TADF Light Emitting Device with Crosslinked Polymer Layer
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Solution Overview
Problem
Existing light emitting devices face a challenge of high driving voltage, which affects their efficiency and performance.
Innovation Solution
A light emitting device is designed with a first organic layer containing a thermally activated delayed fluorescence (TADF) material and a second organic layer comprising a crosslinked polymer compound with a crosslink constitutional unit, utilizing wet methods like spin coating or inkjet printing for layer formation, and subsequent crosslinking through heating or light irradiation to reduce solvent insolubility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional organic layers are used in light emitting devices, then the device structure is simple and ease of manufacture is maintained, but the driving voltage becomes high which reduces efficiency
Solution Approach 1:
The patent employs composite materials by combining TADF light emitting materials with specific host materials (compounds of formulas (1) and (2)) to create an organic layer with optimized energy levels. This composite approach enables lower driving voltage by achieving better energy matching and charge transport properties, while maintaining the simplicity of organic layer fabrication through solution processing methods.
2Use of energy by moving object
If TADF materials with optimized energy levels are used, then light emission efficiency is enhanced and driving voltage is reduced, but the device complexity increases due to additional material requirements
Solution Approach 1:
The patent optimizes the energy level parameters of the host materials (formulas (1) and (2)) to match the TADF light emitting material. By carefully selecting and adjusting these energy level parameters (HOMO, LUMO, triplet energy levels), the device achieves lower driving voltage and higher efficiency without requiring fundamental changes to the device structure or additional complex components.
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 device achieves a lower driving voltage by optimizing the energy levels and oscillator strength of the TADF material, enhancing light emission efficiency and device performance.
Implementation Method 1
a first organic layer containing a thermally activated delayed fluorescence (TADF) material
Implementation Method 2
subsequent crosslinking through heating or light irradiation to reduce solvent insolubility
Data Source
AI summary
To provide a light emitting device showing low driving voltage. A light emitting device having an anode, a cathode, a first organic layer and a second organic layer disposed between the anode and the cathode, wherein the first organic layer is a layer containing a light emitting material represented by the formula (T) and the second organic layer is a layer containing a crosslinked body of a polymer compound containing a crosslink constitutional unit: [wherein, nT1 represents an integer of 0 to 5. nT2 represents an integer of 1 to 10. ArT1 represents a single-ring or condensed-ring monovalent hetero ring group containing a nitrogen atom having no double bond as a ring constituent atom and not containing a nitrogen atom having a double bond as a ring constituent atom. LT1 represents an alkylene group, an arylene group or the like. ArT2 represents a single-ring or condensed-ring hetero ring group containing a nitrogen atom having a double bond as a ring constituent atom.].