Synergetic Influences of Mixed-Host Emitting Layer Structures and Hole Injection Layers on Efficiency and Lifetime of Simplified Phosphorescent Organic Light-Emitting Diodes
SCIE
SCOPUS
- Title
- Synergetic Influences of Mixed-Host Emitting Layer Structures and Hole Injection Layers on Efficiency and Lifetime of Simplified Phosphorescent Organic Light-Emitting Diodes
- Authors
- Han, T.-H; Kim, Y.-H; Kim, M.H; Song, W; Lee, T.-W.
- Date Issued
- 2016-03-09
- Publisher
- AMER CHEMICAL SOC
- Abstract
- We used various nondestructive analyses to investigate various host material systems in the emitting layer (EML) of simple-structured, green phosphorescent organic light-emitting diodes (OLEDs) to clarify how the host systems affect its luminous efficiency (LE) and operational stability. An OLED that has a unipolar single-host EML with conventional poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) showed high operating voltage, low LE (similar to 26.6 cd/A, 13.7 lm/W), and short lifetime (similar to 4.4 h @ 1000 cd/m(2)). However, the combined use of a gradient mixed-host EML and a molecularly controlled HIL that has increased surface work function (WF) remarkably decreased operating voltage and improved LE (similar to 68.7 cd/A, 77.0 lm/W) and lifetime (similar to 70.7 h @ 1000 cd/m(2)). Accumulated charges at the injecting interfaces and formation of a narrow recombination zone close to the interfaces are the major factors that accelerate degradation of charge injection/transport and electroluminescent properties of OLEDs, so achievement of simple-structured OLEDs with high efficiency and long lifetime requires facilitating charge injection and balanced transport into the EMI, and distributing charge carriers and excitons in EML.
- Keywords
- INDIUM-TIN-OXIDE; SMALL-MOLECULE; ELECTROLUMINESCENT DEVICES; TRANSIENT ELECTROLUMINESCENCE; DEGRADATION MECHANISMS; CONJUGATED POLYMERS; EXCITONS
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/35844
- DOI
- 10.1021/acsami.5b11791
- ISSN
- 1944-8244
- Article Type
- Article
- Citation
- ACS APPLIED MATERIALS & INTERFACES, vol. 8, no. 9, page. 6152 - 6163, 2016-03-09
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