Suppressed Blinking and Auger Recombination in Near-Infrared Type-II InP/CdS Nanocrystal Quantum Dots
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- 作者：Allison M. Dennis ; Benjamin D. Mangum ; Andrei Piryatinski ; Young-Shin Park ; Daniel C. Hannah ; Joanna L. Casson ; Darrick J. Williams ; Richard D. Schaller ; Han Htoon ; Jennifer A. Hollingsworth
- 刊名：Nano Letters
- 出版年：2012
- 出版时间：November 14, 2012
- 年：2012
- 卷：12
- 期：11
- 页码：5545-5551
- 全文大小：392K
- 年卷期：v.12,no.11(November 14, 2012)
- ISSN：1530-6992
文摘
Nonblinking excitonic emission from near-infrared and type-II nanocrystal quantum dots (NQDs) is reported for the first time. To realize this unusual degree of stability at the single-dot level, novel InP/CdS core/shell NQDs were synthesized for a range of shell thicknesses (1鈥?1 monolayers of CdS). Ensemble spectroscopy measurements (photoluminescence peak position and radiative lifetimes) and electronic structure calculations established the transition from type-I to type-II band alignment in these heterostructured NQDs. More significantly, single-NQD studies revealed clear evidence for blinking suppression that was not strongly shell-thickness dependent, while photobleaching and biexciton lifetimes trended explicitly with extent of shelling. Specifically, very long biexciton lifetimes鈥攗p to >7 ns鈥攚ere obtained for the thickest-shell structures, indicating dramatic suppression of nonradiative Auger recombination. This new system demonstrates that electronic structure and shell thickness can be employed together to effect control over key single-dot and ensemble NQD photophysical properties.