J
Joshua J. Choi
Researcher at University of Virginia
Publications - 54
Citations - 5589
Joshua J. Choi is an academic researcher from University of Virginia. The author has contributed to research in topics: Perovskite (structure) & Nanocrystal. The author has an hindex of 30, co-authored 52 publications receiving 4777 citations. Previous affiliations of Joshua J. Choi include Eindhoven University of Technology & Columbia University.
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Journal ArticleDOI
Ligand exchange and the stoichiometry of metal chalcogenide nanocrystals: spectroscopic observation of facile metal-carboxylate displacement and binding.
TL;DR: The results demonstrate that nanocrystals lack a single chemical formula, but are instead dynamic structures with concentration-dependent compositions, and suggest that ligands displace L-M(O2CR)2 by cooperatively complexing the displaced metal ion as well as the nanocrystal.
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Bright infrared quantum-dot light-emitting diodes through inter-dot spacing control
Liangfeng Sun,Joshua J. Choi,David Stachnik,Adam Bartnik,Byung-Ryool Hyun,George G. Malliaras,George G. Malliaras,Tobias Hanrath,Frank W. Wise +8 more
TL;DR: By tuning the distance between adjacent PbS quantum dots, thin-film quantum-dot light-emitting diodes are fabricated that operate at infrared wavelengths with radiances eight times higher and external quantum efficiencies two times higher than the highest values previously reported.
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PbSe nanocrystal excitonic solar cells.
Joshua J. Choi,Yee-Fun Lim,Mitk’El B. Santiago-Berríos,Matthew Oh,Byung-Ryool Hyun,Liangfeng Sun,Adam Bartnik,Augusta Goedhart,George G. Malliaras,Héctor D. Abruña,Frank W. Wise,Tobias Hanrath +11 more
TL;DR: The design, fabrication, and characterization of colloidal PbSe nanocrystal (NC)-based photovoltaic test structures that exhibit an excitonic solar cell mechanism are reported, suggesting a charge separation mechanism that is distinct from previously reported Schottky devices and consistent with signatures of excited solar cells.
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Origin of vertical orientation in two-dimensional metal halide perovskites and its effect on photovoltaic performance.
Alexander Z. Chen,Michelle Shiu,Jennifer H. Ma,Matthew R. Alpert,Depei Zhang,Benjamin Foley,Detlef-M. Smilgies,Seunghun Lee,Joshua J. Choi +8 more
TL;DR: Chen et al. reveal that the film formation starts at the liquid-air interface and is thus independent of the choice of substrates, demonstrating control over the degree of preferential orientation of the 2D perovskite layers and its drastic impact on device performance.
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Structure of methylammonium lead iodide within mesoporous titanium dioxide: active material in high-performance perovskite solar cells.
TL;DR: The structure of methylammonium lead(II) iodide perovskite in mesoporous TiO2, as used in high-performance solar cells, is reported, showing a two component nanostructure: one component with medium range crystalline order and another with only local structural coherence.