Effects of Size and Capping Reagents on Biexciton Auger Recombination Dynamics of CdTe Quantum Dots

Kobayashi, Yoshihiro; Pan, Lingyun; Tamai, Naoto

doi:10.1021/jp9018537

Cited by 51 publications

(88 citation statements)

References 45 publications

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“…The power-law dependence τ Auger ∝ D 4.6 of TGA-capped CdTe QDs is also plotted in Figure 5d. 8 τ Auger for the CdTe QDs reported herein depends on QD size and on the luminescence wavelength, similar to previously reported results. 8,47 τ Auger of CdTe2/CdS3 and CdTe4/CdS3 QDs also follows the power-law curve, although their sizes have not been examined.…”

Section: Biexciton Auger Recombination Dynamics For Cdte Core and Cdtsupporting

confidence: 92%

“…For comparison, our previous results for TGA-capped CdTe QDs and CdTe capped with SiO 2 -shell-containing CdS clusters are also plotted here. 8,47 The luminescence peak positions correlate roughly linearly with the particle sizes of CdTe QDs. The power-law dependence τ Auger ∝ D 4.6 of TGA-capped CdTe QDs is also plotted in Figure 5d.…”

Section: Biexciton Auger Recombination Dynamics For Cdte Core and Cdtmentioning

confidence: 88%

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Charge Transfer Dynamics and Auger Recombination of CdTe/CdS Core/Shell Quantum Dots

et al. 2015

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Core/shell semiconductor nanocrystals can be designed to afford type I, quasi-type II, or type II energy-band alignments, differing in the nature of the carrier-relaxation processes. In this study, we synthesized CdTe/CdS core/shell quantum dots (QDs) from four differently sized CdTe core QDs by a hydrothermal method, and we examined their exciton-relaxation dynamics by time-resolved luminescence and transient absorption (TA) spectroscopies. We performed core/shell-selective excitation experiments on large CdTe/CdS core/shell QDs with tetrahedral structures. The relative bleach TA intensities at the 1S state against the lowest exciton state of the CdS shell are different for the core and the shell excitations. We interpret this phenomenon in terms of a small potential barrier in the conduction band, induced by grain boundaries at the core/shell interface of CdTe/CdS core/shell QDs. The evolution of the band alignment from type I to quasi-type II is confirmed by increased luminescence lifetimes, hole localization in the core, and electron delocalization throughout the QD. Moreover, the biexciton Auger recombination lifetime (τ Auger ) of CdTe/CdS core/shell QDs represents a luminescence wavelength dependence that is similar to that of CdTe QDs, which is further support for the quasi-type II band alignment. In the present of potential energy barrier, τ Auger of the large CdTe/CdS core/shell QDs becomes elongated. This study offers a useful guideline for determining the energy-band alignment of semiconductor nanoheterostructures not only according to luminescence lifetimes and exciton-relaxation kinetics but also τ Auger .

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Section: Biexciton Auger Recombination Dynamics For Cdte Core and Cdtsupporting

confidence: 92%

Section: Biexciton Auger Recombination Dynamics For Cdte Core and Cdtmentioning

confidence: 88%

Charge Transfer Dynamics and Auger Recombination of CdTe/CdS Core/Shell Quantum Dots

et al. 2015

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“…Since our simulation method simultaneously takes into account both MEG and MER, it allows us to study the combined MEG/MER dynamics and the interplay between MEG and MER. The MER timescale of a few ps agrees well with extrapolation from experimental results [83][84][85][86][87]. If the MER started from a singly excited DE, we would have obtained a much longer MER time, hundreds of ps, as we reported [50].…”

Section: Interplay Between Impact Ionization and Exciton Recombinationsupporting

confidence: 88%

Time-domain ab initio modeling of excitation dynamics in quantum dots

Neukirch¹,

Hyeon‐Deuk²,

Prezhdo³

2014

Coordination Chemistry Reviews

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The review discusses the results of ab initio time-dependent density functional theory and nonadiabatic molecular dynamics simulations of photoinduced dynamics of charges, excitons, plasmons, and phonons in semiconductor and metallic quantum dots (QD). The simulations create an explicit timedomain representation of the excited-state processes, including elastic and inelastic electron-phonon scattering, multiple exciton generation, fission, and recombination. These nonequilibrium phenomena control the optical and electronic properties of QDs. Our approach can account for QD size and shape, as well as chemical details of QD structure, such as dopants, defects, core/shell regions, surface ligands, and unsaturated bonds. Each of these variations significantly alters the properties of photoexcited QDs.The insights reported in this review provide a comprehensive understanding of the excited-state dynamics in QDs and suggest new ways of controlling the photo-induced processes. The design principles that follow, guide development of photovoltaic cells, electronic and spintronic devices, biological labels, and other systems rooted in the unique physical and chemical properties of nanoscale materials.

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“…Not only do these methods offer control over the charge state of QDs, they also allow for statistically significant measurements on entire ensembles [211], while single-NC experiments are necessarily limited to a small number of NCs. Ensemble transient absorption experiments are most commonly used to study multi-exciton dynamics in NCs [161,173,199,[203][204][205]. Analysis of the fast photoluminescence decay components of NCs under strong excitation can also provide information about multi-exciton decay rates [170,212].…”

Section: Auger Decay Of Multi-carrier States: Ps To Ns Time Scalesmentioning

confidence: 99%

Excited-State Dynamics in Colloidal Semiconductor Nanocrystals

Rabouw

Donegá

2016

Topics in Current Chemistry Collections

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Colloidal semiconductor nanocrystals have attracted continuous worldwide interest over the last three decades owing to their remarkable and unique sizeand shape-, dependent properties. The colloidal nature of these nanomaterials allows one to take full advantage of nanoscale effects to tailor their optoelectronic and physical-chemical properties, yielding materials that combine size-, shape-, and composition-dependent properties with easy surface manipulation and solution processing. These features have turned the study of colloidal semiconductor nanocrystals into a dynamic and multidisciplinary research field, with fascinating fundamental challenges and dazzling application prospects. This review focuses on the excited-state dynamics in these intriguing nanomaterials, covering a range of different relaxation mechanisms that span over 15 orders of magnitude, from a few femtoseconds to a few seconds after photoexcitation. In addition to reviewing the state of the art and highlighting the essential concepts in the field, we also discuss

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Effects of Size and Capping Reagents on Biexciton Auger Recombination Dynamics of CdTe Quantum Dots

Cited by 51 publications

References 45 publications

Charge Transfer Dynamics and Auger Recombination of CdTe/CdS Core/Shell Quantum Dots

Charge Transfer Dynamics and Auger Recombination of CdTe/CdS Core/Shell Quantum Dots

Time-domain ab initio modeling of excitation dynamics in quantum dots

Excited-State Dynamics in Colloidal Semiconductor Nanocrystals

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