Reducing Driving Voltage in Light-Emitting Devices with Optimized Layer Design
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Summary
Problems
Light-emitting devices with a common layer and two emission layers face issues with high driving voltage and color mixing due to the absence of an auxiliary layer, leading to performance problems and lifespan deterioration.
Innovation solutions
Incorporating a first auxiliary layer and a first interlayer between the common layer and the emission layers, where the interlayer's energy levels facilitate hole injection and electron blocking, reducing the driving voltage and improving efficiency.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If an interlayer is positioned between two emission layers to prevent color mixing, then color purity is improved, but the high hole injection barrier results in high driving voltage
Why choose this principle:
The patent divides the hole transport function into two separate layers: a first hole transport layer adjacent to the emission layers and a second hole transport layer adjacent to the common layer. This segmentation allows each layer to be optimized for its specific function – the first layer focuses on hole injection to emission layers with lower HOMO energy level, while the second layer handles hole transport from common layer with higher HOMO energy level, thereby reducing the overall hole injection barrier and driving voltage while maintaining color purity through the interlayer structure
Principle concept:
If an interlayer is positioned between two emission layers to prevent color mixing, then color purity is improved, but the high hole injection barrier results in high driving voltage
Why choose this principle:
The patent introduces an auxiliary layer as an intermediary component between the interlayer and the emission layers. This auxiliary layer serves as a mediator that facilitates hole injection from the interlayer to the emission layers by providing an energy level transition pathway. The auxiliary layer's HOMO energy level is positioned between that of the interlayer and emission layers, creating a stepped energy profile that reduces the injection barrier without compromising the electron-blocking function needed for color purity
Application Domain
Data Source
AI summary:
Incorporating a first auxiliary layer and a first interlayer between the common layer and the emission layers, where the interlayer's energy levels facilitate hole injection and electron blocking, reducing the driving voltage and improving efficiency.
Abstract
A light-emitting device is provided. The light-emitting device includes: a plurality of first electrodes positioned on a first sub-pixel, a second sub-pixel, and a third sub-pixel, respectively; a second electrode facing the plurality of first electrodes; a first emission layer on the first sub-pixel to emit a first color light; a second emission layer on the second sub-pixel to emit a second color light; a first layer integrated with the first sub-pixel, the second sub-pixel, and the third sub-pixel; a first auxiliary layer between the first layer and the first emission layer; and a first interlayer between the first auxiliary layer and the first emission layer. The absolute value of the highest occupied molecular orbital (HOMO) energy level of the first interlayer is greater than the absolute value of the HOMO energy level of the first auxiliary layer, and is smaller than the absolute value of the HOMO energy level of the first emission layer. The absolute value of the lowest unoccupied molecular orbital (LUMO) energy level of the first interlayer is greater than that of a LUMO energy level of the first auxiliary layer, and is smaller than the absolute value of the LUMO energy level of the first emission layer.