CN113322516A

CN113322516A - Lead-free all-inorganic Te4+Doped A2InX5·H2O perovskite material and preparation method and application thereof

Info

Publication number: CN113322516A
Application number: CN202110599846.1A
Authority: CN
Inventors: 匡代彬; 魏俊华
Original assignee: Sun Yat Sen University
Current assignee: Sun Yat Sen University
Priority date: 2021-05-31
Filing date: 2021-05-31
Publication date: 2021-08-31
Anticipated expiration: 2041-05-31
Also published as: CN113322516B

Abstract

The invention discloses a lead-free all-inorganic Te⁴⁺Doped A₂InX₅·H₂O perovskite material and a preparation method and application thereof. The lead-free all-inorganic Te of the invention⁴⁺Doped A₂InX₅·H₂The preparation method of the O perovskite material comprises the following steps: mixing A source, In source, Te source and halogen acid to obtain precursor, heating to dissolve, and precipitating to obtain Te⁴⁺Doping with A₂InX₅·H₂And (4) O single crystal. The material of the invention shows bright orange light emission under the excitation of ultraviolet light, and has great potential in the aspect of remote optical temperature measurement application. Compared with the traditional rare earth-based luminescent material and Pb-based metal halide perovskite nanocrystalline and single crystalThe material of the invention has low preparation temperature, can be synthesized in batches, has rich raw materials, is nontoxic, environment-friendly, good in reproducibility, excellent in humidity and temperature stability, and is expected to realize commercial application.

Description

Lead-free all-inorganic Te4+Doped A2InX5·H2O perovskite material and preparation method and application thereof

Technical Field

The present invention relates to perovskite materialsThe technical field, in particular to a lead-free all-inorganic Te⁴⁺Doped A₂InX₅·H₂O perovskite material and a preparation method and application thereof.

Background

The luminescent material has important application in the fields of solid-state illumination, display devices, X-ray detection imaging and remote optical temperature measurement. At present, commercial luminescent materials are mainly based on rare earth elements, and rare earth resources are used as strategic resources, have limited reserves and are indispensable resources in the fields of electronic industry, aerospace, new energy and the like. The traditional rare earth luminescent material usually needs high-temperature preparation, and has higher cost and energy consumption. Therefore, there is an urgent need to develop a novel luminescent material that can be prepared at a low temperature and is inexpensive.

The metal halide perovskite material has excellent photoelectric property, high carrier mobility, high extinction coefficient and adjustable energy band, and the efficiency of a photovoltaic device of the metal halide perovskite material is up to 25.5 percent at present. Besides the excellent properties in the photovoltaic field, the metal halide perovskite material also shows a very large application prospect in the field of luminescent materials. With CsPbX₃(X ═ Cl, Br, I) nanocrystalline materials are representative, and by adjusting the type and proportion of halogens, CsPbX₃The luminescence spectrum of the nanocrystals can be tuned from the blue region to the near infrared region, covering the entire visible spectrum. Currently, CsPbX is well documented₃The photoluminescence quantum efficiency (PLQY) of the nanocrystalline can reach nearly 100%, the performance can be comparable to that of the traditional rare earth luminescent material, and the nanocrystalline has great potential in the fields of electroluminescent devices and X-ray scintillator detection imaging. However, CsPbX₃The nanocrystals still have many problems: CsPbX₃The nanocrystalline is usually synthesized by a hot injection method, the synthesis process needs inert gas protection, and the subsequent treatment process is complicated and difficult to synthesize in large batch; a large amount of ligands are needed in the synthesis process, and desorption of the ligands often causes agglomeration of the nanocrystals, so that the stability is poor. Compared with the nanocrystalline, the single crystal has more excellent structural stability, can be prepared at low temperature, and can be synthesized in large batch. Generally, a metal halide single crystal having a three-dimensional structure has less exciton bondingCarriers tend to separate rather than recombine, and therefore, reducing the crystal structure dimensions of the material can increase the degree of carrier localization and increase exciton recombination rates, thereby achieving higher photoluminescence efficiency. However, most of the perovskite luminescent single crystal materials are based on lead element and have high environmental toxicity, so that some non-lead perovskite metal halide luminescent single crystals need to be developed and applied to the fields of optical temperature measurement, solid-state illumination, X-ray detection imaging and the like.

