2022
Parra, Sebastian Hurtado; Straus, Daniel B.; Fichera, Bryan T.; Iotov, Natasha; Kagan, Cherie R.; Kikkawa, James M.
Large Exciton Polaron Formation in 2D Hybrid Perovskites via Time-Resolved Photoluminescence Journal Article
In: ACS Nano, vol. 16, iss. 12, pp. 21259–21265, 2022.
@article{Parra2022,
title = {Large Exciton Polaron Formation in 2D Hybrid Perovskites via Time-Resolved Photoluminescence},
author = {Sebastian Hurtado Parra and Daniel B. Straus and Bryan T. Fichera and Natasha Iotov and Cherie R. Kagan and James M. Kikkawa},
url = {https://pubs.acs.org/doi/full/10.1021/acsnano.2c09256},
doi = {10.1021/acsnano.2c09256},
year = {2022},
date = {2022-12-15},
journal = {ACS Nano},
volume = {16},
issue = {12},
pages = {21259–21265},
abstract = {We find evidence for the formation and relaxation of large exciton polarons in 2D organic–inorganic hybrid perovskites. Using ps-scale time-resolved photoluminescence within the phenethylammonium lead iodide family of compounds, we identify a red shifting of emission that we associate with exciton polaron formation time scales of 3–10 ps. Atomic substitutions of the phenethylammonium cation allow local control over the structure of the inorganic lattice, and we show that the structural differences among materials strongly influence the exciton polaron relaxation process, revealing a polaron binding energy that grows larger (up to 15 meV) in more strongly distorted compounds.},
keywords = {2D-materials, exciton-polarons, octahedral distortions, perovskites, time-resolved photoluminescence, transient absorption, transient PL},
pubstate = {published},
tppubtype = {article}
}
We find evidence for the formation and relaxation of large exciton polarons in 2D organic–inorganic hybrid perovskites. Using ps-scale time-resolved photoluminescence within the phenethylammonium lead iodide family of compounds, we identify a red shifting of emission that we associate with exciton polaron formation time scales of 3–10 ps. Atomic substitutions of the phenethylammonium cation allow local control over the structure of the inorganic lattice, and we show that the structural differences among materials strongly influence the exciton polaron relaxation process, revealing a polaron binding energy that grows larger (up to 15 meV) in more strongly distorted compounds.
Gabinet, Uri R.; Lee, Changyeon; Kim, Na Kyung; Hulman, Martin; Thompson, Sarah M.; Kagan, Cherie R.; Osuji, Chinedum O.
Magnetic Field Alignment and Optical Anisotropy of MoS2 Nanosheets Dispersed in a Liquid Crystal Polymer Journal Article
In: The Journal of Physical Chemistry Letters, vol. 13, iss. 34, pp. 7994–8001, 2022.
@article{Gabinet2022,
title = {Magnetic Field Alignment and Optical Anisotropy of MoS2 Nanosheets Dispersed in a Liquid Crystal Polymer},
author = {Uri R. Gabinet and Changyeon Lee and Na Kyung Kim and Martin Hulman and Sarah M. Thompson and Cherie R. Kagan and Chinedum O. Osuji},
url = {https://pubs.acs.org/doi/full/10.1021/acs.jpclett.2c01819},
doi = {10.1021/acs.jpclett.2c01819},
year = {2022},
date = {2022-08-19},
urldate = {2022-08-19},
journal = {The Journal of Physical Chemistry Letters},
volume = {13},
issue = {34},
pages = {7994–8001},
abstract = {Molybdenum disulfide (MoS2) nanosheets exhibit anisotropic optical and electronic properties, stemming from their shape and electronic structure. Unveiling this anisotropy for study and usage in materials and devices requires the ability to control the orientation of dispersed nanosheets, but to date this has proved a challenging proposition. Here, we demonstrate magnetic field driven alignment of MoS2 nanosheets in a liquid crystal (LC) polymer and unveil the optical properties of the resulting anisotropic assembly. Nanosheet optical anisotropy is observed spectroscopically by Raman and direction-dependent photoluminescence (PL) measurements. Resulting data indicate significantly lower PL emission due to optical excitation with electric field oscillation out of plane, parallel to the MoS2c-axis, than that associated with perpendicular excitation, with the dichroic ratio Iperp/Ipar = 3. The approach developed here provides a useful route to elucidate anisotropic optical properties of MoS2 nanosheets and to utilize such properties in new materials and devices.},
keywords = {2D-materials, liquid chromatography, magnetic properties, optical properties, scattering},
pubstate = {published},
tppubtype = {article}
}
Molybdenum disulfide (MoS2) nanosheets exhibit anisotropic optical and electronic properties, stemming from their shape and electronic structure. Unveiling this anisotropy for study and usage in materials and devices requires the ability to control the orientation of dispersed nanosheets, but to date this has proved a challenging proposition. Here, we demonstrate magnetic field driven alignment of MoS2 nanosheets in a liquid crystal (LC) polymer and unveil the optical properties of the resulting anisotropic assembly. Nanosheet optical anisotropy is observed spectroscopically by Raman and direction-dependent photoluminescence (PL) measurements. Resulting data indicate significantly lower PL emission due to optical excitation with electric field oscillation out of plane, parallel to the MoS2c-axis, than that associated with perpendicular excitation, with the dichroic ratio Iperp/Ipar = 3. The approach developed here provides a useful route to elucidate anisotropic optical properties of MoS2 nanosheets and to utilize such properties in new materials and devices.
