A white light long afterglow phosphor and preparation method thereof

Abstract

The present invention is a white light long afterglow phosphor and its preparation method. The structural formula of the phosphor is Cs2(Na 0.9 Ag 0.1 In) 1‑ x Zr x Cl6; wherein 0.1≤x≤0.9; its emission wavelength covers the 350-850nm range, and after 5 minutes of ultraviolet light excitation, the white light afterglow decay time exceeds 0.5-5 hours. The present invention can be synthesized at room temperature, does not require a redox atmosphere, and provides a phosphor with good stability and excellent afterglow decay performance.

Description

Technical Field

[0001] The present invention relates to the field of material technology, in particular to a white light long afterglow phosphor and a preparation method thereof. Background Art

[0002] Long afterglow materials are luminescent materials that can store energy when excited by external light and slowly release the stored energy in the form of light after the excitation light source is turned off. Their diverse and extensive applications have attracted widespread attention. Since oxide materials have abundant oxygen vacancies that provide energy traps, most of the current long afterglow materials are oxides, such as CaAl2O4:Eu 2+ ,Nd 3+ 、Sr2MgSi2O7:Eu 2+ ,Dy 3+ 、SrAl2O4:Eu 2+ ,Dy 3+ However, oxide materials have high formation energy and often show a high dependence on external energy. Their synthesis requires extremely high temperatures and maintenance for several hours, such as above 1300℃ for 6 hours. In addition to the temperature rise and fall steps, the entire reaction process often takes dozens of hours, which undoubtedly increases the time cost. 3+ to Eu 2+ The hydrogen introduced at high temperature during the reduction reaction also becomes one of the safety hazards of the reaction.

[0003] In comparison, perovskite materials have lower formation energy, lower dependence on temperature and support liquid phase synthesis. In recent years, new lead-free perovskite materials have also become a member of the afterglow world, but they are often completed by rare earth or transition metal doping. Unfortunately, it is not easy to dope perovskite materials with rare earth and transition metals. Due to the high activation energy, the feed ratio and doping ratio often show huge differences. For example, the green light emitting Tb 3+ The actual doping rate was 21.6% (Angew. Chem. Int. Ed., 2022, 61, e202210853), and the near-infrared emitting Yb 3+ The material is 40% and the actual doping is 0.5% (Adv.Funct.Mater., 2022, 32, 2110663). For example, the red-emitting Mn 2+ The raw material input is 20%, but the actual doping is 0.11% (Anew.Chem.Int.Ed., 2021, 60, 24450-24455), which will lead to excessive consumption of strategic resources and greatly increase the preparation cost.

[0004] In addition, due to the obvious energy transfer or energy reabsorption problems of multiple doped ions (such as red, green and blue luminescent ions) during the emission process, the designed multi-ion doped white light is often inefficient and short-lived. The white light spectrum achieved by single ion doping is incomplete and often shows a missing luminescence channel, such as Ti 3+ The white light achieved by ion doping shows a clear absence of the red light band, thus exhibiting the emission characteristics of cold white light.

[0005] The literature Light Sci. APPl., 2023, 12, 75 reported a universal synthesis method of lead-free perovskite at room temperature. The article reported a universal lead-free perovskite Cs2Na 1-x Ag x In 1-y Bi y Cl6 synthesis strategy; a new preparation method was developed by doping Cs2NaInCl6 with Ag and Bi. Due to the lack of effective traps, the phenomenon of white light afterglow was not involved.

[0006] Adv. Funct. Mater., 2023, 2311437 reports on a Cs2NaInCl6:xAg,yBi warm-white afterglow phosphor. This paper reports on the warm-white afterglow of a Cs2NaInCl6 system co-doped with Ag and Bi. By precisely controlling the doping ratio of Ag and Bi, an effective trap density is ensured, thus achieving warm-white afterglow performance. However, since afterglow luminescence is weaker than fluorescence, warm-white light is easily perceived as yellow by the human eye at low brightness levels, and proper spectral manipulation is still required to achieve white light.

