Light Emitting Device Composition Energy Level Alignment
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Solution Overview
Problem
Light emitting devices using compositions with low molecular and polymer compounds have room for improvement in light emission efficiency due to the energy level differences between triplet and singlet excited states.
Innovation Solution
A composition comprising a polymer compound with a specific repeating unit and a low molecular compound, both having energy level differences of 0.50 eV or less between their triplet and singlet excited states, is developed, with a specific ratio and content to enhance light emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
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If compositions with conventional low molecular and polymer compounds are used, then the device can be manufactured with existing materials, but the light emission efficiency is insufficient
Solution Approach 1:
The patent changes the energy level parameter by selecting compounds with specific ΔEST values (0.50 eV or less for low molecular compound and over 0.50 eV for polymer compound), optimizing the energy alignment between triplet and singlet states to improve light emission efficiency
Solution Approach 2:
The patent creates a composite light emitting composition combining specific low molecular compounds and polymer compounds with complementary energy level characteristics, where the low molecular compound has ΔEST ≤ 0.50 eV and the polymer compound has ΔEST > 0.50 eV, achieving efficient energy transfer and enhanced light emission
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 significantly improves light emission efficiency in light emitting devices by optimizing the energy level alignment between the polymer and low molecular compounds.
Implementation Method 1
Light emitting devices such as an organic electroluminescent device and the like can be suitably used
Implementation Method 2
the difference between the energy level of the lowest excited triplet state and the energy level of the lowest excited singlet state
Data Source
AI summary
A composition for producing a light emitting device having high light emission efficiency contains: a polymer compound having a repeating unit (Y) and a constitutional unit (SM1) obtained by removing hydrogen atom(s) from a low molecular compound (SM1) in which the absolute value of a difference between the energy levels of the lowest triplet excited state and the lowest singlet excited state is 0.50 eV or less, and a low molecular compound (SM2) in which the absolute value of a difference between the energy levels of the lowest triplet excited state and the lowest singlet excited state is 0.50 eV or less. When dSM1 is the content number per unit mass of the constitutional unit (SM1) and dSM2 is the content number per unit mass of the low molecular compound (SM2), dSM1+dSM2 is 2.0×1019 (number/g) or more and dSM1/dSM2 is 0.020 to 50.