Origin of the Enhanced Photoluminescence from Semiconductor CdSeS Nanocrystals
Origin of the Enhanced Photoluminescence from Semiconductor CdSeS Nanocrystals
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DOI：
10.1021/jz100698m
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发表时间：
2010-06
影响因子：
5.7
通讯作者：
D. Sarma;Angshuman Nag;Pralay K. Santra;Akshay Kumar;S. Sapra;P. Mahadevan
中科院分区：
文献类型：
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作者：
D. Sarma;Angshuman Nag;Pralay K. Santra;Akshay Kumar;S. Sapra;P. Mahadevan
用光电子能谱研究了发光半导体纳米粒子的内部结构，确定了梯度合金结构作为观察到的现象的基本成分。比较光致发光寿命测量为非辐射衰减通道的最小化提供了直接证据，因为在这种梯度结构中，由于晶格参数的逐渐变化，界面缺陷被消除，表现出近单指数衰减。量子力学计算表明，电子和空穴波函数的空间坍塌程度不同，这有助于提高光致发光效率，同时增加激发态的寿命，如实验中观察到的那样。
Internal structures of extraordinarily luminescent semiconductor nanoparticles are probed with photoelectron spectroscopy, establishing a gradient alloy structure as an essential ingredient for the observed phenomenon. Comparative photoluminescence lifetime measurements provide direct evidence for a minimization of nonradiative decay channels because of the removal of interfacial defects due to a progressive change in the lattice parameters in such graded structures, exhibiting a nearly single-exponential decay. Quantum mechanical calculations suggest a differential extent of spatial collapse of the electron and the hole wave functions in a way that helps to enhance the photoluminescence efficiency, while at the same time increasing the lifetime of the excited state, as observed in the experiments.