Electroluminescent Device Double Electron Transport Layer Leakage Current

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Solution Overview

Problem

Existing electroluminescent devices face challenges in improving luminous efficiency due to leakage currents and suboptimal electron transport properties, particularly in emission layers incorporating quantum dots.

Innovation Solution

The electroluminescent device incorporates a double electron transport layer structure, with a first electron transport layer composed of inorganic-organic composite particles and a second electron transport layer made of inorganic oxide particles, where the first layer has a lower work function than the second, enhancing electron transport and preventing leakage currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single electron transport layer is used, then the device structure is simple, but electron transport properties are suboptimal and leakage currents occur

Engineering Contradiction:

Improveelectron transport propertiesVSAvoidelectron transport layer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The electron transport layer is divided into two distinct layers: a first electron transport layer containing inorganic-organic composite particles and a second electron transport layer containing inorganic oxide particles. This segmentation allows each layer to perform specialized functions, with the first layer providing lower work function for efficient electron injection and the second layer providing higher electron mobility, thereby resolving the contradiction between simple structure and optimal electron transport properties.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first electron transport layer uses inorganic-organic composite particles that combine the advantages of both inorganic materials (electron transport capability) and organic materials (flexibility and processability). This composite approach enables the layer to achieve both low work function for efficient electron injection and good electron transport properties, addressing the reliability issue without significantly increasing device complexity.

Inventive Principle:

Principle #40Composite materials

2Productivity

If conventional electron transport layers are used, then manufacturing is simple, but leakage currents reduce luminous efficiency

Engineering Contradiction:

Improveluminous efficiencyVSAvoidleakage current

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

Different regions of the electron transport system are assigned different properties: the first electron transport layer is designed with lower work function materials (inorganic-organic composites) optimized for electron injection from the electrode, while the second layer uses inorganic oxide particles optimized for electron mobility and blocking leakage currents. This local differentiation of material properties allows the system to simultaneously achieve high luminous efficiency and prevent leakage currents.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The first electron transport layer acts as an intermediary between the electrode and the second electron transport layer. It facilitates smooth electron injection from the electrode while the second layer serves as an intermediary that transports these electrons efficiently through the emission layer. This two-stage intermediary approach prevents direct contact between the electrode and the emission layer, thereby preventing leakage currents while maintaining high luminous efficiency.

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration improves luminous efficiency by facilitating smooth electron transport and reducing leakage currents, leading to enhanced luminance and quantum efficiency in electroluminescent devices.

Implementation Method 1

a first electron transport layer disposed on the emission layer and comprising at least two inorganic-organic composite particles; a second electron transport layer disposed on the first electron transport layer and comprising at least two inorganic oxide particles, wherein the first electron transport layer has a lower work function than the second electron transport layer

Methodology Applied

Scientific EffectElectron transport: Conduction (electrical)

Implementation Method 2

the first electron transport layer has a lower work function than the second electron transport layer

Methodology Applied

Scientific EffectWork function difference: Electrical Resistance

Data Source

PatentUS10396306B2Electroluminescent device capable of improving luminous efficiency by preventing a leakage current and improving electron transport properties and a display device including the same

Publication Date: 2019.08.27 SAMSUNG ELECTRONICS CO LTD

AI summary

An electroluminescent device, a method of manufacturing the same, and a display device including the same are disclosed. The electroluminescent device electroluminescent device includes a first electrode; a hole transport layer disposed on the first electrode; an emission layer disposed on the hole transport layer and including at least two light emitting particles; a first electron transport layer disposed on the emission layer and including at least two inorganic-organic composite particles; a second electron transport layer disposed on the first electron transport layer and including at least two inorganic oxide particles; and a second electrode disposed on the second electron transport layer, wherein the first electron transport layer has a lower work function than the second electron transport layer.