OLED Host Layer with Charge Transport Properties

Solution Overview

Problem

Conventional organic light emitting diodes (OLEDs) have complex structures and costly manufacturing processes due to the need for multiple independent charge transport and light emitting layers, which complicates the production and increases costs.

Innovation Solution

Incorporating a host layer with charge transport properties between light emitting layers, which can function as both a charge transport and light emitting layer, reducing the number of independent charge transport layers and simplifying the manufacturing process by eliminating unnecessary layers such as electron or hole transport layers, and using N-type or P-type hosts with high charge mobility rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple independent charge transport layers and light emitting layers are used, then the OLED structure is complete and functional, but the device complexity and manufacturing cost increase

Engineering Contradiction:

ImproveOLED functionalityVSAvoidnumber of layers

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The host layer is designed to perform multiple functions simultaneously: it serves as both a charge transport layer (transporting holes or electrons) and a light emitting layer (emitting photons through electroluminescence). This multi-functionality eliminates the need for separate charge transport layers and light emitting layers, reducing the overall device complexity while maintaining complete OLED functionality.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the charge transport layer and light emitting layer into a single integrated host layer. By merging these two previously separate functional layers, the device structure is simplified, the number of manufacturing steps is reduced, and the overall complexity is decreased while preserving all necessary functions.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If multiple independent charge transport layers and light emitting layers are used, then the OLED structure is complete and functional, but the manufacturing process becomes costly and complex

Engineering Contradiction:

ImproveOLED functionalityVSAvoidmanufacturing process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The host layer is designed to perform multiple functions simultaneously: it serves as both a charge transport layer (transporting holes or electrons) and a light emitting layer (emitting photons through electroluminescence). This multi-functionality eliminates the need for separate charge transport layers and light emitting layers, reducing the overall device complexity while maintaining complete OLED functionality.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the charge transport layer and light emitting layer into a single integrated host layer. By merging these two previously separate functional layers, the device structure is simplified, the number of manufacturing steps is reduced, and the overall complexity is decreased while preserving all necessary functions.

Inventive Principle:

Principle #5Merging (Combining)

3Device complexity

If host layer with charge transport property is used, then the number of layers is reduced and manufacturing is simplified, but the charge mobility rate must be sufficiently high

Engineering Contradiction:

Improvenumber of layersVSAvoidcharge mobility rate

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent specifies precise parameter ranges for the host materials, particularly the charge mobility rate (μh or μe ≥ 10^-4 cm²/Vs) and HOMO/LUMO energy levels. By establishing these quantitative parameters, the invention ensures that the host layer achieves sufficient charge transport performance while maintaining its light emitting function, thus resolving the contradiction between layer reduction and performance maintenance.

Inventive Principle:

Principle #35Parameter changes

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 approach simplifies the OLED manufacturing process, reduces the number of layers, and maintains the properties of the OLED, while allowing for the elimination of specific layers like electron or hole transport layers, thereby lowering production costs and complexity.

Implementation Method 1

At least one light emitting layer comprises a host layer having charge transport property

Methodology Applied

Scientific EffectCharge transport: Conduction (electrical)

Implementation Method 2

the N-type host has electron transport property

Methodology Applied

Scientific EffectElectron transport: Conduction (electrical)

Implementation Method 3

the P-type host has hole transport property

Methodology Applied

Scientific EffectHole transport: Conduction (electrical)

Implementation Method 4

An organic light emitting diode (OLED) typically include a cathode and an anode, and light emitting units between the cathode and the anode

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS9899621B2Organic light emitting diode and display device thereof

Publication Date: 2018.02.20 BOE TECHNOLOGY GROUP CO LTD

AI summary

The present application discloses an organic light emitting diode comprising a cathode; an anode; a plurality of light emitting layers connected in series between the cathode and the anode; and a charge generation layer between at least one pair of adjacent light emitting layers. At least one light emitting layer comprises a host layer having charge transport property.