CdSe Nanoparticle Elasticity and Surface Energy

Huxter, Vanessa M.; Lee, Anna; Lo, Samuel Chun‐Lap; Scholes, Gregory D.

doi:10.1021/nl803275a

Cited by 68 publications

(84 citation statements)

References 27 publications

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“…In addition, we resolve two more acoustic phonon peaks, including a dominant peak, which is generally attributed to the l ¼ 0 breathing mode 9,10 . The relative positions of the phonon peaks confirm the previous assignment (Methods), avoiding sizedependent material properties 39 . Spin relaxation should depend on the magnitude of the applied magnetic field, as the lowest energy l ¼ 2 phonon-mode energy is comparable to the Zeeman splitting found at 7 T. For small Zeeman splittings, relaxation between the two spin states via the emission of a single acoustic phonon would violate energy conservation (Fig.…”

Section: Resultssupporting

confidence: 87%

Magneto-optical properties of trions in non-blinking charged nanocrystals reveal an acoustic phonon bottleneck

et al. 2012

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Charged quantum dots provide an important platform for a range of emerging quantum technologies. Colloidal quantum dots in particular offer unique advantages for such applications (facile synthesis, manipulation and compatibility with a wide range of environments), especially if stable charged states can be harnessed in these materials. Here we engineer the CdSe nanocrystal core and shell structure to efficiently ionize at cryogenic temperatures, resulting in trion emission with a single sharp zero-phonon line and a mono exponential decay. Magneto-optical spectroscopy enables direct determination of electron and hole g-factors. Spin relaxation is observed in high fields, enabling unambiguous identification of the trion charge. Importantly, we show that spin flips are completely inhibited for Zeeman splittings below the low-energy bound for confined acoustic phonons. This reveals a characteristic unique to colloidal quantum dots that will promote the use of these versatile materials in challenging quantum technological applications.

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Section: Resultssupporting

confidence: 87%

Magneto-optical properties of trions in non-blinking charged nanocrystals reveal an acoustic phonon bottleneck

et al. 2012

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“…1a. In particular, the lowest frequency radial breathing mode (l = 0 and m = 0) has been the focus of many experimental investigations, 9,11,19,23 including our recent study of CdSe QDs. 15,20 In this manuscript, we focus specifically on modeling this radial breathing mode.…”

Section: Continuum Linear Elasticity Theorymentioning

confidence: 99%

Including surface ligand effects in continuum elastic models of nanocrystal vibrations

Lee

Mork

Willard

et al. 2017

The Journal of Chemical Physics

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The measured low frequency vibrational energies of some quantum dots (QDs) deviate from the predictions of traditional elastic continuum models. Recent experiments have revealed that these deviations can be tuned by changing the ligands that passivate the QD surface. This observation has led to speculation that these deviations are due to a mass-loading effect of the surface ligands. In this article, we address this speculation by formulating a continuum elastic theory that includes the dynamical loading by elastic surface ligands. We demonstrate that this model is capable of accurately reproducing the l = 0 phonon energy across a variety of different QD samples, including cores with different ligand identities and epitaxially grown CdSe/CdS core/shell heterostructures. We highlight that our model performs well even in the small QD regime, where traditional elastic continuum models are especially prone to failure. Furthermore, we show that our model combined with Raman measurements can be used to infer the elastic properties of surface bound ligands, such as sound velocities and elastic moduli, that are otherwise challenging to measure.

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“…Отметим, что параметры, полученные по формулам (6) для сплава с P i = 0.5 в [4], несколько отличаются от параметров из (8), которые получены для сплава эквиатомного состава. Это связано с тем, что при C = 0.5, согласно (3), вероятность обнаружить атом кремния в решетке Si 0.5 −Ge 0.5 несколько меньше (P Si = 0.4897) из-за меньшего размера атома Si, по сравнению с размером атома Ge.…”

Section: метод расчета термодинамических свойств кристаллаunclassified

Изменение термодинамических свойств твердого раствора Si-Ge при уменьшении размера нанокристалла

Магомедов¹

2019

Физика Твердого Тела

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В рамках модели " среднего атома" для бинарного сплава рассчитано уравнение состояния и термодинамические свойства твердого раствора замещения Si 0.5 −Ge 0.5 . Используя RP-модели нанокристалла, рассчитаны изменения как уравнения состояния, так и термодинамических свойств при переходе от макрокристалла к нанокристаллу из 222 атомов с геометрической поверхностью Гиббса. Расчеты были проведены вдоль изотерм T = 100, 300 и 1000 K, в диапазоне давлений: −1 < P < 7 GPa. Изучено изменение свойств как при изохорическом, так и при изобарическом (P = 0) уменьшении числа атомов в нанокристалле. Показано, что при изобарическом (P = 0) уменьшении размера удельный объем нанокристалла Si 0.5 −Ge 0.5 увеличивается тем больше, чем больше температура нанокристалла.Ключевые слова: нанокристалл, изохора, изобара, кремний, германий.

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CdSe Nanoparticle Elasticity and Surface Energy

Cited by 68 publications

References 27 publications

Magneto-optical properties of trions in non-blinking charged nanocrystals reveal an acoustic phonon bottleneck

Magneto-optical properties of trions in non-blinking charged nanocrystals reveal an acoustic phonon bottleneck

Including surface ligand effects in continuum elastic models of nanocrystal vibrations

Изменение термодинамических свойств твердого раствора Si-Ge при уменьшении размера нанокристалла

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