Rare earth doped calcium lanthanum borate crystal, preparation method and application thereof, and white light emission and color temperature regulation and control method

Abstract

The invention relates to the technical field of solid photoluminescence materials, and provides a rare earth doped calcium lanthanum borate crystal, a preparation method and application thereof, and a white light emission and color temperature regulation method. According to the invention, the lanthanum calcium borate crystal is used as a rare earth ion doped matrix, and the rare earth ions can realize high luminous efficiency and fluorescence quantum yield by virtue of rich energy level structures and excellent optical characteristics. The luminous color temperature can be effectively regulated and controlled by adjusting the concentration of doped ions. In addition, the rare earth doped calcium lanthanum borate crystal provided by the invention is high in laser damage threshold and stable in physicochemical property, and the service life of the rare earth doped calcium lanthanum borate crystal is prolonged. When the rare earth doped calcium lanthanum borate crystal is used as a white light emitting substrate, white light output can be realized directly through ultraviolet light and visible light LD (or LED) pumping. Compared with a traditional solid white light material, the rare earth doped calcium lanthanum borate crystal shows excellent color rendering property and longer luminous life, and an optical pumping system is simple in structure.

Description

Technical Field

[0001] The invention relates to the technical field of solid photoluminescent materials, and in particular to a rare earth doped calcium lanthanum borate crystal, a preparation method and application thereof, and a white light luminescence and color temperature control method. Background Art

[0002] Solid white light emitting diode (LED) and white light laser diode (LD) materials have the advantages of high brightness, low energy consumption, long life and environmental friendliness, and have potential application prospects in lighting and display.

[0003] At present, the most common solution to obtain white light LED (or LD) is through fluorescence conversion, that is, phosphor conversion to obtain white light LED (or LD). The main methods include: combining blue light LED (or LD) with yellow phosphor, part of the blue light is used to excite the phosphor to emit yellow light, and the residual blue light is mixed with the yellow light to form white light; combining blue light LED (or LD) with red and green phosphors, and the red light and green light emitted by the phosphor are mixed with the residual blue light to form white light; combining ultraviolet light or visible light LED (or LD) with blue, green and red three-primary color phosphors, and using appropriate wavelengths to excite the three-primary color phosphors to emit red light, green light and blue light respectively, so as to mix to form white light.

[0004] However, the above-mentioned white light luminescence method is easily affected by the performance of the phosphor itself. For example, the uneven particle size and uneven distribution of the phosphor lead to poor luminescence uniformity, low light conversion efficiency, relatively large light decay, and poor stability. These have hindered the development of white light LEDs (or LDs), especially with the development of high-power white light LEDs (or LDs), exposing the shortcomings of low luminescence efficiency and short life of phosphor materials.

[0005] In summary, providing a new type of fluorescent material with high luminous efficiency, good stability and high resistance to laser damage is of great significance for the development of white light LEDs (or LDs). Summary of the invention

[0006] In view of this, the present invention provides a rare earth doped calcium lanthanum borate crystal and its preparation method and application, white light luminescence and color temperature control method. The rare earth doped calcium lanthanum borate crystal provided by the present invention has excellent nonlinear optical properties, can provide suitable lattices for activated ions to generate luminescence operation without changing the structural properties of the matrix crystal itself, and the rare earth doped calcium lanthanum borate crystal provided by the present invention has a high laser damage threshold (11.5GW / cm 2 ), stable physical and chemical properties, good thermal and mechanical properties (6.5Mohs).

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] A rare earth-doped calcium lanthanum borate crystal, the chemical formula of which is shown in Formula I or Formula II:

[0009] (Re x La 1-x )2CaB 10 O 19 Formula I; (Re x Re y 'La 1-x-y )2CaB 10 O 19 Formula II;

[0010] In Formula I and Formula II: Re and Re' are doped rare earth ions, and the doped rare earth ions are lanthanide rare earth ions except La, the value range of x is 0.001 to 0.999, and the value range of y is 0.001 to 0.999.

[0011] Preferably, the doped rare earth ions include Dy 3+ 、Eu 3+ or Sm 3+ .

[0012] Preferably, the chemical formula of the rare earth-doped calcium lanthanum borate crystal is as shown in Formula I-1, Formula I-2 or Formula II-1:

[0013] (Dy x La 1-x )2CaB 10 O 19 Formula I-1;

[0014] (Eu x La 1-x )2CaB 10 O 19 Formula I-2;

[0015] (Eu x Sm y La 1-x-y )2CaB 10 O 19 Formula II-1.

[0016] The present invention also provides a method for preparing the rare earth-doped calcium lanthanum borate crystals described in the above scheme, comprising the following steps:

[0017] According to the stoichiometric ratio of Formula I or Formula II, a polycrystalline raw material and a flux are mixed and sintered to obtain a mixed polycrystalline powder;

[0018] After the mixed polycrystalline powder is melted, crystal growth and temperature reduction annealing are performed in sequence to obtain the rare earth doped calcium lanthanum borate crystal.

[0019] Preferably, the polycrystalline raw material includes a lanthanum-containing compound, a rare earth ion-doped compound, a calcium-containing compound and a boron-containing compound; the flux includes one or more of a calcium-containing compound, a lithium-containing compound, a boron-containing compound and a molybdenum-containing compound;

[0020] The sintering temperature is 100-1200°C and the holding time is 1-240h;

[0021] The crystal growth method includes a top seed method, an immersion seed method, a pulling method, a flux method or a floating zone method; the cooling rate of the crystal growth process is 0.001 to 30°C / 24h, and the rotation speed is 0.001 to 120rad / min; the cooling rate of the cooling annealing is 10 to 15°C / h.

[0022] The present invention also provides the use of the rare earth-doped calcium lanthanum borate crystals described in the above scheme or the rare earth-doped calcium lanthanum borate crystals prepared by the preparation method described in the above scheme in white light luminescence and white light color temperature control.

[0023] The present invention also provides a white light device, which includes a white light LED device or a white light LD device; the white light LED device includes a pump source and a fluorescent crystal; the white light LD device includes a pump source, a fluorescent crystal and an optical resonator; the fluorescent crystal in the white light LED device and the white light LD device is the rare earth-doped calcium lanthanum borate crystal described in the above scheme or the rare earth-doped calcium lanthanum borate crystal prepared by the preparation method described in the above scheme.

[0024] The present invention also provides a white light luminescence method, which uses a pump source to pump rare earth-doped calcium lanthanum borate crystals to achieve white light luminescence; the rare earth-doped calcium lanthanum borate crystals are the rare earth-doped calcium lanthanum borate crystals described in the above scheme or the rare earth-doped calcium lanthanum borate crystals prepared by the preparation method described in the above scheme.

[0025] Preferably, the pump source is an LED pump source or an LD pump source;

[0026] When the rare earth doped calcium lanthanum borate crystal is (Dy x La 1-x )2CaB 10 O 19 When the crystal is used, the pump source is one or more of ultraviolet light LD, ultraviolet light LED, blue light LD and blue light LED;

[0027] When the rare earth doped calcium lanthanum borate crystal is (Eu x La 1-x )2CaB10 O 19 Crystal or (Eu x Sm y La 1-x-y )2CaB 10 O 19 When the crystal is used, the pump source is one or more of ultraviolet light LD, blue light LD, green light LD, ultraviolet light LED, blue light LED and green light LED.

[0028] The present invention also provides a method for regulating the color temperature of white light luminescence, wherein the color temperature is regulated by adjusting the concentration of rare earth ions doped in rare earth-doped calcium lanthanum borate crystals; the rare earth-doped calcium lanthanum borate crystals are the rare earth-doped calcium lanthanum borate crystals described in the above scheme or the rare earth-doped calcium lanthanum borate crystals prepared by the preparation method described in the above scheme.

[0029] The present invention provides a rare earth doped calcium lanthanum borate crystal, the chemical formula of which is shown in Formula I or Formula II: x La 1-x )2CaB 10 O 19 Formula I; (Re x Re y 'La 1-x-y )2CaB 10 O 19 Formula II; In Formula I and Formula II: Re and Re' are doped rare earth ions, the value range of x is 0.001 to 0.999, and the value range of y is 0.001 to 0.999. The present invention uses calcium lanthanum borate crystals (chemical formula La2CaB 10 O 19 , referred to as LCB) is a matrix doped with rare earth ions. The La atoms and O atoms in the matrix crystal can form LaO 10 At the same time, the Ca atoms in the matrix crystal form CaO8 ligands with O atoms. Since rare earth ions belong to the same lanthanide series and have similar radii, La 3+ The ion site is easily replaced to form a new ReO 10 Ligand; in addition Ca 2+ The ion radius is similar to that of rare earth ions. At a certain rare earth ion doping concentration, some rare earth ions will occupy the Ca 2+Lattice site, forming another ReO8 ligand, realizing double lattice site substitution, and the crystal structure itself is not changed. The rare earth-doped calcium lanthanum borate crystal provided by the present invention combines the advantages of borate crystals and rare earth ions, has a high laser damage threshold, stable physical and chemical properties, good thermal and mechanical properties, which is beneficial to prolong its service life, and also has the luminescence characteristics of rare earth ions and a high fluorescence quantum yield; and the crystal is easy to obtain large-size, high-optical quality single crystals through a single crystal growth process, which is very suitable for large-scale white light LED and LD packaging processing. In summary, the present invention provides a new working medium for the development of solid white light LEDs and LDs. The rare earth-doped calcium lanthanum borate crystals of the present invention can achieve efficient and high-quality white light luminescence, which is of great significance for the development of high-power solid white light LEDs and LDs.

