Phosphorescent OLED Emitter Substituents for Room Temperature Efficiency
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Solution Overview
Problem
Current organic light emitting diodes (OLEDs) face challenges in achieving efficient phosphorescent emission at room temperature, particularly in terms of emitter materials that can effectively produce saturated colors and maintain performance across a wide temperature range.
Innovation Solution
A compound with specific substituents, such as a non-aromatic cyclic or polycyclic group attached to aryl or heteroaryl groups, is used as a phosphorescent emitter in OLEDs, enabling efficient light emission from a triplet excited state to a ground singlet state at room temperature, potentially improving device efficiency and color accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional phosphorescent emitter materials are used in OLEDs, then light emission can be achieved, but emission efficiency and color consistency deteriorate at room temperature due to aggregation and poor alignment
Solution Approach 1:
The patent applies local quality by introducing specific substituent groups (non-aromatic cyclic or polycyclic groups) at particular positions on the emitter molecule. These localized structural modifications create specific intermolecular interaction sites that promote proper molecular alignment and reduce aggregation, thereby simultaneously improving emission efficiency and maintaining color consistency at room temperature.
Solution Approach 2:
The patent changes the molecular structure parameters of the phosphorescent emitter by incorporating non-aromatic cyclic or polycyclic substituents. This structural parameter change alters the physical properties of the emitter, including its aggregation behavior and alignment characteristics, enabling efficient and consistent phosphorescent emission at room temperature without requiring cryogenic conditions.
2Measurement precision
If emitter materials are used that can produce saturated colors, then color accuracy improves, but device operating voltage increases
Solution Approach 1:
The patent modifies the molecular parameters of the emitter material by incorporating non-aromatic cyclic or polycyclic substituents. This structural change optimizes the energy levels and electronic properties of the emitter, enabling it to produce saturated colors with improved color accuracy while reducing the operating voltage required for efficient phosphorescent emission.
3Illumination intensity
If triplet excited state emission is enhanced, then light emission intensity increases, but molecular aggregation increases leading to reduced performance
Solution Approach 1:
The patent applies local quality by introducing specific non-aromatic cyclic or polycyclic substituent groups at strategic positions on the emitter molecule. These localized structural features create specific intermolecular interaction patterns that promote proper molecular spacing and alignment, thereby enhancing triplet excited state emission intensity while preventing detrimental molecular aggregation.
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 enhances the efficiency and color consistency of OLEDs by promoting better emitter alignment and reduced aggregation, resulting in higher efficiency and lower operating voltage while maintaining the same emission color as comparative examples.
Implementation Method 1
enabling efficient light emission from a triplet excited state to a ground singlet state at room temperature
Data Source
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AI summary
A composition comprising a first compound capable of functioning as a phosphorescent emitter in an organic light emitting device at room temperature is provided. The first compound includes at least one substituent R, where each of the at least one substituent R has the formula of: ---G1-G2, where the dashed line denotes the bond through which R is attached in the first compound; G1 is a non-aromatic cyclic or polycyclic group; G2 is selected from aryl and heteroaryl; and G1 and G2 are independently, optionally further substituted with a substituent selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof. Organic light emitting devices, consumer products, and formulations containing the first compound are also provided.