Core-shell quantum dot, quantum dot light emitting diode, quantum dot composition and display device

Abstract

The invention discloses a core-shell quantum dot, a quantum dot light emitting diode, a quantum dot composition and a display device. The core-shell quantum dot comprises a quantum dot core, a first shell layer, a second shell layer and a third shell layer, wherein the first shell layer, the second shell layer and the third shell layer sequentially coat the quantum dot core from inside to outside,the quantum dot core is made of CdZnSe, the first shell layer is made of CdZnSeS, the second shell layer is made of ZnSeS, and the third shell layer is made of CdZnS. According to the core-shell quantum dot provided by the invention, separation of a hole wave function and an electron wave function is realized, the hole wave function is limited in the quantum dot core, the electron wave function is delocalized into the third shell layer, and the hole injection capability and the electron injection capability of the core-shell quantum dot can be respectively adjusted while the emission peak isin the blue light range, so that the injection of carriers is balanced.

Description

Technical field

[0001] This application relates to quantum dot materials, in particular to core-shell quantum dots, quantum dot light-emitting diodes, quantum dot compositions, and display devices. Background technique

[0002] Quantum dot light-emitting diode (QLED), as a strong competitor of organic light-emitting diode (OLED), has been a research hotspot in recent years. In terms of red light QLED, the research group of Professor Xiaogang Peng of Zhejiang University inserted an ultra-thin PMMA insulating layer between the quantum dot light-emitting layer and the electron injection layer by solution spin coating to achieve a balance of carrier injection, making the red light QLED The external quantum efficiency can reach more than 20.5%, the service life is more than 100,000 hours, and its performance has reached or even surpassed commercial OLED products. In terms of green light QLEDs, in 2012, a Korean research group obtained green light quantum dots by coating a 1.6nm thick...

Examples

preparation example Construction

[0028] The preparation method of the above-mentioned core-shell quantum dots can refer to the prior art or be prepared according to the following method: the zinc salt, the first long-chain fatty acid, and the non-coordinating solvent are mixed and heated to obtain the long-chain fatty acid zinc precursor solution; Add the first selenium precursor solution and the first cadmium precursor solution to the precursor solution for heating reaction, and continue to add the second selenium precursor solution for heating reaction to obtain a solution containing CdZnSe quantum dot core; add the first short-chain fatty acid zinc, The second long-chain fatty acid is added to the solution containing the CdZnSe quantum dot core, and the temperature is raised to a specific temperature, and then the second cadmium precursor solution, the third selenium precursor solution, and the first sulfur precursor solution are added for heating reaction to obtain CdZnSe-containing / CdZnSeS quantum dot sol...

Embodiment 1

[0041] (1) Preparation of quantum dot core: Take 4mmol basic zinc carbonate, 4.0mL oleic acid, and 15g octadecene into a three-necked flask. Under the protection of nitrogen atmosphere, heat up to 280℃ to form a clear and transparent solution; then pour into the three-necked flask one by one 2.0mL Se-ODE suspension with a concentration of 0.5mmol / mL and 1.0mL cadmium oleate ODE solution with a concentration of 0.2mmol / mL, warm up to 300°C, add 1.0mL of Se-TBP solution with a concentration of 2mmol / mL, Continue to heat up to 310°C and react for 90 minutes.

[0042] (2) First shell coating: Cool the solution of step (1) to room temperature, under the protection of nitrogen atmosphere, add 3mmol zinc acetate and 7.5mmol oleic acid, then increase the temperature to 180°C and bubbling with nitrogen for 30min, and then increase the temperature to 300°C. Start dropping the Cd-ODE-Se-S-TBP mixed solution (from 1.0 mL of cadmium oleate ODE solution with a concentration of 0.1 mmol / mL, 0.9...

Embodiment 2

[0047] (1) Preparation of quantum dot core: Take 4mmol basic zinc carbonate, 4.0mL oleic acid, and 15g octadecene into a three-necked flask. Under the protection of nitrogen atmosphere, heat up to 280℃ to form a clear and transparent solution; then pour into the three-necked flask one by one 2.0mL Se-ODE suspension with a concentration of 0.5mmol / mL and 1.0mL cadmium oleate ODE solution with a concentration of 0.2mmol / mL, warm up to 300°C, add 1.0mL of Se-TBP solution with a concentration of 2mmol / mL, Continue to heat up to 310°C for 30 min.