[0030] The present invention also provides a white light device, including a white light LED device or a white light LD device; the white light LED device includes a pump source and a fluorescent crystal; the white light LD device includes a pump source, a fluorescent crystal and an optical resonator; the fluorescent crystal in the white light LED device and the white light LD device is the rare earth doped calcium lanthanum borate crystal described in the above scheme or the rare earth doped calcium lanthanum borate crystal prepared by the preparation method described in the above scheme. The present invention constructs a simple optical pumping system, and uses LED (or LD) to directly pump the crystal to obtain white light. Compared with traditional solid white light materials, the rare earth doped calcium lanthanum borate crystal of the present invention exhibits more superior color rendering, longer luminescence life, and the optical pumping system has a simple structure.

[0031] The present invention also provides a white light luminescence method and a white light luminescence color temperature regulation method. The present invention uses calcium lanthanum borate crystal as a white light luminescence crystal matrix, utilizes the absorption energy level of rare earth ions, uses rare earth ion transition channels, and realizes the generation of white light through ultraviolet and visible light band LD (or LED) pumping, and realizes the regulation of white light luminescence color temperature by regulating the doping concentration of rare earth ions. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A diagram showing a white light LED device including a pump source and a fluorescent crystal in an embodiment of the present invention;

[0033] Figure 2 A white light LD device including a pump source, a fluorescent crystal and an optical resonant cavity is shown in the embodiment of the invention;

[0034] Figure 3 X-ray spectra of 3% Dy:LCB, 5% Dy:LCB, 3% Eu:LCB, 7% Eu:LCB, and 10% Eu:LCB crystals in the embodiments of the present invention;

[0035] Figure 4The excitation spectrum of 3% Dy:LCB and 5% Dy:LCB crystals in the embodiment of the present invention under the detection wavelength of 574nm;

[0036] Figure 5 The fluorescence spectra of 3% Dy:LCB and 5% Dy:LCB crystals in the embodiment of the present invention under the excitation wavelengths of 355nm and 445nm;

[0037] Figure 6 The fluorescence quantum yield of 3% Dy:LCB and 5% Dy:LCB crystals in the embodiment of the present invention under the excitation wavelength of 355nm and 445nm;

[0038] Figure 7 The chromaticity coordinate diagram of 3% Dy:LCB and 5% Dy:LCB crystals under excitation at excitation wavelengths of 355nm and 445nm in the embodiment of the present invention;

[0039] Figure 8 The excitation spectra of 3% Eu:LCB, 7% Eu:LCB and 10% Eu:LCB crystals in the embodiment of the present invention under the detection wavelength of 574nm;

[0040] Fig. 9 The fluorescence spectra of 3% Eu:LCB, 7% Eu:LCB and 10% Eu:LCB crystals in the embodiment of the present invention under the excitation wavelengths of 465nm and 532nm;

[0041] Fig.10 The fluorescence quantum yield spectra of 3% Eu:LCB, 7% Eu:LCB and 10% Eu:LCB crystals in the embodiment of the present invention under excitation wavelengths of 465nm and 532nm;

[0042] Fig.11 The chromaticity coordinate diagram of 3% Eu:LCB, 7% Eu:LCB and 10% Eu:LCB crystals in the embodiment of the present invention under the excitation wavelength of 355nm;

[0043] Fig.12 The chromaticity coordinate diagram of 3% Eu:LCB, 7% Eu:LCB and 10% Eu:LCB crystals in the embodiment of the present invention under the excitation wavelengths of 465nm and 532nm;

[0044] Fig.13 This is a chromaticity coordinate diagram of 7% Eu: 3% Sm: LCB crystal in an embodiment of the present invention under excitation wavelengths of 355 nm, 465 nm and 532 nm;

[0045] Fig.14The white light experimental phenomenon diagram of 3% Dy:LCB, 5% Dy:LCB, 3% Eu:LCB, 7% Eu:LCB, and 10% Eu:LCB crystals in the embodiment of the present invention;

[0046] Fig.15 This is a diagram of the white light LD luminescence experiment phenomenon of 5% Dy:LCB crystal. DETAILED DESCRIPTION

[0047] The present invention provides a rare earth-doped calcium lanthanum borate crystal, the chemical formula of which is shown in Formula I or Formula II:

[0048] (Re x La 1-x )2CaB 10 O 19 Formula I; (Re x Re y 'La 1-x-y )2CaB 10 O 19 Formula II;

[0049] In Formula I and Formula II: Re and Re' are doped rare earth ions, and Re and Re' are not La, the value range of x is 0.001 to 0.999, and the value range of y is 0.001 to 0.999.

[0050] In the present invention, in Formula I and Formula II, the value range of x is preferably 0.005-0.5, more preferably 0.03-0.1, specifically 0.03, 0.05, 0.07 or 0.1; the value range of y in Formula II is preferably 0.005-0.5, more preferably 0.03-0.1, specifically 0.03, 0.05, 0.07 or 0.1.

[0051] In the present invention, Re and Re' are doped rare earth ions, and Re and Re' are different; the doped rare earth ions preferably include Dy 3+ 、Eu 3+ or Sm 3+ .

[0052] In the present invention, the chemical formula of the rare earth-doped calcium lanthanum borate crystal is preferably as shown in Formula I-1, Formula I-2 or Formula II-1:

[0053] (Dy x La 1-x )2CaB 10 O 19 Formula I-1;

[0054] (Eu x La 1-x )2CaB 10 O19 Formula I-2;

[0055] (Eu x Sm y La 1-x-y )2CaB 10 O 19 Formula II-1.

[0056] In the present invention, Dy 3+ 、Eu 3+ or Sm 3+ Substituting La in the matrix 3+ or Ca 2+ The lattice sites occupied by the luminescent crystal materials are respectively constituted by formula I-1, formula I-2 and formula II-2. In the specific embodiment of the present invention, Re can also be selected according to actual needs. x and Re y ' is one or two of other lanthanide rare earth ions.

[0057] In the present invention, Formula I, Formula II, Formula I-1, Formula I-2 and Formula II-1 are all theoretical chemical formulas of rare earth-doped calcium lanthanum borate crystals. During subsequent preparation, the ratio of each raw material is determined according to the theoretical chemical formula.

[0058] In a specific embodiment of the present invention, the rare earth doped calcium lanthanum borate crystal is preferably one or more of the crystals shown in the following chemical formula (wherein the doping concentration is the theoretical doping concentration): (Dy 0.03 La 0.97 )2CaB 10 O 19 、(Dy 0.05 La 0.95 )2CaB 10 O 19 、(Eu 0.03 La 0.97 )2CaB 10 O 19 、(Eu 0.07 La 0.93 )2CaB 10 O 19 、(Eu 0.1 La 0.9 )2CaB 10 O 19 、(Eu 0.07 Sm 0.03 La 0.90 )2CaB 10 O 19 , respectively recorded as 3% Dy:LCB, 5% Dy:LCB, 3% Eu:LCB, 7% Eu:LCB, 10% Eu:LCB, 7% Eu:3% Sm:LCB.

[0059] In the present invention, the rare earth doped calcium lanthanum borate crystal has a high laser damage threshold, good mechanical properties, stable physical and chemical properties and good thermal properties, which is of great significance for improving the luminous efficiency of white light LEDs and LDs and extending their service life.

[0060] The present invention also provides a method for preparing the rare earth-doped calcium lanthanum borate crystals described in the above scheme, comprising the following steps:

[0061] According to the stoichiometric ratio of Formula I or Formula II, a polycrystalline raw material and a flux are mixed and sintered to obtain a mixed polycrystalline powder;

[0062] After the mixed polycrystalline powder is melted, crystal growth and temperature reduction annealing are performed in sequence to obtain the rare earth doped calcium lanthanum borate crystal.

[0063] The present invention mixes polycrystalline raw materials and flux according to the stoichiometric ratio of formula I or formula II and sintering them to obtain mixed polycrystalline powder. In the present invention, the polycrystalline raw material preferably includes a lanthanum-containing compound, a rare earth ion-doped compound, a calcium-containing compound and a boron-containing compound; the lanthanum-containing compound preferably includes a lanthanum-containing oxide, specifically lanthanum oxide; the compound containing doped rare earth elements preferably includes an oxide containing doped rare earth elements, expressed as Re2O3 or Re'2O3, specifically one or more of dysprosium oxide, europium oxide and samarium oxide; the calcium-containing compound in the polycrystalline raw material preferably includes one or more of calcium carbonate, calcium oxide, calcium oxalate and calcium hydroxide; the boron-containing compound in the polycrystalline raw material preferably includes one or more of boron oxide and boric acid; in a specific embodiment of the present invention, the polycrystalline raw material is prepared according to the stoichiometric ratio of Re2O3:La2O3:CaCO3:H3BO3=x:(1-x):1:10, or according to the stoichiometric ratio of Re2O3:Re'2O3:La2O3:CaCO3:H3BO3=x:y:(1-xy):1:10. In the present invention, the raw materials are preferably weighed, mixed evenly and ground sufficiently to obtain polycrystalline raw materials.

