the problem, the fluorescent powder and the light emitting device with the fluorescent powder are provided.
According to an embodiment of the present invention, there is provided a near-infrared phosphor including a composition formula A 2-x-d-m Sr x D d E 1-g-y G g O z yCr, and mM inorganic compound, wherein, the A element is one or two of Ca, ba, mg and Zn; d element is one or two of La, gd, tb, Y and Lu; the element E is one or two of Hf, ge and Si; the G element is one or two of Ga, in, sc, al, ce and Bi; m element is one or two of Li, na and K; wherein 0<x≤0.2，0<d≤0.2，0≤g≤0.1，3.7≤z≤4.3，0<y is less than or equal to 0.1, m is less than or equal to 0.2, and the near-infrared fluorescent powder has Ca of cubic crystal system 2 GeO 4 A crystal structure. The following theoretical explanations are developed on the premise of having the crystal structure of the phosphor.
The A position of the fluorescent powder must contain alkaline earth metal Sr element with larger activity, sr is the active element, further nucleation and grain growth of the fluorescent powder are facilitated, and experiments prove that Sr element is beneficial to further improving the crystallization property and the single crystal grain size of the fluorescent powder and improving the luminous intensity. Meanwhile, the Sr element is an alkaline earth metal element with a moderate radius, and lattice distortion caused to material lattices after the Sr element and other alkaline earth metal elements are co-doped is small, so that the luminous intensity of the material is favorably and further improved under the condition that the crystal field is not greatly changed, namely, the emission spectrum is almost unchanged. In addition, the D element is one or two of La, gd, tb, Y and Lu, and is doped into the A element position. The La, gd, tb, Y and Lu elements have larger electronegativity, and can easily form covalent bonds with cations, so that the covalent bonds with stronger covalent bonds are formed, the probability of radiative transition of a luminescence center is increased, and the optical properties of the material, such as luminous intensity and the like, are improved; on the other hand, the La, gd, tb, Y and Lu elements have stronger activity, which is beneficial to increasing the probability of radiative transition of the luminescence center and further improving the optical properties of the material, such as luminous intensity and the like. Moreover, the change of the ion radius and electronegativity of La, gd, tb, Y and Lu can cause the change of the original ligand position, thereby changing the crystal field intensity and the mass center displacement of the luminescence center, the emission spectrum of the fluorescent powder is easy to move, and the emission waveband of the near-infrared fluorescent powder can be effectively enriched.
Wherein, the A element in the compound is Ca and Ba element, the mole percentage of Ba occupying the A element is i,0% < i < 10%. The ionic radius of the Ba element is larger than that of the Ca element, so that when the inorganic compound forming the fluorescent powder contains the Ba element, the original ligand site is expanded, the original crystal field environment is weakened, and the light-emitting waveband of the fluorescent powder is moved to a long wave; however, ba element has a smaller electronegativity than Ca element, so that covalent bonding between cations and oxygen ions is reduced, and the shift of the centroid of the luminescence center can be reduced, thereby shifting the luminescence band of the phosphor to a short wavelength. According to the change of the lattice position and the electronegativity, when the mole percentage of Ba occupying the element A is 0% < i ≦ 10%, the luminescent band of the fluorescent powder hardly moves. On the other hand, the Ba element has higher activity than the Ca element, which is beneficial to the nucleation and grain growth of the fluorescent powder, and experiments prove that the A element is the Ca and Ba elements, which is beneficial to improving the crystallization performance and the single crystal particle size of the fluorescent powder and improving the luminous intensity. According to experimental research, when the content of the element Ba is too low, the increasing effect of the element Ba on the fluorescent powder is not obvious, and the luminous intensity is low, when the content of the element Ba is too high, impurities can be generated, the nonradiative transition probability of the fluorescent powder is increased, and the luminous intensity is also low, so that the molar percentage of the element A occupied by the element Ba is i, and preferably 0% < i ≦ 10%.
Furthermore, under the condition that the A element is Ca and Ba element, the mole percentage of Ba occupying the A element is i, and 0% < i ≦ 10%, the compound must contain Sr element and occupy the A lattice site. When the element a is Ca and Ba, the difference in radii between Ca and Ba is large, which easily causes lattice mismatch and distortion, resulting in low luminous efficiency. The Sr element with the element radius between the Ca element and the Ba element is put into the A element lattice position, so that the conditions of lattice mismatch, distortion and the like can be effectively relieved, and the luminous efficiency of the material is improved. Furthermore, the activity of Sr element is larger than that of Ca element, which is beneficial to further nucleation and grain growth of the fluorescent powder, and experiments prove that Sr element is beneficial to further improving the crystallization property and the single crystal particle size of the fluorescent powder and improving the luminous intensity. According to experimental research, when the content of the Sr element is too low, the luminescent intensity is low because the promotion effect of the Sr element on the phosphor is not obvious, and when the content of the Sr element is too high, impurities may be generated, the probability of non-radiative transition of the phosphor is increased, and the luminescent intensity is also low, so that preferably 0< -x > is less than or equal to 0.12.
