Nanocomposite Optical Coatings for OLED Light Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Organic Light Emitting Diode (OLED) devices suffer from low light emission efficiency due to the low refractive index of encapsulation materials, resulting in significant light loss, and there is a need for materials that can enhance optical transmittance and refractive index for various electronic applications.
Innovation Solution
A dispersion of capped nanocrystals, specifically metal oxide nanocrystals such as zirconium oxide, titanium oxide, and hafnium oxide, with high bulk refractive indexes, are combined with organic coating materials to create a high refractive index, high transparency film or coating that can be easily processed and applied using common coating techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional encapsulation materials with low refractive index are used in OLED devices, then the materials are easy to process and apply, but light emission efficiency is significantly reduced due to low light extraction
Solution Approach 1:
The patent combines metal oxide nanocrystals (such as zinc oxide, titanium oxide, zirconium oxide) with organic polymer matrices to create composite encapsulation materials. These nanocomposites achieve high refractive index (1.8-2.5) while maintaining processability through common coating techniques, resolving the contradiction between ease of manufacture and light emission efficiency by integrating inorganic nanofillers into an organic matrix that retains manufacturing advantages
2Loss of energy
If high refractive index materials are used to improve light extraction, then light emission efficiency increases, but optical transparency is reduced
Solution Approach 1:
The patent employs nanoscale metal oxide crystals (1-100 nm) dispersed within the polymer matrix, where the nanoscale dimensions are specifically chosen to be smaller than the wavelength of visible light. This local quality control at the nanoscale allows the material to achieve high refractive index for improved light extraction while maintaining optical transparency, as the nanocrystals do not scatter visible light significantly
Solution Approach 2:
The patent changes the size parameter of the metal oxide crystals to the nanoscale range (1-100 nm), which fundamentally alters the optical properties. At this scale, the material achieves high refractive index for light extraction while simultaneously maintaining transparency by avoiding light scattering that would occur with larger particles, thus resolving the contradiction between light emission efficiency and optical transparency
3Loss of energy
If metal oxide nanocrystals are incorporated to increase refractive index, then light extraction improves, but material complexity increases
Solution Approach 1:
The patent merges the synthesis of metal oxide nanocrystals with the polymer matrix formation into a single composite material system. The nanocrystals are synthesized directly within the polymer matrix or surface-modified to be compatible with it, creating an integrated nanocomposite that achieves high refractive index without requiring separate processing steps, thus managing material complexity while improving light extraction
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 significantly enhances the light emission efficiency of OLED devices and other applications like LED lighting, touch screens, and solar cells by reducing light loss through the use of high refractive index coatings, while maintaining high optical transparency and processability.
Implementation Method 1
A high percentage of this loss is due to the low refractive index (RI) of the encapsulation materials. A high refractive index high transparency organic coating, with a refractive index around 1.8 or higher, as may be produced with a material of the present disclosure, may dramatically enhance the efficacy of the OLED lighting and display devices
Data Source
AI summary
The present disclosure provides a high refractive index acrylic formulation embedded with sub-10 nm metal oxide nanocrystals. The formulation is ideal for high refractive index, high transparency coating for a variety of optical applications including OLED lighting.