[0064] In the present invention, the flux preferably includes one or more of calcium-containing compounds, lithium-containing compounds, boron-containing compounds and molybdenum-containing compounds; the calcium-containing compounds in the flux preferably include one or more of calcium oxide, calcium carbonate and calcium oxalate; the lithium-containing compounds preferably include one or more of lithium oxide, lithium carbonate and lithium oxalate; the boron-containing compounds in the flux preferably include one or more of boron oxide and boric acid; the molybdenum-containing compound includes molybdenum oxide.

[0065] In the present invention, the flux preferably adopts a CaO-Li2O-B2O3 system, and is preferably a mixture of calcium carbonate, lithium carbonate and boric acid, wherein the molar ratio of calcium carbonate, lithium carbonate and boric acid is preferably 1:2.3:18; in a specific embodiment of the present invention, it is preferably according to (Re x La 1-x )2CaB 10 O 19 :CaCO3:Li2CO3:H3BO3=1:1:2.3:18 or (Re x Re y 'La 1-x-y )2CaB 10 O 19 The raw materials are weighed in a stoichiometric ratio of :CaCO3:Li2CO3:H3BO3=1:1:2.3:18. In the present invention, the flux raw materials are preferably weighed, mixed evenly and ground sufficiently to obtain the flux.

[0066] In the present invention, the sintering temperature is preferably 100-1200°C, more preferably 500-1000°C, the sintering time is preferably 1-240h, more preferably 10-120h, and further preferably 20-60h; the sintering is preferably carried out in an air atmosphere; in a specific embodiment of the present invention, the polycrystalline raw material and flux are preferably placed in an alumina corundum crucible, and then the alumina corundum crucible is placed in a muffle furnace for sintering.

[0067] After obtaining the mixed polycrystalline powder, the present invention melts the mixed polycrystalline powder and then sequentially performs crystal growth and temperature reduction annealing to obtain the rare earth doped calcium lanthanum borate crystal. In the present invention, the melting temperature is preferably 800-1200°C; in a specific embodiment of the present invention, the polycrystalline mixed powder is preferably melted in batches in a platinum crucible at 800-1200°C, and after being fully melted into a molten liquid in a crystal furnace, a platinum stirring paddle is used to stir to obtain a uniformly mixed high-temperature molten liquid.

[0068] In the present invention, the crystal growth method preferably includes a top seeding method, an immersion seeding method, a Czochralski method, a flux method or a floating zone method. The present invention has no requirements on the orientation of the seed crystals used in the crystal growth, and any seed crystal orientation can be selected for crystal growth according to actual needs. In a specific embodiment of the present invention, La2CaB in the

[110] direction is preferably used. 10 O 19 Seed crystal.

[0069] In the present invention, the cooling rate of the crystal growth process is preferably 0.001-30°C / 24h, more preferably 0.1-20°C / 24h, and further preferably 1-15°C / 24h; the rotation speed of the crystal growth is preferably 0.001-120rad / min, more preferably 0.1-100rad / min, and further preferably 1-50rad / min. After the crystal growth is completed, the crystal is preferably taken out from the high-temperature melt and then subjected to cooling annealing.

[0070] In the present invention, the cooling rate of the cooling annealing is preferably 10-15° C. / h, and the terminal temperature of the cooling annealing is room temperature.

[0071] The present invention also provides the application of the rare earth-doped calcium lanthanum borate crystal described in the above scheme or the rare earth-doped calcium lanthanum borate crystal prepared by the preparation method described in the above scheme in white light luminescence and color temperature control. In the present invention, for different rare earth ion-doped calcium lanthanum borate crystals, it is preferred to select a laser pump wavelength and a matching LD or LED as a pump source according to the absorption wavelength of the rare earth ions, and pump the rare earth ion-doped calcium lanthanum borate crystal to achieve white light luminescence. At the same time, by adjusting the doping concentration of the rare earth ions in the crystal, the white light color temperature is controlled, which will be described in detail later.

[0072] The present invention also provides a white light device, which includes a white light LED device or a white light LD device; the white light LED device includes a pump source and a fluorescent crystal; the white light LD device includes a pump source, a fluorescent crystal and an optical resonator; the fluorescent crystal in the white light LED device and the white light LD device is the rare earth-doped calcium lanthanum borate crystal described in the above scheme or the rare earth-doped calcium lanthanum borate crystal prepared by the preparation method described in the above scheme. In the present invention, the pump wavelength range of the pump source in the white light LED device and the white light LD device is 200 to 600 nm. In a specific embodiment of the present invention, a pump source with a matching wavelength is preferably selected according to the excitation spectrum of the crystal; specifically, the pump source in the white light LED device and the white light LD device is preferably an LED pump source or an LD pump source, and the LED pump source preferably includes one or more of an ultraviolet light LED, a blue light LED, and a green light LED, and the LD pump source preferably includes one or more of an ultraviolet light LD, a blue light LD, and a green light LD; in an embodiment of the present invention, it is preferred to select an LD or LED with a matching pump wavelength as a pump source according to the absorption wavelength of the rare earth ion.

[0073] Specifically, the fluorescent crystal in the white light LED device or LD device is (Dy x La 1-x )2CaB 10 O 19When the crystal is used, the pump source is preferably one or more of ultraviolet light LD, ultraviolet light LED, blue light LD and blue light LED, wherein the wavelength of ultraviolet light LD and ultraviolet light LED is preferably 355±5nm, and the wavelength of blue light LD and blue light LED is preferably 445±5nm.

[0074] When the rare earth doped calcium lanthanum borate crystal is (Eu x La 1-x )2CaB 10 O 19 Crystal or (Eu x Sm y La 1-x-y )2CaB 10 O 19 When the fluorescent crystal in the white light LED or LD device is (Eu x La 1-x )2CaB 10 O 19 When a crystal is used, a pump source (blue light LD or LED) with a wavelength of 465±5nm and a pump source (green light LD or LED) with a wavelength of 532±5nm can also be used for joint pumping.

[0075] In the present invention, the (Dy x La 1-x )2CaB 10 O 19 When the crystal is pumped by ultraviolet light LD or LED with a wavelength of 355±5nm, it emits blue light, yellow light and red light, which are mixed to form white light; the (Dy x La 1-x )2CaB 10 O 19 The crystal emits blue light, yellow light and red light under the blue light LD or LED pumping of 445±5nm wavelength, and mixes with the residual pumping blue light to form white light; the (Eu x La 1-x )2CaB 10 O 19 When the crystal is pumped by ultraviolet light LD or LED with a wavelength of 355±5nm, it emits yellow light, orange light and red light, which are mixed to form white light; the (Eu x La 1-x )2CaB 10 O 19The crystal emits yellow light, orange light and red light under the blue light LD or LED pumping of 465±5nm wavelength, and mixes with the residual pumping blue light to form white light; the (Eu x La 1-x )2CaB 10 O 19 When the crystal is pumped by a green light LD or LED with a wavelength of 532±5nm, it emits yellow light, orange light and red light, which are mixed with the residual pumping green light to form white light; the (Eu x La 1-x )2CaB 10 O 19 The crystal emits yellow, orange and red light under the common pumping of 465±5nm and 532±5nm wavelengths, and mixes with the residual pumping blue-green light to form white light; the (Eu x Sm y La 1-x-y )2CaB 10 O 19 When the crystal is pumped by ultraviolet light LD or LED with a wavelength of 355±5nm, it emits yellow light, orange light and red light, which are mixed to form white light; the (Eu x Sm y La 1-x-y )2CaB 10 O 19 The crystal emits yellow light, orange light and red light under the blue light LD or LED pumping of 465±5nm wavelength, and mixes with the residual pumping blue light to form white light; the (Eu x Sm y La 1-x-y )2CaB 10 O 19 When pumped by green light LD or LED at a wavelength of 532±5nm, the crystal emits yellow, orange and red light, which are mixed with the residual green light of the pump to form white light.

[0076] Specifically, the (Dy x La 1-x )2CaB 10 O 19 When the crystal is used as a white light LED device, ultraviolet light LD (or LED) or blue light LD (or LED) is used as the pump source. x La 1-x )2CaB 10 O 19 Dy in crystal 3+ Ionic 6 H 15 / 2 → 6 P 7 / 2 or 6 H 15 / 2 →4 I 15 / 2 Transition channel, respectively Dy 3+ Corresponding to the excitation 6 P 7 / 2 or 4 I 15 / 2 Excited state, in 6 P 7 / 2 , 4 I 15 / 2 The excited electrons undergo radiationless relaxation to 4 F 9 / 2 Excited state, then spontaneous emission transition 4 F 9 / 2 → 6 H 15 / 2 , 4 F 9 / 2 → 6 H 13 / 2 , 4 F 9 / 2 → 6 H 11 / 2 and 4 F 9 / 2 → 6 F 11 / 2 + 6 H 9 / 2 Blue, yellow and red light are obtained and combined with the residual blue light from the pump to produce a white LED.

