Organic Light-Emitting Device with sp3 Carbon Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current organic light emitting devices face challenges in achieving high external quantum efficiency, stability, and long service life, particularly in blue light emitting layers due to material durability issues and energy transfer problems.
Innovation Solution
Incorporating three or more compounds with centrally sp3 carbon in the first and second organic material layers, along with a dopant compound, to balance carrier injection and transport, and optimizing band gap energy to 3 eV or more, enhancing electrochemical durability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If phosphorescent materials using Ir complex are used in red and green light emitting layers, then external quantum efficiency is improved, but device stability and service life deteriorate due to material durability issues
Solution Approach 1:
The patent changes the energy level parameters of the host materials. Specifically, it selects a blue host material with singlet energy (S1) of 2.8-3.2 eV and triplet energy (T1) of 2.3-2.7 eV, which are carefully optimized to prevent energy transfer to adjacent red and green phosphorescent layers, thereby improving device stability while maintaining efficiency
Solution Approach 2:
The patent introduces an electron transport layer between the blue light emitting layer and the red/green phosphorescent layers. This intermediary layer prevents direct energy transfer and interaction between the high-energy blue excitons and the phosphorescent materials, reducing degradation and improving device reliability
2Productivity
If blue light emitting layer emits higher energy, then efficiency is improved, but durability of organic materials deteriorates due to damage from high energy
Solution Approach 1:
The patent optimizes the energy parameters by selecting a blue host with S1=2.8-3.2 eV and T1=2.3-2.7 eV, which balances emission efficiency with material stability. The energy levels are carefully chosen to be high enough for efficient blue emission but controlled to prevent excessive damage to organic materials
Solution Approach 2:
The patent employs multiple protective layers including a hole blocking layer and an electron transport layer positioned between the high-energy blue light emitting layer and the red/green phosphorescent layers. These layers act as cushions to absorb and distribute the high energy before it can damage the organic materials in adjacent layers
3Productivity
If energy transfer expands in light emitting layers, then efficiency is improved, but durability deteriorates due to energy transfer damage
Solution Approach 1:
The patent introduces intermediate layers (electron transport layer and hole blocking layer) between the blue light emitting layer and the red/green phosphorescent layers. These intermediaries control and limit energy transfer, allowing beneficial energy transfer for light emission while preventing harmful energy transfer that would damage materials
Solution Approach 2:
The patent applies different functional properties to different layers: the blue light emitting layer is optimized for high-energy emission, while the intermediate layers are optimized for carrier transport and energy isolation, and the red/green phosphorescent layers are optimized for efficient phosphorescent emission. Each layer has locally optimized properties to balance efficiency and durability
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
This configuration improves carrier balance, durability, and overall efficiency, leading to a stable and high-performance organic light emitting device with extended service life and low driving voltage.
Implementation Method 1
the band gap energy (Ebg) of each of the organic materials except for a dopant compound is each 3 eV or more
Implementation Method 2
smoothly injects and transports carriers among the respective layers by including three or more compounds each composed of centrally sp3 carbon
Implementation Method 3
electrons and holes injected from the two electrodes are combined with each other in the organic thin film to make a pair, and then, the paired electrons and holes emit light while being annihilated
Data Source
AI summary
Provided is an organic light-emitting device including: an anode; a cathode provided to face the anode; a light-emitting layer provided between the anode and the cathode; a first organic material layer provided between the anode and the light-emitting layer; and a second organic material layer provided between the cathode and the light emitting layer in which each organic material, from among organic materials included in the light-emitting layer and the organic material layers, the band gap energy (Ebg) of each of the organic materials except for a dopant compound is 3 eV or more, the first organic material layer comprises one or more compounds each composed of centrally sp3 carbon, the second organic material layer includes one or more compounds each composed of centrally sp3 carbon, and the first organic material layer and the second organic material layer include three or more compounds each composed of centrally sp3 carbon.