Triazine-Based Electron Transport Layer for OLED Efficiency
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Solution Overview
Problem
Current organic light emitting diode (OLED) devices face challenges in achieving high external quantum efficiency and low driving voltage due to limitations in electron and hole transport layers, particularly in forming efficient exciplex systems with suitable molecular orbital level differences.
Innovation Solution
The use of a triazine-based compound, CN-T2T, as an electron transport layer or in combination with organic compounds to form exciplexes, which have a LUMO-HOMO level difference of 2.92 eV or less, enhancing carrier accumulation and mobility, and incorporating red dopants with lower singlet and triplet energies to improve efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional electron and hole transport layers are used in OLED devices, then the device structure is simple and fabrication is easier, but the external quantum efficiency is low and driving voltage is high
Solution Approach 1:
The patent employs composite material systems by combining triazine-based compounds with specific organic compounds to form exciplex systems. This composite approach enables simultaneous achievement of high external quantum efficiency and low driving voltage while maintaining fabrication simplicity, as the exciplex formation occurs naturally through molecular orbital level matching without requiring complex additional processing steps.
2Device complexity
If conventional electron and hole transport layers are used in OLED devices, then the device structure is simple, but the driving voltage is high
Solution Approach 1:
The patent applies parameter changes by carefully selecting organic compounds with specific molecular orbital energy levels that match the triazine-based compound to form exciplexes. This energy level parameter optimization enables low driving voltage operation while maintaining simple device structure, as the exciplex system naturally facilitates efficient charge transport and recombination at reduced voltage conditions.
3Productivity
If triazine-based compound forms exciplex with organic compound, then external quantum efficiency is high and driving voltage is low, but the molecular orbital level matching requirement is stringent
Solution Approach 1:
The patent applies local quality by focusing on the specific interface region where the triazine-based compound and organic compound form the exciplex. By optimizing the molecular orbital energy levels at this local interface, the patent achieves high external quantum efficiency and low driving voltage. The stringent level matching requirement is addressed by selecting organic compounds with complementary energy levels that locally satisfy the exciplex formation criteria.
4Reliability
If triazine-based compound is used to form exciplex system, then carrier mobility is balanced and efficiency is improved, but the selection of suitable organic compounds is limited
Solution Approach 1:
The patent uses the exciplex system as an intermediary between the triazine-based compound and the organic compound. This intermediary exciplex state facilitates balanced carrier mobility and improved efficiency by creating a favorable energy landscape for charge transport. The mediator approach allows for controlled interaction between the compounds, achieving reliability in carrier mobility while managing the compound selection constraints through energy level compatibility.
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 implementation of CN-T2T in OLED devices results in high external quantum efficiency and low driving voltage, enabling the production of efficient light-emitting devices with balanced carrier mobility and effective exciplex formation, suitable for various color emissions.
Implementation Method 1
A combination of the triazine-based compound and the organic compound forms an exciplex, wherein a difference between a lowest unoccupied molecular orbital (LUMO) level of the triazine-based compound and a highest occupied molecular orbital (HOMO) level of the organic compound is 2.92 eV or less
Data Source
AI summary
Provided is a triazine-based compound represented by following formula (I). ##STR00001##