OLED Host Materials with Non-Polar Bonds for Lifetime
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current organic light-emitting diode (OLED) technologies face challenges in achieving saturated colors for full-color displays, particularly in producing red, green, and blue pixels with high efficiency and operational lifetimes, while maintaining low device lifetimes due to polar C-heteroatom bonds and recrystallization issues in solution-processable materials.
Innovation Solution
The development of OLEDs incorporating host materials with electron and hole transporting moieties, specifically compounds with C, Si, and Ge atoms, which form strong non-polar bonds, ensuring high triplet energies and charge mobility, along with a cohost emissive layer design that includes a first host, a second host or sensitizer, and an emitter, optimized for recombination efficiency and extended operational lifetimes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional organic materials with polar C-heteroatom bonds are used in OLEDs, then the materials are solution-processable and relatively inexpensive, but the devices suffer from low operational lifetimes due to bond instability and recrystallization issues
Solution Approach 1:
The patent changes the chemical bonding parameters by replacing polar C-heteroatom bonds with non-polar C-C bonds in the host material structure. This fundamental parameter change maintains solution processability while dramatically improving operational lifetime by eliminating the inherent instability of polar bonds and preventing recrystallization
Solution Approach 2:
The patent employs composite host materials comprising multiple components with specific functional groups that work synergistically. The composite structure combines the stability of non-polar C-C bonds with the solution processability required for manufacturing, achieving both reliability and ease of manufacture simultaneously
2Device complexity
If OLEDs use white light emission with absorption filters to produce saturated colors, then the device structure can be simplified, but the color saturation and efficiency are reduced compared to direct emissive colors
Solution Approach 1:
The patent applies local quality by designing host materials with specific local chemical environments that favor formation of non-polar C-C bonds. This localized structural optimization maintains overall device simplicity while enabling direct emission of saturated colors from the organic layer itself
Solution Approach 2:
The patent extracts the need for absorption filters by enabling the organic emissive layer to directly produce saturated red, green, and blue colors. This removal of filter layers simplifies the device structure while maintaining or improving color saturation through direct emission
3Ease of manufacture
If solution-processable organic materials are used in OLEDs, then manufacturing cost is reduced, but recrystallization issues occur that degrade device performance and lifetime
Solution Approach 1:
The patent changes the molecular parameters of the organic materials by incorporating structures that form non-polar C-C bonds, which have different crystallization behavior. This parameter change allows solution processing at lower costs while preventing the recrystallization degradation that plagues conventional materials
Solution Approach 2:
The patent adopts materials that are inexpensive and solution-processable but were previously limited by short operational lifetimes. By addressing the lifetime issue through non-polar bonding, the patent makes these cheap materials viable for long-lasting devices
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
This approach enables OLEDs to achieve high recombination efficiency, sufficient charge mobility, and extended operational lifetimes, surpassing the limitations of polar bonds and recrystallization issues, thereby improving the production of saturated colors and overall device performance.
Implementation Method 1
OLEDs make use of thin organic films that emit light when voltage is applied across the device
Data Source
AI summary
An organic light emitting device including an anode; a hole transporting layer; an emissive region; an electron transporting layer; and a cathode is provided. The emissive region includes a first compound, H1; a second compound, H2; and a third compound, D1. The first compound is a first host, which only includes elements selected from C, Si, Ge, H, and D; the second compound is a second host or a first sensitizer; and the third compound is an emitter. Formulations, emissive regions, and premixed co-evaporation sources containing the first, second, and third compounds are also provided.