Carrier Dynamics in Highly Quantum-Confined, Colloidal Indium Antimonide Nanocrystals
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- 作者：Angela Y. Chang ; Wenyong Liu ; Dmitri V. Talapin ; Richard D. Schaller
- 刊名：ACS Nano
- 出版年：2014
- 出版时间：August 26, 2014
- 年：2014
- 卷：8
- 期：8
- 页码：8513-8519
- 全文大小：524K
- ISSN：1936-086X
文摘
Nanometer-sized particles of indium antimonide (InSb) offer opportunities in areas such as solar energy conversion and single photon sources. Here, we measure electron鈥揾ole pair dynamics, spectra, and absorption cross sections of strongly quantum-confined colloidal InSb nanocrystal quantum dots using femtosecond transient absorption. For all samples, we observe a bleach feature that develops on ultrafast time scales, which notably moves to lower energy during the first several picoseconds following excitation. We associate this unusual red shift, which becomes larger for larger particles and more distinct at lower sample temperatures, with hot exciton cooling through states that we suggest arise from energetically proximal conduction band levels. From controlled optical excitation intensities, we determine biexciton lifetimes, which range from 2 to 20 ps for the studied 3鈥? nm diameter particle sizes.