Near-Unity Quantum Yield in Semiconducting Nanostructures: Structural Understanding Leading to Energy Efficient Applications
Near-Unity Quantum Yield in Semiconducting Nanostructures: Structural Understanding Leading to Energy Efficient Applications
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DOI：
10.1021/jz401958u
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发表时间：
2013-10-17
影响因子：
5.7
通讯作者：
Viswanatha, Ranjani
中科院分区：
文献类型：
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作者：
Saha, Avijit;Chellappan, Kishore V.;Viswanatha, Ranjani
核/壳结构的双量子点（NQD）作为高效的电致发光材料在下转换荧光粉和发光二极管（LED）等器件中显示出巨大的潜力。这些装置的效率通过使用高量子产率（QY）材料而非线性地增强。虽然厚壳CdSe/CdS NQD实现了具有用于器件应用的固有优势的相对高QY材料，但由于缺乏微观结构与其物理性质的相关性，它们的QY并不接近统一。在这里，在这封信中，我们表明，界面缺陷的控制是至关重要的，以实现一个接近统一的QY使用的CdSe/CdS NQD的微观结构研究。从这些NQD作为有源层获得的简单的未优化的LED表现出超过7000 Cd/m（2）的性能，具有类似于1.5 Im/W的功率转换效率，这与最好的基于NQD的LED（1-3%）相当，尽管没有电子注入缓冲层。
Core/shell nanocrystal quantum dots (NQDs) have shown great potential as efficient electroluminescent materials in devices like down-conversion phosphors and light-emitting diodes (LEDs). The efficiency of these devices is nonlinearly enhanced by the use of high quantum yield (QY) materials. Though relatively high QY materials with inherent advantages for use in device applications are achieved by thick-shell CdSe/CdS NQDs, their QY is not anywhere near unity due to lack of correlation of the microstructure with their photophysical properties. Here, in this Letter, we show that the control of interfacial defects is crucial to achieve a near-unity QY using microstructure studies of CdSe/CdS NQDs. Simple unoptimized LEDs obtained from these NQDs as the active layer demonstrate performances in excess of 7000 Cd/m(2) with a power conversion efficiency of similar to 1.5 Im/W that is comparable to those of the best NQD-based LEDs (1-3%) despite the absence of an electron-injecting buffer layer.