The element E is one or two of Hf, ge and Si, wherein Si has a small radius, and silicate has the characteristic of wide absorption band, when Si is doped into a host material, the material can be kept to have effective near infrared emission, and meanwhile, the light-emitting waveband can be shifted to short wave. In another preferred embodiment of the present application, the element E is Hf and Ge, hf has a larger radius than Ge, and tends to expand the lattice of the material matrix, so that the crystal field intensity is reduced and the emission wavelength band of the phosphor is shifted to a long wavelength. Moreover, the activity of Hf is greater than Ge, which is beneficial to playing a dissolving-assisting effect in the process of synthesizing the near-infrared fluorescent powder, is beneficial to nucleation and grain growth, and improves the luminous intensity. According to experimental research, when the content of the Hf element is too low, the promotion effect of the Hf on the fluorescent powder is not obvious, the luminous intensity is low, when the content of the Hf element is too high, the phenomena of concentration quenching, impurity occurrence, crystal structure change of a target product and the like can be generated, and non-radiative transition enhancement is caused, so that the luminous intensity is also low, and therefore, the mole percentage of the element E occupied by the Hf is j, and j is 0% < j < 8%.
Furthermore, G element is one of Ce and Bi, and the matrix is independently doped with Cr 3+ Covers the visible wavelength band from blue to red. When the G element is one of Ce and Bi, ce and Bi ions can be doped into the matrix as a sensitizer to show yellow-green light emission, and the emission spectrum and Cr of the sensitizer 3+ The absorption spectra are overlapped, and Ce and Bi ions can be converted into Cr 3+ Energy transfer of (3), increase of Cr 3+ Near infrared luminous intensity. According to experimental research, when the content of the G element is too low, the sensitizer is less, the energy transfer effect is not obvious, the luminous intensity is lower, and when the content of the G element is too high, concentration burst can occurExtinguished to cause an increase in radiationless transition and therefore the luminous intensity is likewise low, and therefore 0 is preferred<g is less than or equal to 0.1. Further, the energy transfer effect is best selected according to the most efficient ratio of activator (luminescent center) and sensitizer, preferably g =4/3y.
Besides, the G element can be one or two of Ga, in, sc and Al and enters an E lattice site. Ga. The original ligand position can be changed due to different ionic radiuses and electronegativity of In, sc and Al elements, so that the crystal field intensity and the mass center displacement of a luminescence center are changed, the emission spectrum of the fluorescent powder is easy to move, and the emission waveband of the near-infrared fluorescent powder can be effectively enriched. Moreover, according to experimental verification, on the premise of ensuring a pure phase structure, g is more than or equal to 0 and less than or equal to 0.1.
The D element is one or two of La, gd, tb, Y and Lu, and is doped into the position of the A element. The La, gd, tb, Y and Lu elements have larger electronegativity, and can easily form covalent bonds with cations, so that the covalent bonds with stronger covalent bonds are formed, the probability of radiative transition of a luminescence center is increased, and the optical properties of the material, such as luminous intensity and the like, are improved; on the other hand, the La, gd, tb, Y and Lu elements have stronger activity, which is beneficial to increasing the probability of radiative transition of the luminescence center and further improving the optical properties of the material, such as luminous intensity and the like. Moreover, the change of the ion radius and electronegativity of La, gd, tb, Y and Lu can cause the change of the original ligand position, thereby changing the crystal field intensity and the mass center displacement of the luminescence center, the emission spectrum of the fluorescent powder is easy to move, and the emission waveband of the near-infrared fluorescent powder can be effectively enriched. Further, preferably, the element D is one of Y, gd and Lu, and enters the site of the A lattice. In rare earth elements, the ionic radii of Y, gd and Lu are smaller, so that the original ligand site shrinkage is facilitated, the crystal field intensity is changed, the emission spectrum of the fluorescent powder is easy to generate short-wave movement, and the emission band of the near-infrared fluorescent powder is enriched; on the other hand, the ionic radius is reduced, so that the distance shrinkage of chemical bonds is facilitated, the material has a more compact spatial structure, and the performances of the material such as luminous intensity and the like are improved. In addition, Y, gd and Lu have larger electronegativity and are easy to react with O 2- Forming chemical bonds with stronger covalency, and the stronger covalency is beneficial to increaseThe probability of radiation transition of the luminescent center further improves the optical properties of the material, such as luminous intensity and the like. And Y, gd and Lu have stronger activity as rare earth elements, are favorable for the nucleation reaction of the material and improve the luminescence property. In particular, gd 3+ Having radiative transitions in the matrix (e.g.: 6 P J - 8 S 7/2 ) The fluorescent powder can provide excitation energy except for an excitation light source for a luminescence center, and is favorable for improving the luminescence intensity of the fluorescent powder. According to experimental research, 0 is preferred<d≤0.07。
Furthermore, the M element is one of Li, na and K, enters the A lattice position, the Li, na and K are all metals, the number of electrons on the outermost layer is 1, and the constraint of atomic cores on electrons outside the core on the outermost layer is small, so that the melting point of the raw materials is low, the fluorescent powder is facilitated to melt, the crystallization performance and the single crystal particle size of the fluorescent powder are improved, and the luminous intensity is improved. Further, the A site is a divalent ion site, and after doping with trivalent D ion, it is easy to form minute defects in the phosphor due to charge mismatch, and these defects result in low luminous intensity. Therefore, the doping of the univalent ions Li, na and K can effectively avoid the defects generated by charge imbalance, carry out charge compensation and fluxing and improve the luminous intensity of the fluorescent powder. From the SEM image, the appearance of the fluorescent powder added with the Li, na and K additives is greatly improved, the fluorescent powder is similar to a sphere, the appearance is more regular, and the improvement of the luminous intensity of the fluorescent powder is facilitated. In addition, the more regular shape is beneficial to the encapsulation of the fluorescent powder, so that the luminescent device has more excellent optical performance. According to valence equilibrium theory and experimental verification, m = d is preferable.
