Disclosure of Invention
The invention aims to provide a yellow long-afterglow luminescent material which can emit yellow afterglow visible to naked eyes under a low-light environment and has stronger afterglow intensity and afterglow duration.
The invention also aims to provide a preparation method of the yellow long-afterglow luminescent material, which has the advantages of simple preparation process, easily controlled conditions, low equipment requirement, no generation of toxic gas in the preparation process and no pollution to the environment.
The technical problem to be solved by the invention is realized by adopting the following technical scheme.
A yellow long-afterglow luminescent material uses barium germanystinate as base of luminescent material and trivalent rare-earth ion Dy3+The expression of the yellow long afterglow luminescent material as an activator is as follows: ba1-xSnGe3O9:xDy3+Or Ba1-x-ySnGe3O9:xDy3+-yRe; wherein Re is selected from La3+、Ce3+、Pr3+、Nd3+、Sm3+、Eu3+、Gd3+、Tb3+、Ho3+、Yb3+、Lu3+、Er3+One or more of; x is more than or equal to 0.0005 and less than or equal to 0.05, and y is more than or equal to 0.0005 and less than or equal to 0.05.
The invention also provides a preparation method of the yellow long-afterglow luminescent material, which comprises the following steps:
s1, respectively weighing a Ba-containing compound, a Sn-containing compound, a Ge-containing compound, a Dy-containing compound and a Re-containing compound according to the molar ratio of each element in the expression, mixing and grinding the weighed raw materials to obtain raw material powder;
s2, carrying out primary calcination on the raw material powder, cooling and grinding to obtain a pre-sintered sample;
and S3, carrying out secondary calcination on the pre-sintered sample, grinding after cooling, and then sieving to obtain the yellow long-afterglow luminescent material powder.
The yellow long-afterglow luminescent material and the preparation method thereof have the beneficial effects that:
(1) the invention adopts the traditional solid phase method to prepare the long-afterglow luminescent material, has simple preparation process, easily controlled conditions and low equipment requirement, adopts the raw materials of Ba, Sn and Ge which are rich in elements on earth, belongs to green environment-friendly materials, generates no toxic gas in the preparation process and has no pollution to the environment. Compared with common aluminate, the prepared barium germanosuccinate has higher stability and is not easy to deliquesce in atmospheric atmosphere. Therefore, the long afterglow material prepared by using the barium germanium stannate as the substrate has more stable chemical properties.
(2) The yellow long afterglow luminescent material Ba prepared by the invention1-xSnGe3O9:xDy3+After being excited under an ultraviolet lamp for a period of time, the material can emit yellow afterglow visible to the naked eye in a weak light environment, the emission peak is about 580nm, and the material has stronger afterglow intensity, slower afterglow attenuation and longer afterglow duration.
(3) The yellow long afterglow luminescent material Ba prepared by the invention1-x-ySnGe3O9:xDy3+In yRe, Dy3+Co-doping with other different ions, e.g. La3+、Ce3+、Pr3+、Nd3+、Sm3+、Eu3+、Gd3+、Tb3+、Ho3+、Yb3+、Lu3+、Er3+By doping with different elements, the number of carrier traps in the base material is increased or the light emission band of the sample is changed.
(4) The yellow long-afterglow luminescent material prepared by the invention can be mixed with organic high-molecular materials to prepare a film or a resin body, and the film or the resin body is used as a luminescent film or a luminescent device with yellow afterglow, so that the invention lays a foundation for the practical application of the luminescent film in the fields of emergency lighting, photoelectronic devices or elements, instrument display and the like.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
The following describes a yellow long afterglow luminescent material and a preparation method thereof according to an embodiment of the present invention.