[0007] To date, the design of white light afterglow materials that fully cover the visible spectrum without energy reabsorption remains a huge challenge in this field. Summary of the Invention

[0008] The purpose of the present invention is to provide a white light long afterglow phosphor and its preparation method to solve the problems existing in the current technology, such as high oxide formation energy, hydrogen safety hazards, excessive consumption of rare earth by perovskite materials, and difficulty in designing white light afterglow. The phosphor is a new white light afterglow material with no rare earth or transition metal doping and full coverage of the visible spectrum. The specific chemical formula is Cs2(Na 0.9 Ag 0.1 In) 1-x Zr xCl6 (0.1≤x≤0.9) has an emission wavelength range of 350-850nm. After 5 minutes of UV excitation, the white light afterglow decays for 0.5-5 hours. The phosphor is obtained by grinding the appropriately mixed raw materials in concentrated hydrochloric acid. This phosphor can be synthesized at room temperature, does not require a redox atmosphere, and exhibits excellent stability and afterglow decay.

[0009] Technical solution of the present invention

[0010] A white light long afterglow phosphor, the structural formula of the phosphor is Cs2(Na 0.9 Ag 0.1 In) 1-x Zr x Cl6(0.1≤x≤0.9);

[0011] The emission wavelength of this phosphor covers the range of 350-850nm. As the Zr doping amount increases from 0.1 to 0.9, the luminescent color of the sample gradually changes from warm white light to cool white light; after 5 minutes of ultraviolet light excitation, the white light afterglow decay time is 0.5-5 hours.

[0012] White light afterglow phosphor, through Cs2Na 0.9 Ag 0.1 The method of doping Zr in InCl6 matrix (Zr replaces In position and introduces adjacent Na or Ag vacancies) realizes spectrum and trap regulation, thereby achieving the purpose of white light afterglow emission. 0.9 Ag 0.1 Both InCl6 and Cs2ZrCl6 exhibit simple cubic structures and P1 space groups, so they do not exhibit obvious phase separation problems even when heavily doped.

[0013] The method for preparing the white light long afterglow phosphor comprises the following steps:

[0014] (1) adding a Cs-containing compound, a Na-containing compound, an Ag-containing compound, a Zr-containing compound, and an In-containing compound into a mortar and mixing them according to the ratio of the constituent elements of the phosphor to obtain a mixture;

[0015] Wherein, the Cs-containing compound is Cs chloride, acetate or carbonate;

[0016] The Na-containing compound is a chloride, acetate or carbonate of Na;

[0017] The Ag-containing compound is Ag chloride or acetate;

[0018] The Zr-containing compound is Zr chloride, acetate or carbonate;

[0019] The In-containing compound is a chloride or acetate of In;

[0020] The ratio of the above salts is based on the Cs2(Na 0.9 Ag 0.1 In) 1-x Zr x The corresponding material ratio in Cl6 (0.1≤x≤0.9) is Cs:Na:Ag:Zr:In=2:0.9*(1-x):0.1*(1-x):x:(1-x);

[0021] (2) Add concentrated hydrochloric acid to the mortar and grind for 1-5 minutes;

[0022] Wherein, 1-6 mL of concentrated hydrochloric acid is added for every 2 mmol of the Cs compound; the concentration of the concentrated hydrochloric acid is 30-38 wt %.

[0023] (3) Centrifuge the product at 3000-5000 rpm for 1-60 s;

[0024] (4) After centrifugation, pour off the supernatant and wash the precipitate with anhydrous ethanol;

[0025] (5) Repeat "step (3)-step (4)" 1 to 3 times to ensure that there is no hydrochloric acid residue in the product;

[0026] (6) Dry the final precipitate in an oven at 50-80°C for about 2-3 hours, take it out and grind it to obtain phosphor powder.

[0027] The technical features of the present invention are:

[0028] The present invention is based on Cs2Na with warm white light emission characteristics 0.9 Ag 0.1 InCl6 is doped with Zr elements in different proportions. Zr enters the crystal lattice and produces corresponding blue light emission when excited by external light, which complements the warm white light emission caused by the lack of blue light components in the matrix and achieves the goal of near-pure white light emission. In addition, the incorporation of Zr causes defects in the local crystal lattice, thereby introducing trap centers that can capture electrons and realizing the afterglow characteristics.

