Exciplex Host TADF Dopant Composite for OLED Efficiency
Solution Overview
Problem
Current organic light-emitting devices based on exciplex materials lack optimal energy level relationships between host and dopant materials, leading to suboptimal efficiency and stability.
Innovation Solution
An organic light-emitting composite material is developed, comprising an exciplex host material formed by mixing electron donor and acceptor materials with a thermal activation delayed fluorescence (TADF) dopant, where specific energy level differences and ratios enhance energy transfer and carrier injection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If exciplex materials are used as host material in organic light-emitting devices, then device structure is simplified and drive voltage is reduced, but energy transfer efficiency and device stability are suboptimal due to lack of optimal energy level relationships
Solution Approach 1:
The patent applies parameter changes by establishing specific energy level relationships between host and dopant materials. The host material's triplet energy level (T1) is set to be higher than the dopant's T1 level by at least 0.1 eV, and the singlet-triplet energy gap (ΔEST) of the dopant is controlled to be 0.05-0.2 eV. These parameter optimizations ensure efficient energy transfer while maintaining device stability, resolving the contradiction between simplified structure and device reliability.
Solution Approach 2:
The patent employs composite materials by combining exciplex host materials with TADF dopant materials to create an optimized light-emitting layer. The exciplex host (formed by electron donor and acceptor materials) provides simplified structure and low drive voltage, while the TADF dopant with controlled energy levels ensures efficient energy transfer and enhanced stability, achieving both benefits simultaneously.
2Device complexity
If exciplex host material is used without optimized energy level relationships, then device structure is simple, but energy transfer efficiency is suboptimal
Solution Approach 1:
The patent resolves this contradiction by optimizing key energy level parameters: the host's T1 level is set higher than the dopant's T1 level by ≥0.1 eV to enable efficient energy transfer, while the dopant's ΔEST is controlled to 0.05-0.2 eV to facilitate reverse intersystem crossing. These parameter optimizations achieve high energy transfer efficiency while maintaining the simplicity of the exciplex host structure.
3Ease of manufacture
If conventional organic light-emitting materials are used, then manufacturing process is simple and cost is low, but internal quantum efficiency cannot reach 100%
Solution Approach 1:
The patent combines conventional organic light-emitting materials with TADF dopant materials to create a composite light-emitting layer. The conventional host material maintains simple manufacturing processes and low costs, while the TADF dopant with small ΔEST (0.05-0.2 eV) enables efficient reverse intersystem crossing, allowing the device to achieve theoretical 100% internal quantum efficiency without complex phosphorescent materials.
Solution Approach 2:
The patent changes the energy level parameters of the light-emitting materials, specifically controlling the dopant's singlet-triplet energy gap (ΔEST) to be 0.05-0.2 eV. This parameter optimization enables efficient triplet exciton utilization through reverse intersystem crossing, achieving 100% internal quantum efficiency while maintaining the simplicity and low cost of conventional organic material manufacturing.
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 solution results in higher device efficiency, lower voltage, high color purity, and extended service life for organic light-emitting devices.
Implementation Method 1
the dopant material being at least one organic light-emitting material having a thermal activation delayed fluorescence effect
Implementation Method 2
the TADF light-emitting material can realize effective reverse intersystem crossing (RISC) so as to be converted from triplet state (T1) to singlet state (S1), thereby collecting non-radiation triplet excitons for emitting light
Implementation Method 3
the host material being an exciplex formed by mixing at least one electron donor material and at least one electron acceptor material
Implementation Method 4
electrons from the cathode and the holes from anode together flow into the organic material layer to form exciplexes, and these exciplexes transit back to a ground state and emit light
Data Source
AI summary
An objective of the disclosure is to provide an organic light-emitting composite material based on an exciplex, which, when used as a light-emitting layer, can enhance the efficiency of an organic electroluminescent device. The disclosure also relates to an organic light-emitting device comprising the organic light-emitting composite material, and use of the organic light-emitting composite material of the disclosure for an organic electron device.