OLED Electron Injection Layer Compound for Efficiency and Voltage

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Solution Overview

Problem

Single-emission-layer top emission OLEDs face challenges in efficiency and voltage performance, requiring improvements to maintain good driving voltage and stable vacuum processability and lifetime.

Innovation Solution

An organic electronic device with an electron injection layer comprising a specific compound of the formula (I), where L1 and L2 are bonded via a single bond to Ar2 to Ar5, with X1 and X2 being O, S, or Se, and R1 to R4 being alkyl or aryl, enhancing electron injection and transport.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional electron transport materials are used in single-emission-layer top emission OLEDs, then the device structure is simple, but the efficiency and voltage performance are insufficient

Engineering Contradiction:

ImproveefficiencyVSAvoiddevice structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent modifies the molecular structure parameters of the electron transport material by introducing specific substituents (L1, L2, Ar1, Ar2-Ar5 groups) with defined chemical formulas and properties. This changes the electronic and steric parameters of the material to optimize electron transport efficiency while maintaining a relatively simple single-emission-layer device structure.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite molecular structure combining multiple functional groups (L1, L2, Ar1, Ar2-Ar5) into a single electron transport material compound. This composite approach integrates electron transport, injection, and stability functions into one material, improving device efficiency without requiring complex multi-material structures.

Inventive Principle:

Principle #40Composite materials

2Reliability

If electron injection layer is added to facilitate electron transport from cathode into ETL, then electron injection is improved, but device complexity and manufacturing steps increase

Engineering Contradiction:

Improveelectron injection performanceVSAvoidnumber of layers

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The electron injection layer material is designed to perform multiple functions simultaneously: electron injection from the cathode, electron transport through the layer, and compatibility with both the cathode and ETL. This multi-functionality improves electron injection performance while minimizing the need for additional specialized layers, thus controlling device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If conventional organic electronic diodes are used, then the basic functionality is achieved, but efficiency and voltage characteristics need improvement

Engineering Contradiction:

ImproveefficiencyVSAvoiddriving voltage

Core Design Contradiction:

ProductivityVSPower

Solution Approach 1:

The patent optimizes the HOMO-LUMO energy level parameters and electron mobility parameters of the electron transport material through specific molecular design. This changes the electrical parameters to achieve better efficiency and more favorable voltage characteristics in the OLED device.

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

The solution improves the efficiency and voltage performance of single-emission-layer top emission OLEDs while maintaining stable vacuum processability and lifetime, achieving balanced hole and electron injection for enhanced light emission.

Implementation Method 1

To facilitate electron transport from the cathode into the ETL, the OLED may further comprise an electron injection layer (EIL) arranged between the cathode and the ETL

Methodology Applied

Scientific EffectElectron injection: