Gabriel Dunn
University of California, Berkeley
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Featured researches published by Gabriel Dunn.
Science | 2016
Xingchen Ye; Matthew R. Jones; Layne B. Frechette; Qian Chen; Alexander S. Powers; Peter Ercius; Gabriel Dunn; Grant M. Rotskoff; Son C. Nguyen; Vivekananda P. Adiga; Alex Zettl; Eran Rabani; Phillip L. Geissler; A. Paul Alivisatos
Watching it all fall apart The control of the shape and size of metal nanoparticles can be very sensitive to the growth conditions of the particles. Ye et al. studied the reverse process: They tracked the dissolution of gold nanoparticles in a redox environment inside a liquid cell within an electron microscope, controlling the particle dissolution with the electron beam. Tracking short-lived particle shapes revealed structures of greater or lesser stability. The findings suggest kinetic routes to particle sizes and shapes that would otherwise be difficult to generate. Science, this issue p. 874 Dissolution pathways and kinetic shapes of gold nanoparticles are observed inside an electron microscope. Chemists have developed mechanistic insight into numerous chemical reactions by thoroughly characterizing nonequilibrium species. Although methods to probe these processes are well established for molecules, analogous techniques for understanding intermediate structures in nanomaterials have been lacking. We monitor the shape evolution of individual anisotropic gold nanostructures as they are oxidatively etched in a graphene liquid cell with a controlled redox environment. Short-lived, nonequilibrium nanocrystals are observed, structurally analyzed, and rationalized through Monte Carlo simulations. Understanding these reaction trajectories provides important fundamental insight connecting high-energy nanocrystal morphologies to the development of kinetically stabilized surface features and demonstrates the importance of developing tools capable of probing short-lived nanoscale species at the single-particle level.
Nano Letters | 2015
Hamid Reza Barzegar; Eduardo Gracia-Espino; Aiming Yan; Claudia Ojeda-Aristizabal; Gabriel Dunn; Thomas Wågberg; Alex Zettl
We examine a variant of so-called carbon nanotube peapods by packing C60 molecules inside the open edge ducts of collapsed carbon nanotubes. C60 insertion is accomplished through a facile single-step solution-based process. Theoretical modeling is used to evaluate favorable low-energy structural configurations. Overfilling of the collapsed tubes allows infiltration of C60 over the full cross-section of the tubes and consequent partial or complete reinflation, yielding few-wall, large diameter cylindrical nanotubes packed with crystalline C60 solid cores.
Nano Research | 2017
Hamid Reza Barzegar; Aiming Yan; Sinisa Coh; Eduardo Gracia-Espino; Claudia Ojeda-Aristizabal; Gabriel Dunn; Marvin L. Cohen; Steven G. Louie; Thomas Wågberg; Alex Zettl
We study the collapsing and subsequent spontaneous twisting of a carbon nanotube by in situ transmission electron microscopy (TEM). A custom-sized nanotube is first created in the microscope by selectively extracting shells from a parent multi-walled tube. The few-walled, large-diameter daughter nanotube is driven to collapse via mechanical stimulation, after which the ribbon-like collapsed tube spontaneously twists along its long axis. In situ diffraction experiments fully characterize the uncollapsed and collapsed tubes. The experimental observations and associated theoretical analysis indicate that the origin of the twisting is compressive strain.
Nano Letters | 2016
Hamid Reza Barzegar; Aiming Yan; Sinisa Coh; Eduardo Gracia-Espino; Gabriel Dunn; Thomas Wågberg; Steven G. Louie; Marvin L. Cohen; Alex Zettl
Scientific Reports | 2017
Stephen Gilbert; Gabriel Dunn; A Azizi; Ted Pham; Brian Shevitski; E Dimitrov; Stanley Liu; Shaul Aloni; Alex Zettl
arXiv: Materials Science | 2017
S. Matt Gilbert; Gabriel Dunn; Thang Pham; Brian Shevitski; Edgar Dimitrov; Shaul Aloni; Alex Zettl
Bulletin of the American Physical Society | 2018
Stephen Gilbert; Gabriel Dunn; Amin Azizi; Thang Pham; Brian Shevitski; Stanley Liu; Shaul Aloni; Alex Zettl
Physica Status Solidi B-basic Solid State Physics | 2017
Gabriel Dunn; Konlin Shen; Hamid Reza Barzegar; Wu Shi; Jason N. Belling; Tran N. H. Nguyen; Emil Barkovich; Kyle Chism; Michel M. Maharbiz; Michael R. DeWeese; Alex Zettl
arXiv: Mesoscale and Nanoscale Physics | 2016
Hamid Reza Barzegar; Aiming Yan; Sinisa Coh; Eduardo Gracia-Espino; Claudia Ojeda-Aristizabal; Gabriel Dunn; Marvin L. Cohen; Steven G. Louie; Thomas Wågberg; Alex Zettl
Physica Status Solidi B-basic Solid State Physics | 2016
Haider I. Rasool; Gabriel Dunn; Aidin Fathalizadeh; Alex Zettl