Spirobifluorene Derivatives for OLED Hole Transport and Electron Blocking

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Solution Overview

Problem

Existing organic electroluminescent devices (OLEDs) face challenges in improving performance metrics such as lifetime, efficiency, and operating voltage, particularly in layers with hole-transporting functions like hole-injecting, transport, and electron blocking layers, where suitable materials with hole-transporting properties are lacking.

Innovation Solution

The use of spirobifluorene derivatives with amine or bridged amine groups in specific positions, combined with certain chemical substituents, as materials for hole-transporting, electron-blocking, and emitting layers in OLEDs, offering excellent hole-conducting and electron-blocking properties, high thermal stability, and good solubility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional hole-transporting materials are used in OLEDs, then the device structure is simple and manufacturing is easier, but the lifetime, efficiency, and operating voltage performance are insufficient

Engineering Contradiction:

Improvedevice lifetimeVSAvoidmaterial structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent modifies the molecular structure parameters of hole-transporting materials by introducing specific spirobifluorene cores with amine groups at defined positions (2-position) and specific substituents (Ar1, Ar2, Ar3) to achieve improved lifetime, efficiency, and operating voltage while maintaining reasonable structural complexity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates composite molecular structures combining spirobifluorene cores, amine groups, and aromatic/heteroaromatic substituents to form new hole-transporting materials that exhibit synergistic properties improving device performance across multiple parameters simultaneously

Inventive Principle:

Principle #40Composite materials

2Productivity

If hole-transporting materials with higher efficiency are sought, then device performance improves, but the available material options are limited and material development is challenging

Engineering Contradiction:

Improvehole transport efficiencyVSAvoidmaterial synthesis difficulty

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent segments the hole-transporting material into distinct functional modules: a spirobifluorene core providing structural stability, amine groups for hole transport, and tunable aromatic/heteroaromatic substituents, allowing independent optimization of each component to achieve high efficiency while facilitating systematic material development

Inventive Principle:

Principle #1Segmentation

3Reliability

If materials with better electron-blocking properties are used, then device efficiency improves, but the glass transition temperature and thermal stability requirements become more stringent

Engineering Contradiction:

Improveelectron-blocking performanceVSAvoidglass transition temperature

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent applies local quality by positioning electron-blocking functional groups specifically at the 2-position of the spirobifluorene core while maintaining other regions of the molecule optimized for hole transport and thermal stability, achieving localized electron-blocking functionality without compromising overall thermal properties

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP3658541B1Spirobifluorene derivatives for use in electronic devices

Publication Date: 2025.11.26 MERCK PATENT GMBH

AI summary

The present application relates to a spirobifluorene derivative of a specific formula (I) which is suitable for use in electronic devices.