AVS 51st International Symposium
    Organic Films and Devices Tuesday Sessions
       Session OF-TuP

Paper OF-TuP15
Damage Mechanism of Emitting Polymer Treated by Low Pressure Plasma

Tuesday, November 16, 2004, 4:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: D.Y. Lee, Yonsei University, Korea
Authors: D.Y. Lee, Yonsei University, Korea
H.K. Baik, Yonsei University, Korea
K.M. Song, Konkuk University, Korea
S.J. Lee, Kyungsung University, Korea
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In this study, we investigated the damage mechanism of emitting polymer (poly(9,9-dioctylfluorene)(PFO)) films for organic light emitting diode (OLED). For top emission organic light emitting diode (TOLED), indium tin oxide (ITO) films are used as a cathode material due to its high transparency in visible light. In conventional, ITO is deposited by RF/DC magnetron sputtering. But there have been many reports that sputtering process including high energy ions and neutrals degrades emitting polymer. Therefore, metal buffer layer must be inserted between emitting polymer and ITO films, not only to improve electron injection but also to prevent polymer damage. It is very important to reduce a thickness of buffer layer as thin as possible so that low driving voltage and high transparency are achieved. However, low thickness of buffer layer is not effective in prevention of polymer damage from magnetron sputtering. So, this problem is pending unsolvable. We used plasma treatment on emitting polymer (PFO) to eluciate damage mechanism so as to find effective solution for polymer degradation. Low pressure glow discharge was perform with He and O2 gas at 2ï,´10-1 torr. Anode electrode is patterned ITO films and hole transport layer is PEDOT. Al/LiF films were deposited on blue Emitting polymer (PFO) as a electron injection layer and cathode buffer. ITO films was fabricated by RF magnetron sputtering at room temperature. ITO target (SnO2: In2O3 = 1: 9) was sputtered by mixture gas of argon and oxygen. Oxygen partial pressure, working pressure and other deposition parameters were optimized. RF coupled DC was used as a power source and its voltage was changed from 45 V(only RF) to 350 V(only DC). The temperature of cesium reservoir was varied from 80 to 200 °C. Negative sputtered particles including In, Sn, O and electron were generated from the target surface and accelerated to the substrate by target voltage.