Thermally Controlled Cyclic Insertion/Ejection of Dopant Ions and Reversible Zinc Blende/Wurtzite Phase Changes in ZnS Nanostructures

Karan, Niladri S.; Sarkar, Suresh; Kundu, Paromita; Ravishankar, N.; Pradhan, Narayan

doi:10.1021/ja109625v

Cited by 100 publications

(107 citation statements)

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“…22 For example, soft synthesis enabled control over zincblende/wurtzite polytypism in binary II-VI and III-V semiconductors. [23][24][25][26][27][28] Recently, our group successfully expanded this approach to I-II-V ternary semiconductors, where a previously unknown, cubic half-Heusler polytype of LiZnSb was synthesized for the first time. 6 Clearly, the binary and more complex ternary Zintl phases formed from Li, Zn, and Sb are a particularly interesting family of compounds to explore utilizing kinetic control due to the large number of potential crystalline products with variable crystal chemistry.…”

Section: Introductionmentioning

confidence: 99%

Expanding the I–II–V Phase Space: Soft Synthesis of Polytypic Ternary and Binary Zinc Antimonides

et al. 2018

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Soft chemistry methods offer the possibility of synthesizing metastable and kinetic products that are unobtainable through thermodynamically-controlled, high-temperature reactions. A recent solution-phase exploration of Li-Zn-Sb phase space revealed a previously unknown cubic half-Heusler MgAgAs-type LiZnSb polytype. Interestingly, this new cubic phase was calculated to be the most thermodynamically stable, despite prior literature reporting only two other ternary phases (the hexagonal half-Heusler LiGaGe-type LiZnSb, and the full-Heusler Li2ZnSb). This surprising discovery, coupled with the intriguing optoelectronic and transport properties of many antimony containing Zintl phases, required a thorough exploration of syn-thetic parameters. Here, we systematically study the effects that different precursor concentrations, injection order, nucleation and growth temperatures, and reaction time have on the solution-phase synthesis of these materials. By doing so, we identify conditions that selectively yield several unique ternary (c-LiZnSb vs. h*-LiZnSb), binary (ZnSb vs. Zn8Sb7), and metallic (Zn, Sb) products. Further, we find one of the ternary phases adopts a variant of the previously observed hexagonal LiZnSb struc-ture. Our results demonstrate the utility of low temperature solution phase-soft synthesis-methods in accessing and mining a rich phase space. We anticipate that this work will motivate further exploration of multinary I-II-V compounds, as well as encourage similarly thorough investigations of related Zintl systems by solution phase methods. Disciplines Materials ChemistryComments "This document is the unedited Author's version of a Submitted Work that was subsequently accepted for publication in Chemistry of Materials, copyright © American Chemical Society after peer review. To access the final edited and published work see http://dx.doi.org/10.1021/acs.chemmater.8b02910. ABSTRACT: Soft chemistry methods offer the possibility of synthesizing metastable and kinetic products that are unobtainable through thermodynamically-controlled, high-temperature reactions. A recent solution-phase exploration of Li-Zn-Sb phase space revealed a previously unknown cubic half-Heusler MgAgAs-type LiZnSb polytype. Interestingly, this new cubic phase was calculated to be the most thermodynamically stable, despite prior literature reporting only two other ternary phases (the hexagonal half-Heusler LiGaGe-type LiZnSb, and the full-Heusler Li2ZnSb). This surprising discovery, coupled with the intriguing optoelectronic and transport properties of many antimony containing Zintl phases, required a thorough exploration of synthetic parameters. Here, we systematically study the effects that different precursor concentrations, injection order, nucleation and growth temperatures, and reaction time have on the solution-phase synthesis of these materials. By doing so, we identify conditions that selectively yield several unique ternary (c-LiZnSb vs. h*-LiZnSb), binary (ZnSb vs. Zn8Sb7), and metallic (Zn, Sb) products. Furt...

