Exciplex OLED Emitters for Stable High-Efficiency Green and Red Emission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
There is a need for highly stable and efficient green and red emitters in organic light emitting diodes (OLEDs) to improve the performance and longevity of OLED displays, as current materials face challenges in achieving optimal stability and efficiency.
Innovation Solution
The development of an OLED structure comprising a first complex and a second complex, where the OLED emits luminescent radiation due to the formation of exciplexes, either within, between, or both within and between the complexes, enhancing the stability and efficiency of the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fluorescent or phosphorescent emitters are used in OLEDs, then the device can achieve basic light emission, but the stability and efficiency are insufficient for long-term commercial applications
Solution Approach 1:
The patent employs exciplex emitters formed by combining two different organic compounds (host and guest molecules) to create a composite light-emitting system. This composite approach allows the material to simultaneously achieve high stability through the host matrix and high efficiency through the guest emitter, resolving the contradiction between reliability and productivity. The exciplex formation between distinct molecular components enables both durability and high quantum yield.
2Productivity
If highly efficient emitters are developed, then the luminescent performance improves, but the stability and longevity of the OLED device deteriorates
Solution Approach 1:
The patent uses an exciplex system where the host molecule acts as an intermediary between the injected charges and the guest emitter. The host accepts charges and energy, then transfers them to the guest through exciplex formation, protecting the guest from direct charge injection damage while maintaining high efficiency. This intermediary mechanism enables both high productivity and extended device longevity.
3Stability of the object's composition
If phosphorescent blue emitters are used to achieve stable blue light emission, then the color stability improves, but the overall device efficiency and commercial viability worsen due to material scarcity and complexity
Solution Approach 1:
The patent replaces expensive, complex phosphorescent blue emitters with fluorescent blue exciplex emitters based on abundant, commercially available organic compounds. The exciplex system achieves comparable color stability without requiring rare metals or complex synthesis, dramatically improving ease of manufacture and commercial viability while maintaining color performance.
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 proposed solution results in a highly efficient and stable OLED device with improved luminescent performance, as demonstrated by the Pd3O8-P excimer emitter achieving a photoluminescence quantum yield of 86% and external quantum efficiency of 33%, with a half lifetime of 800,000 hours at 5 mA/cm2, making it suitable for large size displays.
Implementation Method 1
when a voltage is applied across the anode and cathode at room temperature, the OLED emits a luminescent radiation that comprises one or more luminescent radiation components resulting from the formation of at least one exciplex
Implementation Method 2
the exciplex is formed by at least one of the following aggregate types: 1) at least one aggregate within the first complex, and at least one aggregate within the second complex; 2) at least one aggregate between the first and the second complex
Implementation Method 3
the Pd3O8-P excimer emitter achieving a photoluminescence quantum yield of 86%
Data Source
AI summary
Organic light emitting devices (OLEDs) are described, the OLEDs comprising an anode; a cathode; and an organic region, disposed between the anode and the cathode, comprising a first complex and a second complex; wherein when a voltage is applied across the anode and cathode at room temperature, the OLED emits a luminescent radiation that comprises one or more luminescent radiation components resulting from the formation of at least one exciplex; wherein the exciplex is formed by at least one of the following aggregate types: 1) at least one aggregate within the first complex, and at least one aggregate within the second complex; 2) at least one aggregate between the first and the second complex; and 3) both 1 and 2.