Kim, Dahin; Ndaya, Dennis; Bosire, Reuben; Masese, Francis K.; Li, Weixingyue; Thompson, Sarah M.; Kagan, Cherie R.; Murray, Christopher B.; Kasi, Rajeswari M.; Osuji, Chinedum O.
Dynamic magnetic field alignment and polarized emission of semiconductor nanoplatelets in a liquid crystal polymer Journal Article
In: Nature Communications, vol. 13, no. 2507 , 2022.
@article{Kim2022,
title = {Dynamic magnetic field alignment and polarized emission of semiconductor nanoplatelets in a liquid crystal polymer},
author = {Dahin Kim and Dennis Ndaya and Reuben Bosire and Francis K. Masese and Weixingyue Li and Sarah M. Thompson and Cherie R. Kagan and Christopher B. Murray and Rajeswari M. Kasi and Chinedum O. Osuji},
url = {https://www.nature.com/articles/s41467-022-30200-2},
doi = {10.1038/s41467-022-30200-2},
year = {2022},
date = {2022-05-06},
urldate = {2022-05-06},
journal = {Nature Communications},
volume = {13},
number = {2507 },
abstract = {Reconfigurable arrays of 2D nanomaterials are essential for the realization of switchable and intelligent material systems. Using liquid crystals (LCs) as a medium represents a promising approach, in principle, to enable such control. In practice, however, this approach is hampered by the difficulty of achieving stable dispersions of nanomaterials. Here, we report on good dispersions of pristine CdSe nanoplatelets (NPLs) in LCs, and reversible, rapid control of their alignment and associated anisotropic photoluminescence, using a magnetic field. We reveal that dispersion stability is greatly enhanced using polymeric, rather than small molecule, LCs and is considerably greater in the smectic phases of the resulting systems relative to the nematic phases. Aligned composites exhibit highly polarized emission that is readily manipulated by field-realignment. Such dynamic alignment of optically-active 2D nanomaterials may enable the development of programmable materials for photonic applications and the methodology can guide designs for anisotropic nanomaterial composites for a broad set of related nanomaterials.},
keywords = {2D-materials, CdSe, liquid crystals},
pubstate = {published},
tppubtype = {article}
}
Reconfigurable arrays of 2D nanomaterials are essential for the realization of switchable and intelligent material systems. Using liquid crystals (LCs) as a medium represents a promising approach, in principle, to enable such control. In practice, however, this approach is hampered by the difficulty of achieving stable dispersions of nanomaterials. Here, we report on good dispersions of pristine CdSe nanoplatelets (NPLs) in LCs, and reversible, rapid control of their alignment and associated anisotropic photoluminescence, using a magnetic field. We reveal that dispersion stability is greatly enhanced using polymeric, rather than small molecule, LCs and is considerably greater in the smectic phases of the resulting systems relative to the nematic phases. Aligned composites exhibit highly polarized emission that is readily manipulated by field-realignment. Such dynamic alignment of optically-active 2D nanomaterials may enable the development of programmable materials for photonic applications and the methodology can guide designs for anisotropic nanomaterial composites for a broad set of related nanomaterials.
