OLED Light Absorbing Dye Blocks Harmful UV
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Solution Overview
Problem
Organic light emitting devices face efficiency reduction and increased driving voltage due to exposure to ultraviolet radiation and visible light in the 380 nm to 410 nm wavelength range, which can damage phosphorescent light emitting materials and reduce performance.
Innovation Solution
Incorporating a first light absorbing dye with an absorption wavelength of 380 nm to 410 nm in the second organic layer, which blocks external light in this range, preventing it from reaching the phosphorescent light emitting material in the first organic layer, thereby maintaining efficiency and reducing voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If phosphorescent light emitting material is used in the first organic layer, then light emission efficiency is improved, but exposure to ultraviolet radiation and visible light in the 380 nm to 410 nm wavelength range causes efficiency reduction and driving voltage increase
Solution Approach 1:
A second organic layer containing a light absorbing dye is introduced as an intermediary between the external environment and the phosphorescent light emitting material in the first organic layer. This intermediary layer absorbs harmful ultraviolet and visible light in the 380 nm to 410 nm wavelength range, preventing it from reaching and damaging the phosphorescent material, thereby maintaining both efficiency and performance stability
Solution Approach 2:
The harmful ultraviolet and visible light in the 380 nm to 410 nm wavelength range is converted into a beneficial filtering mechanism. The light absorbing dye in the second organic layer transforms the harmful radiation into absorbed energy, preventing it from degrading the phosphorescent material while the dye itself benefits from being part of the protective structure
2Reliability
If external light blocking is implemented to protect phosphorescent material, then performance stability is improved, but device structure complexity increases
Solution Approach 1:
The light blocking function is merged with the existing second organic layer structure, which already serves as part of the device's organic layer stack. By incorporating the light absorbing dye into this existing layer rather than adding a separate protective component, the solution maintains performance stability while minimizing increases in structural complexity
Solution Approach 2:
The second organic layer is designed to serve multiple functions: it acts as both a structural component of the organic layer stack and a protective filter against harmful light. The light absorbing dye within this layer provides universal protection against ultraviolet and visible light in the 380 nm to 410 nm range, making the structure multi-functional and reducing the need for additional dedicated protective layers
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 solution effectively prevents efficiency reduction and voltage increase by absorbing and blocking harmful light, ensuring stable performance of the organic light emitting device.
Implementation Method 1
a first light absorbing dye having an absorption wavelength of about 380 nm to 410 nm
Data Source
AI summary
An organic light emitting device and a display device, the organic light emitting device including a first electrode; a first organic layer on the first electrode; a first charge generating layer on the first organic layer; a second organic layer on the first charge generating layer, the second organic layer including a first light absorbing dye having an absorption wavelength of about 380 nm to 410 nm; and a second electrode on the second organic layer, wherein light is emitted from the device in the direction from the first electrode to the second electrode.