The compound must contain Sr element and occupy A lattice site. When the element a is Ca and Ba, the difference in radii between Ca and Ba is large, which easily causes lattice mismatch and distortion, resulting in low luminous efficiency. The Sr element with the element radius between the Ca element and the Ba element is put into the lattice site of the A element, so that the conditions of lattice mismatch, distortion and the like can be effectively relieved, and the luminous efficiency of the material is improved. Furthermore, the activity of Sr element is larger than that of Ca element, which is beneficial to further nucleation and grain growth of the fluorescent powder, and experiments prove that Sr element is beneficial to further improving the crystallization property and the single crystal particle size of the fluorescent powder and improving the luminous intensity. According to experimental studies, when the content of Sr element is too small, the luminescence intensity is lower because the promotion effect of Sr element on the phosphor is insignificant, and when the content of Sr element is too high, impurity production may be caused, resulting in an increase in the probability of radiationless transition of the phosphor, and the luminescence intensity is also lower, therefore, 0 & ltx & lt 0.2 (preferably 0 & ltx & lt 0.12).
O ions are the only anions in the matrix, and the value range of z is more than or equal to 3.7 and less than or equal to 4.3, so that on one hand, positive and negative charges in the material are balanced, and the material is prevented from generating serious charge imbalance to cause luminescence quenching; on the other hand, oxygen atoms and other cation elements form polyhedrons in the material, each polyhedron takes the oxygen atoms as a link point to form a unit cell structure of the whole material, and the appropriate range of O content can ensure the pure phase structure of the material, so that the structure of the material is not collapsed, the performance of the material is ensured, and otherwise, luminescence quenching can be caused.
The Cr element is used as a luminescence center, namely an activator, and can enable the material to generate near infrared light, according to experimental verification, the value range of the content is preferably less than or equal to 0-1 and is less than or equal to 0-0 y, when the content of the Cr element is too small, the luminescence intensity is low, and when the concentration of the Cr element is too high, luminescence quenching is easily caused.
The M element can be used as a material for charge compensation and fluxing, so that the material has better crystallinity, and the light effect of the material is improved. For assisting experiments, the value range can be more than or equal to 0 and less than or equal to 0.2, and m = d is preferred.
The phosphor described above in the present application may preferably adopt the following preparation method provided in the present application, the preparation method including: step 1), taking simple substances selected from A element, D element, E element, G element, M element, cr element, nitride, oxide or alloy thereof as raw materials, and mixing the raw materials to obtain a mixture; step 2), placing the mixture obtained in the step 1) into a container and roasting the mixture in nitrogen or other non-oxidizing atmosphere to obtain a roasted product, wherein the maximum sintering temperature is 900-1200 ℃, and the heat preservation time is 2-6 hours; and 3) sequentially crushing, washing, sieving and drying the roasted product in the step 2 to obtain the fluorescent powder.
The peak wavelengths of the absorption spectra of the inorganic compounds with the above composition are located in near infrared bands of 400-460nm, 600-660nm and 700-800nm, and the emission peak wavelength covers the range of 1270-1330nm.
In another exemplary embodiment of the present application, there is provided a light emitting device including a phosphor and an excitation light source, the phosphor including the above-described phosphor. Because the fluorescent powder has high luminous intensity and the emission spectrum is easy to regulate and control, the working stability of the luminescent device with the fluorescent powder is high, the service life of the luminescent device is long, and the luminescent device is suitable for various different requirements.
