Solid‐State Chemistry on the Nanoscale: Ion Transport through Interstitial Sites or Vacancies?

Bothe, Cornelia; Kornowski, Andreas; Tornatzky, Hans; Schmidtke, Christian; Lange, Holger; Maultzsch, Janina; Weller, Horst

doi:10.1002/anie.201507263

Cited by 40 publications

(59 citation statements)

References 27 publications

(60 reference statements)

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“…Based on a variety of experimental data, two mechanisms have been proposed for describing the kinetics of CE: a ‘vacancy-mediated' mechanism 18 21 24 and a ‘kick-out' mechanism 32 . The ‘vacancy-mediated' mechanism suggests that Pb ions from the PbS core migrate through Cd vacancies 18 21 24 ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Atomistic understanding of cation exchange in PbS nanocrystals using simulations with pseudoligands

et al. 2016

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Cation exchange is a powerful tool for the synthesis of nanostructures such as core–shell nanocrystals, however, the underlying mechanism is poorly understood. Interactions of cations with ligands and solvent molecules are systematically ignored in simulations. Here, we introduce the concept of pseudoligands to incorporate cation-ligand-solvent interactions in molecular dynamics. This leads to excellent agreement with experimental data on cation exchange of PbS nanocrystals, whereby Pb ions are partially replaced by Cd ions from solution. The temperature and the ligand-type control the exchange rate and equilibrium composition of cations in the nanocrystal. Our simulations reveal that Pb ions are kicked out by exchanged Cd interstitials and migrate through interstitial sites, aided by local relaxations at core–shell interfaces and point defects. We also predict that high-pressure conditions facilitate strongly enhanced cation exchange reactions at elevated temperatures. Our approach is easily extendable to other semiconductor compounds and to other families of nanocrystals.

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Section: Resultsmentioning

confidence: 99%

Atomistic understanding of cation exchange in PbS nanocrystals using simulations with pseudoligands

et al. 2016

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“…Bothe et al, in a recent study, proposed a model in which the ion diffusion and exchange processes are exclusively mediated by interstitial lattice sites. 145 This conclusion was reached by studying two model CE reactions that involve the exposure of PbSe or ZnSe NCs to Cd 2+ ions. Both CE processes, as seen in the previous section, had been previously explained as mediated by vacancies.…”

Section: Mechanisms and Kinetics Of Cementioning

confidence: 99%

Section: Mechanisms and Kinetics Of Cementioning

confidence: 99%

Forging Colloidal Nanostructures via Cation Exchange Reactions

2016

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Among the various postsynthesis treatments of colloidal nanocrystals that have been developed to date, transformations by cation exchange have recently emerged as an extremely versatile tool that has given access to a wide variety of materials and nanostructures. One notable example in this direction is represented by partial cation exchange, by which preformed nanocrystals can be either transformed to alloy nanocrystals or to various types of nanoheterostructures possessing core/shell, segmented, or striped architectures. In this review, we provide an up to date overview of the complex colloidal nanostructures that could be prepared so far by cation exchange. At the same time, the review gives an account of the fundamental thermodynamic and kinetic parameters governing these types of reactions, as they are currently understood, and outlines the main open issues and possible future developments in the field.

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“…The ion exchange strategy for preparing PSCs can be classified either as cation or as anion exchange. The cation exchange reaction, first proposed by Alivisatos et al,95 has been widely used to synthesize nanostructured chalcogenides (ZnX, CdX, Cu 2− x X, where X = S, Se, Te) 96. Usually, cation exchange occurs under relatively low temperature, mainly due to thermodynamic driving force to form a new structure with lower internal energy.…”

Section: Basic Features Of Pscsmentioning

confidence: 99%

Porous Single‐Crystal‐Based Inorganic Semiconductor Photocatalysts for Energy Production and Environmental Remediation: Preparation, Modification, and Applications

Niu

Albero

Atienzar

et al. 2020

Adv Funct Materials

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Semiconductor photocatalytic and photovoltaic performance depends on crystallinity and surface area to a large extent. One strategy that has recently emergyed to improve semiconductor photoresponse efficiency is their synthesis as porous single crystals (PSCs), therefore providing simultaneously high crystallinity, minimization of grain boundaries, and large specific surface area. Other factors, such as high density of active sites, and enhanced light absorption, also contribute to increased PSC photoresponse with respect to analogous bulk or amorphous materials. This review initially presents the concept and main properties of PSCs. Then, the synthetic routes and the applications as photocatalysts and as photovoltaic devices, mainly in sunlight applications, are summarized. The synthetic procedures have been classified according to the mechanism of pore generation. Applications cover photocatalysis for environmental remediation, solar fuels production, selective photooxidation of organic compounds, and photovoltaic devices. Finally, a summary and views on future developments are provided. The purpose of this review is to show how the use of PSCs is a powerful general methodology applicable beyond metal oxides and can ultimately lead to sufficient photoresponse efficiency, bringing these processes close to commercial application.

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Solid‐State Chemistry on the Nanoscale: Ion Transport through Interstitial Sites or Vacancies?

Cited by 40 publications

References 27 publications

Atomistic understanding of cation exchange in PbS nanocrystals using simulations with pseudoligands

Atomistic understanding of cation exchange in PbS nanocrystals using simulations with pseudoligands

Forging Colloidal Nanostructures via Cation Exchange Reactions

Porous Single‐Crystal‐Based Inorganic Semiconductor Photocatalysts for Energy Production and Environmental Remediation: Preparation, Modification, and Applications

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