[0029] Beneficial effects of the present invention

[0030] (1) The present invention realizes an afterglow emitting material with nearly pure white light covering the entire visible spectrum.

[0031] (2) The present invention does not require doping with rare earth or transition metals, which reduces the synthesis cost and protects strategic resources such as rare earth.

[0032] (3) The present invention does not require dangerous synthesis conditions such as high temperature, high pressure, and hydrogen atmosphere.

[0033] (4) This invention provides a white light realization solution for the academic community, which has promoted the development of the afterglow field. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The given is Cs2(Na 0.9 Ag 0.1 In) 0.6 Zr 0.4 XRD of Cl6 and standard cards of Cs2NaInCl6 and Cs2ZrCl6;

[0035] Figure 2 The given is Cs2(Na 0.9 Ag 0.1 In) 0.6 Zr 0.4 Fluorescence excitation spectrum of Cl6;

[0036] Figure 3 The given is Cs2(Na 0.9 Ag 0.1 In) 0.6 Zr 0.4 Fluorescence emission spectrum of Cl6;

[0037] Figure 4 The given is Cs2(Na 0.9 Ag 0.1 In) 0.6 Zr 0.4 Afterglow emission spectrum of Cl6;

[0038] Figure 5 The given is Cs2(Na 0.9 Ag 0.1 In) 0.6 Zr 0.4 Afterglow decay spectrum of Cl6;

[0039] Figure 6 The given is Cs2(Na 0.9 Ag 0.1 In) 0.9 Zr 0.1 XRD of Cl6 and standard cards of Cs2NaInCl6;

[0040] Figure 7 The given is Cs2(Na 0.9 Ag 0.1 In) 0.9 Zr 0.1 Fluorescence excitation spectrum of Cl6;

[0041] Figure 8 The given is Cs2(Na 0.9 Ag0.1 In) 0.9 Zr 0.1 Fluorescence emission spectrum of Cl6;

[0042] Figure 9 The given is Cs2(Na 0.9 Ag 0.1 In) 0.9 Zr 0.1 Afterglow emission spectrum of Cl6;

[0043] Figure 10 The given is Cs2(Na 0.9 Ag 0.1 In) 0.9 Zr 0.1 Afterglow decay spectrum of Cl6;

[0044] Figure 11 The given is Cs2(Na 0.9 Ag 0.1 In) 0.1 Zr 0.9 XRD of Cl6 and standard cards of Cs2ZrCl6;

[0045] Figure 12 The given is Cs2(Na 0.9 Ag 0.1 In) 0.1 Zr 0.9 Fluorescence excitation spectrum of Cl6;

[0046] Figure 13 The given is Cs2(Na 0.9 Ag 0.1 In) 0.1 Zr 0.9 Fluorescence emission spectrum of Cl6;

[0047] Figure 14 The given is Cs2(Na 0.9 Ag 0.1 In) 0.1 Zr 0.9 Afterglow emission spectrum of Cl6;

[0048] Figure 15 The given is Cs2(Na 0.9 Ag 0.1 In) 0.1 Zr 0.9 Afterglow decay spectrum of Cl6;

[0049] Figure 16 The given is Cs2(Na 0.9 Ag 0.1 In) 1-x Zrx Comparison of afterglow decay curves in Cl6 when x is 0.1, 0.4, and 0.9. DETAILED DESCRIPTION

[0050] Example 1: Cs2(Na 0.9 Ag 0.1 In) 0.6 Zr 0.4 Cl6 sample

[0051] The preparation method of the present invention is as follows: 2 mmol CsCl (0.3367 g) powder, 0.54 mmol NaCl (0.0316 g) powder, 0.06 mmol AgCl (0.0086 g) powder, 0.6 mmol InCl3·4H2O (0.1759 g) powder and 0.4 mmol ZrCl4 (0.0932 g) powder are weighed and mixed in a mortar, 1 mL 38 wt% concentrated hydrochloric acid is added and ground for 1 min.

[0052] After the preparation is completed, the mixture is centrifuged at 5000 rpm for 1 second, and then washed with ethanol. The "centrifugation-washing" process is repeated three times. The final precipitate is placed in an oven and dried at 60°C for about 2 hours to obtain the final powdered sample.