The optical temperature measuring material has important application in the fields of national defense, military, civil use and life science, and can be used for searching for some suitable materials and applying the suitable materials to the temperature measuring field by combining the characteristics of low cost and solution-soluble preparation of the metal halide perovskite material. At present, Cs has been reported in the literature₄SnBr₆The metal halide based luminescent single crystal material is used for optical thermometry, however, Sn²⁺Oxidation occurs easily and instability prevents further application in commercial optical thermometry. Therefore, it is necessary to develop some optical thermometric materials with high thermometric sensitivity, good stability and non-lead and non-toxic.

Indium (In) is a commonly used metal element In the electronics industry and has been applied to the new perovskite metal halide structures. A. the₂InX₅·H₂O is a novel double perovskite material, vacancy and In-X₅O octahedra form an ordered crystal structure, In-X₅The O octahedrons are isolated from each other to form a 0D structure. The exciton localization degree in the 0D structure is higher, and a platform is provided for designing and synthesizing a plurality of single crystal materials with high luminous efficiency. However, In the highly symmetrical crystal structure, In³⁺The intrinsic electron transition at the metal center is a forbidden transition and generally has low luminous efficiency. By Cs₂InCl₅·H₂O is representative, intrinsic Cs₂InCl₅·H₂O hardly observed a light emission phenomenon.

Disclosure of Invention

The invention aims at overcoming the defects and shortcomings of the prior art and providing the lead-free all-inorganic Te⁴⁺Doped A₂InX₅·H₂An O perovskite material.

Another object of the present invention is to provide the above lead-free all-inorganic Te⁴⁺Doped A₂InX₅·H₂A preparation method of an O perovskite material.

It is still another object of the present invention to provide the above lead-free all-inorganic Te⁴⁺Doped A₂InX₅·H₂Application of O perovskite material.

The purpose of the invention is realized by the following technical scheme: leadless all-inorganic Te⁴⁺Doped A₂InX₅·H₂The preparation method of the O perovskite material comprises the following steps: mixing A source, In source, Te source and halogen acid (HX) to obtain precursor, heating to dissolve, cooling to precipitate crystal, and obtaining Te⁴⁺Doping with A₂InX₅·H₂And (4) O single crystal.

The hydrohalic acid (HX) X is at least one of Cl, Br and I; more preferably Cl.

A in the A source is preferably at least one of K, Rb and Cs.

The A source is preferably AX, A₂CO₃And A (OAc).

The In source is preferably In₂O₃、InX₃、In(OAc)₃At least one of them.

The Te source is preferably TeO₂、TeX₄At least one of them.

X In the A source, the In source and the Te source is preferably at least one of Cl, Br and I; more preferably Cl.

The A source and the In source are preferably used In an amount that the molar ratio of A to In is 2: calculating the ratio of 0.1 to 1; more preferably, the molar ratio of A to In is 2: 1, calculating the mixture ratio;

the amount of HX used should be less than the maximum solubility of the starting material at room temperature.

The dosage of the Te source is calculated according to the proportion that Te accounts for more than 0 and less than 100 percent of the molar weight of In; preferably calculated according to the proportion of 0.3 to 30 percent of the molar weight of In; more preferably, it is calculated as 0.3% of the molar amount of In.

The heating dissolution is that the solution is completely dissolved by heating at room temperature to 250 ℃; preferably 160 c to complete dissolution.

And the crystal is precipitated by cooling to room temperature.

The room temperature is 25-35 ℃.

The Te precipitated⁴⁺Doping with A₂InX₅·H₂And filtering and washing the O single crystal.

Leadless all-inorganic Te⁴⁺Doped A₂InX₅·H₂The O perovskite material is prepared by the preparation method.

The above lead-free all-inorganic Te⁴⁺Doped A₂InX₅·H₂The O perovskite material is applied to remote optical temperature measurement, solid-state illumination, display equipment, anti-counterfeiting, optical detection and optical/photoelectric catalysis.

