Choi Seungkeun, Kim Sung-Jin, Fuentes-Hernandez Canek, Kippelen Bernard
School of Electrical and Computer Engineering and Center for Organic Photonics and Electronics, Georgia Institute of Technology, 777 Atlantic Drive, Atlanta, Georgia 30332, USA.
Opt Express. 2011 Jul 4;19 Suppl 4:A793-803. doi: 10.1364/OE.19.00A793.
We report on ITO-free large-area organic light-emitting diodes (OLEDs) fabricated on glass substrates comprising α-NPD as a hole transport layer (HTL) and coevaporated CBP:Ir(ppy)(3) as the emission layer. Indium-tin-oxide (ITO) was replaced with a conductive polymer electrode and an electroplated thick metal grid was used to improve the homogeneity of the potential distribution over the transparent polymer electrode. An electrical model of a metal grid integrated OLED shows the benefits of the use of metal grids in terms of improving the uniformity of the light emitted as the area of the OLED increases as well as the conductivity of the transparent electrode decreases. By integrating metal grids with polymer electrodes, the luminance increases more than 24% at 6 V and 45% at 7 V compared to the polymer electrode devices without a metal grid. This implies that a lower voltage can be applied to achieve the same luminance, hence lowering the power consumption. Furthermore, metal grid integrated OLEDs exhibited less variation in light emission compared to devices without a metal grid.
我们报道了在玻璃基板上制备的无铟锡氧化物（ITO）大面积有机发光二极管（OLED），其包含α-萘基二苯胺（α-NPD）作为空穴传输层（HTL），以及共蒸发的4,4'-N,N'-二咔唑基联苯（CBP）：三（2-苯基吡啶）铱（Ir(ppy)(3)）作为发光层。用导电聚合物电极替代铟锡氧化物（ITO），并使用电镀厚金属网格来改善透明聚合物电极上电位分布的均匀性。集成金属网格的OLED的电学模型显示，随着OLED面积增加以及透明电极电导率降低，使用金属网格在改善发光均匀性方面具有优势。通过将金属网格与聚合物电极集成，与没有金属网格的聚合物电极器件相比，在6V时亮度增加超过24%，在7V时亮度增加45%。这意味着可以施加更低的电压来实现相同的亮度，从而降低功耗。此外，与没有金属网格的器件相比，集成金属网格的OLED发光变化更小。