[0077] Specifically, the (Dy x La 1-x )2CaB 10 O 19 When the crystal is used as a white light LD device, ultraviolet light LD (or LED) or blue light LD (or LED) is used as the pump source. x La 1-x )2CaB 10 O 19 Dy in crystal 3+ Ionic 6 H 15 / 2 → 6 P 7 / 2 or 6 H 15 / 2 → 4 I 15 / 2 Transition channel, respectively Dy 3+ Corresponding to the excitation 6 P 7 / 2 or 4 I 15 / 2 Excited state, in 6 P 7 / 2 , 4 I 15 / 2The excited electrons undergo radiationless relaxation to 4 F 9 / 2 The excited state, 4 F 9 / 2 and 6 H 11 / 2 Energy level or 4 F 9 / 2 and 6 H 13 / 2 Energy level or 4 F 9 / 2 and 6 H 15 / 2 After the number of particles is inverted between energy levels, stimulated radiation transitions are performed. 4 F 9 / 2 → 6 H 15 / 2 , 4 F 9 / 2 → 6 H 13 / 2 , 4 F 9 / 2 → 6 H 11 / 2 and 4 F 9 / 2 → 6 F 11 / 2 + 6 H 9 / 2 Blue, yellow and red light are obtained and combined with the residual blue light from the pump to produce white light LD.

[0078] Specifically, using the (Eu x La 1-x )2CaB 10 O 19 Crystal or (Eu x Sm y La 1-x-y )2CaB 10 O 19 When the crystal is used as a white light LED device, ultraviolet light LD (or LED), blue light LD (or LED) or green light LD (or LED) is used as the pump source. x La 1-x )2CaB 10 O 19 Crystal or (Eu x Sm y La 1-x-y )2CaB 10 O 19 Eu in crystal 3+ Ionic 7 F0→ 5 L6 or 7 F0→ 5 D2 or 7 F0→5 D1 transition channel, respectively, Eu 3+ Corresponding to the excitation 5 L6 or 5 D2 or 5 D1 excited state, in 5 L6, 5 D2, 5 The electrons in the D1 excited state transition to 5 D0 excited state, and then through spontaneous emission transition 5 D0→ 7 F0, 5 D0→ 7 F1, 5 D0→ 7 F2, 5 D0→ 7 F3 and 5 D0→ 7 F4 obtains visible yellow, orange and red light, and combines it with the residual blue and green light from the pump to produce white light LED.

[0079] Specifically, using the (Eu x La 1-x )2CaB 10 O 19 Crystal or (Eu x Sm y La 1-x-y )2CaB 10 O 19 When the crystal is used as a white light LD device, ultraviolet light LD (or LED), blue light LD (or LED) or green light LD (or LED) is used as the pump source. x La 1-x )2CaB 10 O 19 Crystal or (Eu x Sm y La 1-x-y )2CaB 10 O 19 Eu in crystal 3+ Ionic 7 F0→ 5 L6 or 7 F0→ 5 D2 or 7 F0→ 5 D1 transition channel, respectively, Eu 3+ Corresponding to the excitation 5 L6 or 5 D2 or 5 D1 excited state, in 5 L6, 5 D2, 5The electrons in the D1 excited state transition to 5 D0 excited state, 5 D0 and 7 F0 energy level or 5 D0 and 7 F2 level or 5 D0 and 7 F3 energy level or 5 D0 and 7 After the particle number inversion is achieved between the F4 energy levels, stimulated radiation transition is then achieved. 5 D0→ 7 F0, 5 D0→ 7 F1, 5 D0→ 7 F2, 5 D0→ 7 F3 and 5 D0→ 7 F4 obtains visible yellow, orange and red light, and combines it with the residual blue and green light from the pump to produce white light LD.

[0080] The present invention also provides a white light luminescence method, which uses a pump source to pump rare earth-doped calcium lanthanum borate crystals to achieve white light luminescence; the rare earth-doped calcium lanthanum borate crystals are the rare earth-doped calcium lanthanum borate crystals described in the above scheme or the rare earth-doped calcium lanthanum borate crystals prepared by the preparation method described in the above scheme.

[0081] In the present invention, the pump source is an LED pump source or an LD pump source; when the rare earth doped calcium lanthanum borate crystal is (Dy x La 1-x )2CaB 10 O 19 Crystal, (Eu x La 1-x )2CaB 10 O 19 Crystal or (Eu x Sm y La 1-x-y )2CaB 10 O 19 When using a crystal, the corresponding pump source is consistent with the above solution and will not be described here.

[0082] The present invention also provides a method for controlling the color temperature of white light, wherein the color temperature is controlled by adjusting the concentration of rare earth ions doped in the rare earth doped calcium lanthanum borate crystal; the adjustable range of the color temperature is 1800K to 10000K. x La 1-x )2CaB 10 O 19When the crystal emits white light, the Dy doped 3+ The doping concentration of the ions can effectively adjust the luminous intensity of the crystal, thereby optimizing the ratio of the blue light, yellow light and red light emitted by the crystal to the residual blue light of the pump pumping, thereby achieving the color temperature control of the white light emission; in the present invention, the (Eu x La 1-x )2CaB 10 O 19 Crystal or (Eu x Sm y La 1-x-y )2CaB 10 O 19 When the crystal emits white light, by adjusting the Eu doping in the crystal 3+ The doping concentration of ions can effectively adjust the luminescence intensity of the crystal, and then optimize the ratio of the yellow light, orange light and red light emitted by the crystal to the residual blue-green light of the pump, thereby achieving color temperature control of white light emission.

[0083] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0084] Example 1

[0085] (Dy 0.03 La 0.97 )2CaB 10 O 19 The method for preparing a crystal and realizing white light output comprises the following steps:

[0086] (1) Ingredients: According to (Dy 0.03 La 0.97 )2CaB 10 O 19 The raw materials are weighed, and the raw materials are dysprosium oxide, lanthanum oxide, calcium carbonate and boric acid. After weighing, they are mixed evenly and fully ground; CaO-Li2O-B2O3 system is used as flux, and the stoichiometric ratio (Dy2O3:La2O3:CaCO3:H3BO3) is adjusted. 0.03 La 0.97 )2CaB 10 O 19 :CaCO3:Li2O3:H3BO3=1:1:2.3:18 Weigh the raw materials, including calcium carbonate, lithium carbonate and boric acid, mix them evenly and grind them thoroughly after weighing.

[0087] (2) Sintering: The polycrystalline raw material and flux raw material uniformly mixed in step (1) are placed in an alumina corundum crucible, and the alumina corundum crucible is placed in a muffle furnace. The crucible is sintered in an air atmosphere at a sintering temperature of 950° C. and a holding time of 15 h to obtain a polycrystalline mixed powder.

[0088] (3) Preparation of high-melt solution: The polycrystalline mixed powder prepared in step (2) is melted in batches in a platinum crucible at 1020° C., fully melted into a high-temperature melt in a crystal furnace, and fully stirred with a platinum stirring paddle to obtain a uniform high-temperature melt.

[0089] (4) Crystal growth: La2CaB in the

[110] direction 10 O 19 The single crystal is used as a seed crystal and is grown in the high-temperature melt obtained in step (3) according to the top seed crystal growth process.

[0090] (5) Cooling annealing: After the crystal growth in step (4) is completed, the crystal is taken out from the high-temperature melt and cooled to room temperature at a rate of 10°C / h to obtain (Dy 0.03 La 0.97 )2CaB 10 O 19 Crystal (denoted as 3% Dy:LCB).

[0091] (6) White light LED experiment: Select 355nm ultraviolet light LD or 445nm blue light LD as the pump source, use precision optical polished single crystal components, and use direct pumping to conduct white light experiments. The experimental equipment used is as follows Figure 1 As shown in the figure; the output laser of the pump source is incident vertically on the crystal surface through the collimation and focusing system, and passes through the Dy in the 3% Dy:LCB crystal. 3+ Ionic 6 H 15 / 2 → 6 P 7 / 2 or 6 H 15 / 2 → 4 I 15 / 2 Transition channel, respectively Dy 3+ Corresponding to the excitation 6 P 7 / 2 or 4 I 15 / 2 Excited state, in 6 P 7 / 2 , 4 I 15 / 2 The excited electrons undergo radiationless relaxation to 4 F 9 / 2 Excited state, then spontaneous emission transition 4 F 9 / 2 → 6H 15 / 2 , 4 F 9 / 2 → 6 H 13 / 2 , 4 F 9 / 2 → 6 H 11 / 2 and 4 F 9 / 2 → 6 F 11 / 2 + 6 H 9 / 2 Blue light, yellow light and red light are obtained and combined with the residual blue light from pumping to produce white light LED; a spectrum collector is then used to collect the white light emission spectrum.

[0092] The X-ray diffraction pattern of the 3% Dy:LCB crystal prepared in this example is as follows: Figure 3 As shown, the excitation spectrum is as follows Figure 4 The fluorescence spectrum is shown in Figure 5 The fluorescence quantum yield is shown as Figure 6 As shown, the chromaticity diagram coordinates are Figure 7 As shown, the white light experimental crystal emits light as Fig.14 shown. Figure 3 The results show that Dy 3+ The LCB crystal structure is not affected when doped; Figure 4 It shows that at 350nm( 6 H 15 / 2 → 4 I 9 / 2 ) and 450nm( 6 H 15 / 2 → 4 I 15 / 2 ) band excites Dy 3+ Transition-related peaks allow the selection of pump sources with matching wavelengths; Figure 5 It shows that under the excitation of 355nm and 445nm, the spectrum shows two main emissions, namely the blue light region of 460-500nm ( 4 F 9 / 2 → 6 H 15 / 2 )、Yellow light region 550~600nm( 4 F 9 / 2 → 6 H 13 / 2 ), and the weak red light region 640~660nm( 4 F 9 / 2 → 6 H 11 / 2 ) and 730~770nm( 4 F 9 / 2 → 6 F11 / 2 + 6 H 9 / 2 ), the red light emission is obviously insufficient, and by adjusting the ratio of the emitted yellow light and blue light as well as the residual blue light of the pump, white light can be emitted for the LED lighting field; Figure 6 It shows that the fluorescence quantum yield of the crystal under the excitation wavelength of 355nm and 445nm is 35.1% and 27.22% respectively; Figure 7 It shows that the chromaticity coordinate position under the excitation wavelength of 355nm is: x=0.3937, y=0.4375 (such as Figure 7 Point A in the middle), the chromaticity coordinate position under the excitation wavelength of 445nm is: and x = 0.3798, y = 0.3799 (such as Figure 7 The color coordinates are all in the white light area, and the color temperature is 4000K; Fig.14 It shows that under the excitation wavelength of 355nm and 445nm, 3%Dy:LCB crystal emits homogeneous white light.

