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 limitations of fluorescent materials and the short lifespan of some phosphorescent materials used in commercial applications.
Innovation Solution
An OLED structure incorporating a specific emissive layer with a host material represented by Formula 7 and Formula 9, and a dopant organometallic compound of the form Ir(LA)m(LB)n, where LA and LB are defined ligands, is used to enhance luminous efficiency and lifespan, with the organometallic compound being a heteroleptic metal complex that facilitates efficient charge and exciton energy transfer.
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 becomes short
Solution Approach 1:
The patent changes the chemical composition parameters of the emissive layer by using specific host-guest combinations (e.g., mCP host with Ir(ppy)3 dopant at controlled concentrations) to achieve both high luminous efficiency and extended lifespan, moving away from conventional phosphorescent materials with fixed compositions
Solution Approach 2:
The patent employs composite material systems combining host materials (e.g., mCP, TCTA), guest dopants (e.g., Ir(ppy)3, Ir(piq)3), and auxiliary compounds to create an emissive layer that achieves synergistic effects, simultaneously improving luminous efficiency through triplet exciton utilization and extending operational lifespan through stable molecular structures
2Duration of action of moving object
If fluorescent material is used to extend luminous lifespan, then luminous lifespan is improved, but luminous efficiency becomes low
Solution Approach 1:
The patent modifies the energy utilization parameters by incorporating heavy metal-containing dopants (Ir, Pt) into the emissive layer, which change the spin-orbit coupling parameters and enable triplet exciton harvesting, thereby improving luminous efficiency while maintaining stable operational characteristics
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 OLED structure improves luminous efficiency and extends the lifespan by utilizing the organometallic compound's ability to control photoluminescence color purity and emission colors, reducing driving voltages and enhancing overall performance.
Implementation Method 1
the organometallic compound's ability to control photoluminescence color purity and emission colors
Implementation Method 2
An OLED structure incorporating a specific emissive layer with a host material represented by Formula 7 and Formula 9, and a dopant organometallic compound of the form Ir(LA)m(LB)n
Data Source
AI summary
An organic light emitting diode (OLED) in which at least one emitting material layer includes a dopant having the structure represented by Formula 1 and a biscarbazole-base 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]