Straus, Daniel B.; Kagan, Cherie R.
Photophysics of Two-Dimensional Semiconducting Organic-Inorganic Metal-Halide Perovskites Journal Article
In: Annual Review of Physical Chemistry, vol. 73, iss. 1, 2022.
@article{Straus2021,
title = {Photophysics of Two-Dimensional Semiconducting Organic-Inorganic Metal-Halide Perovskites},
author = {Daniel B. Straus and Cherie R. Kagan},
url = {https://www.annualreviews.org/doi/10.1146/annurev-physchem-082820-015402
https://arxiv.org/abs/2108.13501},
doi = {10.1146/annurev-physchem-082820-015402},
year = {2022},
date = {2022-02-04},
urldate = {2022-02-04},
journal = {Annual Review of Physical Chemistry},
volume = {73},
issue = {1},
abstract = {2D organic-inorganic hybrid perovskites (2DHPs) consist of alternating anionic metal-halide and cationic organic layers. They have widely tunable structural and optical properties. We review the role of the organic cation in defining the structural and optical properties of 2DHPs through example lead iodide 2DHPs. Even though excitons reside in the metal halide layers, the organic and inorganic frameworks cannot be separated-they must be considered as a single unit to fully understand the photophysics of 2DHPs. We correlate cation-induced distortion and disorder in the inorganic lattice with the resulting optical properties. We also discuss the role of the cation in creating and altering the discrete excitonic structure that appears at cryogenic temperatures in some 2DHPs, including the cation-dependent presence of hot exciton photoluminescence. We conclude our review with an outlook for 2DHPs, highlighting existing gaps in fundamental knowledge as well as potential future applications.},
keywords = {2D-materials, hybrid perovskite, perovskites},
pubstate = {published},
tppubtype = {article}
}
2D organic-inorganic hybrid perovskites (2DHPs) consist of alternating anionic metal-halide and cationic organic layers. They have widely tunable structural and optical properties. We review the role of the organic cation in defining the structural and optical properties of 2DHPs through example lead iodide 2DHPs. Even though excitons reside in the metal halide layers, the organic and inorganic frameworks cannot be separated-they must be considered as a single unit to fully understand the photophysics of 2DHPs. We correlate cation-induced distortion and disorder in the inorganic lattice with the resulting optical properties. We also discuss the role of the cation in creating and altering the discrete excitonic structure that appears at cryogenic temperatures in some 2DHPs, including the cation-dependent presence of hot exciton photoluminescence. We conclude our review with an outlook for 2DHPs, highlighting existing gaps in fundamental knowledge as well as potential future applications.
2021
Gabinet, Uri R.; Lee, Changyeon; Poling-Skutvik, Ryan; Keane, Daniel; Kim, Na Kyung; Dong, Ruiqi; Vicars, Zachariah; Cai, Yusheng; Thosar, Aniket U.; Grun, Alexander; Thompson, Sarah M.; Patel, Amish J.; Kagan, Cherie R.; Composto, Russell J.; Osuji, Chinedum O.
Nanocomposites of 2D-MoS2 Exfoliated in Thermotropic Liquid Crystals Journal Article
In: ACS Materials Letters, vol. 3, no. 6, pp. 704–712, 2021.