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Section: Introductionmentioning

confidence: 99%

Expanding the I–II–V Phase Space: Soft Synthesis of Polytypic Ternary and Binary Zinc Antimonides

et al. 2018

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“…[23][24][25][26][27] Apart from influencing the properties of materials, dopants can also interfere with the ongoing crystal growth process and assist the formation of the structural architecture of various nanoscale materials. [31][32][33][34][35][36][37][38][39] Through adsorption onto the growth facets, dopants can slow down or even stop the directional growth of the nanomaterials and they can also change the phase as well as shape of some nanostructures. [31][32][33][34][35][36] It is also reported that the shape of the host nanostructures can be tuned depending on the dopant percentage.…”

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confidence: 99%

Dopant-Controlled Selenization in Pd Nanocrystals: The Triggered Kirkendall Effect

et al. 2015

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Doping foreign impurities in host nanomaterials can induce new materials properties. In addition, doping can also influence the crystallization process and change the shape and/or phase of the host material. While dopant-induced changes in the properties of materials have been well studied, the concept of doping and its chemistry in the design of different nanostructures has rarely been investigated. In order to further understand the doping chemistry, this study investigated the dopant-controlled enhancement of the rate of the chemical reaction during the transformation from one doped material to another and the consequent effect on the shape evolution of the nanostructures. These are performed during the selenization of metal Pd(0), using Ag dopant. While the controlled process produced cuboidal Pd17Se15 from the quasi-spherical nanocrystals of Pd(0), on doping, the shape of Pd17Se15 transformed into hollow cubes. The rate was also enhanced by more than 30 times for the doped case in comparison to undoped Pd(0). Importantly, while for the undoped nanocrystals, the selenization approached in one direction, where for the doped particles, it occurred all around the nanocrystals and triggered the Kirkendall effect. Detailed investigations were conducted to elucidate the influence of the dopant on both the rate and directional approach of selenization in Pd(0), initiation of the fast diffusion of Pd, change in shape, and formation of the hollow structures. To our understanding, the role of dopants in controlling chemical processes is of fundamental importance, and this will undoubtedly broaden the scope of research on the chemistry of doping and crystal growth in solution.

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“…Although both ZB and WZ crystal structures show similar trend regarding FC/ZFC bifurcation and TD/TI ratio, the magnitudes of these values are quite different. This is quite evident upon considering the fact that dopant ions mostly reside near the surface of WZ CdS nanoparticles and are responsible for generation of carriers at the surface [6,22]. These carriers are mostly responsible for enhancing the TI component in magnetic susceptibility as seen in powder WZ sample as compared to powder ZB sample.…”

Section: Resultsmentioning

confidence: 99%

“…Magnetic semiconducting nanoparticles have been widely regarded as the potential candidate for extensive research in wider areas of material science due to its semiconducting [1][2][3] and magnetic [4,5] properties for the last couple of decades [6][7][8]. In this context, dilute magnetic semiconductors (DMSs) [2,3] and dilute magnetic oxides (DMOs) [8,9] have been extensively studied to integrate both magnetic and semiconducting properties.…”

Section: Introductionmentioning

confidence: 99%

Understanding bifurcations in FC–ZFC magnetization of dilutely Fe3+ doped CdS nanoparticles

Ghosh

Paul

Raj

2015

Solid State Communications

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Thermally Controlled Cyclic Insertion/Ejection of Dopant Ions and Reversible Zinc Blende/Wurtzite Phase Changes in ZnS Nanostructures

Cited by 100 publications

References 54 publications

Expanding the I–II–V Phase Space: Soft Synthesis of Polytypic Ternary and Binary Zinc Antimonides

Expanding the I–II–V Phase Space: Soft Synthesis of Polytypic Ternary and Binary Zinc Antimonides

Dopant-Controlled Selenization in Pd Nanocrystals: The Triggered Kirkendall Effect

Understanding bifurcations in FC–ZFC magnetization of dilutely Fe3+ doped CdS nanoparticles

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