Divalent Lanthanide Coordination Compound for Stable Blue OLED Emission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current blue emitting materials for OLEDs, such as TADF and Ph emitters, suffer from low chemical stability due to charge-separated states upon excitation, leading to chemical decomposition and short operational lifetimes, as well as broad emission spectra that require color filters, reducing efficiency.
Innovation Solution
A neutrally charged metal-organic coordination compound is developed, featuring a divalent lanthanide coordinated by a cyclic organic ligand with two monoanionic groups covalently linked, which stabilizes the divalent oxidation state and prevents oxidation, maintaining the deep blue emission and improving operational stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If TADF or Ph blue emitters are used to achieve blue light emission, then light emission efficiency is improved, but chemical stability deteriorates due to charge-separated states causing chemical decomposition
Solution Approach 1:
The patent changes the oxidation state parameter of the lanthanide from the stable trivalent state to the divalent state, which enables blue light emission with narrow spectra while avoiding the charge-separated state problem that plagues TADF and Ph emitters. This parameter change fundamentally alters the emission mechanism and resolves the chemical stability issue.
Solution Approach 2:
The patent creates a composite coordination compound combining divalent lanthanide ions with cyclic organic ligands containing monoanionic groups. This composite structure stabilizes the divalent oxidation state and enables both high efficiency blue emission and chemical stability, resolving the contradiction between efficiency and reliability.
2Illumination intensity
If TADF or Ph emitters are used to achieve blue light emission, then emission intensity is improved, but operational lifetime deteriorates due to bond cleavage from high energy excitation
Solution Approach 1:
By changing to divalent lanthanide emission, the patent eliminates the need for high-energy excitation that causes bond cleavage in TADF and Ph emitters. The divalent lanthanide emissions occur from intra-atomic transitions that do not create charge-separated states, thereby maintaining both high emission intensity and long operational lifetime.
3Manufacturing precision
If color filters are used to sharpen emission spectra, then color purity is improved, but efficiency deteriorates
Solution Approach 1:
The divalent lanthanide emission inherently provides narrow spectra due to the atomic transition characteristics, eliminating the need for color filters. This parameter change in the emission source itself achieves high color purity without the efficiency penalty of color filtering.
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 compound achieves deep blue, saturated emission with high operational stability in OLED devices, preventing drift under electrical fields, and allows for solution-processing and sublimation, enhancing the feasibility of large-area OLED displays.
Implementation Method 1
a divalent lanthanide coordinated by a cyclic organic ligand with two monoanionic groups covalently linked
Implementation Method 2
stabilizes the divalent oxidation state and prevents oxidation
Implementation Method 3
electroluminescent coordination compound
Implementation Method 4
deep blue, saturated emission
Implementation Method 5
allows for solution-processing and sublimation
Data Source
Figure 1A
Figure 1B~1C
Figure 2A~2B
AI summary
A metal-organic coordination compound, which is neutrally charged and wherein the coordination compound comprises at least one divalent lanthanide coordinated by a cyclic organic ligand, wherein the cyclic organic ligand contains two monoanionic groups covalently linked with the cyclic organic ligand and being separated from each other by a sequence of at least two intervening atoms.