The aim of the inventor is to synthesize a single crystal material which has excellent luminescence property and can be applied to solid state illumination and optical temperature measurement. The inventors have made many attempts to include host lattice and dopant selection, for example, by introducing a very common luminescence center Mn into a host material of Cs-Sn-Cl²⁺No luminescence was observed. When a Cs-Bi-X material is used as a substrate and luminescent metal centers such as Sb, In, Al, Cu, Sn and the like are introduced, any phenomenon of improving the luminescent property of the material is not observed. Then, the inventors made a lot of attempts in Cs-Zn-X based materials, and still did not obtain a material with good luminescence properties. The inventors speculate that a material with better luminescence property can be obtained without randomly doping ions in the crystal structure, and a certain synergistic effect is required between the host material and the dopant. In addition, a single crystal material system is different from a nano crystal system, doping cannot simply realize passivation defects to improve the luminescence performance like in the nano crystal system, and optimization design of structure and performance is needed.

Indium (In) is a commonly used metal element In the electronics industry and has been applied to the new perovskite metal halide structures. A. the₂InX₅·H₂O is a novel double perovskite material, vacancy and In-X₅O octahedra form an ordered crystal structure, In-X₅The O octahedrons are isolated from each other to form a 0D structure. The exciton localization degree in the 0D structure is higher, and a platform is provided for designing and synthesizing a plurality of single crystal materials with high luminous efficiency. However, In the highly symmetrical crystal structure, In³⁺The intrinsic electron transition at the metal center is a forbidden transition and generally has low luminous efficiency. By Cs₂InCl₅·H₂O is representative, intrinsic Cs₂InCl₅·H₂O hardly observed a light emission phenomenon. To improve A₂InX₅·H₂The luminescent properties of O materials, the inventors have made numerous attempts, first of all, to introduce common activators, such as Mn, into the crystal lattice²⁺，Mn²⁺Generally with red emission, the inventors hoped to be able to synthesize materials with higher luminescent quantum efficiency and to be able to be used for optical thermometry. However, Mn is introduced²⁺After that, no luminescence phenomenon was observed as expected. Subsequently, the inventors introduced Sn into the structure²⁺，Sn²⁺Having an electronic structure of 5s²Generally, Sn is considered²⁺Has higher optical activity, however, in Sn²⁺In the doped system, the inventors also did not observe the corresponding luminescence phenomenon. Then, the inventor tries to introduce metal Bi with the same valence as In, changes various synthesis methods including a solvent volatilization method, a solvent vapor resistant auxiliary method, a hydrothermal method and a one-pot synthesis In halogen acid, and does not improve A₂InX₅·H₂Luminescent properties of O materials. Next, other equivalent metals, such as Al, Ga, etc., have been tried, and still the objective of changing the light emitting properties has not been achieved. The inventors have turned to some attempts at exotic metals, e.g. Sn⁴⁺，Te⁴⁺，Zr⁴⁺Etc. it was found that only Te⁴⁺When the fluorescent material is introduced into crystal lattices, strong orange light emission occurs, the luminescent life of the material shows strong temperature dependence, and a fluorescence attenuation curve shows a single exponential process; with decreasing temperature, the lifetime varies from the ns range to the μ s range (only in the ns to μ s range may be convenientRapid detection), a lifetime in this range is convenient to measure; intrinsic A₂InX₅·H₂O host does not emit light, so Te is doped⁴⁺Only one luminescence process exists after the fluorescence lifetime and the kinetic process are convenient to analyze; the luminescence spectrum can be well coupled with a visible light detector (compared with the luminescence peaks of some materials which are positioned in an infrared region, the infrared light detection difficulty is increased, and the materials are not suitable for being used as optical temperature measuring materials), so that Te⁴⁺Doped A₂InX₅·H₂O completely meets the requirement of being used as an optical temperature measuring material. The inventors attribute it to Te⁴⁺Special electronic structure of (Te)⁴⁺Has an outermost electronic structure of 5s²Relative to Bi³⁺And Sn⁴⁺The activity of the metal center is higher. The inventors also found that this would be 5s as well²Sb of electronic structure³⁺Doped to A₂InX₅·H₂Orange light emission also appears in O material matrix crystal lattices, but the optical temperature measurement capability of the O material matrix crystal lattices is further researched, and the luminous life of the O material matrix crystal lattices is basically not changed along with the temperature, so that the O material matrix crystal lattices lose the capability of being used as the optical temperature measurement material. Thus, in A₂InX₅·H₂In the matrix lattice of O material, Te is introduced⁴⁺Can cause strong luminescence and can be used for optical thermometry, which can not be realized by simply doping luminescent ions into any host crystal lattice, and a certain synergistic effect is needed between the host and the dopant.

