Lee Chun-Yu, Chen Yi-Min, Deng Yao-Zong, Kuo Ya-Pei, Chen Peng-Yu, Tsai Leo, Lin Ming-Yi
AU Optronics Corporation, Hsinchu 30078, Taiwan.
Department of Electrical Engineering, National United University, Miaoli 36003, Taiwan.
Nanomaterials (Basel). 2020 Apr 2;10(4):663. doi: 10.3390/nano10040663.
In this study, we report on the application of a dielectric/ultra-thin metal/dielectric (DMD) multilayer consisting of ytterbium (Yb)-doped molybdenum oxide (MoO)/silver (Ag)/MoO stacked as the transparent cathode in top-emitting green quantum dot light-emitting diodes (QLED). By optimizing the Yb doping ratio, we have highly improved the electron injection ability from 0.01 to 0.35. In addition, the dielectric/ultra-thin metal/dielectric (DMD) cathode also shows a low sheet resistance of only 12.2 Ω/sq, which is superior to the resistance of the commercially-available indium tin oxide (ITO) electrode (~15 Ω/sq). The DMD multilayer exhibits a maximum transmittance of 75% and an average transmittance of 70% over the visible range of 400-700 nm. The optimized DMD-based G-QLED has a smaller current leakage at low driving voltage. The optimized DMD-based G-QLED enhances the current density than that of G-QLED with indium zinc oxide (IZO) as a cathode. The fabricated DMD-based G-QLED shows a low turn-on voltage of 2.2 V, a high current efficiency of 38 cd/A, and external quantum efficiency of 9.8. These findings support the fabricated DMD multilayer as a promising cathode for transparent top-emitting diodes.
在本研究中，我们报道了一种由掺镱（Yb）的氧化钼（MoO）/银（Ag）/MoO堆叠而成的介电/超薄金属/介电（DMD）多层结构作为透明阴极应用于顶部发射绿色量子点发光二极管（QLED）。通过优化Yb掺杂比例，我们将电子注入能力从0.01大幅提高到了0.35。此外，介电/超薄金属/介电（DMD）阴极还显示出仅12.2Ω/sq的低方块电阻，优于市售氧化铟锡（ITO）电极的电阻（约15Ω/sq）。DMD多层结构在400 - 700nm的可见光范围内最大透射率为75%，平均透射率为70%。优化后的基于DMD的G-QLED在低驱动电压下具有较小的漏电流。与以铟锌氧化物（IZO）为阴极的G-QLED相比，优化后的基于DMD的G-QLED提高了电流密度。制备的基于DMD的G-QLED开启电压低至2.2V，电流效率高达38cd/A，外量子效率为9.8。这些发现支持所制备的DMD多层结构作为透明顶部发射二极管的一种有前景的阴极材料。
