We investigate the effects of the hole transport layer (HTL) and the buffer layer in a CdSe/ZnS quantum-dot LED (QLED) to reveal several important performance trade-offs in the QLED design. Our fabricated QLED samples show that, among the three common HTL materials, poly(9-vinlycarbazole) (PVK), poly[N,N’-bis(4-butylphenyl)-N,N’-bis(phenyl)-benzidine] (poly- TPD), and poly(9,9-dioctylfluorene-co-N-(4-(3-methylpropyl)) diphenylamine) (TFB), PVK provides the highest luminance of $1.0\times 10^{5}$ cd/m², but the smallest modulation bandwidth of 2.0 MHz, while TFB provides the lowest luminance of $5.8\times 10^{4}$ cd/m², but the largest bandwidth of 6.5 MHz. For each HTL material, there exists an optimal HTL thickness for the illumination performance, but the bandwidth decreases with an increase in the HTL thickness. The incorporation of a LiF buffer layer in a QLED can significantly increase the luminance, but at the expense of the modulation bandwidth. Our results are useful for the design of QLEDs for visible light communication applications.

中文翻译：

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量子点 LED 照明和调制性能之间的权衡

我们研究了 CdSe/ZnS 量子点 LED (QLED) 中空穴传输层 (HTL) 和缓冲层的影响，以揭示 QLED 设计中的几个重要性能权衡。我们制造的 QLED 样品表明，在三种常见的 HTL 材料中，聚（9-乙烯基咔唑）（PVK）、聚[N,N'-双（4-丁基苯基）-N,N'-双（苯基）-联苯胺] （聚-TPD）和聚（9,9-二辛基芴-共-N-（4-（3-甲基丙基））二苯胺）（TFB），PVK提供最高的亮度 $1.0\乘以 10^{5}$ cd/m ²，但最小调制带宽为 2.0 MHz，而 TFB 提供最低亮度 $5.8\乘以 10^{4}$ cd/m ²，但最大带宽为 6.5 MHz。对于每种 HTL 材料，都存在照明性能的最佳 HTL 厚度，但带宽随着 HTL 厚度的增加而减小。在 QLED 中加入 LiF 缓冲层可以显着提高亮度，但会牺牲调制带宽。我们的结果对于设计用于可见光通信应用的 QLED 很有用。