[0048] (2) First shell coating: Cool the solution of step (1) to room temperature, under the protection of nitrogen atmosphere, add 2mmol zinc acetate and 5mmol oleic acid, then heat up to 180°C and blow nitrogen for 30min, then heat up to 300°C, start Add dropwise the Cd-ODE-Se-S-TBP mixed solution (from 1.5 mL of cadmium oleate ODE solution with a concentration of 0.1 mmol / mL, 0.8 mL of Se-TBP with a concentration of 1 mmol / mL, and 0.2 mL...

Technical field

[0001] This application relates to quantum dot materials, in particular to core-shell quantum dots, quantum dot light-emitting diodes, quantum dot compositions, and display devices. Background technique

[0002] Quantum dot light-emitting diode (QLED), as a strong competitor of organic light-emitting diode (OLED), has been a research hotspot in recent years. In terms of red light QLED, the research group of Professor Xiaogang Peng of Zhejiang University inserted an ultra-thin PMMA insulating layer between the quantum dot light-emitting layer and the electron injection layer by solution spin coating to achieve a balance of carrier injection, making the red light QLED The external quantum efficiency can reach more than 20.5%, the service life is more than 100,000 hours, and its performance has reached or even surpassed commercial OLED products. In terms of green light QLEDs, in 2012, a Korean research group obtained green light quantum dots by coating a 1.6nm thick...

Examples

preparation example Construction

[0028] The preparation method of the above-mentioned core-shell quantum dots can refer to the prior art or be prepared according to the following method: the zinc salt, the first long-chain fatty acid, and the non-coordinating solvent are mixed and heated to obtain the long-chain fatty acid zinc precursor solution; Add the first selenium precursor solution and the first cadmium precursor solution to the precursor solution for heating reaction, and continue to add the second selenium precursor solution for heating reaction to obtain a solution containing CdZnSe quantum dot core; add the first short-chain fatty acid zinc, The second long-chain fatty acid is added to the solution containing the CdZnSe quantum dot core, and the temperature is raised to a specific temperature, and then the second cadmium precursor solution, the third selenium precursor solution, and the first sulfur precursor solution are added for heating reaction to obtain CdZnSe-containing / CdZnSeS quantum dot sol...

Embodiment 1

[0041] (1) Preparation of quantum dot core: Take 4mmol basic zinc carbonate, 4.0mL oleic acid, and 15g octadecene into a three-necked flask. Under the protection of nitrogen atmosphere, heat up to 280℃ to form a clear and transparent solution; then pour into the three-necked flask one by one 2.0mL Se-ODE suspension with a concentration of 0.5mmol / mL and 1.0mL cadmium oleate ODE solution with a concentration of 0.2mmol / mL, warm up to 300°C, add 1.0mL of Se-TBP solution with a concentration of 2mmol / mL, Continue to heat up to 310°C and react for 90 minutes.

[0042] (2) First shell coating: Cool the solution of step (1) to room temperature, under the protection of nitrogen atmosphere, add 3mmol zinc acetate and 7.5mmol oleic acid, then increase the temperature to 180°C and bubbling with nitrogen for 30min, and then increase the temperature to 300°C. Start dropping the Cd-ODE-Se-S-TBP mixed solution (from 1.0 mL of cadmium oleate ODE solution with a concentration of 0.1 mmol / mL, 0.9...

Embodiment 2

[0047] (1) Preparation of quantum dot core: Take 4mmol basic zinc carbonate, 4.0mL oleic acid, and 15g octadecene into a three-necked flask. Under the protection of nitrogen atmosphere, heat up to 280℃ to form a clear and transparent solution; then pour into the three-necked flask one by one 2.0mL Se-ODE suspension with a concentration of 0.5mmol / mL and 1.0mL cadmium oleate ODE solution with a concentration of 0.2mmol / mL, warm up to 300°C, add 1.0mL of Se-TBP solution with a concentration of 2mmol / mL, Continue to heat up to 310°C for 30 min.

[0048] (2) First shell coating: Cool the solution of step (1) to room temperature, under the protection of nitrogen atmosphere, add 2mmol zinc acetate and 5mmol oleic acid, then heat up to 180°C and blow nitrogen for 30min, then heat up to 300°C, start Add dropwise the Cd-ODE-Se-S-TBP mixed solution (from 1.5 mL of cadmium oleate ODE solution with a concentration of 0.1 mmol / mL, 0.8 mL of Se-TBP with a concentration of 1 mmol / mL, and 0.2 mL...

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