[0093] Example 2

[0094] (Dy 0.05 La 0.95 )2CaB 10 O 19 The method for preparing a crystal and realizing white light output comprises the following steps:

[0095] (1) Ingredients: According to (Dy 0.05 La 0.95 )2CaB 10 O 19 The raw materials are weighed in the chemical stoichiometric ratio of Dy2O3:La2O3:CaCO3:H3BO3 = 0.05:0.95:1:10. The raw materials are dysprosium oxide, lanthanum oxide, calcium carbonate and boric acid. After weighing, they are mixed evenly and fully ground. The CaO-Li2O-B2O3 system is used as a flux. According to the chemical stoichiometric ratio (Dy2O3:La2O3:CaCO3:H3BO3), the raw materials are weighed in the chemical stoichiometric ratio of Dy2O3:La2O3:CaCO3:H3BO3 = 0.05:0.95:1:10. 0.05 La 0.95 )2CaB 10 O 19 :CaCO3:Li2O3:H3BO3=1:1:2.3:18 Weigh the raw materials, including calcium carbonate, lithium carbonate and boric acid, mix them evenly and grind them thoroughly after weighing.

[0096] (2) Sintering: The polycrystalline raw material and flux raw material uniformly mixed in step (1) are placed in an alumina corundum crucible, and the alumina corundum crucible is placed in a muffle furnace. The crucible is sintered in an air atmosphere at a sintering temperature of 950° C. and a holding time of 15 h to obtain a polycrystalline mixed powder.

[0097] (3) Preparation of high-temperature melt: The polycrystalline mixed powder prepared in step (2) is melted in batches in a platinum crucible at 1020° C., fully melted into a high-temperature melt in a crystal furnace, and fully stirred with a platinum stirring paddle to obtain a uniformly mixed high-temperature melt.

[0098] (4) Crystal growth: La2CaB in the

[110] direction 10 O 19 The single crystal is used as a seed crystal and is grown in the high-temperature melt obtained in step (3) according to the top seed crystal growth process.

[0099] (5) Cooling annealing: After the crystal growth in step (4) is completed, the crystal is taken out from the high-temperature melt and cooled to room temperature at a rate of 10°C / h to obtain (Dy 0.05 La 0.95 )2CaB 10 O 19 Crystal (denoted as 5% Dy:LCB).

[0100] (6) White light LED experiment: Select 355nm ultraviolet light LD or 445nm blue light LD as the pump source, use precision optical polished single crystal components, and use direct pumping to conduct white light experiments. The experimental equipment used is as follows Figure 1 As shown in the figure; the pump source output laser is incident vertically on the crystal surface through the collimation and focusing system, and passes through the Dy in the 5% Dy:LCB crystal. 3+ Ionic 6 H 15 / 2 → 6 P 7 / 2 or 6 H 15 / 2 → 4 I 15 / 2 Transition channel, respectively Dy 3+ Corresponding to the excitation 6 P 7 / 2 or 4 I 15 / 2 Excited state, in 6 P 7 / 2 , 4 I 15 / 2 The excited electrons undergo radiationless relaxation to 4 F 9 / 2 Excited state, then spontaneous emission transition 4 F 9 / 2 → 6 H 15 / 2 , 4 F 9 / 2 → 6 H 13 / 2 , 4 F 9 / 2 → 6 H11 / 2 and 4 F 9 / 2 → 6 F 11 / 2 + 6 H 9 / 2 Blue light, yellow light and red light are obtained and combined with the residual blue light from pumping to produce white light LED; a spectrum collector is then used to collect the white light emission spectrum.

[0101] (7) White light LD experiment: A 445nm blue light LD was selected as the pump source. A single crystal element with precision optical polishing was used to conduct a white light experiment using direct pumping. The device used was as follows: Figure 2 As shown in the figure, the output laser of the pump source enters the resonant cavity through the collimation and focusing system and vertically incident on the crystal surface, passing through the Dy in the 5% Dy:LCB crystal. 3+ Ionic 6 H 15 / 2 → 6 P 7 / 2 or 6 H 15 / 2 → 4 I 15 / 2 Transition channel, respectively Dy 3+ Corresponding to the excitation 6 P 7 / 2 or 4 I 15 / 2 The excited state, 4 F 9 / 2 and 6 H 11 / 2 Energy level or 4 F 9 / 2 and 6 H 13 / 2 Energy level or 4 F 9 / 2 and 6 H 15 / 2 After the number of particles is inverted between energy levels, stimulated radiation transitions are performed. 4 F 9 / 2 → 6 H 15 / 2 , 4 F 9 / 2 → 6 H 13 / 2 , 4 F 9 / 2 → 6 H 11 / 2 and 4 F 9 / 2 → 6 F 11 / 2 + 6 H 9 / 2 Blue light, yellow light and red light are obtained and combined with the residual blue light from the pump to produce white light LD. Fig.15As shown, under 445nm blue light LD pumping, 5% Dy:LCB crystal can emit white light uniformly from the resonant cavity. Since the resonant cavity is opaque, the crystal light emission cannot be seen directly. The white light is reflected on the front and rear lenses of the resonant cavity and can be observed.

[0102] The X-ray diffraction pattern of the 5% Dy:LCB crystal prepared in this example is as follows Figure 3 As shown, the excitation spectrum is as follows Figure 4 The fluorescence spectrum is shown in Figure 5 The fluorescence quantum yield is shown as Figure 6 As shown, the chromaticity diagram coordinates are Figure 7 As shown, the white light experimental crystal emits light as Fig.14 shown. Figure 3 It shows that Dy 3+ The LCB crystal structure is not affected when doped; Figure 4 It shows that at 350nm( 6 H 15 / 2 → 4 I 9 / 2 ) and 450nm( 6 H 15 / 2 → 4 I 15 / 2 ) band excites Dy 3+ Transition-related peaks allow the selection of pump sources with matching wavelengths; Figure 5 It shows that under the excitation of 355nm and 445nm, the fluorescence spectrum obtained at 355nm is stronger, and the spectrum shows two main emissions, namely the blue light region of 460-500nm ( 4 F 9 / 2 → 6 H 15 / 2 )、550~600nm yellow light area( 4 F 9 / 2 → 6 H 13 / 2 ), and the weak red light region 640~660nm( 4 F 9 / 2 → 6 H 11 / 2 ) and 730~770nm( 4 F 9 / 2 → 6 F 11 / 2 + 6 H 9 / 2 ), the red light emission is obviously insufficient, and by adjusting the ratio of emitted yellow light and blue light as well as the residual blue light of the pump, white light can be emitted for use in the field of LED lighting; Figure 6 It shows that the fluorescence quantum yield of the crystal under the excitation wavelength of 355nm and 445nm is 43.46% and 25.06% respectively; Figure 7It shows that the chromaticity coordinate position under the excitation wavelength of 355nm is: x=0.3891, y=0.4217 (such as Figure 7 The chromaticity coordinates under the excitation wavelength of 445nm are: x=0.3743, y=0.3715 (such as Figure 7 Point B' in the middle), the color temperature is in the white light area, and the color temperature is 4000K; Fig.14 It shows that 5% Dy:LCB crystal emits homogeneous white light under excitation wavelengths of 355nm and 445nm.

[0103] Compared with the 3% Dy:LCB crystal in Example 1, the fluorescence intensity of the 5% Dy:LCB crystal in Example 2 is increased by about 6 times, the fluorescence quantum yield is increased by 8.36%, and the white light chromaticity coordinate result is more inclined to white light.

[0104] Example 3

[0105] (Eu 0.03 La 0.97 )2CaB 10 O 19 The method for preparing a crystal and realizing white light output comprises the following steps:

[0106] (1) Ingredients: According to (Eu 0.03 La 0.97 )2CaB 10 O 19 The raw materials are weighed in the chemical stoichiometric ratio of Eu2O3:La2O3:CaCO3:H3BO3=0.03:0.97:1:10. The raw materials are europium oxide, lanthanum oxide, calcium carbonate and boric acid. After weighing, they are mixed evenly and fully ground. The CaO-Li2O-B2O3 system is used as a flux. According to the chemical stoichiometric ratio (Eu 0.03 La 0.97 )2CaB 10 O 19 :CaCO3:Li2O3:H3BO3=1:1:2.3:18 Weigh the raw materials, including calcium carbonate, lithium carbonate and boric acid, mix them evenly and grind them thoroughly after weighing.

