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Lervik A, Svenum IH, Wang Z, Cabriolu R, Riccardi E, Andersson S, van Erp TS. The role of pressure and defects in the wurtzite to rock salt transition in cadmium selenide. Phys Chem Chem Phys 2022; 24:8378-8386. [PMID: 35332892 DOI: 10.1039/d1cp05051f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using molecular dynamics and path sampling techniques we investigated the effect of pressure and defects in the wurtzite to rock salt transition in cadmium selenide (CdSe). In the pressure range 2-10 GPa, rate constants of transition are in the order of 10-23 to 105 s-1 for the transformation of a relatively small wurtzite crystal consisting of 1024 atoms with periodic boundary conditions. The transition paths predominantly evolve through an intermediate 5-coordinated structure, as reported before, though its typical lifetime within the transition paths is particularly long in the intermediate pressure range (4-6 GPa). The defects were created by removing Cd-Se pairs from an otherwise perfect crystal. The removals were either selected fully randomized or grouped in clusters (cavity creation). We find that the rate of transition due to the defects increases by several orders of magnitude even for a single pair removal. This is caused by a change in the transition mechanism that no longer proceeds via the intermediate 5-coordinated structure, when defects are present. Further, the cavity creation yields a lower rate than the fully randomized removal.
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Affiliation(s)
- Anders Lervik
- Department of Chemistry, Norwegian University of Science and Technology, Høgskoleringen 5, 7491 Trondheim, Norway.
| | - Ingeborg-Helene Svenum
- Department of Materials and Nanotechnology, SINTEF Industry, P.O. Box 4760 Torgarden, 7465 Trondheim, Norway
| | - Zhaohui Wang
- Department of Metal Production and Processing, SINTEF Industry, P.O. Box 4760 Torgarden, 7465 Trondheim, Norway
| | - Raffaela Cabriolu
- Department of Chemistry, Norwegian University of Science and Technology, Høgskoleringen 5, 7491 Trondheim, Norway. .,Department of Physics, Norwegian University of Science and Technology, Høgskoleringen 5, 7491 Trondheim, Norway
| | - Enrico Riccardi
- Department of Chemistry, Norwegian University of Science and Technology, Høgskoleringen 5, 7491 Trondheim, Norway. .,Department of Informatics, UiO, Gaustadalléen 23B, 0373 Oslo, Norway
| | - Stefan Andersson
- Department of Metal Production and Processing, SINTEF Industry, P.O. Box 4760 Torgarden, 7465 Trondheim, Norway
| | - Titus S van Erp
- Department of Chemistry, Norwegian University of Science and Technology, Høgskoleringen 5, 7491 Trondheim, Norway.
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2
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Jobbins SA, Boulfelfel SE, Leoni S. Metashooting: a novel tool for free energy reconstruction from polymorphic phase transition mechanisms. Faraday Discuss 2018; 211:235-251. [PMID: 30039129 DOI: 10.1039/c8fd00053k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We introduce a novel scheme for the mechanistic investigation of solid-solid phase transitions, which we dub 'metashooting'. Combining transition path sampling, molecular dynamics and metadynamics, this scheme allows for both a complete mechanistic analysis and detailed mapping of the free energy surface. This is illustrated by performing metashooting calculations on the pressure-induced B4/B3 → B1 phase transition in ZnO. The resulting free energy map helps to clarify the role of intermediate configurations along this activated process and the competition between different mechanistic regimes with superior accuracy. We argue that metashooting can be efficiently applied to a broader class of activated processes.
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Zhang B, Zhu T, Ou M, Rowell N, Fan H, Han J, Tan L, Dove MT, Ren Y, Zuo X, Han S, Zeng J, Yu K. Thermally-induced reversible structural isomerization in colloidal semiconductor CdS magic-size clusters. Nat Commun 2018; 9:2499. [PMID: 29950666 PMCID: PMC6021431 DOI: 10.1038/s41467-018-04842-0] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 05/30/2018] [Indexed: 01/22/2023] Open
Abstract
Structural isomerism of colloidal semiconductor nanocrystals has been largely unexplored. Here, we report one pair of structural isomers identified for colloidal nanocrystals which exhibit thermally-induced reversible transformations behaving like molecular isomerization. The two isomers are CdS magic-size clusters with sharp absorption peaks at 311 and 322 nm. They have identical cluster masses, but slightly different structures. Furthermore, their interconversions follow first-order unimolecular reaction kinetics. We anticipate that such isomeric kinetics are applicable to a variety of small-size functional nanomaterials, and that the methodology developed for our kinetic study will be helpful to investigate and exploit solid–solid transformations in other semiconductor nanocrystals. The findings on structural isomerism should stimulate attention toward advanced design and synthesis of functional nanomaterials enabled by structural transformations. Few structural isomers of colloids, with identical masses but different structures, have been identified. Here, the authors observe an interesting example of structural isomerism in a pair of semiconductor magic-size clusters, which reversibly transform between one another with first-order unimolecular reaction kinetics.
