Constructing Highly Efficient Blue OLEDs with External Quantum Efficiencies up to 7.5 % Based on Anthracene
Xu-Hui Zheng1,2, Ting-Ting Huang3, Guo-Xi Yang1
1Department of Chemistry and Key Laboratory for Preparation and Application of Ordered, Structural Material of Guangdong Province, Shantou University, Guangdong, 515063, P. R. China.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|September 23, 2021
Summary
Researchers developed new deep-blue fluorescent emitters for organic light-emitting diodes (OLEDs). These materials achieve high efficiency and color purity, addressing a key challenge in display technology.
Area of Science:
- Materials Science
- Organic Electronics
- Photophysics
Background:
- Achieving high-performance deep-blue organic light-emitting diodes (OLEDs) with pure colors remains a significant challenge for practical applications.
- Bipolar fluorescent emitters utilizing hybrid local and charge transfer (HLCT) states offer a potential solution for efficient deep-blue emission.
Purpose of the Study:
- To design and synthesize novel, highly twisted D-π-A fluorescent emitters for efficient deep-blue OLEDs.
- To investigate the relationship between molecular structure, photophysical properties, and device performance.
- To explore the potential of the hot exciton hybrid local and charge transfer (HLCT) mechanism in achieving high efficiency.
Main Methods:
- Synthesis of two D-π-A fluorescent emitters, ICz-An-PPI and IP-An-PPI, incorporating an anthracene core.
- Fabrication and characterization of non-doped and doped OLED devices using the synthesized emitters.
- Evaluation of device performance, including external quantum efficiency (EQE), Commissioning Efficiency (CE), and Commission Internationale de l'Éclairage (CIE) coordinates.
Main Results:
- Both emitters demonstrated excellent thermal stability, high photoluminescent quantum yields, and bipolar charge transport capabilities.
- Non-doped OLEDs achieved maximum external quantum efficiencies (EQEmax) of 4.32% and 5.41% with deep-blue color coordinates.
- Doped devices exhibited superior performance, with one achieving an EQEmax of 7.51% and CIE coordinates (0.150, 0.118), nearing the NTSC standard and demonstrating high efficiency for deep-blue OLEDs with CIEy < 0.12.
Conclusions:
- The developed deep-blue fluorescent emitters, particularly IP-An-PPI, show significant promise for high-efficiency OLED applications.
- The observed high performance is potentially linked to the hot exciton HLCT mechanism.
- This study presents a viable strategy for designing advanced deep-blue emitting materials for next-generation displays and lighting.