[0053] Test conditions: The crystal structure of the samples was determined using a Rigaku X-ray diffractometer, using a Cu target as the radiation source, a tube voltage of 40 kV, a tube current of 40 mA, a scan step of 0.02°, a scan speed of 15° / min, and a scan range of 10°-70°. The emission and excitation spectra of the samples were obtained using an FS5 spectrometer.

[0054] Experimental results: Figure 1 The given is Cs2(Na 0.9 Ag 0.1 In) 0.6 Zr 0.4 The XRD of Cl6 and the standard cards of Cs2NaInCl6 and Cs2ZrCl6 show that the target product has been obtained through this experimental scheme;

[0055] Figure 2 The given is Cs2(Na 0.9 Ag 0.1 In) 0.6 Zr 0.4 The fluorescence excitation spectrum of Cl6 shows the optimal excitation intensity around 260 nm;

[0056] Figure 3 The given is Cs2(Na 0.9 Ag 0.1 In)0.6 Zr 0.4 The fluorescence emission spectrum of Cl6 covers the range of about 350-850nm, with an emission peak of about 560nm;

[0057] Figure 4 The given is Cs2(Na 0.9 Ag 0.1 In) 0.6 Zr 0.4 The afterglow emission spectrum of Cl6 covers a range of about 350-800nm, and the afterglow emission peak is about 530nm;

[0058] Figure 5 The given is Cs2(Na 0.9 Ag 0.1 In) 0.6 Zr 0.4 The afterglow decay spectrum of Cl6 shows that the signal-to-noise ratio of the afterglow signal is relatively strong, proving that the sample has excellent afterglow characteristics and shows potential application value in the fields of multi-color channel anti-counterfeiting, multi-channel information storage, and artistic creation.

[0059] Example 2: Cs2(Na 0.9 Ag 0.1 In) 0.9 Zr 0.1 Cl6 sample

[0060] The preparation method of the present invention is as follows: 2 mmol CsCl (0.3367 g) powder, 0.81 mmol NaCl (0.0474 g) powder, 0.09 mmol AgCl (0.0129 g) powder, 0.6 mmol InCl3·4H2O (0.2639 g) powder and 0.1 mmol ZrCl4 (0.0233 g) powder are weighed in a mortar, 6 mL of 30 wt% concentrated hydrochloric acid is added and ground for 5 min.

[0061] After the preparation is completed, the mixture is centrifuged at 3000 rpm for 60 seconds, and then washed with ethanol, which is repeated three times. The final precipitate is placed in an oven and dried at 80°C for about 2 hours to obtain the final powdered sample.

[0062] Test conditions: the same as in Example 1.

[0063] Experimental results: Figure 6 The given is Cs2(Na 0.9 Ag 0.1 In) 0.9 Zr 0.1 The XRD of Cl6 and the standard card of Cs2NaInCl6 show that the target product has been obtained through this experimental scheme;

[0064] Figure 7 The given is Cs2(Na 0.9 Ag 0.1 In) 0.9 Zr 0.1 The fluorescence excitation spectrum of Cl6 shows the optimal excitation intensity around 265 nm;

[0065] Figure 8 The given is Cs2(Na 0.9 Ag 0.1 In) 0.9 Zr 0.1 The fluorescence emission spectrum of Cl6 covers a range of approximately 400-850nm, with an emission peak of approximately 590nm;

[0066] Figure 9 The given is Cs2(Na 0.9 Ag 0.1 In) 0.9 Zr 0.1 The afterglow emission spectrum of Cl6 covers a range of about 400-800nm, and the afterglow emission peak is about 590nm;

[0067] Figure 10 The given is Cs2(Na 0.9 Ag 0.1 In) 0.9 Zr 0.1 The afterglow decay spectrum of Cl6 shows a strong signal-to-noise ratio, proving that the sample has excellent afterglow characteristics.

[0068] Example 3: Cs2(Na 0.9 Ag 0.1 In) 0.1 Zr 0.9 Cl6 sample

[0069] The preparation method of the present invention is as follows: 2 mmol CsCl (0.3367 g) powder, 0.09 mmol NaCl (0.0053 g) powder, 0.01 mmol CH3COOAg (0.0017 g) powder, 0.1 mmol InCl3 (0.0186 g) powder and 0.9 mmol ZrCl4 (0.2097 g) powder are weighed in a mortar, 3 mL of 35 wt% concentrated hydrochloric acid is added and ground for 2 min.