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Affiliation(s)
- Baowei Zhang
- Institute of Atomic and Molecular Physics, Sichuan University, 610065, Chengdu, PR China
| | - Tingting Zhu
- Institute of Atomic and Molecular Physics, Sichuan University, 610065, Chengdu, PR China
| | - Mingyang Ou
- School of Materials Science and Engineering, Huazhong University of Science & Technology, 430074, Wuhan, PR China
| | - Nelson Rowell
- National Research Council of Canada, Ottawa, Ontario, K1A 0R6, Canada
| | - Hongsong Fan
- Engineering Research Center in Biomaterials, Sichuan University, 610065, Chengdu, PR China
| | - Jiantao Han
- School of Materials Science and Engineering, Huazhong University of Science & Technology, 430074, Wuhan, PR China
| | - Lei Tan
- School of Physics and Astronomy, Queen Mary University of London, London, E1 4NS, UK
| | - Martin T Dove
- School of Physics and Astronomy, Queen Mary University of London, London, E1 4NS, UK.,School of Physical Science and Technology, Sichuan University, 610065, Chengdu, PR China
| | - Yang Ren
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Xiaobing Zuo
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Shuo Han
- Institute of Atomic and Molecular Physics, Sichuan University, 610065, Chengdu, PR China.
| | - Jianrong Zeng
- Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 201204, Shanghai, PR China.
| | - Kui Yu
- Institute of Atomic and Molecular Physics, Sichuan University, 610065, Chengdu, PR China. .,Engineering Research Center in Biomaterials, Sichuan University, 610065, Chengdu, PR China. .,School of Chemical Engineering, Sichuan University, 610065, Chengdu, PR China.
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4
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Kelley AM. Comparison of three empirical force fields for phonon calculations in CdSe quantum dots. J Chem Phys 2016; 144:214702. [DOI: 10.1063/1.4952990] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Affiliation(s)
- Anne Myers Kelley
- Chemistry and Chemical Biology, University of California, Merced, 5200 North Lake Road, Merced, California 95343, USA
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Selli D, Boulfelfel SE, Schapotschnikow P, Donadio D, Leoni S. Hierarchical thermoelectrics: crystal grain boundaries as scalable phonon scatterers. NANOSCALE 2016; 8:3729-3738. [PMID: 26815914 DOI: 10.1039/c5nr05279c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Thermoelectric materials are strategically valuable for sustainable development, as they allow for the generation of electrical energy from wasted heat. In recent years several strategies have demonstrated some efficiency in improving thermoelectric properties. Dopants affect carrier concentration, while thermal conductivity can be influenced by alloying and nanostructuring. Features at the nanoscale positively contribute to scattering phonons, however those with long mean free paths remain difficult to alter. Here we use the concept of hierarchical nano-grains to demonstrate thermal conductivity reduction in rocksalt lead chalcogenides. We demonstrate that grains can be obtained by taking advantage of the reconstructions along the phase transition path that connects the rocksalt structure to its high-pressure form. Since grain features naturally change as a function of size, they impact thermal conductivity over different length scales. To understand this effect we use a combination of advanced molecular dynamics techniques to engineer grains and to evaluate thermal conductivity in PbSe. By affecting grain morphologies only, i.e. at constant chemistry, two distinct effects emerge: the lattice thermal conductivity is significantly lowered with respect to the perfect crystal, and its temperature dependence is markedly suppressed. This is due to an increased scattering of low-frequency phonons by grain boundaries over different size scales. Along this line we propose a viable process to produce hierarchical thermoelectric materials by applying pressure via a mechanical load or a shockwave as a novel paradigm for material design.