In a preferred embodiment, the excitation light source is a semiconductor light emitting diode light source, and it is further preferred that the excitation light source has a semiconductor chip with an emission peak wavelength of 400-460nm or 600-660 nm.
At present, the commercial LED excitation light source has an excitation wave band within the range, specifically, two excitation light sources are provided, and the light-emitting diode within the wavelength range is beneficial to photoluminescence of fluorescent powder.
In order to further improve the light emitting effect of the light emitting device, it is preferable that the phosphor further includes other phosphors including a visible light phosphor having an emission wavelength range of 500 to 780nm and a near infrared phosphor having an emission wavelength range of 780 to 1550 nm. The visible light phosphor is a phosphor with an emission wavelength range of 500-780nm, including but not limited to (Mg, zn) (Ca, sr, ba) 3 Si 2 O 8 :Eu 2+ 、(Ca,Sr,Ba)Si 2 N 2 O 2 :Eu 2+ 、β-SiAlON:Eu 2+ 、(Lu,Y,Gd) 3 (Al,Ga) 5 O 12 :Ce 3+ ,Tb 3+ 、(Lu,Y,Gd) 3 (Al,Ga) 5 O 12 :Ce 3+ 、(La,Y,Lu) 3 Si 6 N 11 :Ce 3+ 、(Ca,Sr,Ba) 2 Si 5 N 8 :Eu 2+ 、(Ca,Sr)AlSiN 3 :Eu 2+ 、K 2 (Si,Ge)F 6 :Mn 4+ 、(Sr,Ca,Ba) 4 (Al,Sc,Ga,In) 14 O 25 :Mn 4+ 、(La,Y,Gd,Lu) 3 (Al,Ga)(Ge,Si) 5 O 16 :Mn 4+ 、CaO·Al 2 O 3 ·Ga 2 O 3 ·ZnO·MnO 2 ·Li 2 O、(Lu,Y,Gd) 3 (Al,Ga) 5 O 12 :Mn 4+ One or more of. The near infrared fluorescent powder is a fluorescent powder with the emission wavelength range of 780-1550nm, and comprises but is not limited to (La, Y, gd, lu) 3 (Al,Ga) 5 (Ge,Si)O 14 :Cr 3+ ,Yb 3+ ,Er 3+ 、Sc 2 O 3 ·Ga 2 O 3 ·(Cr,Yb,Nd,Er) 2 O 3 、(La,Lu,Y,Gd)(Sc,Ga,Al,In) 3 B 4 O 12 :Cr 3+ ,Yb 3+ ,Er 3+ One or more of. Wherein, in each substance, the term "indicates that the element in parentheses may be a single component or a solid solution containing more than one element, for example: (Ca, sr) AlSiN 3 :Eu 2+ Is represented as CaAlSiN 3 :Eu 2+ 、SrAlSiN 3 :Eu 2+ And Ca 1-α Sr α AlSiN 3 :Eu 2+ (0<α<1) One or more of (b) and (c). The near-infrared fluorescent powder disclosed by the invention is matched with the fluorescent powder for use, so that a light-emitting device emits light with high luminous efficiency and excellent spectrum continuity or special wave bands for special use, the problems that the chip technology with the longer near-infrared luminous efficiency, especially the emission peak wavelength position located at the 1270-1330nm wave band, is difficult to realize, the luminous efficiency is low and the light-emitting device emits spectrum continuity is poor in the existing infrared chip technology are solved, and the application requirements of numerous traditional and novel fields including application fields of semiconductor material alignment detection, metal flaw detection, environmental light source, medical food detection, water quality detection and the like are met.
The following are specific examples of the present invention, and are only for the purpose of illustrating the near-infrared phosphor and the optical device according to the present invention, but the present invention is not limited to the following examples.
Example 1
The near-infrared phosphor provided in this embodiment comprises a compound with a composition formula of Ca 1.79 Sr 0.2 Lu 0.01 Ge 0.94 O 4.005 0.06Cr. Grinding and mixing the weighed oxide raw materials according to the stoichiometric ratio of the chemical formula to obtain a mixture; grinding and uniformly mixing the mixture, calcining at 1250 ℃ for 5 hours, and cooling to obtain a calcined product; and carrying out post-treatment such as crushing, grinding, grading, screening and washing on the obtained roasted product to obtain the near-infrared fluorescent powder intermediate.
The obtained near-infrared sample was subjected to absorption and emission spectrum measurement using a fluorescence spectrometer, and the absorption and emission spectrum of the near-infrared phosphor sample prepared in example 1 is shown in fig. 1-2. As can be seen from the figures 1-2, the obtained near-infrared fluorescent powder sample has effective absorption in the near-infrared wave band ranges of 400-460nm, 600-660nm and 700-800nm, the emission wavelength covers 1150-1500nm, and the emission peak position is 1292nm. The results obtained are shown in Table 1.
