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Light-emitting diode and preparation method thereof

A technology of light-emitting diodes and light-emitting layers, which is applied in semiconductor/solid-state device manufacturing, electrical components, circuits, etc., and can solve problems such as device efficiency drop and efficiency roll-off

Inactive Publication Date: 2020-08-28
HENAN UNIVERSITY
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the first point-value light-emitting device based on quantum dots was successfully constructed in 1994, the efficiency of the external quantum dots of the three primary colors of light-emitting diodes has reached 20%. However, almost all QLEDs have an insurmountable shortcoming, that is, the efficiency of the device As the current density (brightness or voltage) increases rapidly, this phenomenon is called efficiency roll-off, which is currently a crucial problem restricting the development and application of the entire QLEDs field.

Method used

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  • Light-emitting diode and preparation method thereof
  • Light-emitting diode and preparation method thereof
  • Light-emitting diode and preparation method thereof

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preparation example Construction

[0047] The present invention also provides a method for preparing a light-emitting diode described in the above technical solution, comprising the following steps:

[0048] After sequentially preparing a hole injection layer, a hole transport layer, a light-emitting layer and an electron transport layer on the upper surface of the bottom electrode, evaporating the top electrode to obtain the light-emitting diode;

[0049] The raw material for the preparation of the luminescent layer is quantum dots with gradient alloy core-shell structure;

[0050] The quantum dots of the gradient alloy core-shell structure have a particle size ≥ 10nm;

[0051] The quantum dots of the gradient alloy core-shell structure are arranged in a gap-filling manner.

[0052] In the present invention, before the hole injection layer is prepared on the upper surface of the bottom electrode, it is also preferred to sequentially clean the bottom electrode and perform ultraviolet-ozone treatment, and the t...

Embodiment 1

[0057] After the ITO glass substrate was cleaned and treated with UV-ozone (15min) in sequence, the upper surface of the ITO glass substrate was spin-coated (rotating at 2000 rpm) with 35nm thick poly(3,4-ethylenedioxythiophene ): after polystyrene sulfonate is used as the hole injection layer, dry (150° C., 15 min); continue to spin-coat (rotating speed is 3000 rpm) 20nm thick poly[( 9,9-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine)] as the hole transport layer, dried ( 150° C., 15 min); on the upper surface of the hole transport layer, spin-coat (rotating speed is 2500 rpm) 15 nm thick CdSe / Zn x Cd 1-x Se / ZnSe y S 1-y After / ZnS (diameter is 15nm) as luminous layer (1 layer), dry (60 ℃, 15min); On the upper surface of described luminescent layer, spin-coat (rotating speed is 3000 rpm) 50nm thick zinc oxide as electron transport layer, on the upper surface of the electron transport layer with Evaporate 100nm-thick Al as the top electrode at a s...

Embodiment 2

[0060] After the ITO glass substrate was cleaned and treated with UV-ozone (15min) in sequence, the upper surface of the ITO glass substrate was spin-coated (3000 rpm) with 40nm thick polystyrene sulfonate (PEDOT:PSS) After being used as a hole injection layer, dry (150°C, 15min); continue to spin-coat (3000 rpm) 20nm-thick poly[(9,9-dioctylfluorene) on the upper surface of the hole injection layer -2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine)] as the hole transport layer, dried (150°C, 15min); The upper surface of the hole transport layer is spin-coated (rotating speed is 2500 rev / min) 18nm thick Zn x Cd 1-x Se / ZnSe y S 1-y (diameter is 18nm) after being used as luminous layer (1 layer), dry (60 ℃, 15min); After the upper surface of described luminescent layer is spin-coated (rotating speed is 3000 rpm) 50nm thick zinc oxide is used as electron transport layer , on the upper surface of the electron transport layer with Evaporate 100nm-thick Al as the top elec...

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Abstract

The invention relates to the technical field of light emitting diodes, particularly to a light emitting diode and a preparation method thereof. According to the invention, gradient alloy core-shell structure quantum dots are selected as a light-emitting layer, QLEDs without efficiency roll-off is achieved by accurately regulating and controlling the thickness and arrangement of the light-emittinglayer in the QLED, and the problem that the external quantum efficiency of a device is subjected to efficiency roll-off along with increase of current density and brightness in all QLEDs in the past is solved; and according to the record of the embodiment, the brightness of the light emitting diode is within 200000 cd / m<2>, the current density of the light emitting diode is within 500 mA / cm<2>, the efficiency can be kept at about 20%, and the efficiency deviation does not exceed 5%.

Description

technical field [0001] The invention relates to the technical field of light emitting diodes, in particular to a light emitting diode and a preparation method thereof. Background technique [0002] Light-emitting diodes (QLEDs) based on fluorescent quantum dots have good application prospects in the field of lighting due to their good luminous intensity, color purity, and low cost. Since the first point-value light-emitting device based on quantum dots was successfully constructed in 1994, the efficiency of the external quantum dots of the three primary colors of light-emitting diodes has reached 20%. However, almost all QLEDs have an insurmountable shortcoming, that is, the efficiency of the device As the current density (luminance or voltage) increases rapidly, this phenomenon is called efficiency roll-off, which is currently a crucial problem restricting the development and application of the entire QLEDs field. [0003] Studies have shown that there are three main reaso...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L51/50H01L51/54H01L51/56
CPCH10K50/115H10K2102/00H10K71/00
Inventor 申怀彬巴国航桂志祥高岩杜祖亮
Owner HENAN UNIVERSITY
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