[0107] (2) Sintering: The polycrystalline raw material and flux raw material uniformly mixed in step (1) are placed in an alumina corundum crucible, and the alumina corundum crucible is placed in a muffle furnace. The crucible is sintered in an air atmosphere at a sintering temperature of 950° C. and a holding time of 15 h to obtain a polycrystalline mixed powder.

[0108] (3) Preparation of high-temperature melt: The polycrystalline mixed powder prepared in step (2) is melted in batches in a platinum crucible at 1020° C., fully melted into a high-temperature melt in a crystal furnace, and fully stirred with a platinum stirring paddle to obtain a uniformly mixed high-temperature melt.

[0109] (4) Crystal growth: La2CaB in the

[110] direction 10 O 19 The single crystal is used as a seed crystal and is grown in the high-temperature melt obtained in step (3) according to the top seed crystal growth process.

[0110] (5) Cooling annealing: After the crystal growth in step (4) is completed, the crystal is taken out from the high-temperature melt and cooled to room temperature at a rate of 10°C / h to obtain (Eu 0.03 La 0.97 )2CaB 10 O 19 crystal (denoted as 3% Eu:LCB).

[0111] (6) White light LED experiment: Select 355nm ultraviolet light LD, 465nm blue light LD or 532nm green light LD as the pump source, or use 465nm blue light LD and 532nm green light LD as the pump source at the same time, use precision optical polished single crystal elements, and use direct pumping to conduct fluorescence experiments. The experimental device used is as follows Figure 1 As shown in the figure, the pump source output laser is incident vertically on the crystal surface through the collimation and focusing system, and passes through the Eu in the 3% Eu:LCB crystal. 3+ Ionic 7 F0→ 5 L6 or 7 F0→ 5 D2 or 7 F0→ 5 D1 transition channel, respectively, Eu 3+ Corresponding to the excitation 5 L6 or 5 D2 or 5 D1 excited state, in 5 L6, 5 D2, 5 The electrons in the D1 excited state transition to 5 D0 excited state, and then through spontaneous emission transition 5 D0→ 7 F0, 5 D0→ 7 F1, 5 D0→ 7 F2, 5 D0→ 7 F3 and 5 D0→ 7 F4 obtains visible yellow, orange and red light, and combines it with the residual blue and green light from the pump to produce white light LED; a spectrum collector is then used to collect the white light emission spectrum.

[0112] The X-ray diffraction pattern of the 3% Eu:LCB crystal prepared in this example is as follows Figure 3 As shown, the excitation spectrum is as follows Figure 8 The fluorescence spectrum is shown in Fig. 9 The fluorescence quantum yield is shown as Fig.10 As shown, the chromaticity diagram coordinates are Fig.11 and Fig.12 As shown, the white light experimental crystal emits light as Fig.14 shown. Figure 3 It shows that Eu 3+ The LCB crystal structure is not affected when doped; Figure 8 It shows that at 395nm( 7 F0→ 5 L6)、465nm( 7 F0→ 5 D2), and 532nm( 7 F1 → 5 The presence of D1) band excites Eu 3+ Transition-related peaks allow the selection of pump sources with matching wavelengths; Fig. 9 It shows that under the excitation of 465nm and 532nm, the fluorescence spectrum obtained at 465nm is stronger, and the spectrum shows three main emissions, namely the yellow light region of 575-580nm and 580-605nm ( 5 D0→ 7 F0, 5 D0→ 7 F1), 605~630nm orange light area ( 5 D0→ 7 F2) and 640~660nm( 5 D0→ 7 F3), 680~720nm red light area ( 5 D0→ 7 F4), white light emission and color temperature adjustment are achieved by adjusting the ratio of the residual pump light and the yellow-orange-red light emitted by the crystal; Fig.10 It shows that the fluorescence quantum yield of the crystal under the excitation wavelength of 465nm and 532nm is 52.45% and 44.46% respectively; Fig.11 It shows that the chromaticity coordinate position under the excitation wavelength of 355nm is: x=0.4534, y=0.3422 (such as Fig.11 Point C in the middle), the color temperature is 2400K; Fig.12 It shows that the chromaticity coordinate position under the excitation wavelength of 465nm is: x=0.3179, y=0.2166 (such as Fig.12 The chromaticity coordinates under the excitation wavelength of 532nm are: x=0.4188, y=0.4341 (as Fig.12 The color temperatures are 10000K and 3500K respectively; the chromaticity coordinates under the common excitation of 465nm and 532nm are: x=0.3404, y=0.3208 (such as Fig.12 Center C”’ point), color temperature is 5000K; Fig.14 It shows that 3% Eu:LCB crystal emits homogeneous white light under excitation wavelengths of 465nm and 532nm.

[0113] Example 4

[0114] (Eu 0.07 La 0.93 )2CaB 10 O 19 The method for preparing a crystal and realizing white light output comprises the following steps:

[0115] (1) Ingredients: According to (Eu 0.07 La 0.93 )2CaB 10 O 19 The raw materials are weighed in the chemical stoichiometric ratio of Eu2O3:La2O3:CaCO3:H3BO3=0.07:0.93:1:10. The raw materials are europium oxide, lanthanum oxide, calcium carbonate and boric acid. After weighing, they are mixed evenly and fully ground. The CaO-Li2O-B2O3 system is used as a flux. According to the chemical stoichiometric ratio (Eu 0.07 La 0.93 )2CaB 10 O 19 :CaCO3:Li2O3:H3BO3=1:1:2.3:18 Weigh the raw materials, including calcium carbonate, lithium carbonate and boric acid, mix them evenly and grind them thoroughly after weighing.

[0116] (2) Sintering: The polycrystalline raw material and flux raw material uniformly mixed in step (1) are placed in an alumina corundum crucible, placed in a muffle furnace, and sintered in an air atmosphere at a sintering temperature of 950° C. for a holding time of 15 h to obtain a polycrystalline mixed powder.

[0117] (3) Preparation of high-temperature melt: The polycrystalline mixed powder prepared in step (2) is melted in batches in a platinum crucible at 1020° C., fully melted into a high-temperature melt in a crystal furnace, and fully stirred with a platinum stirring paddle to obtain a uniformly mixed high-temperature melt.

[0118] (4) Crystal growth: La2CaB in the

[110] direction 10 O 19 The single crystal is used as a seed crystal and is grown in the high-temperature melt obtained in step (3) according to the top seed crystal growth process.

[0119] (5) Cooling annealing: After the crystal growth in step (4) is completed, the crystal is taken out from the high-temperature melt and cooled to room temperature at a rate of 10°C / h to obtain (Eu 0.07 La 0.93 )2CaB 10 O 19 crystal (denoted as 7% Eu:LCB).

[0120] (6) White light LED experiment: Select 355nm ultraviolet light LD, 465nm blue light LD or 532nm green light LD as the pump source, or use 465nm blue light LD and 532nm green light LD as the pump source at the same time, use precision optical polished single crystal elements, and use direct pumping to conduct fluorescence experiments. The experimental device used is as follows Figure 1 As shown in the figure, the pump source output laser is incident vertically on the crystal surface through the collimation and focusing system, and passes through the Eu in the 7% Eu:LCB crystal. 3+ Ionic 7 F0→ 5 L6 or 7 F0→ 5 D2 or 7 F0→ 5 D1 transition channel, respectively, Eu 3+ Corresponding to the excitation 5 L6 or 5 D2 or 5 D1 excited state, in 5 L6, 5 D2, 5 The electrons in the D1 excited state transition to 5 D0 excited state, and then through spontaneous emission transition 5 D0→ 7 F0, 5 D0→ 7 F1, 5 D0→ 7 F2, 5 D0→ 7 F3 and 5 D0→ 7 F4 obtains visible yellow, orange and red light, and combines it with the residual blue and green light from the pump to produce white light LED; a spectrum collector is then used to collect the white light emission spectrum.

[0121] The X-ray diffraction pattern of the 7% Eu:LCB crystal prepared in this example is as follows Figure 3 As shown, the excitation spectrum is as follows Figure 8 The fluorescence spectrum is shown in Fig. 9 The fluorescence quantum yield is shown as Fig.10 As shown, the chromaticity diagram coordinates are Fig.11 and Fig.12As shown, the white light experimental crystal emits light as Fig.14 shown. Figure 3 It shows that Eu 3+ The LCB crystal structure is not affected when doped; Figure 8 It shows that at 395nm( 7 F0→ 5 L6)、465nm( 7 F0→ 5 D2), and 532nm( 7 F1 → 5 The presence of D1) band excites Eu 3+ Transition-related peaks allow the selection of pump sources with matching wavelengths; Fig. 9 It shows that under the excitation of 465nm and 532nm, the fluorescence spectrum obtained at 465nm is stronger, and the spectrum shows three main emissions, namely the yellow light region of 575-580nm and 580-605nm ( 5 D0→ 7 F0, 5 D0→ 7 F1), 605~630nm orange light area ( 5 D0→ 7 F2) and 640~660nm( 5 D0→ 7 F3), 680~720nm red light area ( 5 D0→ 7 F4), white light emission and color temperature adjustment are achieved by adjusting the ratio of the residual pump light and the yellow-orange-red light emitted by the crystal; Fig.10 It shows that the fluorescence quantum yield of the crystal under the excitation wavelength of 465nm and 532nm is 55.28% and 43.56% respectively; Fig.11 It shows that the chromaticity coordinate position under the excitation wavelength of 355nm is: x=0.4968, y=0.3451 (such as Fig.11 Point D in the figure), the color temperature is 1900K; Fig.12 It shows that the chromaticity coordinate position under the excitation wavelength of 465nm is: x=0.3699, y=0.2437 (such as Fig.12 The chromaticity coordinates under the excitation wavelength of 532nm are x=0.4542 and y=0.3935 (e.g. Fig.12 The color temperatures are 3000K and 2600K respectively; the chromaticity coordinates under the common excitation of 465nm and 532nm are: x=0.3564, y=0.3251 (such as Fig.12 Middle D”’ point), the color temperature is 4500K; Fig.14It shows that 7% Eu:LCB crystal emits homogeneous white light under excitation wavelengths of 465nm and 532nm.