TABLE 1
The materials and luminescence properties of the near-infrared phosphors prepared in the above examples 1 to 56 and comparative examples are shown in table 1. Note: the relative luminescence intensity of the examples is the actual luminescence intensity divided by the actual luminescence intensity of the comparative example, multiplied by 100%, based on the luminescence intensity of the comparative example as a reference value of 100%.
By comparing the data of the examples and comparative examples in table 1 above, it can be easily found that: for theA 2-x-d- m Sr x D d E 1-g-y G g O z yCr, mM inorganic compound, wherein, the element A is Ca and Ba; doping a proper amount of active alkaline earth metal Sr element into the lattice site A, and selecting Gd, Y and Lu rare earth elements with smaller radius and larger electronegativity as D elements to enter the position of the element A; the element E is Hf and Ge; the G element selects proper sensitizers Ce and Bi which can emit in a visible light region; adding univalent elements M which can be used as a charge compensator and a cosolvent and can be Li, na and K; the mode can realize the regulation and control of the spectral emission peak position in the range of 1270-1330nm wave band and the improvement of luminous intensity, and more efficient near-infrared broadband emission is obtained.
Comparing example 1 with the comparative example, it is found that Sr must be contained in the compound, and the use of rare earth element with smaller ion radius as D element is beneficial to improving the luminous intensity of the near-infrared phosphor. The activity of Sr element is larger than Ca element, which is beneficial to the nucleation growth of phosphor powder, and improves the crystallization property and the single crystal particle size. Meanwhile, the D element is a rare earth element with a smaller radius, and the D element is one of Y, gd and Lu and enters the A lattice site. In rare earth elements, the ionic radii of Y, gd and Lu are smaller, so that the contraction of the original ligand site is facilitated, the crystal field intensity is changed, the short-wave movement of the emission spectrum of the fluorescent powder is easy to occur, and the emission band of the near-infrared fluorescent powder is enriched; on the other hand, the reduction of the ionic radius is beneficial to the distance contraction of chemical bonds, so that the material has a more compact space structure, and the performances of the material such as luminous intensity and the like are improved. In addition, Y, gd and Lu have larger electronegativity and are easy to react with O 2- And a chemical bond with stronger covalent property is formed, and the stronger covalent bond property is favorable for increasing the probability of radiative transition of a luminescence center, and further improving the optical properties of the material, such as luminous intensity and the like. And, gd 3+ Having radiative transitions in the matrix (e.g.: 6 P J - 8 S 7/2 ) The fluorescent powder can provide excitation energy except for an excitation light source for a luminescence center, and is favorable for improving the luminescence intensity of the fluorescent powder. In addition, Y, gd and Lu as rare earth elements have stronger activity, are beneficial to nucleation and grain growth of materials, and further promoteAnd (4) luminous performance. As can be seen from the SEM image (fig. 4), the example 1 sample has more regular grain growth, larger grains, and can achieve higher luminous intensity than the comparative example.
Comparing examples 1-6, it can be found that the A elements in the compound are Ca and Ba elements, and the mole percentage of Ba occupying the A element is i,0% < i ≦ 10%, which is beneficial to the enhancement of the luminous intensity of the material. The ionic radius of the Ba element is larger than that of the Ca element, so that when the inorganic compound forming the fluorescent powder contains the Ba element, the original ligand site is expanded, the original crystal field environment is weakened, and the light-emitting waveband of the fluorescent powder is moved to a long wave; however, ba element has a smaller electronegativity than Ca element, so that covalent bonding between cations and oxygen ions is reduced, and the shift of the centroid of the luminescence center can be reduced, thereby shifting the luminescence band of the phosphor to a short wavelength. According to the change of the lattice position and the electronegativity, when the mole percentage of Ba occupying the element A is 0% < i ≦ 10%, the luminescent band of the fluorescent powder hardly moves. On the other hand, the Ba element has higher activity than the Ca element, which is beneficial to the nucleation and grain growth of the phosphor, and experiments prove that the A element is Ca and Ba elements, which is beneficial to improving the crystallization property and the single crystal particle size of the phosphor and improving the luminous intensity (fig. 4 shows the SEM images of the embodiment 1 and the embodiment 5). Moreover, according to experimental studies, it is found that when the content of Ba element is too low, the increasing effect of Ba element on the phosphor is not obvious, and the luminous intensity is low, and when the content of Ba element is too high, impurities may be generated, resulting in an increase in the probability of nonradiative transition of the phosphor, and the luminous intensity is also low, so the mole percentage of Ba occupying a element is i, preferably 0% < i ≦ 10% (example 6).
