Triplet-Triplet Annihilation Upconversion Layer for OLED Blue Light
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current OLED technologies face limitations in achieving efficient and stable blue light emission, which affects the performance and longevity of blue OLEDs, and require coherent light sources for wavelength conversion, leading to inefficiencies in display applications.
Innovation Solution
The implementation of a triplet-triplet annihilation up-conversion (TTA-UC) process using a layer comprising donor and acceptor materials in OLED devices, which absorbs light and converts it to shorter wavelengths, particularly for generating blue light from green or red OLEDs, eliminating the need for coherent sources and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional OLED materials are used to produce blue light directly, then the device complexity is reduced, but the operational lifetime and stability deteriorate due to the use of less stable blue compounds
Solution Approach 1:
The patent introduces an upconversion layer as an intermediary component between the OLED and the viewer. This layer contains donor and acceptor materials that convert longer wavelength emissions (500-600 nm) from the OLED into shorter wavelength blue light (400-500 nm). The OLED itself uses stable green or red emitting materials instead of unstable blue compounds, while the upconversion layer performs the wavelength transformation function, thus resolving the contradiction between reliability and device complexity.
Solution Approach 2:
The patent changes the optical parameters of the system by introducing materials with specific absorption and emission characteristics. The donor material absorbs light in the 500-600 nm range and the acceptor material emits in the 400-500 nm range, creating a parameter transformation from longer to shorter wavelengths. This allows the use of stable emitting materials in the OLED while achieving blue light output through parameter transformation in the upconversion layer.
2Productivity
If existing upconversion technologies are used, then blue light production is achieved, but the conversion efficiency is low and coherent light sources are required
Solution Approach 1:
The patent employs donor and acceptor materials as intermediary substances in the upconversion layer. These materials facilitate efficient energy transfer through triplet-triplet annihilation mechanisms, achieving up to 60% conversion efficiency. The donor material absorbs photons from the OLED and transfers energy to the acceptor material, which then emits blue light, creating an efficient intermediary conversion process that does not require coherent light sources.
Solution Approach 2:
The patent replaces the requirement for coherent light sources (such as lasers) with an incoherent broad-spectrum emission from conventional OLEDs. The upconversion layer is designed to work with incoherent light by using materials with broad absorption bands that can capture photons across the 500-600 nm range, substituting the need for complex coherent light generation mechanisms with simpler material-based wavelength conversion.
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 approach achieves up to 60% efficiency in wavelength conversion, prolongs device operational lifetime, and allows for the generation of blue light without using less stable blue compounds, suitable for cool white OLEDs and monochrome blue light production, with improved color temperature and CRI.
Implementation Method 1
triplet-triplet annihilation up-conversation (TTA-UC) layer using donor and acceptor materials that absorb and convert light with a peak wavelength of 500-600 nm to emit light in the 400-500 nm range
Implementation Method 2
OLEDs make use of thin organic films that emit light when voltage is applied across the device
Data Source
AI summary
Novel devices comprising a layer including compounds that are capable of triplet triplet annihilation up conversation (TTA-UC) and techniques for operating the same are provided. In particular, the up-conversation layer absorbs light emitted by the OLED device and emits up-converted light with shorter wavelength in response. These devices and techniques may be used to provide improved lifetime for blue emitting devices.