Origins of Low Quantum Efficiencies in Quantum Dot LEDs
Origins of Low Quantum Efficiencies in Quantum Dot LEDs
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DOI：
10.1002/adfm.201203191
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发表时间：
2013-06-25
影响因子：
19
通讯作者：
Wood, Vanessa
中科院分区：
文献类型：
--
作者：
Bozyigit, Deniz;Yarema, Olesya;Wood, Vanessa
下一代发光器件（LED）技术的前景是研究量子点（QD）的主要驱动力。目前量子点发光二极管的低效率通常归因于通过俄歇过程的带电量子点的发光猝灭。虽然新的量子点化学成功地抑制俄歇复合，高性能的量子点发光二极管与这些材料尚未得到证明。在这里，QD-LED的性能被证明是由电场显着限制。实验场相关的光致发光衰减的研究和紧束缚模拟表明，独立的充电，电场可以强烈淬火量子点固体的发光减少电子和空穴波函数重叠，从而降低辐射复合率。量化一系列CdSe/CdS量子点固体的这种效应揭示了对量子点能带结构的强烈依赖，这使得量子点材料和器件架构的清晰设计策略的轮廓能够改善QD-LED性能。
The promise for next generation light-emitting device (LED) technologies is a major driver for research on nanocrystal quantum dots (QDs). The low efficiencies of current QD-LEDs are often attributed to luminescence quenching of charged QDs through Auger-processes. Although new QD chemistries successfully suppress Auger recombination, high performance QD-LEDs with these materials have yet to be demonstrated. Here, QD-LED performance is shown to be significantly limited by the electric field. Experimental field-dependent photoluminescence decay studies and tight-binding simulations are used to show that independent of charging, the electric field can strongly quench the luminescence of QD solids by reducing the electron and hole wavefunction overlap, thereby lowering the radiative recombination rate. Quantifying this effect for a series of CdSe/CdS QD solids reveals a strong dependence on the QD band structure, which enables the outline of clear design strategies for QD materials and device architectures to improve QD-LED performance.