Compared with the prior art, the invention has the following beneficial effects:

1. the invention is in A₂InX₅·H₂Introduction of Te into O single crystal material⁴⁺And metal ions, and growing the single crystal by a hydrothermal method, wherein the obtained single crystal shows bright orange light emission under the excitation of ultraviolet light. Due to Te⁴⁺5s²Electrons are very sensitive to temperature changes, and therefore, the lead-free all-inorganic Te⁴⁺Doping with A₂InX₅·H₂The O perovskite material can be used as a remote optical temperature measuring material.

2. Compared with the traditional rare earth-based luminescent material, Pb-based metal halide perovskite nanocrystalline and single crystal luminescentMaterial, Te prepared by the invention⁴⁺Doping with A₂InX₅·H₂The O perovskite material has low preparation temperature, can be synthesized in a large scale, has rich raw materials, no toxicity, environmental friendliness, good reproducibility and excellent humidity and temperature stability, shows great potential in the aspect of remote optical temperature measurement application, and is expected to realize commercial application.

Drawings

FIG. 1 is Te⁴⁺Doped Cs₂InCl₅·H₂The synthesis process of the O single crystal is shown schematically.

FIG. 2 is Te⁴⁺Doped Cs₂InCl₅·H₂A photographic image of O single crystal; wherein A is under visible light and B is under ultraviolet light.

FIG. 3 is Te⁴⁺Doped Cs₂InCl₅·H₂Powder diffraction result diagram of O single crystal.

FIG. 4 is Te⁴⁺Doped Cs₂InCl₅·H₂Steady state fluorescence spectrum of O single crystal.

FIG. 5 is Te⁴⁺Doped Cs₂InCl₅·H₂Transient fluorescence spectrum of O single crystal.

FIG. 6 is a photographic view of a flexible solid state lighting film; wherein A and C are under visible light, and B and D are under ultraviolet light.

FIG. 7 is Te⁴⁺Doped Cs₂InCl₅·H₂A temperature-changing transient fluorescence test result graph of the O single crystal; wherein, A is TRPL attenuation curve under different temperatures, B is the relation curve of average life and temperature under different temperatures, and C is the sensitivity curve under different temperatures.

FIG. 8 is a graph of temperature change transient fluorescence test results for a flexible solid state lighting film; wherein A is a TRPL attenuation curve at different temperatures, and B is a relation curve of average life and temperature at different temperatures.

FIG. 9 is 30% Te⁴⁺Doped Cs₂InCl₅·H₂Powder diffraction result diagram of O single crystal.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. 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.

Example 10.3% Te⁴⁺Doped Cs₂InCl₅·H₂O single crystal

In a polytetrafluoroethylene reaction kettle inner container, 2mmol CsCl and 0.5mmol In are added₂O₃、0.003mmol TeO₂And 5mL of HCl are mixed according to a molar ratio, and stirring is kept for at least 30min to obtain a precipitate and a mother liquor as a precursor. Sealing the polytetrafluoroethylene reaction kettle containing the precursor, preserving heat at 180 ℃ to completely dissolve the precursor, slowly cooling to room temperature after 20 hours, separating out the single crystal from halogen acid, filtering and washing to obtain a product Te⁴⁺Doping with A₂InX₅·H₂O single crystal (fig. 1). The synthesized single crystal was pale yellow in appearance under visible light, and emitted strong orange light under excitation of ultraviolet light (fig. 2). The phase of the material is analyzed by combining X-ray powder diffraction with the main material Cs₂InCl₅·H₂The standard powder diffraction patterns of O single crystal were identical (FIG. 3), indicating that Te was synthesized⁴⁺Doped Cs₂InCl₅·H₂The O single crystal is pure phase.

