Perovskite nanocrystalline with alkali metal ion passivated surface defects as well as preparation and application of perovskite nanocrystalline

An alkali metal ion, perovskite technology, applied in nanotechnology, final product manufacturing, sustainable manufacturing/processing, etc., can solve problems such as hindering the charge transport of NCs light-emitting diodes, high dynamic instability, affecting LED performance, etc. The effect of improving electrical transport performance, device brightness and external quantum efficiency, and reducing organic ligand density

Active Publication Date: 2020-04-28
HUAZHONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the currently used ligands are usually long-chain organic ligands, although it can passivate the defects on the surface of NCs well and endow the NCs ink with good stability, but these insulating organic components will seriously hinder the light-emitting diodes of NCs ( charge transport within the LED), thereby affecting the performance of the LED
In addition, these long-chain organic ligands are usually highly dynamic and unstable, and are easily detached from the surface during the purification of NCs, resulting in the generation of defect states.

Method used

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  • Perovskite nanocrystalline with alkali metal ion passivated surface defects as well as preparation and application of perovskite nanocrystalline
  • Perovskite nanocrystalline with alkali metal ion passivated surface defects as well as preparation and application of perovskite nanocrystalline
  • Perovskite nanocrystalline with alkali metal ion passivated surface defects as well as preparation and application of perovskite nanocrystalline

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preparation example Construction

[0049] Generally speaking, the preparation method of the perovskite nanocrystal of alkali metal ion passivation surface defect in the present invention comprises the following steps: the ligand solution of alkali metal ion and the ligand solution of monovalent cation are mixed, fast (time is not More than 2s) into the stirred poor solution of divalent metal halides with quaternary ammonium salts as solubilizers. After the perovskite is formed, add the poor solution of organic ligands to the mixed solution to obtain perovskite nanocrystals. liquid, purifying the perovskite nanocrystal crude liquid to obtain a colloidal solution of perovskite nanocrystals in which surface defects are passivated by alkali metal ions;

[0050] Wherein, the halogen element in the halide is one or more of F, Cl, Br, I;

[0051] Alkali metal ions are selected from Li + 、Na + 、K + , Rb + One or more of them are derived from alkali metal inorganic salts.

[0052] In some embodiments, when the alka...

Embodiment 1

[0081] This embodiment provides a method for preparing perovskite nanocrystals with potassium ions passivating surface defects, and applying the nanocrystals prepared by this method to light-emitting diodes, which specifically includes the following steps:

[0082] 1. CsPb(Br / Cl) 3 Preparation of NCs solution: accurate weighing of PbBr with electronic balance 2 (0.125mmol, 0.046g), PbCl 2 (0.125mmol, 0.035g) and tetra-n-octylammonium bromide (0.750mmol, 0.410mg), add 5mL of toluene as a solvent, and stir on a magnetic stirrer until the raw materials are fully dissolved. Prepare Cs with a concentration of 0.1mol / L respectively 2 CO 3 The octanoic acid solution with a concentration of 0.1mol / L of K 2 CO 3 octanoic acid solution. Pipette 300 μL of Cs 2 CO 3 octanoic acid solution, 50 μL K 2 CO 3 The octanoic acid solution and 305 μL octanoic acid solution were thoroughly mixed in a bullet plastic tube. The mixed solution in the bullet plastic tube was quickly dropped ...

Embodiment 2

[0100] Compared with Example 1, embodiment 2 is only different in step 1 (that is, the preparation of NCs solution), and step 2 (that is, the preparation of light-emitting diodes) only needs to use the NCs solution obtained in corresponding step 1. In step 2, The overall technological process sequence, the setting of specific parameter conditions, etc. are all the same as in Example 1. Step 1 is as follows:

[0101] CbBr 3 Preparation of NCs solution: accurate weighing of PbBr with electronic balance 2 (0.250mmol, 0.092g) and tetra-n-octylammonium bromide (0.750mmol, 0.410mg), add 5mL of toluene as a solvent, and stir on a magnetic stirrer until the raw materials are fully dissolved. Prepare Cs with a concentration of 0.1mol / L respectively 2 CO 3 The octanoic acid solution with a concentration of 0.1mol / L of K 2 CO 3 octanoic acid solution. Pipette 300 μL of Cs 2 CO 3 octanoic acid solution, 50 μL K 2 CO 3 The octanoic acid solution and 305 μL octanoic acid solutio...

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Abstract

The invention belongs to the field of photoelectric materials, and discloses perovskite nanocrystalline with alkali metal ion passivated surface defects as well as preparation and application of the perovskite nanocrystalline. The preparation method comprises the steps of mixing a ligand solution containing alkali metal ions with a ligand solution of nanocrystalline A-site positive ions, and adding the mixture into a poor solution of a divalent metal halide taking quaternary ammonium salt as a dissolution promoter to obtain a mixed solution; after perovskite is formed, adding a poor solution of an organic ligand into the perovskite to obtain a perovskite nanocrystalline crude solution, and obtaining nanocrystalline colloid with passivated surface defects after purification treatment. According to the invention, the preparation method is improved, alkali metal ions such as potassium ions and sodium ions are introduced in the process of preparing the nanocrystalline by adopting a ligand-assisted re-precipitation method, and the alkali metal ions serve as metal ion ligands and replace part of surface active organic ligands, so that the generation of halogen vacancies in the nanocrystalline can be inhibited, effective passivation of surface defects of the perovskite nanocrystalline is achieved, and the luminous efficiency and the electric conductivity of the material are effectively improved.

Description

technical field [0001] The invention belongs to the field of photoelectric materials, and more specifically relates to a perovskite nanocrystal whose surface defects are passivated by alkali metal ions and its preparation and application. Background technique [0002] Perovskite light-emitting diodes (PeLEDs) are powerful candidates for next-generation solid-state lighting and high-definition displays due to their high photoluminescence quantum yield (PLQY), tunable emission wavelength in the visible spectral band, and narrow emission linewidth. . In the past few years, the development of PeLEDs emitting red and green light has been very rapid, and their corresponding external quantum efficiencies have exceeded 20%. However, the research progress of blue-emitting PeLEDs is far behind that of red and green light, mainly because it is difficult to obtain high-quality blue-emitting perovskite luminescent materials. [0003] Mixed with all inorganic cesium lead bromine chlorin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L31/18H01L31/032H01L31/036H01L33/26H01L33/00B82Y40/00
CPCB82Y40/00H01L31/032H01L31/036H01L31/18H01L33/005H01L33/26Y02P70/50
Inventor 王磊阳妃陈虹婷张瑞
Owner HUAZHONG UNIV OF SCI & TECH
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