OLED Emissive Layer Host-Dopant Composition for Efficiency and Lifespan
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Solution Overview
Problem
Current organic light emitting diodes (OLEDs) face challenges in achieving high luminous efficiency and long luminous lifespan, particularly due to the short lifespan of phosphorescent materials used in commercial applications.
Innovation Solution
The development of an OLED structure incorporating an emissive layer with a host material represented by specific formulas and an organometallic compound as a dopant, which includes a metal atom linked to a fused hetero-aromatic ring ligand, enhances charge transfer and maintains stable chemical conformation for improved efficiency and lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If phosphorescent material is used to improve luminous efficiency, then luminous efficiency is improved, but luminous lifespan deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the emissive layer by using specific host-guest combinations (first host with formula 7, second host with formula 9, and iridium complex dopant with formula 1) to achieve both high luminous efficiency and extended lifespan, resolving the contradiction between these two parameters
Solution Approach 2:
The patent employs a composite emissive layer structure combining multiple materials with specific functions: first host material for charge transport, second host material for exciton management, and phosphorescent dopant for light emission. This composite approach enables simultaneous achievement of high efficiency and long lifespan
2Loss of energy
If driving voltage is reduced to improve energy efficiency, then energy consumption is reduced, but luminous efficiency may deteriorate
Solution Approach 1:
The patent optimizes the energy level parameters of the host and dopant materials to enable efficient charge injection and transport at lower voltages while maintaining high luminous efficiency through proper HOMO-LUMO level alignment in the emissive layer
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 configuration reduces driving voltages and enhances luminous efficiency and lifespan of OLEDs by facilitating rapid charge and exciton energy transfer, while maintaining color purity and stability.
Implementation Method 1
facilitating rapid charge and exciton energy transfer
Implementation Method 2
facilitating rapid charge and exciton energy transfer
Implementation Method 3
phosphorescent material can show high luminous efficiency since it uses triplet exciton energy as well as singlet exciton energy in the luminous process
Implementation Method 4
an organic light emitting diode that includes a first electrode; a second electrode facing the first electrode; and an emissive layer disposed between the first and second electrodes
Data Source
AI summary
An organic light emitting diode (OLED) in which at least one emitting material layer includes a dopant having the following structure represented by Formula 1 and a fused hetero-aromatic-based host and/or an azine-based host, and an organic light emitting device including the OLED. The OLED and the organic light emitting device including the host and the dopant can improve their luminous efficiency and luminous lifespan.Ir(LA)m(LB)n [Formula 1]