Controlled Alloying of the Core-Shell Interface in CdSe/CdS Quantum Dots for Suppression of Auger Recombination

被引:427
作者
Bae, Wan Ki [1 ]
Padilha, Lazaro A. [1 ]
Park, Young-Shin [1 ]
McDaniel, Hunter [1 ]
Robel, Istvan [1 ]
Pietryga, Jeffrey M. [1 ]
Klimov, Victor I. [1 ]
机构
[1] Los Alamos Natl Lab, Ctr Adv Solar Photophys, Los Alamos, NM 87545 USA
关键词
nanocrystal; quantum dot; core/shell; alloyed core/shell interface; CdSe/CdS; CdSe/CdSexS1-x/CdS; Auger recombination; SEMICONDUCTOR NANOCRYSTALS; BLINKING; INTENSITY; DYNAMICS; VOLUME; YIELDS; LIGHT;
D O I
10.1021/nn4002825
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
The influence of a CdSexS1-x interfacial alloyed layer on the photophysical properties of core/shell CdSe/CdS nanocrystal quantum dots (QDs) is investigated by comparing reference QDs with a sharp core/shell interface to alloyed structures with an intermediate CdSexS1-x, layer at the core/shell interface. To fully realize the structural contrast, we have developed two novel synthetic approaches: a method for fast CdS-shell growth, which results in an abrupt core/shell boundary (no intentional or unintentional alloying), and a method for depositing a CdSexS1-x alloy layer of controlled composition onto the CdSe core prior to the growth of the CdS shell. Both types of QDs possess similar size-dependent single-exciton properties (photoluminescence energy, quantum yield, and decay lifetime). However the alloyed QDs show a significantly longer biexciton lifetime and up to a 3-fold Increase in the biexciton emission efficiency compared to the reference samples. These results provide direct evidence that the structure of the QD interface has a significant effect on the rate of nonradiative Auger recombination, which dominates biexciton decay. We also observe that the energy gradient at the core-shell interface introduced by the alloyed layer accelerates hole trapping from the shell to the core states, which results in suppression of shell emission. This comparative study offers practical guidelines for controlling multicarrier Auger recombination without a significant effect on either spectral or dynamical properties of single excitons. The proposed strategy should be applicable to QDs of a variety of compositions (including, e.g., infrared-emitting QDs) and can benefit numerous applications from light emitting diodes and lasers to photodetectors and photovoltaics.
引用
收藏
页码:3411 / 3419
页数:9
相关论文
共 37 条
[1]   The effect of Auger heating on intraband carrier relaxation in semiconductor quantum rods [J].
Achermann, Marc ;
Bartko, Andrew P. ;
Hollingsworth, Jennifer A. ;
Klimov, Victor I. .
NATURE PHYSICS, 2006, 2 (08) :557-561
[2]   Nano-engineered electron-hole exchange interaction controls exciton dynamics in core-shell semiconductor nanocrystals [J].
Brovelli, S. ;
Schaller, R. D. ;
Crooker, S. A. ;
Garcia-Santamaria, F. ;
Chen, Y. ;
Viswanatha, R. ;
Hollingsworth, J. A. ;
Htoon, H. ;
Klimov, V. I. .
NATURE COMMUNICATIONS, 2011, 2
[3]  
Chen O, 2013, NAT MATER, V12, P445, DOI [10.1038/NMAT3539, 10.1038/nmat3539]
[4]   Giant multishell CdSe nanocrystal quantum dots with suppressed blinking [J].
Chen, Yongfen ;
Vela, Javier ;
Htoon, Han ;
Casson, Joanna L. ;
Werder, Donald J. ;
Bussian, David A. ;
Klimov, Victor I. ;
Hollingsworth, Jennifer A. .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2008, 130 (15) :5026-5027
[5]   Auger Recombination Suppression in Nanocrystals with Asymmetric Electron-Hole Confinement [J].
Climente, Juan I. ;
Movilla, Jose L. ;
Planelles, Josep .
SMALL, 2012, 8 (05) :754-759
[6]   Suppression of Auger Processes in Confined Structures [J].
Cragg, George E. ;
Efros, Alexander L. .
NANO LETTERS, 2010, 10 (01) :313-317
[7]   (CdSe)ZnS core-shell quantum dots: Synthesis and characterization of a size series of highly luminescent nanocrystallites [J].
Dabbousi, BO ;
RodriguezViejo, J ;
Mikulec, FV ;
Heine, JR ;
Mattoussi, H ;
Ober, R ;
Jensen, KF ;
Bawendi, MG .
JOURNAL OF PHYSICAL CHEMISTRY B, 1997, 101 (46) :9463-9475
[8]   Dynamic Hole Blockade Yields Two-Color Quantum and Classical Light from Dot-in-Bulk Nanocrystals [J].
Galland, Christophe ;
Brovelli, Sergio ;
Bae, Wan Ki ;
Padilha, Lazaro A. ;
Meinardi, Francesco ;
Klimov, Victor I. .
NANO LETTERS, 2013, 13 (01) :321-328
[9]   Lifetime blinking in nonblinking nanocrystal quantum dots [J].
Galland, Christophe ;
Ghosh, Yagnaseni ;
Steinbrueck, Andrea ;
Hollingsworth, Jennifer A. ;
Htoon, Han ;
Klimov, Victor I. .
NATURE COMMUNICATIONS, 2012, 3
[10]   Breakdown of Volume Scaling in Auger Recombination in CdSe/CdS Heteronanocrystals: The Role of the Core-Shell Interface [J].
Garcia-Santamaria, Florencio ;
Brovelli, Sergio ;
Viswanatha, Ranjani ;
Hollingsworth, Jennifer A. ;
Htoon, Han ;
Crooker, Scott A. ;
Klimov, Victor I. .
NANO LETTERS, 2011, 11 (02) :687-693