Phosphorescent Compositions with Hetero-Ring Hosts for Energy Transfer
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Solution Overview
Problem
Existing light emitting devices fabricated using certain compositions, such as those containing FIrpic or Dopant-1, are insufficient in light emission efficiency.
Innovation Solution
A composition comprising a phosphorescent compound and a compound with a condensed hetero ring skeleton containing specific atoms, where the energy levels and atom count are optimized to enhance energy transfer, resulting in improved light emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a composition containing FIrpic or Dopant-1 and compound A-65 is used in a light emitting device, then the device can be fabricated, but the light emission efficiency is insufficient
Solution Approach 1:
The patent changes the chemical structure parameters of the host compound from compound A-65 to compounds with condensed hetero ring skeletons containing nitrogen and/or boron atoms. This structural parameter change optimizes the energy level alignment and molecular interactions, thereby improving light emission efficiency while maintaining fabrication capability
Solution Approach 2:
The patent creates an optimized composite material system by selecting specific phosphorescent dopants (FIrpic or Dopant-1) combined with host compounds having condensed hetero ring skeletons. The composite achieves synergistic effects where the host-guest interaction is optimized for both ease of fabrication and high light emission efficiency
2Loss of energy
If the energy level difference between phosphorescent compound and compound (F) is too large, then energy transfer is inefficient, but if the difference is too small, then color purity decreases
Solution Approach 1:
The patent precisely controls the energy level parameter by selecting host compounds with specific condensed hetero ring structures. The nitrogen and boron atoms in the condensed rings provide optimal HOMO-LUMO energy levels that create the ideal energy gap for efficient energy transfer while preserving color purity through controlled emission wavelengths
3Loss of energy
If the number of nitrogen or boron atoms in the condensed hetero ring skeleton is increased, then energy transfer efficiency improves, but molecular weight increases
Solution Approach 1:
The patent applies local quality by concentrating nitrogen and boron atoms specifically within the condensed hetero ring skeleton rather than distributing them throughout the entire molecule. This localized arrangement maximizes energy transfer efficiency at the critical host-guest interface while keeping the overall molecular weight manageable through compact structural design
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 composition leads to a light emitting device with enhanced light emission efficiency and color purity, particularly when used in devices with color filters.
Implementation Method 1
wherein if the value of the energy level of the lowest triplet excited state of the phosphorescent compound is expressed as TP (eV), the value of the energy level of the lowest triplet excited state of compound (F) is expressed as TF (eV), then |TP-TF|=0.15 or more and 0.80 or less
Implementation Method 2
a phosphorescent compound represented by the formula (1)... the value of the energy level of the lowest triplet excited state of the phosphorescent compound
Data Source
AI summary
To provide a composition which is useful for production of a light emitting device excellent in light emission efficiency. A composition containing a phosphorescent compound represented by the formula (1) and a compound (F) having a condensed hetero ring skeleton containing at least one atom (a) selected from the group consisting of a nitrogen atom and a boron atom in the ring, wherein if the value of the energy level in the lowest triplet excited state of the above-described phosphorescent compound is expressed as Tp (eV), the value of the energy level of the lowest triplet excited state of the above-described compound (F) is expressed as TF (eV) and the number of the above-described atom (a) in the above-described condensed hetero ring skeleton per 1000 of the molecular weight of the above-described compound (F) is expressed as Nf, then, the formula (A) and the formula (B) are satisfied: TP−TF≥0.15 0.01≤Nf≤4.5