[0122] Example 5

[0123] (Eu 0.10 La 0.90 )2CaB 10 O 19 The method for preparing a crystal and realizing white light output comprises the following steps:

[0124] (1) Ingredients: According to (Eu 0.10 La 0.90 )2CaB 10 O 19 The raw materials are weighed in the chemical stoichiometric ratio of Eu2O3:La2O3:CaCO3:H3BO3=0.10:0.90:1:10. The raw materials are europium oxide, lanthanum oxide, calcium carbonate and boric acid. After weighing, they are mixed evenly and fully ground. The CaO-Li2O-B2O3 system is used as a flux. According to the chemical stoichiometric ratio (Eu 0.10 La 0.90 )2CaB 10 O 19 :CaCO3:Li2O3:H3BO3=1:1:2.3:18 Weigh the raw materials, including calcium carbonate, lithium carbonate and boric acid, mix them evenly and grind them thoroughly after weighing.

[0125] (2) Sintering: The polycrystalline raw material and flux raw material uniformly mixed in step (1) are placed in an alumina corundum crucible, placed in a muffle furnace, and sintered in an air atmosphere at a sintering temperature of 950° C. for a holding time of 15 h to obtain a polycrystalline mixed powder.

[0126] (3) Preparation of high-temperature melt: The polycrystalline mixed powder prepared in step (2) is melted in batches in a platinum crucible at 1020° C., fully melted into a high-temperature melt in a crystal furnace, and fully stirred with a platinum stirring paddle to obtain a uniformly mixed high-temperature melt.

[0127] (4) Crystal growth: La2CaB in the

[110] direction 10 O 19 The single crystal is used as a seed crystal and is grown in the high-temperature melt obtained in step (3) according to the top seed crystal growth process.

[0128] (5) Cooling annealing: After the crystal growth in step (4) is completed, the crystal is taken out from the high-temperature melt and cooled to room temperature at a rate of 10°C / h to obtain (Eu 0.10 La 0.90 )2CaB 10 O 19crystal (denoted as 10% Eu:LCB).

[0129] (6) White light LED experiment: Select 355nm ultraviolet light LD, 465nm blue light LD or 532nm green light LD as the pump source, or use 465nm blue light LD and 532nm green light LD as the pump source at the same time, use precision optical polished single crystal elements, and use direct pumping to conduct fluorescence experiments. The experimental device used is as follows Figure 1 As shown in the figure, the pump source output laser is incident vertically on the crystal surface through the collimation and focusing system, and passes through the Eu in the 10% Eu:LCB crystal. 3+ Ionic 7 F0→ 5 L6 or 7 F0→ 5 D2 or 7 F0→ 5 D1 transition channel, respectively, Eu 3+ Corresponding to the excitation 5 L6 or 5 D2 or 5 D1 excited state, in 5 L6, 5 D2, 5 The electrons in the D1 excited state transition to 5 D0 excited state, and then through spontaneous emission transition 5 D0→ 7 F0, 5 D0→ 7 F1, 5 D0→ 7 F2, 5 D0→ 7 F3 and 5 D0→ 7 F4 obtains visible yellow, orange and red light, and combines it with the residual blue and green light from the pump to produce white light LED; a spectrum collector is then used to collect the white light emission spectrum.

[0130] The X-ray diffraction pattern of the 10% Eu:LCB crystal prepared in this example is as follows Figure 3 As shown, the excitation spectrum is as follows Figure 8 The fluorescence spectrum is shown in Fig. 9 The fluorescence quantum yield is shown as Fig.10 As shown, the chromaticity diagram coordinates are Fig.11 and Fig.12 As shown, the white light experimental crystal emits light as Fig.14 shown. Figure 3 It shows that Eu 3+ The LCB crystal structure is not affected when doped; Figure 8 It shows that at 395nm( 7 F0→5 L6)、465nm( 7 F0→ 5 D2), and 532nm( 7 F1 → 5 The presence of D1) band excites Eu 3+ Transition-related peaks allow the selection of pump sources with matching wavelengths; Fig. 9 It shows that under the excitation of 465nm and 532nm, the fluorescence spectrum obtained at 465nm is stronger, and the spectrum shows three main emissions, namely the yellow light region of 575-580nm and 580-605nm ( 5 D0→ 7 F0, 5 D0→ 7 F1), 605~630nm orange light area ( 5 D0→ 7 F2) and 640~660nm( 5 D0→ 7 F3), 680~720nm red light area ( 5 D0→ 7 F4), white light emission and color temperature adjustment are achieved by adjusting the ratio of the residual pump light and the yellow-orange-red light emitted by the crystal; Fig.10 It shows that the fluorescence quantum yield of the crystal under the excitation wavelength of 465nm and 532nm is 61.47% and 41.21% respectively; Fig.11 It shows that the chromaticity coordinate position under the excitation wavelength of 355nm is: x=0.5084, y=0.3457 (such as Fig.11 Middle point E), the color temperature is 1800K; Fig.12 It shows that the chromaticity coordinate position under the excitation wavelength of 465nm is: x=0.4310, y=0.2758 (such as Fig.12 The chromaticity coordinates under the excitation wavelength of 532nm are: x=0.5031, y=0.3958 (e.g. Fig.12 The color temperatures are 1800K and 2100K respectively; the chromaticity coordinates under the common excitation of 465nm and 532nm are: x=0.3818, y=0.3162 (such as Fig.12 Middle E'' point), color temperature is 3500K; Fig.14 It shows that 10% Eu:LCB crystal emits homogeneous white light under excitation wavelengths of 465nm and 532nm.

[0131] By comparing Example 3, Example 4 and Example 5, it can be found that 3% Eu:LCB, 7% Eu:LCB and 10% Eu:LCB crystals increase with the increase of Eu 3+With the increase of doping concentration, the fluorescence emission increases by 8 to 10 times, and the fluorescence quantum yield increases by about 9.02%; according to the chromaticity diagram coordinate position under 355nm excitation ( Fig.11 ) It can be seen that as the rare earth ion doping concentration increases, the color temperature deviates from the white light region, the chromaticity coordinates move from point C (x = 0.4534, y = 0.3422) to point E (x = 0.5084, y = 0.3457), and the color temperature changes from 2400K to 1800K; similarly, the chromaticity coordinate position changes of the above crystals under single excitation and common excitation at 465nm and 532nm are shown in the figure below. Fig.12 As shown in the figure, at the chromaticity diagram coordinate position under 465nm excitation, as the rare earth ion doping concentration increases, the color temperature deviates more from the white light region, the chromaticity coordinate moves from point C' (x = 0.3179, y = 0.2166) to point E' (x = 0.4310, y = 0.2758), and the color temperature changes from 10000K to 2000K; according to the chromaticity diagram coordinate position under 532nm excitation, it can be seen that as the rare earth ion doping concentration increases, the color temperature deviates more from the white light region, the chromaticity coordinate moves from point C' (x = 0.4188, y = 0.4341) to point E' (x = 0.4310, y = 0.2758), and the color temperature changes from 10000K to 2000K. The color temperature changes from 3500K to 2100K when the white light chromaticity diagram coordinates C'' of the 3% Eu:LCB crystal under the common excitation of 465nm and 532nm are located in the white light region. As the rare earth ion doping concentration increases, the color temperature coordinates deviate from the white light region. The C''(x=0.3404, y=0.3208) point moves to the E''(x=0.3818, y=0.3162) point, and the color temperature changes from 5000K to 3500K. The results show that with the increase of Eu 3+ The increase of doping concentration enhances the red light emission, thus the red light emission enhancement causes the chromaticity coordinates to be more biased towards the red light region. Fig.14 As shown in the white light experimental phenomenon diagram, the light emitted by the crystal is uniform, and the tone of the light emitted by the crystal with lower doping concentration is more white.

[0132] Example 6

[0133] (Eu 0.07 Sm 0.03 La 0.90 )2CaB 10 O 19 The method for preparing a crystal and realizing white light output comprises the following steps:

[0134] (1) Ingredients: According to (Eu 0.07 Sm 0.03 La 0.90 )2CaB 10 O 19The raw materials are weighed in the chemical stoichiometric ratio of Eu2O3:Sm2O3:La2O3:CaCO3:H3BO3=0.07:0.03:0.90:1:10. The raw materials are europium oxide, samarium oxide, lanthanum oxide, calcium carbonate and boric acid. After weighing, they are mixed evenly and fully ground. The CaO-Li2O-B2O3 system is used as a flux. According to the chemical stoichiometric ratio (Eu2O3:Sm2O3:La2O3:CaCO3:H3BO3), the raw materials are weighed in the chemical stoichiometric ratio of Eu2O3:Sm2O3:La2O3:CaCO3:H3BO3=0.07:0.03:0.90:1:10. The raw materials are europium oxide, samarium oxide, lanthanum oxide, calcium carbonate and boric acid. After weighing, they are mixed evenly and fully ground. 0.07 Sm 0.03 La 0.90 )2CaB 10 O 19 :CaCO3:Li2O3:H3BO3=1:1:2.3:18 Weigh the raw materials, including calcium carbonate, lithium carbonate and boric acid, mix them evenly and grind them thoroughly after weighing.

