A method for preparing cesium-lead-bromine quantum dot electroluminescent device by conjugated molecular ligand solid-liquid exchange method

A technology for preparing cesium lead bromine quantum and electroluminescent devices, which is applied in semiconductor/solid-state device manufacturing, semiconductor devices, electro-solid devices, etc., can solve the problems of limiting carrier transport, catching up with the gap of light-emitting diodes, etc., to improve luminescence Effects of efficiency, low roughness, high luminescence quantum yield

Active Publication Date: 2019-07-19
HEFEI UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, compared with CsPbBr polycrystalline thin films or other organic-inorganic hybrid perovskite systems (maximum brightness >50,000 cd / m2), there is still a big gap for CsPbBr quantum dot light-emitting diodes to catch up.
Fortunately, several works mentioned above have shown that the surface of CsPbBr quantum dots has an important influence on the performance of electroluminescent diodes, and we speculate that the long-chain ligands oleylamine and oleic acid on the surface of quantum dots limit the performance of light-emitting diodes. Further improvement, because these long-chain ligands are insulating materials, they will limit the transport of carriers

Method used

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  • A method for preparing cesium-lead-bromine quantum dot electroluminescent device by conjugated molecular ligand solid-liquid exchange method
  • A method for preparing cesium-lead-bromine quantum dot electroluminescent device by conjugated molecular ligand solid-liquid exchange method
  • A method for preparing cesium-lead-bromine quantum dot electroluminescent device by conjugated molecular ligand solid-liquid exchange method

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Embodiment 1: Synthesis and purification of cesium lead bromine quantum dots

[0036] 1a. Preparation of Cesium Oleate Precursor

[0037] First, add 0.5g of cesium carbonate, 2mL of oleic acid and 50mL of octadecene into a 100mL round-bottomed three-necked flask, vacuumize and heat to 120°C for 30 minutes, then stop vacuuming and blow nitrogen for 10 minutes, then start again Vacuumize and cycle three times to remove the moisture and oxygen in the flask, and finally obtain a colorless and clear solution, which is the cesium oleate precursor, which is stirred at 70°C and protected by nitrogen gas, and set aside;

[0038] 1b. Synthesis of cesium lead bromine quantum dots

[0039] Add 0.8g of lead bromide and 50mL of octadecene into a 500ml round-bottomed three-necked flask, stir and heat to 120°C, then vacuumize for one hour, then add 5mL of oleic acid and 5ml of oleylamine, and vacuumize for reaction 15-30 minutes until the lead bromide is completely dissolved, then st...

Embodiment 2

[0042] Embodiment 2: the preparation of phenylalkyl ammonium bromide ligand solution

[0043] Add 1g of phenalkylamine and 15mL of ethanol into a 50mL three-necked flask, stir at 0°C, then dropwise add an equimolar amount of hydrogen bromide aqueous solution (48%), and stop the reaction after stirring for 2 hours at 0°C. Add 45mL ether to the reaction solution, filter to obtain the precipitate, dissolve the precipitate with 5mL ethanol, then add 20mL ether, filter to obtain the precipitate, repeat the dissolution and precipitation process 2-3 times to obtain the phenylalkylammonium bromide ligand; Mmol phenylalkylammonium bromide ligand and 400 μL oleic acid were dissolved in 32 mL methyl acetate, and ultrasonically dispersed to obtain a colorless and clear ligand solution;

[0044] The phenalkylamine is benzalkonium, phenethylamine, amphetamine or phentermine.

[0045] The phenylalkylammonium bromide is benzylammonium bromide, phenethylammonium bromide, phenylpropylammonium ...

Embodiment 3

[0047] First, treat the ITO sheet with ozone for 15 minutes, then spin-coat a layer of poly-3,4-ethylenedioxythiophene on the surface of the ITO sheet (4000 spin-coating for 40 seconds), and anneal at 140 ° C for 10 minutes; Spin-coat a solution of poly[bis(4-phenyl)(4-butylphenyl)amine]chlorobenzene at a concentration of 8 mg / mL in the box (4000 spin-coating for 60 seconds), and anneal at 120°C for 20 minutes; Then spin-coat the 20mg / mL cesium-lead-bromine quantum dot solution prepared in Example 1 (2500 spin-coating for 60 seconds), and process it for 5 minutes at 80°C; ×10 -6 40 nm-thick 1,3,5-tris(1-phenyl-1Hbenzimidazol-2-yl)benzene, 1 nm-thick lithium fluoride and 100 nm-thick aluminum electrode were sequentially vapor-deposited under Pa.

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Abstract

The invention discloses a method for preparing cesium-lead-bromine quantum dot electroluminescence device through the solid-liquid exchange method of conjugated molecular ligands. First, the thermal injection method is used to synthesize the cesium-lead-bromine quantum dot, and the quantum dot is purified by methyl acetate. ; then in the oxidation of poly(3,4-ethylenedioxythiophene, poly[bis(4-phenyl)(4-butylphenyl)amine]chlorobenzene and poly(9-vinylcarbazole)chlorobenzene) covered with poly(3,4-ethylenedioxythiophene) On the indium tin, the purified cesium lead bromine quantum dots are then spin-coated, and the solid-liquid ligand exchange is carried out; imidazol-2-yl)benzene, lithium fluoride and aluminum. The invention can produce cesium lead bromine quantum dot electroluminescence diode with high brightness, high efficiency and low opening voltage.

Description

technical field [0001] The invention relates to a method for preparing cesium-lead-bromine quantum dot electroluminescent devices through the solid-liquid exchange method of conjugated molecular ligands. The high-performance cesium-lead-bromine is prepared by introducing π-conjugated small molecules through the solid-liquid ligand exchange method Quantum dot electroluminescent devices. Background technique [0002] All inorganic cesium lead halide (CsPbX 3 , X=Cl, Br, I) perovskite quantum dots have the characteristics of high quantum yield, high luminous color saturation and size-tunable optical bandgap, so since the Kovalenko research group reported this perovskite quantum dot for the first time Since their synthesis by thermal injection of dots, they have been used as the most promising candidate light source materials for various optical devices, such as electroluminescent diodes, photodetectors, lasers, and solar cells. [0003] In the field of perovskite electrolumin...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01L51/56H01L51/54
CPCH10K85/00H10K71/00
Inventor 蒋阳李国鹏程敏朱志峰胥恩泽权俊杰
Owner HEFEI UNIV OF TECH
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