| 학회 | 한국재료학회 |
| 학술대회 | 2015년 봄 (05/14 ~ 05/15, 구미코) |
| 권호 | 21권 1호 |
| 발표분야 | G. 나노/박막 재료 |
| 제목 | Al2O3 Thin Fim Density Dependence for Passivation Layer |
| 초록 | Passivation layer for organic light-emitting diodes (OLEDs) has been a major research area in organic semiconducting materials and devices. OLEDs have numerous advantages such as high brightness, high contrast ratio, low cost, ultrathin, and more adaptability for flexible substrates. However, OLEDs require passivation layer to protect them from oxidative species such as water and oxygen because of the high sensitivity of organic material. One of passivation method which is glass encapsulation process used for OLED encapsulation is limited in flexibility due to its solid nature. Thus, instead of glass encapsulation, thin film encapsulation (TFE) or passivation using Al2O3 deposited by atomic layer deposition (ALD) has been studied intensively. However, its water vapor transmission rate (WVTR) is not close to the 10-6 order of WVTR required for OLED. The reason that the moisture permeation barrier thin film deposited by ALD has a relatively high WVTR is due to a low film density. This low density means that many defects, such as pinholes and OH- groups, exist in the Al2O3 films. These defects are connected to each other in the layer, and then form a penetration path for H2O and O2 from the atmosphere to the inner layer. To attempt to solve this problem, we suggest multi-density layer structure using one material consisting of two layers with different densities. In this study, the multi-density layer structure of Al2O3 films was deposited by remote plasma atomic layer deposition (RPALD) repetitively with different densities. Because of this unique different density structure, it is more difficult to form paths through the layers by connecting defects in this structure. The moisture barrier performance of this structure is analyzed by using WVTRs, and a Ca degradation test was performed to calculate WVTRs. The lowest WVTR of the multi-density layer structure is 4.7 X 10-5 gm-2 day-1, which is one order of magnitude less than the WVTR value of the benchmark single-density layer. This mechanism was analyzed by X-ray reflectivity (XRR), elastic recoil detection (ERD), angle resolved X-ray photoelectron spectroscopy (AR XPS) analysis, and high resolution transmission electron microscopy (HRTEM). |
| 저자 | 신석윤, 함기열, 이주현, 서원덕, 전형탁 |
| 소속 | 한양대 |
| 키워드 | Passivation; OLED; TFE; Al<SUB>2</SUB>O<SUB>3</SUB>; ALD; WVTR |
