Yun, Jung Min Park, Min Ho Kim, Yu Bin Choi, Min Jung Kim, Seunghwan Yi, Yeonjin Park, Soohyung Kang, Seong Jun 2024-11-07T02:00:42Z 2024-11-07T02:00:42Z 2024-11-06 2024-10 https://pubs.kist.re.kr/handle/201004/150993 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. English MDPI Open Access Publishing Improvement of the Stability of Quantum-Dot Light Emitting Diodes Using Inorganic HfOx Hole Transport Layer Article 10.3390/ma17194739 1 Materials, v.17, no.19 Materials 17 19 Y scie scopus 001334108100001 2-s2.0-85206486536 Chemistry, Physical Materials Science, Multidisciplinary Metallurgy & Metallurgical Engineering Physics, Applied Physics, Condensed Matter Chemistry Materials Science Metallurgy & Metallurgical Engineering Physics Article HIGHLY EFFICIENT QLEDs all-inorganic device quantum dots stable oxygen vacancies optoelectronics solution process