Improvement of the Stability of Quantum-Dot Light Emitting Diodes Using Inorganic HfOx Hole Transport Layer
- Authors
- Yun, Jung Min; Park, Min Ho; Kim, Yu Bin; Choi, Min Jung; Kim, Seunghwan; Yi, Yeonjin; Park, Soohyung; Kang, Seong Jun
- Issue Date
- 2024-10
- Publisher
- MDPI Open Access Publishing
- Citation
- Materials, v.17, no.19
- Abstract
- One of the major challenges in QLED research is improving the stability of the devices. In this study, we fabricated all inorganic quantum-dot light emitting diodes (QLEDs) using hafnium oxide (HfOx) as the hole transport layer (HTL), a material commonly used for insulator. Oxygen vacancies in HfOx create defect states below the Fermi level, providing a pathway for hole injection. The concentration of these oxygen vacancies can be controlled by the annealing temperature. We optimized the all-inorganic QLEDs with HfOx as the HTL by changing the annealing temperature. The optimized QLEDs with HfOx as the HTL showed a maximum luminance and current efficiency of 66,258 cd/m2 and 9.7 cd/A, respectively. The fabricated all-inorganic QLEDs exhibited remarkable stability, particularly when compared to devices using organic materials for the HTL. Under extended storage in ambient conditions, the all-inorganic device demonstrated a significantly enhanced operating lifetime (T50) of 5.5 h, which is 11 times longer than that of QLEDs using an organic HTL. These results indicate that the all-inorganic QLEDs structure, with ITO/MoO3/HfOx/QDs/ZnMgO/Al, exhibits superior stability compared to organic-inorganic hybrid QLEDs.
- Keywords
- HIGHLY EFFICIENT; QLEDs; all-inorganic device; quantum dots; stable; oxygen vacancies; optoelectronics; solution process
- URI
- https://pubs.kist.re.kr/handle/201004/150993
- DOI
- 10.3390/ma17194739
- Appears in Collections:
- KIST Article > 2024
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