The luminescent properties of the material are further elucidated by spectroscopic characterization. 0.3% Te⁴⁺Doped Cs₂InCl₅·H₂And in the steady-state fluorescence spectrum of the O single crystal (figure 4), an emission peak is positioned at 660nm, the half-width of a luminescence spectrum is 140nm, and the large Stokes shift is realized. The transient fluorescence spectrum of the material (fig. 5) shows that the decay curve is a single exponential process, resulting in a luminescence lifetime of 0.7 mus at 660nm for the material. Doping of Te⁴⁺Then, the larger Stokes shift, the wide luminescence half-peak width and the lifetime in the order of sub-microsecond to microsecond indicate that the luminescence mechanism of the material is self-trapping exciton luminescence.

Example 2Te⁴⁺Doped Cs₂InCl₅·H₂Flexible solid state lighting applications of O single crystals

Te obtained in example 1⁴⁺Doped Cs₂InCl₅·H₂O single crystal was ground to obtain 0.5g of ground Te⁴⁺Doped Cs₂InCl₅·H₂O powder was mixed with 5g of Polydimethylsiloxane (PDMS) prepolymer and 0.5g of a crosslinking agent (the PDMS prepolymer and the crosslinking agent are DOWSIL, respectively)^TMEI-1184Optical encapsulating Part A and DOWSIL^TMEI-1184Optical encapsulating Part B), and heating and curing to obtain the flexible solid lighting film. Under uv illumination, the film emitted bright orange light (fig. 6), representing an application potential in the field of flexible solid state lighting.

Example 3Te⁴⁺Doped Cs₂InCl₅·H₂Optical temperature measurement application of O single crystal material

Te⁴⁺Has an outermost electronic structure of 5s²And 5s²The electrons are very sensitive to temperature change and have the potential of being used as a remote optical temperature measurement material. As shown in FIG. 7, 0.3% Te prepared in example 1⁴⁺Doped Cs₂InCl₅·H₂The average life of the O single crystal at room temperature is about 700ns, and the O single crystal shows single exponential decay, which shows that only one luminescence process exists, the average life is sharply increased along with the reduction of the temperature, and the life is about 6 mus at 80K; fitting the average life at different temperatures to obtain a thermal quenching temperature T_q266K, the sensitive range is 222K to 310K, and the sensitivity is as high as 0.06K^-1The temperature measurement material is equivalent to the highest value of the rare earth-based optical temperature measurement material reported in the current literature. Te (Te)⁴⁺Doped Cs₂InCl₅·H₂The O single crystal has very considerable prospect in the field of remote optical temperature measurement.

Example 4 use of Te⁴⁺Doped Cs₂InCl₅·H₂Optical temperature measurement application of flexible film prepared from O single crystal

To further show Te⁴⁺Doped Cs₂InCl₅·H₂Practical application potential of O in optical temperature measurementThe flexible film synthesized in embodiment 2 of the present invention is applied to optical temperature measurement. As a result, as shown in FIG. 8, the transient fluorescence curve of the thin film also shows a single exponential decay after the flexible thin film is formed, in accordance with the single crystal material, and the fluorescence lifetime becomes longer as the temperature decreases. The flexible film is beneficial to being applied to various industry fields, and the real-time temperature measurement can be realized only by simply coating the film or a polymer precursor on the surface of an object.

