Aza-Substituted Phosphine Oxide OLED Matrix

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Solution Overview

Problem

Existing organic light-emitting diodes (OLEDs) face challenges in achieving high efficiency and low voltage operation due to limitations in charge carrier injection and exciton formation, particularly in the use of rare-earth complexes and ambipolar host materials.

Innovation Solution

A compound with a specific structure, comprising a metal cation salt or complex and a charge transporting matrix, is used to enhance electrical properties, acting as an electron transporting and injecting material, with a conjugated system that localizes the lowest unoccupied molecular orbital (LUMO) for improved electron transport and blocking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If rare-earth complexes and ambipolar host materials are used in OLEDs, then light emission is achieved, but efficiency and operating voltage remain suboptimal due to limitations in charge carrier injection and exciton formation

Engineering Contradiction:
ImproveOLED efficiencyVSAvoidoperating voltage
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent changes the chemical composition parameters of the host material by incorporating phosphine oxide groups and carbazole groups in specific configurations. This modifies the electronic structure, HOMO-LUMO levels, and charge transport properties of the material, enabling improved charge carrier injection and exciton formation that simultaneously increases efficiency and reduces operating voltage

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates composite host materials by combining phosphine oxide groups, carbazole groups, and diphenyl bridges in a single molecular structure. This composite approach allows the material to exhibit multiple functions including electron transport, hole transport, and exciton management, resolving the contradiction between efficiency and voltage by integrating charge carrier injection and exciton formation capabilities

Inventive Principle:
Principle #40Composite materials

2Reliability

If conventional organic materials are used for charge transport, then device fabrication is simplified, but electrical properties and charge carrier injection are insufficient

Engineering Contradiction:
Improvecharge carrier injectionVSAvoidmaterial structure complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent modifies the electrical parameters of organic materials by introducing phosphine oxide and carbazole functional groups, which change the HOMO-LUMO energy levels, electron affinity, and hole mobility. These parameter changes improve charge carrier injection reliability while maintaining compatibility with conventional solution-based fabrication methods

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses the organic host material as an intermediary between electrodes and luminescent centers, facilitating charge carrier injection and transport. The specific molecular structure acts as a mediator that enables efficient charge transfer while maintaining ease of manufacture through solution processing

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

The solution results in OLEDs with improved efficiency and reduced operating voltage, as evidenced by lower voltage requirements and higher quantum efficiencies compared to comparative compounds, demonstrating enhanced electrical properties and exciton blocking capabilities.

Implementation Method 1

Examples of conjugated systems of delocalized electrons are systems of alternating pi- and sigma bonds

Methodology Applied
Scientific EffectConjugated system of delocalized electrons:

Implementation Method 2

the lowest unoccupied molecular orbital (LUMO) of the compound (I) is localized mainly on its electron transporting units E

Methodology Applied
Scientific EffectLUMO localization:

Implementation Method 3

The salt or complex of a metal cation works in the inventive semiconducting material as an electrical dopant

Methodology Applied
Scientific EffectElectrical doping:

Implementation Method 4

the compound of formula (I) has the function of a charge transporting matrix

Methodology Applied
Scientific EffectCharge transport:

Data Source

PatentEP3249714B1Semiconducting material comprising aza-substituted phosphine oxide matrix and metal salt
Publication Date: 2021.03.17 NOVALED GMBH
  • EP3249714B1 patent drawingFigure 1~2
  • EP3249714B1 patent drawingFigure 3~4
  • EP3249714B1 patent drawingFigure 5~6

AI summary

The present invention relates to a semiconducting material comprising at least one salt or complex of a metal cation and an aza-substituted phosphine oxide compound with improved electrical properties, and to a compound suitable for this organic semiconducting material and an electronic device utilizing the improved electrical properties of the semiconducting material.