[0070] After the preparation is completed, the mixture is centrifuged at 5000 rpm for 10 seconds, and then washed with ethanol, which is repeated three times. The final precipitate is placed in an oven and dried at 50°C for about 3 hours to obtain the final powder sample.

[0071] Test conditions: the same as in Example 1.

[0072] Experimental results: Figure 11 The given is Cs2(Na 0.9 Ag 0.1 In) 0.1 Zr 0.9 The XRD of Cl6 and the standard card of Cs2ZrCl6 show that the target product has been obtained through this experimental scheme;

[0073] Figure 12 The given is Cs2(Na 0.9 Ag 0.1 In) 0.1 Zr 0.9 The fluorescence excitation spectrum of Cl6 shows the optimal excitation intensity around 245 nm;

[0074] Figure 13 The given is Cs2(Na 0.9 Ag 0.1 In) 0.1 Zr 0.9 The fluorescence emission spectrum of Cl6 covers the range of about 300-700nm, with an emission peak of about 460nm;

[0075] Figure 14 The given is Cs2(Na 0.9 Ag 0.1 In) 0.1 Zr 0.9 The afterglow emission spectrum of Cl6 covers a range of about 400-700nm, and the afterglow emission peak is about 520nm;

[0076] Figure 15 The given is Cs2(Na 0.9 Ag 0.1 In) 0.1 Zr 0.9 The afterglow decay spectrum of Cl6 shows acceptable signal-to-noise ratio of the afterglow signal, proving that the sample has observable afterglow characteristics.

[0077] Figure 16 The given is Cs2(Na 0.9 Ag 0.1 In) 1-x Zr x Comparing the afterglow decay curves of Cl6 when x is 0.1, 0.4 and 0.9 respectively, it can be seen that when the Zr content is 0.4, the afterglow signal is optimal and the afterglow decay lasts for 5 hours, reflecting excellent afterglow performance; when the Zr content is 0.9, the afterglow signal is weakest, but it can still continue to decay for 0.5 hours.

[0078] Matters not covered by the present invention are known technologies.

Claims

1. A white light long afterglow phosphor, characterized by The structural formula of the phosphor is Cs2(Na 0.9 Ag 0.1 In) 1-x Zr x Cl6, where 0.1≤x≤0.

9.

2. The white light long-afterglow phosphor according to claim 1, characterized in that the emission wavelength of the phosphor covers the range of 350-850nm, and as the Zr doping amount increases from 0.1 to 0.9, the luminescent color of the sample gradually changes from warm white light to cool white light; after 5 minutes of ultraviolet light excitation, the white light afterglow decay time is 0.5-5 hours.

3. The method for preparing the white light long afterglow phosphor according to claim 1, wherein the method comprises the following steps: (1) According to the ratio of the constituent elements of the phosphor, a Cs-containing compound, a Na-containing compound, an Ag-containing compound, a Zr-containing compound, and an In-containing compound are added to a mortar and mixed to obtain a mixture; in, The Cs-containing compound is a chloride, acetate or carbonate of Cs; The Na-containing compound is a chloride, acetate or carbonate of Na; The Ag-containing compound is Ag chloride or acetate; The Zr-containing compound is Zr chloride, acetate or carbonate; The In-containing compound is a chloride or acetate of In; (2) Add concentrated hydrochloric acid to the mortar and grind for 1-5 minutes; Wherein, 1-6 mL of concentrated hydrochloric acid was added for every 2 mmol of Cs compound; (3) Centrifuge the product at 3000-5000 rpm for 1-60 s; (4) After centrifugation, pour off the supernatant and wash the precipitate with anhydrous ethanol; (5) Repeat "step (3) - step (4)" 1 to 3 times; (6) The final precipitate was placed at 50-80 o C oven for 2-3 hours, take out and crush to obtain phosphor powder.

4. The method for preparing a white light long afterglow phosphor according to claim 3, wherein the concentration of concentrated hydrochloric acid is 30-38 wt%.

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