Aspect Ratio Dependence of Auger Recombination and Carrier Multiplication in PbSe Nanorods
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- 作者：Lazaro A. Padilha ; John T. Stewart ; Richard L. Sandberg ; Wan Ki Bae ; Weon-Kyu Koh ; Jeffrey M. Pietryga ; Victor I. Klimov
- 刊名：Nano Letters
- 出版年：2013
- 出版时间：March 13, 2013
- 年：2013
- 卷：13
- 期：3
- 页码：1092-1099
- 全文大小：478K
- 年卷期：v.13,no.3(March 13, 2013)
- ISSN：1530-6992
文摘
Nanomaterials with efficient carrier multiplication (CM), that is, generation of multiple electron鈥揾ole pairs by single photons, have been the object of intense scientific interest as potential enablers of high efficiency generation-III photovoltaics. In this work, we explore nanocrystal shape control as a means for enhancing CM. Specifically, we investigate the influence of aspect ratio (蟻) of PbSe nanorods (NRs) on both CM and the inverse of this process, Auger recombination. We observe that Auger lifetimes in NRs increase with increasing particle volume and for a fixed cross-sectional size follow a linear dependence on the NR length. For a given band gap energy, the CM efficiency in NRs shows a significant dependence on aspect ratio and exhibits a maximum at 蟻 6鈥? for which the multiexciton yields are a factor of ca. 2 higher than those in quantum dots with a similar bandgap energy. To rationalize our experimental observations, we analyze the influence of dimensionality on both CM and non-CM energy-loss mechanisms and offer possible explanations for the seemingly divergent effects the transition from zero- to one-dimensional confinement has on the closely related processes of Auger recombination and CM.