Date
Place
- Room B (Room 324)
- 42. OLED System and Integration
- August 21, 2015 (Friday)
- 09:00 ~ 10:35
- [42-2]
- 09:25 ~ 09:40
- Title:Common Red Layer in Full-Color Phosphorescent Organic Light-Emitting Diodes for Simple Fabrication of RGB Subpixels
- Jeonghun Kwak (Dong-A Univ., Korea), Hyunkoo Lee (ETRI, Korea), and Changhee Lee (Seoul Nat'l Univ., Korea)
Abstract: Here, we introduce a novel common red layer (CRL) structure in phosphorescent OLEDs for simple fabrication of red (R), green (G), and blue (B) subpixels in full-color displays by reducing one metal mask step. In contrast to the conventional structure and the previous common blue layer structures in the electron transport layer (ETL),?the CRL, which is a red phosphorescent dye-doped layer, was placed in the hole transport layer (HTL). We examined the hole transporting properties of the red dye-doped CRLs by changing the highest-occupied-molecular-orbital (HOMO) energy level of hole transporting host materials. From the experiment, we could find that the trap-level, which defined as the difference of the HOMO levels between the host and dopant materials, significantly affects to the device efficiency and current density of HTLs. Based on the results, we could finally demonstrated efficient RGB-emitting devices by incorporating the CRL. Because the electroluminescence spectra of the green and blue devices with the CRL were nearly identical to those of the green and blue devices without the CRL, the color coordinates of green and blue was almost same with the devices without the CRL. Therefore, the CRL enables us to fabricate practical full-color OLED displays much simply by reducing one metal mask step and cost.?
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