OLED Emissive Layer Host-Dopant Engineering 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 and the low efficiency of fluorescent materials.
Innovation Solution
The development of an OLED structure incorporating a specific organometallic compound as a dopant, combined with biscarbazole-based and azine-based hosts, and spiro-bifluorene-based and benzimidazole-based charge transport layers, which enhances charge and exciton energy transfer, reducing driving voltage and improving efficiency and lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If phosphorescent material is used to achieve high luminous efficiency, then luminous efficiency is improved, but luminous lifespan deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the emitting material layer by using specific host-guest combinations (biscarbazole-based and azine-based hosts with iridium complexes) and optimizing dopant concentrations to achieve both high luminous efficiency and extended lifespan
Solution Approach 2:
The patent employs composite material systems combining multiple hosts (biscarbazole-based and azine-based) with iridium complex dopants in the emitting layer, and combines spiro-bifluorene-based hole transport layer with benzimidazole-based electron transport layer to create a synergistic system that improves both efficiency and stability
2Duration of action of moving object
If fluorescent material is used to extend luminous lifespan, then luminous lifespan is improved, but luminous efficiency deteriorates
Solution Approach 1:
The patent changes the emission mechanism parameter from fluorescent (singlet exciton only) to phosphorescent (triplet and singlet excitons) by using iridium complex dopants with appropriate hosts, enabling utilization of both singlet and triplet excitons for light emission
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 enhances the luminous efficiency and extends the luminous lifespan of OLEDs by facilitating rapid charge and exciton energy transfer, leading to improved color purity and reduced driving voltages.
Implementation Method 1
the at least one emitting material layer includes: a host including: a first host represented by a structure represented by Formula 7, and a second host represented by a structure represented by Formula 9, and a dopant including an organometallic compound represented by a structure of Formula 1
Implementation Method 2
the at least one hole transport layer includes an organic compound represented by a structure of Formula 11, and wherein the at least one electron transport layer includes an organic compound represented by structure of Formula 13
Data Source
AI summary
The present disclosure relates to an organic light emitting diode (OLED) in which at least one emitting material layer includes a dopant having the following structure of Formula 1 and a biscarbazole-based material and/or an azine-based material, at least one hole transport layer includes a spiro-bifluorene-based material and at least one electron transport layer includes a benzimidazole-based material, 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]