OLED Ink Composition for Low-Viscosity Solution Processing

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Solution Overview

Problem

Existing methods for manufacturing organic light-emitting devices using small-molecule materials require high-vacuum facilities and complex processes, and solution-processed devices face issues with high viscosity and solvent resistance, limiting the applicability of inkjet processes.

Innovation Solution

An ink composition comprising a phosphine oxide-based charge transporting organic material, specific solvents, and a polar aprotic solvent system with controlled Hansen parameters and viscosity, enabling a solution process like inkjet printing for layer formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a vacuum deposition method is used to deposit small-molecule organic light-emitting material, then high-performance organic light-emitting device is obtained, but high-vacuum facility or complicated manufacturing process is required

Engineering Contradiction:

Improvedevice performanceVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical vacuum deposition system with a solution-based inkjet printing system. The ink composition containing phosphine oxide-based charge transporting organic material dissolved in specific solvents is deposited via inkjet printing, eliminating the need for high-vacuum facilities while maintaining device performance through solution processing

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical state of the organic material from vapor phase (vacuum deposition) to solution phase (inkjet printing). By controlling solvent selection, concentration, and drying conditions, the material is deposited from solution, fundamentally changing the deposition parameters and enabling simpler manufacturing equipment

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If solution process is used for manufacturing organic light-emitting device, then manufacturing complexity is reduced, but high viscosity and solvent resistance issues limit applicability

Engineering Contradiction:

Improvemanufacturing process complexityVSAvoidprocessability

Core Design Contradiction:

Device complexityVSEase of manufacture

Solution Approach 1:

The patent optimizes solution parameters including solvent selection (chlorobenzene, dichloromethane, chloroform), concentration (0.1-10 wt%), and additives to achieve viscosity between 1-100 cP at room temperature. These parameter adjustments ensure the ink is suitable for inkjet printing while maintaining material functionality

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite ink composition by combining phosphine oxide-based organic material with specifically selected solvents and additives. This composite formulation achieves optimal balance between viscosity, solvent resistance, and printability, enabling successful inkjet printing of organic light-emitting devices

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS12486421B2Ink composition for light-emitting device and light emitting device manufactured using same

Publication Date: 2025.12.02 SAMSUNG DISPLAY CO LTD

AI summary

An ink composition for a light-emitting device includes a phosphine oxide-based charge transporting organic material, a first solvent represented by Formula 1, a second solvent represented by Formula 2, and a third solvent that is polar aprotic. A light-emitting device includes a layer prepared with the in composition. An electronic apparatus includes the light-emitting device:HOR1(O)mR2OH [Formula 1]R11OR12. [Formula 2]