Example 530% Te⁴⁺Doped Cs₂InCl₅·H₂O single crystal

Te in example 1⁴⁺The doping amount is adjusted to be 30% of the In molar amount, and the obtained single crystal also shows bright orange light emission under the excitation of ultraviolet light. Similarly, In a Teflon reactor vessel, 2mmol CsCl, 0.5mmol In₂O₃、0.3mmol TeO₂And 5mL of HCl are mixed according to a molar ratio, and stirring is kept for at least 30min to obtain a precipitate and a mother liquor as a precursor. Sealing the polytetrafluoroethylene reaction kettle containing the precursor, preserving heat at 180 ℃ to completely dissolve the precursor, slowly cooling to room temperature after 20 hours, separating out the single crystal from halogen acid, filtering and washing to obtain a product Te⁴⁺Doping with A₂InX₅·H₂And (4) O single crystal. The synthesized single crystal can emit orange light under the excitation of ultraviolet light, which shows that Te can be obtained after the charging proportion of the Te source is increased⁴⁺Doped Cs₂InCl₅·H₂And (4) O single crystal. The phase of the material is analyzed by combining X-ray powder diffraction with the main material Cs₂InCl₅·H₂The standard powder diffraction patterns of O single crystal were identical (FIG. 9), indicating that Te was synthesized⁴⁺Doped Cs₂InCl₅·H₂The O single crystal is pure phase.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.

Claims

1. Leadless all-inorganic Te⁴⁺Doped A₂InX₅·H₂The preparation method of the O perovskite material is characterized by comprising the following steps: mixing A source, In source, Te source and halogen acid HX to obtain precursor, heating for dissolving, cooling to precipitate crystal, and obtaining Te⁴⁺Doping with A₂InX₅·H₂And (4) O single crystal.

2. The lead-free all-inorganic Te according to claim 1⁴⁺Doped A₂InX₅·H₂A process for the preparation of an O perovskite material,

the A source is AX and A₂CO₃At least one of AOAc;

a in the source A is at least one of K, Rb and Cs;

the In source is In₂O₃、InX₃、In(OAc)₃At least one of (1);

the Te source is TeO₂、TeX₄At least one of (1);

x In the A source, the In source and the Te source is at least one of Cl, Br and I;

and X of the hydrohalic acid HX is at least one of Cl, Br and I.

3. The lead-free all-inorganic Te according to claim 2⁴⁺Doped A₂InX₅·H₂A process for the preparation of an O perovskite material,

x In the A source, the In source and the Te source is Cl;

and X of the hydrohalic acid HX is Cl.

4. The lead-free all-inorganic Te according to any one of claims 1 to 3⁴⁺Doped A₂InX₅·H₂A process for the preparation of an O perovskite material,

the dosage of the A source and the In source is that according to a mole ratio of A, In, the A source and the In source are 2: calculating the ratio of 0.1 to 1;

the dosage of the HX is less than the maximum solubility of the raw material at room temperature;

the dosage of the Te source is calculated according to the proportion that Te accounts for more than 0 and less than 100 percent of the molar weight of In.

5. The lead-free all-inorganic Te according to claim 4⁴⁺Doped A₂InX₅·H₂A process for the preparation of an O perovskite material,

the dosage of the A source and the In source is that according to the molar ratio of A to In, the A source and the In source are 2: 1, calculating the mixture ratio;

the dosage of the Te source is calculated according to the proportion of 0.3 to 30 percent of the molar weight of the Te source In.

6. The lead-free all-inorganic Te according to claim 5⁴⁺Doped A₂InX₅·H₂The preparation method of the O perovskite material is characterized In that the dosage of the Te source is calculated according to the proportion of 0.3 percent of the molar weight of the Te source In.

7. The lead-free all-inorganic Te according to claim 1⁴⁺Doped A₂InX₅·H₂A process for the preparation of an O perovskite material,

the heating dissolution is that the solution is completely dissolved by heating at room temperature to 250 ℃;

the crystal is precipitated by cooling to room temperature;

8. Leadless all-inorganic Te⁴⁺Doped A₂InX₅·H₂An O-perovskite material produced by the production method according to any one of claims 1 to 7.

9. The lead-free all-inorganic Te claimed in claim 8⁴⁺Doped A₂InX₅·H₂O perovskite material in remote optical temperature measurement, solid state illumination, display device, anti-counterfeiting and optical detectionAnd applications in photo/photoelectrocatalysis.