Examples 6 to 8 in comparison, it was found that under the conditions that the A elements were Ca and Ba elements, ba occupied the A element in a molar percentage of i,0% < i.ltoreq.10%, sr element must be contained in the compound to occupy the lattice sites of A, and the Sr content is preferably 0< -x.ltoreq.0.12, contributing to the enhancement of the luminous intensity. When the element a is Ca and Ba, the difference in radii between Ca and Ba is large, which easily causes lattice mismatch and distortion, resulting in low luminous efficiency. The Sr element with the element radius between the Ca element and the Ba element is put into the A element lattice position, so that the conditions of lattice mismatch, distortion and the like can be effectively relieved, and the luminous efficiency of the material is improved. Furthermore, the activity of Sr element is larger than that of Ca element, which is beneficial to further nucleation and grain growth of the fluorescent powder, and experiments prove that Sr element is beneficial to further improving the crystallization property and the single crystal particle size of the fluorescent powder and improving the luminous intensity. According to experimental research, when the content of Sr element is too low, the luminescent intensity is low because the promoting effect of Sr element on phosphor is not obvious, and when the content of Sr element is too high, impurities may be generated, resulting in the increase of the probability of non-radiative transition of phosphor, and the luminescent intensity is also low, therefore, it is preferable that 0< -x > 0.12 (example 8).
By comparing examples 9-15, it can be seen that the E elements are Hf and Ge elements, and preferably the mole percentage of Hf to the E element is j, and that 0% < j ≦ 8% is favorable for increasing the luminous intensity of the near-infrared phosphor. The radius of Hf element is larger than that of Ge element, so that the material matrix lattice is easy to expand, the crystal field strength is reduced, and the emission wave band of the fluorescent powder moves to long wave. Moreover, the activity of Hf is greater than Ge, which is beneficial to playing a dissolving-assisting effect in the process of synthesizing the near-infrared fluorescent powder, is beneficial to nucleation and grain growth, and improves the luminous intensity. According to experimental research, when the content of the Hf element is too low, the promotion effect of the Hf on the fluorescent powder is not obvious, the luminous intensity is low, when the content of the Hf element is too high, the phenomena of concentration quenching, impurity appearance, crystal structure change of a target product and the like can be generated, and the non-radiative transition is enhanced, so that the luminous intensity is also low, and therefore, the mole percentage of the element E occupied by the Hf is j, and j is 0% < j ≦ 8% (example 15).
Comparison of examples 16-28 shows that the G element is one of Ce and Bi, which is beneficial to further improving the luminous efficiency of the phosphor. Matrix alone doped with Cr 3+ Covers the visible wavelength range from blue to red. When the G element is one of Ce and Bi, ce and Bi ions can be doped into the matrix as a sensitizer to show yellow-green light emission, and the emission spectrum and Cr of the yellow-green light emission 3+ The absorption spectra are overlapped, and Ce and Bi ions can be converted into Cr 3+ Energy transfer of, improvingCr 3+ Near infrared luminous intensity. According to experimental research, when the content of the G element is too small, the luminous intensity is also low because the sensitizer is small, the energy transfer effect is not obvious, and the luminous intensity is low, and when the content of the G element is too high, concentration quenching can occur to cause nonradiative transition enhancement, so that 0 is preferred<g.ltoreq.0.1 (examples 25 to 26). Besides, the G element can be one or two of Ga, in, sc and Al, and enters an E lattice position to carry out emission spectrum adjustment. Ga. The original ligand position can be changed due to different ionic radii and electronegativities of In, sc and Al elements, so that the crystal field intensity and the mass center displacement of a luminescence center are changed, the emission spectrum of the fluorescent powder is easy to move, and the emission waveband of the near-infrared fluorescent powder can be effectively enriched. Moreover, according to experimental verification, on the premise of ensuring pure phase, g is more than or equal to 0 and less than or equal to 0.1.
