Mesitylene Triazine Electron Transport Material for Lower OLED Optical Loss
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Solution Overview
Problem
Conventional OLED devices suffer from significant light output efficiency losses due to surface plasma polariton losses, wave guide losses, and substrate losses, limiting their external quantum efficiency to around 22%, despite optimal internal quantum efficiency and electrical balance.
Innovation Solution
An electron transport material with a compound structure based on mesitylene triazine, designed for high carrier mobility and low refractive index, is used to suppress surface plasma state losses, enhancing forward luminous efficiency by more than 14% compared to traditional materials like TPBi.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a microstructure is added in the device to reduce surface plasma loss and wave guide loss, then external quantum efficiency is increased by about 10%-30%, but the manufacture process becomes complex with low yield and high cost
Solution Approach 1:
The patent changes the optical parameter (refractive index) of the electron transport layer by selecting specific materials with refractive indices between 1.6-1.8, rather than using conventional materials with higher refractive indices. This parameter change directly reduces surface plasma loss and wave guide loss without requiring complex microstructure additions, thereby improving external quantum efficiency while maintaining manufacturing simplicity
Solution Approach 2:
The patent adopts the optical field distribution characteristics of microcavity structures through material selection and layer thickness optimization, achieving similar light extraction enhancement effects without physically implementing complex microcavity microstructures. This allows the device to benefit from improved light outcoupling while avoiding the manufacturing complexity of actual microcavity fabrication
2Loss of energy
If conventional electron transport materials with high refractive index are used, then carrier transport is adequate, but surface plasma state loss is significant and forward luminous efficiency is limited
Solution Approach 1:
The patent systematically changes the refractive index parameter of the electron transport layer from conventional high values (>1.9) to optimized lower values (1.6-1.8). This parameter optimization reduces the refractive index contrast at interfaces, thereby suppressing surface plasma state loss and improving forward luminous efficiency while maintaining adequate electron transport performance through careful material selection
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 electron transport material effectively reduces surface plasma state losses in OLEDs, improving external quantum efficiency and overall light output efficiency by inhibiting intermolecular stacking and maintaining low refractive indices, thereby increasing the forward luminous efficiency of OLED devices.
Implementation Method 1
The main forms of the loss are: a SPP (surface plasma polariton) loss caused by the metal electrodes
Implementation Method 2
a Wave Guide loss caused by a high refractive index of an organic layer and ITO etc.
Data Source
AI summary
The present disclosure relates to an electron transport material and an application thereof. According to the electron transport material, a structure of a molecular is designed and selected to be constructed by a group having a high carrier mobility, such that the molecule has a higher carrier mobility. In addition, a core group of the molecule is a structure based on mesitylene triazine. The molecular rigidity of the structure is strong, and the intermolecular stacking can be effectively inhibited, such that the material has a lower refractive index, and the surface plasma polariton loss of an organic light-emitting device can be effectively suppressed. The forward light-emitting efficiency of the light-emitting device can be improved by more than 14% by applying the electron transport material to the device.