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Affiliation(s)
- Daniele Selli
- Cardiff University, School of Chemistry, Park Place, CF10 3AT, Cardiff, UK
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Mangel S, Aronovitch E, Enyashin AN, Houben L, Bar-Sadan M. Atomic-Scale Evolution of a Growing Core–Shell Nanoparticle. J Am Chem Soc 2014; 136:12564-7. [DOI: 10.1021/ja506323s] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Shai Mangel
- Department
of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Eran Aronovitch
- Department
of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Andrey N. Enyashin
- Institute of Solid State Chemistry UB RAS, Ekaterinburg 620219, Russian Federation
| | - Lothar Houben
- Peter Grünberg Institut 5 and Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich
GmbH, 52425 Jülich, Germany
| | - Maya Bar-Sadan
- Department
of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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Grünwald M, Zayak A, Neaton JB, Geissler PL, Rabani E. Transferable pair potentials for CdS and ZnS crystals. J Chem Phys 2012; 136:234111. [PMID: 22779585 DOI: 10.1063/1.4729468] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A set of interatomic pair potentials is developed for CdS and ZnS crystals. We show that a simple energy function, which has been used to describe the properties of CdSe [E. Rabani, J. Chem. Phys. 116, 258 (2002)], can be parametrized to accurately describe the lattice and elastic constants, and phonon dispersion relations of bulk CdS and ZnS in the wurtzite and rocksalt crystal structures. The predicted coexistence pressure of the wurtzite and rocksalt structures as well as the equation of state are in good agreement with experimental observations. These new pair potentials enable the study of a wide range of processes in bulk and nanocrystalline II-VI semiconductor materials.
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Affiliation(s)
- Michael Grünwald
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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8
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Selli D, Boulfelfel SE, Baburin IA, Seifert G, Leoni S. Framework reconstruction between hR8 and cI16 germaniums: A molecular dynamics study. RSC Adv 2012. [DOI: 10.1039/c2ra20837g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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9
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Kelley AM. Electron-phonon coupling in CdSe nanocrystals from an atomistic phonon model. ACS NANO 2011; 5:5254-5262. [PMID: 21598957 DOI: 10.1021/nn201475d] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Phonon frequencies and eigenvectors, electron-phonon couplings, and the associated resonance Raman spectra have been calculated for approximately spherical, wurtzite form CdSe nanocrystals having radii of 1.4 to 2.3 nm and containing 318 to 1498 atoms. Calculations of the equilibrium geometries and phonon modes are carried out using an empirical force field, and the electron and hole wave functions are calculated as particle-in-a-sphere envelope functions multiplying the Bloch functions, with valence-band mixing included for the hole functions. The coupling of each phonon mode to the 1S(e)-1S(3/2) and 1S(e)-2S(3/2) excitations is evaluated directly from the change in Coulombic energy along the phonon coordinate. Ten to 50 different modes in each crystal have significant Huang-Rhys factors, clustered around two frequency regions: acoustic phonons at 20-40 cm(-1) depending on crystal size, and optical phonons at 185-200 cm(-1). The Huang-Rhys factors are larger for the acoustic modes than for the optical modes and decrease with increasing crystal size, and the Huang-Rhys factors for each group of modes are smaller for the 1S(e)-2S(3/2) than for the 1S(e)-1S(3/2) excitation. These results are compared with measurements of electron-phonon coupling in CdSe nanocrystals using different experimental techniques.
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Affiliation(s)
- Anne Myers Kelley
- School of Natural Sciences, University of California, Merced, 5200 North Lake Road, Merced, California 95343, United States.
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Bealing C, Fugallo G, Martonák R, Molteni C. Constant pressure molecular dynamics simulations for ellipsoidal, cylindrical and cuboidal nano-objects based on inertia tensor information. Phys Chem Chem Phys 2010; 12:8542-50. [DOI: 10.1039/c004053c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Clive Bealing
- King's College London, Physics Department, Strand, London WC2R 2LS, UK
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11
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Grünwald M, Dellago C. Transition state analysis of solid-solid transformations in nanocrystals. J Chem Phys 2009; 131:164116. [DOI: 10.1063/1.3253700] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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12
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Bealing C, Martoňák R, Molteni C. Pressure-induced structural phase transitions in CdSe: A metadynamics study. J Chem Phys 2009; 130:124712. [DOI: 10.1063/1.3086043] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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