Comparison of examples 29-40 shows that the D element is one or two of La, gd, tb, Y and Lu, and the doping into the A element position can carry out emission spectrum adjustment. The La, gd, tb, Y and Lu elements have larger electronegativity, and can easily form covalent bonds with cations, so that the covalent bonds with stronger covalent bonds are formed, the probability of radiative transition of a luminescence center is increased, and the optical properties of the material, such as luminous intensity and the like, are improved; on the other hand, the La, gd, tb, Y and Lu elements have stronger activity, which is beneficial to increasing the probability of radiative transition of a luminescence center and further improving the optical properties of the material, such as luminous intensity and the like. In addition, the change of La, gd, tb, Y and Lu ionic radius and electronegativity can cause the original ligand position to change, thereby changing the crystal field intensity and the mass center displacement of the luminescence center, the emission spectrum of the fluorescent powder is easy to move, and the emission waveband of the near-infrared fluorescent powder can be effectively enriched. Preferably, the element D is one of Y, gd and Lu, enters the lattice A, and can improve the luminous intensity of the material under the condition of adjusting the emission spectrum. In rare earth elements, the ionic radii of Y, gd and Lu are smaller, so that the contraction of the original ligand site is facilitated, the crystal field intensity is changed, the short-wave movement of the emission spectrum of the fluorescent powder is easy to occur, and the emission band of the near-infrared fluorescent powder is enriched; on the other hand, the reduction of the ionic radius is beneficial to the distance contraction of chemical bonds, so that the material is madeThe material has a more compact spatial structure, and the performances of the material such as luminous intensity and the like are improved. In addition, Y, gd and Lu have larger electronegativity and are easy to react with O 2- And a chemical bond with stronger covalent property is formed, and the stronger covalent bond property is favorable for increasing the probability of radiative transition of a luminescence center, and further improving the optical properties of the material, such as luminous intensity and the like. And Y, gd and Lu have stronger activity as rare earth elements, are favorable for the nucleation reaction of the material and improve the luminescence property. And, gd 3+ Having radiative transitions in the matrix (e.g.: 6 P J - 8 S 7/2 ) The fluorescent powder can provide excitation energy except for an excitation light source for a luminescence center, and is favorable for improving the luminescence intensity of the fluorescent powder. According to experimental research, 0 is preferred<d.ltoreq.0.07 (examples 37 to 40).
According to examples 29 to 30 and 53 to 55, it can be seen that the sensitizer has a better energy transfer effect to the luminescence center and the phosphor has a higher luminescence intensity when g =4/3y.
Comparison of examples 41 to 47 shows that the M element is one of Li, na and K, and enters the A site, so that the crystallinity and the grain size of the material can be further improved, and the luminous intensity can be improved. Li, na and K are all metals, the number of electrons on the outermost layer is 1, and the constraint of atomic cores to electrons outside the core of the outermost layer is small, so that the melting point of the raw materials is low, the melting-assisting effect on the fluorescent powder is achieved, the crystallization performance and the single crystal particle size of the fluorescent powder are improved, and the luminous intensity is improved. Further, the A site is a divalent ion site, and after doping with trivalent D ion, it is easy to form minute defects in the phosphor due to charge mismatch, and these defects result in low luminous intensity. Therefore, the doping of the univalent ions Li, na and K can effectively avoid the defects generated by charge imbalance, carry out charge compensation and fluxing and improve the luminous intensity of the fluorescent powder. From the SEM image, it can be found that the shape of the fluorescent powder added with the Li, na and K auxiliary agents is greatly improved, the fluorescent powder is in a similar spherical shape, the shape is more regular, and the improvement of the luminous intensity of the fluorescent powder is facilitated (figure 4). In addition, the more regular shape is beneficial to the encapsulation of the fluorescent powder, so that the luminescent device has more excellent optical performance. According to experimental verification, m = d (examples 44, 46) is preferred.
The following embodiments are light emitting devices made by using the broadband near-infrared phosphor of the present invention as a light emitting material, and take the structure of a light emitting device known in the art as an example, and in some embodiments, as shown in fig. 5, the light emitting device includes a light emitting material 1, a semiconductor chip 2, a lead 3, a heat sink 4, a base 5, and a glass cover 6. The heat sink 4 is fixed on the base 5, the semiconductor chip 2 is fixed on the heat sink 4, the lead pins 3 are led out, the luminescent material 1 covers the semiconductor chip 2, the visible light luminescent material layer 6 covers the near-infrared luminescent material layer 1, and the glass cover 6 covers the outside of the luminescent material 1.
Example 57
The light emitting device described in this embodiment uses a semiconductor chip with a wavelength of 460nm as a light source, and the light emitting material is a near-infrared phosphor having a chemical formula of Ca 1.84 Sr 0.08 Lu 0.04 Ge 0.817 Hf 0.043 Bi 0.08 O 3.98 :0.06Cr,0.04Na + Accurately weighing raw materials according to a stoichiometric ratio, and grinding and mixing the weighed raw materials to obtain a mixture; calcining the mixture at 1200 ℃ for 5h, and cooling to obtain a calcined product; and (3) carrying out crushing, grinding, grading, screening and washing on the obtained roasted product, and then treating to obtain the near-infrared fluorescent powder. In addition, in this embodiment, la with an emission wavelength range of 500-780nm is selected 2.85 Si 6 N 11 :0.15Ce 3+ 、(Ca 0.2 Sr 0.8 ) 0.95 AlSiN 3 :0.05Eu 2+ And near infrared fluorescent powder (La, Y, gd, lu) with emission wavelength range of 780-1550nm 3 (Al,Ga) 5 (Ge,Si)O 14 :Cr 3+ ,Yb 3+ ,Er 3+ 、Sc 2 O 3 ·Ga 2 O 3 ·(Cr,Yb,Nd,Er) 2 O 3 . In the embodiment, the mass ratio of the near-infrared luminescent material to the silica gel is 2.8:1, uniformly mixing, stirring and defoaming to obtain a mixture of the visible light fluorescence conversion layer, covering the mixture on the surface of the LED chip layer in a spraying mode, and baking to solidify the mixture into the visible light fluorescence layer. And then mixing the visible light luminescent material and the silica gel according to the mass ratio of 0.3:1, uniformly mixing and covering the mixture on the near-infrared fluorescence conversion layer, curing, and packaging to obtain the required LED light-emitting device. The light source of the optical device provided in each example was turned on with a constant current (forward voltage 2.683V, forward current 60.0 mA) using a high-precision fast spectral radiometer integrating sphere test system, and the luminous power of the light-emitting device described in this example was 82.10mW.
