Composite Organic Inorganic Layer for OLED Phosphorescence
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Organic light-emitting devices (OLEDs) face challenges in achieving high internal quantum efficiency due to non-radiative decay mechanisms of triplet excitons, which result in lower luminescent efficiencies, especially at room temperature, as they typically do not phosphoresce from triplet excited states.
Innovation Solution
A composite organic/inorganic layer is formed by reacting vanadium or molybdenum alkoxide with a charge transport compound having multiple hydroxyl groups to create a covalently bonded layer, enhancing the electron affinity and conductivity, thereby confining organic molecules close to high atomic number atoms for improved phosphorescent transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional organic emissive layers are used, then the device structure is simple, but the internal quantum efficiency is limited due to non-radiative decay of triplet excitons
Solution Approach 1:
The patent applies composite materials by combining organic charge transport compounds with inorganic metal oxide nanoparticles (vanadium, molybdenum, or tungsten oxides) to create a hybrid emissive layer. This composite structure enables phosphorescent emission from triplet excitons while maintaining charge transport functionality, resolving the contradiction between simple structure and high efficiency by integrating multiple material classes with complementary properties.
2Reliability
If thick metal layers are used for non-transparent electrodes, then electrical conductivity is improved, but light emission through the electrode is reduced
Solution Approach 1:
The patent applies local quality by creating functionally distinct regions within the emissive layer: areas adjacent to the non-transparent electrode that facilitate charge injection and transport, and regions closer to the transparent electrode that optimize light extraction. The metal oxide nanoparticles are strategically positioned to enhance electron affinity and conductivity at the electrode interface while maintaining phosphorescent emission properties throughout the layer, allowing thick metal electrodes to maintain both conductivity and light emission capability.
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 enhances phosphorescent efficiency over fluorescent emission, potentially achieving 100% internal quantum efficiency by promoting radiative decay of triplet excitons, leading to improved OLED performance and longer operational lifetimes.
Implementation Method 1
reacting vanadium or molybdenum alkoxide with a charge transport compound having multiple hydroxyl groups to create a covalently bonded layer
Implementation Method 2
enhancing the electron affinity and conductivity, thereby confining organic molecules close to high atomic number atoms
Implementation Method 3
confining organic molecules close to high atomic number atoms for improved phosphorescent transitions
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Organic electronic devices comprising a covalently bonded organic/inorganic composite layer. The composite layer may be formed by the reaction of a metal alkoxide with a charge transport compound having one or more hydroxyl groups. Examples of metal alkoxides that can be used include vanadium alkoxides, molybdenum alkoxides, titanium alkoxides, or silicon alkoxides. This composite layer can be used for any of the various charge conducting layers in an organic electronic device, including the hole injection layer.