Abstract
The relationship between thickness of electron transport layer (ETL) and device performance of organic light-emitting diodes (OLEDs) was investigated. Especially, we prepared various OLEDs by varying the thickness of ETL to investigate the difference of device performance. Very interestingly, the device efficiency of green phosphorescent organic light emitting diodes (PHOLEDs) was significantly improved when the thickness of ETL was optimized even though we did not change any materials for such devices except that we applied highly conductive Li doped ETL. This means that the only one factor which is associated with an improvement of device efficiency could be originated from the constructive optical interference. As a result, the simple modification of PHOLEDs only by changing the optical thickness condition causes a dramatic improvement of current efficiency (up to 82.4 cd/A) as well as external quantum efficiency (EQE, up to 23.8%), respectively. Those values correspond to the much more improved ones (by ∼34.4%) compared to those obtained from the normal devices with thin ETL as a reference.
| Original language | English |
|---|---|
| Pages (from-to) | 49-54 |
| Number of pages | 6 |
| Journal | Organic Electronics |
| Volume | 20 |
| DOIs | |
| Publication status | Published - May 2015 |
Bibliographical note
Publisher Copyright:© 2015 Elsevier B.V.All rights reserved.
Keywords
- Cavity effect
- Charge balance
- Efficiency
- Green phosphorescent OLED
- Li doped ETL