Biexciton state causes photoluminescence fluctuations in CdSe/ZnS core/shell quantum dots at high photoexcitation densities
Biexciton state causes photoluminescence fluctuations in CdSe/ZnS core/shell quantum dots at high photoexcitation densities
复制标题
DOI：
10.1103/physrevb.88.155440
复制
发表时间：
2013-10
影响因子：
3.7
通讯作者：
N. Yoshikawa;H. Hirori;H. Watanabe;T. Aoki;T. Ihara;R. Kusuda;C. Wolpert;T. Fujiwara;A. Kusumi;Y. Kanemitsu;Koichiro Tanaka
中科院分区：
文献类型：
--
作者：
N. Yoshikawa;H. Hirori;H. Watanabe;T. Aoki;T. Ihara;R. Kusuda;C. Wolpert;T. Fujiwara;A. Kusumi;Y. Kanemitsu;Koichiro Tanaka
利用单点 PL 光谱研究了单个 CdSe/ZnS 量子点光致发光（PL）闪烁的激发密度依赖性。随着激发密度的增加，除了高发射（ON）和非发射（OFF）状态之外，还会出现中间状态。对 PL 闪烁行为（PL 强度、发现这些状态的概率、时间概率分布以及 PL 光谱和寿命）的激发密度依赖性的系统研究表明，中间态可归因于在高密度激发状态下通过双激子生成和量子点充电（电离）产生的带电激子（三重子）状态。我们的结果表明，双激子的产生是三重子状态的前兆，而不是关闭状态的前兆。
The excitation density dependence of photoluminescence (PL) blinking of single CdSe/ZnS quantum dots was studied by means of single-dot PL spectroscopy. As the excitation density increases, an intermediate state appears in addition to the highly emissive (ON) and nonemissive (OFF) states. The systematic study of the excitation density dependence of PL blinking behavior (PL intensity, probabilities of finding these states, time probability distributions, and PL spectra and lifetimes) suggests that the intermediate state can be attributed to a charged exciton (trion) state generated through biexciton generation and charging (ionization) of a quantum dot under a high-density excitation regime. Our results indicate that the biexciton generation is a precursor of the trion state and not of the OFF state.