OLED Organic Compound LUMO Tuning for Voltage Stability

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Solution Overview

Problem

Existing organic semiconductor materials in organic light-emitting diodes (OLEDs) face challenges in achieving improved operating voltage stability over time, which affects the performance and longevity of the devices.

Innovation Solution

The development of an organic compound with specific structural and electronic properties, including a LUMO level within a defined range, enhances the stability and efficiency of the semiconductor layer by optimizing the balance of hole and electron injection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing organic semiconductor materials are used in OLEDs, then the device can operate and emit light, but the operating voltage stability deteriorates over time, affecting device lifetime

Engineering Contradiction:

Improveoperating voltage stabilityVSAvoiddevice lifetime

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent modifies the molecular structure of organic semiconductor materials by introducing specific substituents (fluoroaryl groups, cyano groups, and carboxylic acid groups) at defined positions on the phenyl ring. These structural parameter changes optimize the LUMO energy level to be within -4.7 eV to -5.25 eV, which improves electron injection efficiency and stabilizes operating voltage over time, thereby extending device lifetime

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates composite organic semiconductor compounds combining multiple functional groups (fluoroaryl, cyano, and carboxylic acid substituents) on a single molecular framework. This composite structure synergistically improves both electron injection characteristics and long-term voltage stability, resolving the contradiction between initial device performance and long-term reliability

Inventive Principle:

Principle #40Composite materials

2Productivity

If the LUMO level of the organic compound is optimized for efficient electron injection, then electron injection efficiency improves, but the balance with hole injection may be disrupted

Engineering Contradiction:

Improveelectron injection efficiencyVSAvoidcharge balance stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The patent introduces electron-withdrawing groups (cyano and carboxylic acid) at specific local positions (positions 3 and 5) on the phenyl ring, while maintaining the core molecular structure intact. This localized modification optimizes electron injection through the LUMO level without significantly affecting hole injection characteristics, thus maintaining charge balance stability while improving electron injection efficiency

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

By precisely controlling the LUMO energy level parameter to fall within the specific range of -4.7 eV to -5.25 eV through systematic molecular design, the patent achieves optimal electron injection efficiency while the overall molecular architecture preserves balanced charge transport properties

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP4168379B1Organic compound of formula (i) for use in organic electronic devices, an organic electronic device comprising a compound of formula (i) and a display device comprising the organic electronic device

Publication Date: 2026.02.11 NOVALED GMBH

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Figure 3

AI summary

The present invention relates to a compound of formula (I) and an organic electronic device comprising a semiconductor layer which comprises a compound of formula (I).