The embodiment of the invention provides a yellow long-afterglow luminescent material, which takes barium germanium stannate as a luminescent material substrate and trivalent rare earth ions Dy3+The expression of the yellow long afterglow luminescent material as an activator is as follows: ba1-xSnGe3O9:xDy3+Or Ba1-x-ySnGe3O9:xDy3+-yRe; wherein Re is selected from La3+、Ce3+、Pr3+、Nd3+、Sm3+、Eu3+、Gd3+、Tb3+、Ho3+、Yb3+、Lu3+、Er3+One or more of; x is more than or equal to 0.0005 and less than or equal to 0.05, and y is more than or equal to 0.0005 and less than or equal to 0.05. Wherein x and y represent mole percent. The invention takes germanium barium stannate material as a substrate and adopts trivalent rare earth ions Dy3+As an activator, by single doping with Dy3+Form traps in the substrate to trap free electrons, and can also be used for La3+、Ce3+、Pr3+、Nd3+、Sm3+、Eu3+、Gd3+、Tb3+、Ho3+、Yb3+、Lu3+、Er3+With Dy3+And co-doping, wherein the number of carrier traps in the substrate material is increased or the luminescence waveband of a sample is changed through doping of different elements, so that the prepared yellow long-afterglow luminescent material has stronger afterglow intensity and afterglow duration, generates afterglow luminescence visible to the naked eye, and lays a foundation for the practical application of the yellow long-afterglow luminescent material in the fields of emergency lighting, optoelectronic devices or elements, instrument display and the like.
Further, the ratio of x to y is 1: 0.5-1.5. More preferably, the ratio of x and y is 1: 1. The ratio of x and y is controlled to ensure that Dy with sufficient concentration is present3+Ions, as activators and luminescent centers. Avoid the excessive Re element, the impure prepared long afterglow material and the luminous efficiency of the long afterglow materialThe fruit drops. Wherein the optimal proportion of x is 0.02.
The embodiment of the invention also provides a preparation method of the yellow long-afterglow luminescent material, which comprises the following steps:
s1, respectively weighing a Ba-containing compound, a Sn-containing compound, a Ge-containing compound, a Dy-containing compound and a Re-containing compound according to the molar ratio of each element in the expression, mixing and grinding the weighed raw materials to obtain raw material powder.
Further, in step S1, each of the raw materials is selected from an oxide containing a corresponding element, a salt, or a mixture of both; wherein the salt is selected from nitrate and/or carbonate. In a preferred embodiment of the present invention, the Ba-containing compound is selected from an oxide, a nitrate or a carbonate thereof, the Sn-and Ge-containing compound is selected from an oxide thereof, and the Dy-and Re-containing compound is selected from an oxide or a nitrate thereof.
Preferably, in the embodiment of the present invention, BaCO is selected3、SnO2、GeO2、Dy2O3The raw materials are easily available and relatively inexpensive as raw materials for synthesis. And Ba, Sn and Ge are rich elements on earth, and belong to green environment-friendly materials, and the prepared finished product has no pollution to the environment.
Further, in step S1, the grinding step is: and mixing the Ba-containing compound, the Sn-containing compound, the Ge-containing compound, the Dy-containing compound and the Re-containing compound, adding a solvent, and grinding for 1-4 h. Wherein the solvent is absolute ethyl alcohol, water or a mixture of the absolute ethyl alcohol and the water. The raw materials are mixed and ground, so that the elements are uniformly distributed, and the full reaction in the subsequent steps is facilitated. The ethanol or water is added for grinding, so that the grinding is more uniform, and the raw materials do not react.
And S2, carrying out primary calcination on the raw material powder, cooling and grinding to obtain a pre-sintered sample.
Heating the raw material powder to 700-1000 ℃ at a speed of 1-10 ℃/min under an air atmosphere, firing for 2-4 hours, cooling to 200-500 ℃ at a cooling rate of 5-15 ℃/min, and naturally cooling to room temperature along with the furnace to obtain the pre-sintered sample.
Further, heating the raw material powder to 750-850 ℃ at a speed of 2-5 ℃/min in an air atmosphere, and burning for 2-4 hours to obtain the pre-sintered sample. The temperature rise speed is controlled, so that the raw materials are prevented from being reacted unevenly due to overlarge temperature difference. More preferably, the temperature is raised at a rate of 5 ℃/min.
Furthermore, the temperature is reduced to 200-300 ℃ at a rate of 10-15 ℃/min, and then the mixture is naturally cooled to room temperature along with the furnace. The annealing temperature is controlled, so that the reaction temperature is reduced rapidly, the experimental time is shortened, and the continuous sintering growth of the product in the annealing process due to overlong annealing time is avoided.
And S3, carrying out secondary calcination on the pre-sintered sample, grinding after cooling, and then sieving to obtain the yellow long-afterglow luminescent material powder.
Further, in step S3, the second calcination step is: and heating the pre-sintered sample to 1200-1400 ℃ at a speed of 1-10 ℃/min in an air atmosphere, and firing for 3-8 hours.
Further, the raw material powder is heated to 1200-1400 ℃ at a speed of 4-8 ℃/min in the air atmosphere, and is burned for 5-8 hours. The above conditions make the reaction more complete and do not make the temperature rise process too slow.
The method of calcining firstly, grinding secondly and calcining secondly is adopted, so that the sintering growth of the product in the calcining process can be inhibited, the full reaction in the calcining process is ensured, the prepared product has pure components, and the prepared long afterglow luminescent material powder is more exquisite. And the atmosphere of the two-time calcination is only air atmosphere, and the valence-change reaction does not occur in the reaction process, so that the method has lower cost and more advantages compared with the prior art of calcining in reducing atmosphere.
Further, in step S3, the mesh number of the screen is 20-50 meshes. And filtering the prepared powder by using a screen to ensure that the particle size of the prepared long-afterglow luminescent material powder is consistent, uniform and fine.
Further, the method also comprises the step of sealing the yellow long-afterglow luminescent material powder:
s4, mixing the yellow long afterglow luminescent material powder and organic high polymer material to obtain the film or resin body. The prepared yellow long-afterglow luminescent material powder can be mixed with organic high-molecular materials such as silica gel and resin to prepare a film or a resin body, so that the transmission and storage of light energy are realized.
The embodiment of the invention provides a yellow long-afterglow luminescent material which can emit light in an afterglow form in a dark place under the excitation of an ultraviolet lamp, and the afterglow luminescent intensity can be observed by naked eyes. And the afterglow attenuation is slow, and the afterglow emission time can last for hours. The characteristics can lead the yellow long afterglow luminescent material to be applied to the fields of night emergency indicating devices, optoelectronic devices, instrument display devices, illuminating devices, home decorations and the like.
The features and properties of the present invention are described in further detail below with reference to examples.
Examples 1 to 6
Embodiments 1 to 6 respectively provide a yellow long-afterglow luminescent material, which includes the following steps:
(1) the raw materials of each element are weighed according to the following table and mixed, and absolute ethyl alcohol is added for full grinding for 3 hours, so that raw material powder is obtained.
(2) Placing the raw material powder into a high-temperature tube furnace, heating to 800 ℃ at the speed of 5 ℃/min under the air atmosphere, burning for 2 hours, then cooling to 200 ℃ at the speed of 10 ℃/min, and then naturally cooling to room temperature along with the furnace to obtain a pre-sintered sample.
(3) And after the pre-sintered sample is cooled to room temperature, taking out and fully grinding, putting the pre-sintered sample into the high-temperature tube furnace again, heating to 1300 ℃ at the speed of 7 ℃/min in the air atmosphere, firing for 4 hours, and naturally cooling to room temperature along with the furnace.
(4) And (4) grinding the cooled sample again, and sieving the ground sample by using a 20-50-mesh sieve to obtain the yellow long-afterglow luminescent material.
(5) The yellow long afterglow luminescent material powder is put into a transparent test tube and is excited by ultraviolet light to test the optical performance of the test tube.
The lowest vertical line in the figure is pure phase BaSnGe3O9The diffraction peak and pure phase BaSnGe of the yellow long afterglow luminescent material prepared in the embodiments 1 to 53O9The diffraction peak of the doped Dy is kept consistent, and the doped Dy is not detected3+Other phases of the rare earth ions show that the prepared sample has the characteristic of high purity and is doped with the rare earth ions Dy3+The crystal structure is not disturbed.
FIG. 3 is the emission spectrum of the yellow-afterglow long-afterglow luminescent material prepared in example 3 of the present invention. It can be seen that the emission peaks at 490nm, 580nm and 680nm are Dy3+Thereby showing Dy3+In the luminescent material base, as luminescent centers.
FIG. 4 shows afterglow spectra of yellow long afterglow phosphors prepared in embodiments 1 to 5 of the material of the present invention. As can be seen from the figure, the afterglow emission peaks of examples 1 to 5 are around 580nm, which shows yellow afterglow, and are Dy3+Is/are as follows4F9/2To6H13/2And (4) energy level transition. And examples 1 to 5 all had strong afterglow emission intensity. Among them, the remaining luminance emission intensity is strongest in example 3 compared with other examples.
The embodiments described above are some, but not all embodiments of the invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.