[0135] (2) Sintering: The polycrystalline raw material and flux raw material uniformly mixed in step (1) are placed in an alumina corundum crucible, placed in a muffle furnace, and sintered in an air atmosphere at a sintering temperature of 950° C. for a holding time of 15 h to obtain a polycrystalline mixed powder.

[0136] (3) Preparation of high-temperature melt: The polycrystalline mixed powder prepared in step (2) is melted in batches in a platinum crucible at 1020° C., fully melted into a high-temperature melt in a crystal furnace, and fully stirred with a platinum stirring paddle to obtain a uniformly mixed high-temperature melt.

[0137] (4) Crystal growth: La2CaB in the

[110] direction 10 O 19 The single crystal is used as a seed crystal and is grown in the high-temperature melt obtained in step (3) according to the top seed crystal growth process.

[0138] (5) Cooling annealing: After the crystal growth in step (4) is completed, the crystal is taken out from the high-temperature melt and cooled to room temperature at a rate of 10°C / h to obtain (Eu 0.07 Sm 0.03 La 0.90 )2CaB 10 O 19 crystal (denoted as 7% Eu:3% Sm:LCB).

[0139] (6) White light LED experiment: Select 355nm ultraviolet light LD, 465nm blue light LD or 532nm green light LD as the pump source, use precision optical polished single crystal components, and use direct pumping to conduct fluorescence experiments. The experimental equipment used is as follows Figure 1 As shown in the figure, the pump source output laser is incident vertically on the crystal surface through the collimation and focusing system, and passes through the Eu in the 7% Eu:3% Sm:LCB crystal. 3+ Ionic 7 F0→ 5 L6 or7 F0→ 5 D2 or 7 F0→ 5 D1 transition channel, respectively, Eu 3+ Corresponding to the excitation 5 L6 or 5 D2 or 5 D1 excited state, in 5 L6, 5 D2, 5 The electrons in the D1 excited state transition to 5 D0 excited state, and then through spontaneous emission transition 5 D0→ 7 F0, 5 D0→ 7 F1, 5 D0→ 7 F2, 5 D0→ 7 F3 and 5 D0→ 7 F4 obtains visible yellow, orange and red light, and combines it with the residual blue and green light from the pump to produce white light LED; a spectrum collector is then used to collect the white light emission spectrum.

[0140] The chromaticity diagram coordinates of the 7% Eu:3% Sm:LCB crystal prepared in this embodiment are as follows: Fig.13 As shown, Fig.13 It shows that the chromaticity coordinate position under the excitation wavelength of 355nm is: x=0.5672, y=0.0.3569 (such as Fig.13 The color temperature is 1650K; the chromaticity coordinate position under the excitation wavelength of 465nm is: x=0.5216, y=0.3439 (such as Fig.13 The chromaticity coordinates under the excitation wavelength of 532nm are: x = 0.5672, y = 0.3628 (such as Fig.13 F” point), the color temperature is 1450K.

[0141] The above experimental results show that as Dy 3+ As the doping concentration increases, the white light emitted by the crystal is closer to the chromaticity coordinates of ideal white light. Therefore, a higher concentration of Dy 3+ Doping is more suitable for the application of white light LED. 3+ As the doping concentration increases, the red light emission of the crystal increases, causing the chromaticity coordinates of the white light LED to deviate from the white light region. 3+ Doping can improve the color rendering of white light emitted by the crystal, making it more suitable for white light LED applications.

[0142] At present, the main materials of solid white light LED and LD excited by light on the market are phosphor materials, which have short fluorescence life, low conversion efficiency and luminous power, and imperfect uniformity of white light. The rare earth doped calcium lanthanum borate crystal provided by the present invention is directly pumped by LD or LED in ultraviolet light (355nm) and visible light band (445nm, 465nm, 532nm) to carry out white light experiments, successfully achieving stable output of high-quality and uniform white light, and achieving excellent white light luminescence. And the color temperature of white light luminescence is effectively adjusted by changing the rare earth ion doping concentration, and the color temperature can be adjusted in the range of 1800K to 10000K. At the same time, the rare earth doped calcium lanthanum borate crystal has a high laser damage threshold, stable physical and chemical properties and good thermal properties, which is of great significance for improving the luminous efficiency of white light LED and LD and extending the service life. In addition, the crystal is easy to obtain large-size single crystals through a single crystal growth process, and exhibits good mechanical properties, which is very suitable for large-scale white light LED and LD packaging processing.

[0143] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A rare earth doped calcium lanthanum borate crystal, characterized in that: The chemical formula is shown in Formula I or Formula II: (Re x La 1-x )2CaB 10 O 19 Formula I; (Re x Re y 'La 1-x-y )2CaB 10 O 19 Formula II; In Formula I and Formula II: Re and Re' are doped rare earth ions, and the doped rare earth ions are lanthanide rare earth ions except La, the value range of x is 0.001 to 0.999, and the value range of y is 0.001 to 0.

999.

2. The rare earth doped calcium lanthanum borate crystal according to claim 1, characterized in that: The doped rare earth ions include Dy 3+ 、Eu 3+ or Sm 3+ .

3. The rare earth doped calcium lanthanum borate crystal according to claim 1, characterized in that: The chemical formula of the rare earth-doped calcium lanthanum borate crystal is as shown in Formula I-1, Formula I-2 or Formula II-1: (Dy x La 1-x )2CaB 10 O 19 Formula I-1; (Eu x La 1-x )2CaB 10 O 19 Formula I-2; (Eu x Sm y La 1-x-y )2CaB 10 O 19 Formula II-1.

4. The method for preparing rare earth doped calcium lanthanum borate crystals according to any one of claims 1 to 3, characterized in that: The following steps are involved: According to the stoichiometric ratio of Formula I or Formula II, a polycrystalline raw material and a flux are mixed and sintered to obtain a mixed polycrystalline powder; After the mixed polycrystalline powder is melted, crystal growth and temperature reduction annealing are performed in sequence to obtain the rare earth doped calcium lanthanum borate crystal.

5. The preparation method according to claim 4, characterized in that: The polycrystalline raw material includes a lanthanum-containing compound, a rare earth ion-doped compound, a calcium-containing compound and a boron-containing compound; the flux includes one or more of a calcium-containing compound, a lithium-containing compound, a boron-containing compound and a molybdenum-containing compound; The sintering temperature is 100-1200°C and the holding time is 1-240h; The crystal growth method includes a top seed method, an immersion seed method, a pulling method, a flux method or a floating zone method; the cooling rate of the crystal growth process is 0.001 to 30°C / 24h, and the rotation speed is 0.001 to 120rad / min; the cooling rate of the cooling annealing is 10 to 15°C / h.

6. Use of the rare earth-doped calcium lanthanum borate crystals according to any one of claims 1 to 3 or the rare earth-doped calcium lanthanum borate crystals prepared by the preparation method according to any one of claims 4 to 5 in white light luminescence and white light color temperature control.

7. A white light device, characterized in that: The white light device includes a white light LED device or a white light LD device; the white light LED device includes a pump source and a fluorescent crystal; the white light LD device includes a pump source, a fluorescent crystal and an optical resonator; the fluorescent crystal in the white light LED device and the white light LD device is the rare earth doped calcium lanthanum borate crystal described in any one of claims 1 to 3 or the rare earth doped calcium lanthanum borate crystal prepared by the preparation method described in any one of claims 4 to 5.

8. A white light emitting method, characterized in that: A pump source is used to pump a rare earth-doped calcium lanthanum borate crystal to achieve white light emission; the rare earth-doped calcium lanthanum borate crystal is the rare earth-doped calcium lanthanum borate crystal according to any one of claims 1 to 3 or the rare earth-doped calcium lanthanum borate crystal prepared by the preparation method according to any one of claims 4 to 5.

9. The white light emitting method according to claim 8, characterized in that: The pump source is an LED pump source or an LD pump source; When the rare earth doped calcium lanthanum borate crystal is (Dy x La 1-x )2CaB 10 O 19 When the crystal is used, the pump source is one or more of ultraviolet light LD, ultraviolet light LED, blue light LD and blue light LED; When the rare earth doped calcium lanthanum borate crystal is (Eu x La 1-x )2CaB 10 O 19 Crystal or (Eu x Sm y La 1-x-y )2CaB 10 O 19 When the crystal is used, the pump source is one or more of ultraviolet light LD, blue light LD, green light LD, ultraviolet light LED, blue light LED and green light LED.

10. A method for controlling the color temperature of white light, characterized in that: The color temperature is controlled by adjusting the concentration of rare earth ions doped in rare earth-doped calcium lanthanum borate crystals; the rare earth-doped calcium lanthanum borate crystals are the rare earth-doped calcium lanthanum borate crystals described in any one of claims 1 to 3 or the rare earth-doped calcium lanthanum borate crystals prepared by the preparation method described in any one of claims 4 to 5.

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