Manipulation of Hole and Exciton Distributions in Organic Light-Emitting Diodes with Dual Emission Layers

The efficiency improvement of organic light-emitting diodes (OLEDs) is important but challenging. Here, we introduce a unique OLED with a hole modulation layer (HML) in the middle of its emission layer (EML). The external quantum efficiency and power efficiency can be improved by approximately 58% w...

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Bibliographic Details
Published inElectronic materials letters Vol. 20; no. 3; pp. 232 - 242
Main Authors Song, Suk-Ho, Yoo, Jae-In, Kim, Hyo-Bin, Kang, Sung-Cheon, Kim, Kanghoon, Park, Sung-Jae, Yan, Qun, Song, Jang-Kun
Format Journal Article
LanguageEnglish
Published Seoul The Korean Institute of Metals and Materials 01.05.2024
Springer Nature B.V
대한금속·재료학회
Subjects
Characterization and Evaluation of Materials
Chemistry and Materials Science
Condensed Matter Physics
Current density
Efficiency
Emission
Excitons
Light emitting diodes
Low currents
Magnetics and Photonics
Materials Science
Nanotechnology
Nanotechnology and Microengineering
Optical and Electronic Materials
Organic light emitting diodes
Original Article - Electronics
Power efficiency
Quantum efficiency
전자/정보통신공학
Charge modulation layer
Efficiency improvement
Dual EMLs
OLED
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Summary:The efficiency improvement of organic light-emitting diodes (OLEDs) is important but challenging. Here, we introduce a unique OLED with a hole modulation layer (HML) in the middle of its emission layer (EML). The external quantum efficiency and power efficiency can be improved by approximately 58% when an HML with optimized thickness is inserted. HML insertion can efficiently retard hole flow, thus improving ( i ) exciton distribution uniformity and ( ii ) local electron–hole charge balance. A systematic study of the individual contributions of two EMLs separated by the HML shows that the former factor dominantly works at low current densities (< 10 mA/cm 2 ), whereas the latter factor functions over the entire current density range of the OLED. Therefore, the efficiency improvement is greatest at low current densities, which aligns with the typical operating range in display applications. The results provide a deeper understanding of the OLED emission mechanism, and the proposed OLED structure can significantly benefit high-performance OLED displays. Graphical Abstract
ISSN:1738-8090
2093-6788
DOI:10.1007/s13391-023-00452-1