Ultrastable and High-Efficiency Deep Red QLEDs through Giant Continuously Graded Colloidal Quantum Dots with Shell
Xiaonan Liu1, Lei Wang2, Yan Gao2
1Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, Experimental Center of Advanced Materials, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China.
Nano Letters
|July 5, 2023
Summary
Researchers developed deep red Quantum Dot (QD) light-emitting diodes (QLEDs) using ZnCdSe/ZnSeS QDs. These QLEDs achieve high efficiency and record operational stability for advanced displays.
Area of Science:
- Materials Science
- Optoelectronics
- Nanotechnology
Background:
- Quantum dot (QD) light-emitting diodes (QLEDs) are promising for advanced displays and lighting.
- Achieving deep red emission ( > 630 nm) for wide color gamuts in QLEDs remains a challenge.
- Existing deep red QLEDs often lack sufficient efficiency and operational stability.
Purpose of the Study:
- To synthesize deep red emitting ZnCdSe/ZnSeS quantum dots (QDs).
- To fabricate and characterize QLEDs utilizing these novel QDs.
- To evaluate the efficiency, stability, and durability of the developed QLEDs.
Main Methods:
- Synthesis of ZnCdSe/ZnSeS QDs with a gradient core-shell structure (approx. 16 nm diameter).
- Fabrication of QLED devices using the synthesized deep red QDs.
- Performance testing including external quantum efficiency, luminance, operational lifetime (T95), shelf stability, and cycle stability.
Main Results:
- The synthesized ZnCdSe/ZnSeS QDs exhibit high quantum yield and reduced hole injection barrier.
- QLEDs demonstrated an external quantum efficiency exceeding 20% across a wide luminance range (200–90000 cd m⁻²).
- A record T95 operational lifetime exceeding 20,000 hours at 1000 cd m⁻², along with outstanding shelf (>100 days) and cycle (>10 cycles) stability were achieved.
Conclusions:
- The developed deep red QLEDs based on ZnCdSe/ZnSeS QDs offer excellent performance and stability.
- These findings represent a significant advancement towards practical QLED applications requiring deep red emission.
- The enhanced stability and durability of these QLEDs pave the way for their accelerated adoption in next-generation displays.
