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Method for broadening the light emitting range of lead-free double perovskite

A luminous range, double perovskite technology, applied in the direction of luminescent materials, chemical instruments and methods, can solve the problems of material stability reduction, lattice distortion, nervous system damage, etc., and achieve the effect of simple steps and low preparation cost

Active Publication Date: 2019-11-12
ZHENGZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, some researchers have chemically sheared Pb-based perovskite through large-sized organic cations, making the Pb-based perovskite structure two-dimensional and causing lattice distortion, thereby broadening the emission spectrum range, which is generally in the range of 400-650. nm, but the large-sized organic cations and the lead element in it have a negative effect on the water-soluble Pb 2+ Ions have irreversible damage to the human nervous system, and will also lead to a decrease in the stability of the material

Method used

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  • Method for broadening the light emitting range of lead-free double perovskite
  • Method for broadening the light emitting range of lead-free double perovskite

Examples

Experimental program
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Effect test

Embodiment 1

[0030] T301 stainless steel is used as the sealing gasket, and the diamond anvil device is used to pre-press it to a thickness of 50 microns, and then a small hole with a diameter of 120 microns is drilled in the center of the pre-compression position as a pressure chamber. Cs 2 AgBr 6 Thin-film perovskite samples are put into the pressure chamber, sealed with silicone oil as the pressure transmission medium, and the in-situ test is carried out while the diamond anvil generates pressure. The device is as follows: figure 1 shown. Continue to increase the pressure to 22 GPa and then completely release the pressure, and use the Raman spectrometer to test the Cs 2 AgBr 6 Fluorescent signal of perovskite. The result is as Figure 5 Shown, Cs 2 AgBr 6 The fluorescence peak of perovskite first blue-shifted to 600 nm, then red-shifted to 700 nm, and the fluorescence range widened from 520 nm to 1000 nm, with a half-maximum width of 230 nm. Moreover, the pressure was increased ...

Embodiment 2

[0032] The same sample and counter-anvil packaging method as in Example 1 were used. Using the 488 nm laser of the Raman spectrometer as the excitation light, the pressure was continuously increased to 16 GPa, and then the pressure was completely released. The fluorescent signal of the test sample is as follows: Figure 6 As shown, the fluorescence of the sample was blue-shifted to 600 nm and then red-shifted, and a new luminescence shoulder peak appeared in the long wavelength direction, which led to the broadening of the fluorescence spectral range, and its fluorescence range was broadened from 520 nm to 740 nm, half The height and width are 230 nm. After the pressure was removed, the new luminescent shoulder peaks were also retained, and the pressure-treated sample retained the property of fluorescence spectrum broadening, with a half-maximum width of 245 nm.

Embodiment 3

[0034] The same sample and counter-anvil packaging method as in Example 1 were used. Using the 514.5 nm laser of the Raman spectrometer as the excitation light, the pressure was continuously increased to 4 GPa, and then the pressure was completely released to test the fluorescence signal of the sample. The results are as follows: Figure 7 Shown, Cs 2 AgBr 6The perovskite sample had a similar spectral blue shift during the pressurization process, and returned to its original position after the pressure was removed, without spectral broadening.

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Abstract

The invention relates to a method for broadening the light emitting range of lead-free double perovskite. The method comprises: placing submicron-scale Cs2AgBiBr6 as a sample in a pressure chamber, continuously pressurizing the sample by using a diamond anvil cell press as a pressurizing device and using silicone oil as a pressure transmitting medium, and releasing the pressure to achieve a normalpressure so as to obtain the Cs2AgBiBr6 perovskite with a broadened fluorescence range. According to the present invention, by applying external pressure, the pressure can change the atom arrangementmode and the electronic structure so as to affect the interaction between the atoms; and the inorganic octahedrons AgBr6 and BiBr6 in Cs2AgBiBr6 are twisted under the pressure, such that the same length of the Ag-Br bond and the Bi-Br bond is respectively converted into the two bond lengths so as to increase the number of the STEE states between the band gaps and expand the fluorescence emissionrange, wherein the fluorescence range of the Cs2AgBiBr6 material is broadened to 520-1000 nm, and the full width at half maximum is broadened to 230-245 nm.

Description

technical field [0001] The invention belongs to the technical field of perovskite light-emitting materials, and in particular relates to a method for widening the light-emitting range of metal halide perovskite. Background technique [0002] As an emerging semiconductor material that has received extensive attention and research in recent years, perovskite has a series of advantages such as low preparation cost, high light absorption coefficient, large carrier diffusion length, and high luminous quantum yield. It is widely used in solar cells, light-emitting diodes, etc. , photoelectric sensors and other aspects have important potential applications. Single-matrix broad-spectrum luminescent materials can avoid a series of shortcomings of current commercial lighting multi-matrix phosphors, such as self-absorption between different materials leading to decreased efficiency and color instability. Based on this purpose, researchers have been working on finding ways to broaden t...

Claims

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Application Information

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IPC IPC(8): C09K11/74
CPCC09K11/7435
Inventor 杨西贵吕超凡单崇新
Owner ZHENGZHOU UNIV
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