The performance parameters of the optical device obtained by packaging the near-infrared luminescent material in each embodiment of the invention are shown in table 2.
TABLE 2
From the above table 2, it can be seen that the phosphor in the optical device of the present invention can be effectively excited by the LED chip, and the optical device combining the visible light luminescent material and the near infrared luminescent material can realize dual emission of visible light in a wavelength band of 500-780nm and near infrared in a wavelength band of 780-1550nm, and the device has suitable luminous flux, continuous emission spectrum or special waveform emission spectrum, and has great application prospects in environmental light source, medical food detection, water quality detection and semiconductor material alignment detection.
The powder can be applied to the field of semiconductor material alignment detection after being matched with near-infrared fluorescent powder with the peak position of about 1500 nm; the powder provided by the invention is matched with a plurality of devices which are provided with wide-band/narrow-band emission fluorescent powder in the red light and 780-1550nm region, and can be used in the fields of medical food detection, water quality detection and the like; the powder is matched with a plurality of fluorescent powders which have broadband/narrowband emission in visible light of 500-780nm wave band and near infrared of 780-1550nm wave band, and can be used in the fields of environmental light sources, medical food detection, water quality detection and the like.
It should be understood that the above-described embodiments of the present invention are merely illustrative of or explaining the principles of the invention and are not to be construed as limiting the invention. Therefore, any modification, equivalent replacement, improvement and the like made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. Further, it is intended that the appended claims cover all such variations and modifications as fall within the scope and boundaries of the appended claims or the equivalents of such scope and boundaries.
Claims (10)
1. A near-infrared phosphor is characterized in that the near-infrared phosphor comprises a composition formula A 2-x-d-m Sr x D d E 1-g- y G g O z yCr, mM inorganic compound, wherein,
the element A is one or two of Ca, ba, mg and Zn;
the D element is one or two of La, gd, tb, Y and Lu;
the element E is one or two of Hf, ge and Si;
the G element is one or two of Ga, in, sc, al, ce and Bi;
m element is one or two of Li, na and K;
wherein 0<x≤0.2，0<d≤0.2，0≤g≤0.1，3.7≤z≤4.3，0<y is less than or equal to 0.1, m is less than or equal to 0 and less than or equal to 0.2, and the near-infrared fluorescent powder has Ca of a cubic crystal system 2 GeO 4 A crystal structure.
2. The near-infrared phosphor of claim 1, wherein the element a is Ca and Ba, and the molar percentage of Ba in the element a is i,0% < i ≦ 10%.
3. The near-infrared phosphor of claim 2, wherein 0<x ≦ 0.12.
4. The near-infrared phosphor of claim 1, wherein the elements E are elements Hf and Ge, the mole percentage of Hf to the elements E is j, and 0% < j ≦ 8%.
5. The near-infrared phosphor of claim 3 or 4, wherein the G element is one of Ce and Bi, and 0-t G ≦ 0.1.
6. The near-infrared phosphor of claim 5, characterized in that g =4/3y.
7. The near-infrared phosphor of claim 6, wherein D is one of Y, gd, and Lu, and 0< -D is less than or equal to 0.07.
8. The near-red phosphor of claim 7, wherein M is one of Li, na, and K, and M = d.
9. A light-emitting device comprising a light source and a luminescent material, wherein the luminescent material comprises the near-infrared phosphor of any one of claims 1-8.
10. The light-emitting device according to claim 9, wherein the light source is a semiconductor chip having an emission peak wavelength in a range of 400 to 460nm or 600 to 660nm, and the light-emitting material further comprises a visible light phosphor having an emission wavelength in a range of 500 to 780nm and a near infrared phosphor having an emission wavelength in a range of 780 to 1550 nm.
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| JP2019087711A (en) * | 2017-11-10 | 2019-06-06 | 三菱ケミカル株式会社 | Infrared light-emitting device and phosphor |
| CN112824480A (en) * | 2019-11-20 | 2021-05-21 | 西安鸿宇光电技术有限公司 | Near-infrared luminescent material, preparation method thereof and luminescent device containing material |
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