@article{Gabinet2021,
title = {Nanocomposites of 2D-MoS2 Exfoliated in Thermotropic Liquid Crystals},
author = {Uri R. Gabinet and Changyeon Lee and Ryan Poling-Skutvik and Daniel Keane and Na Kyung Kim and Ruiqi Dong and Zachariah Vicars and Yusheng Cai and Aniket U. Thosar and Alexander Grun and Sarah M. Thompson and Amish J. Patel and Cherie R. Kagan and Russell J. Composto and Chinedum O. Osuji},
url = {https://pubs.acs.org/doi/abs/10.1021/acsmaterialslett.1c00222},
doi = {10.1021/acsmaterialslett.1c00222},
year = {2021},
date = {2021-05-05},
urldate = {2021-05-05},
journal = {ACS Materials Letters},
volume = {3},
number = {6},
pages = {704–712},
abstract = {Atomically thin MoS2 nanosheets are of interest due to unique electronic, optical, and catalytic properties that are absent in the bulk material. Methods to prepare nanosheets from bulk material that facilitate studies of 2D-MoS2 and the fabrication of useful devices have consequently assumed considerable importance. Here, we report the simultaneous exfoliation and stable dispersion of MoS2 nanosheets in a liquid crystal. Exfoliation of bulk MoS2 in mesogen-containing solutions produced stable dispersions of 2D-MoS2 that retained suspension stability for several weeks. Solvent removal in cast films yielded nanocomposites of 2D-MoS2. Preservation of single- and few-sheet MoS2 was confirmed utilizing UV–vis and Raman spectroscopy in the nematic and isotropic fluid states of the system and, remarkably, in the solid crystal as well. Importantly, the MoS2 nanosheets remained well-dispersed upon polymerization of the reactive mesogen to form a liquid crystal polymer. The ability to stably disperse 2D-MoS2 in a structured fluid opens up new possibilities for studying anisotropic properties of MoS2 and for exploiting such properties in responsive materials.},
keywords = {2D-materials, colloids, exfoliation, polymerization, surface interactions},
pubstate = {published},
tppubtype = {article}
}
Atomically thin MoS2 nanosheets are of interest due to unique electronic, optical, and catalytic properties that are absent in the bulk material. Methods to prepare nanosheets from bulk material that facilitate studies of 2D-MoS2 and the fabrication of useful devices have consequently assumed considerable importance. Here, we report the simultaneous exfoliation and stable dispersion of MoS2 nanosheets in a liquid crystal. Exfoliation of bulk MoS2 in mesogen-containing solutions produced stable dispersions of 2D-MoS2 that retained suspension stability for several weeks. Solvent removal in cast films yielded nanocomposites of 2D-MoS2. Preservation of single- and few-sheet MoS2 was confirmed utilizing UV–vis and Raman spectroscopy in the nematic and isotropic fluid states of the system and, remarkably, in the solid crystal as well. Importantly, the MoS2 nanosheets remained well-dispersed upon polymerization of the reactive mesogen to form a liquid crystal polymer. The ability to stably disperse 2D-MoS2 in a structured fluid opens up new possibilities for studying anisotropic properties of MoS2 and for exploiting such properties in responsive materials.
2019
Straus, Daniel B.; Iotov, Natasha; Gau, Michael R.; Zhao, Qinghua; Carroll, Patrick J.; Kagan, Cherie R.
Longer Cations Increase Energetic Disorder in Excitonic 2D Hybrid Perovskites Journal Article
In: Journal of Physical Chemistry Letters, vol. 10, no. 6, pp. 1198–1205, 2019.
@article{Straus2019,
title = {Longer Cations Increase Energetic Disorder in Excitonic 2D Hybrid Perovskites},
author = {Daniel B. Straus and Natasha Iotov and Michael R. Gau and Qinghua Zhao and Patrick J. Carroll and Cherie R. Kagan},
url = {https://pubs.acs.org/doi/10.1021/acs.jpclett.9b00247},
doi = {10.1021/acs.jpclett.9b00247},
year = {2019},
date = {2019-02-26},
journal = {Journal of Physical Chemistry Letters},
volume = {10},
number = {6},
pages = {1198–1205},
abstract = {We synthesize and characterize derivatives of the two-dimensional hybrid perovskite (2DHP) phenethylammonium lead iodide ((PEA)2PbI4) in which the para H on the cation is replaced with F, Cl, CH3, or Br. These substitutions increase the length of the cation but leave the cross-sectional area unchanged, resulting in structurally similar PbI42– frameworks with increasing interlayer spacing. Longer cations result in broader, blue-shifted excitonic absorption spectra with reduced or eliminated structure, indicating greater energetic disorder. Photoluminescence spectra are largely invariant and insensitive to cation length, suggesting polaron formation stabilizes a structural and electronic minimum. Temperature-dependent line width analysis reveals excitons couple to a vibration on the organic framework that is weakly sensitive to these cation substitutions, and Raman spectra and electronic structure calculations support the presence of such a cationic mode. Despite carriers being confined to the inorganic framework, the length of the organic cation alters the optical and electronic properties of 2DHPs.},
keywords = {2D-materials, perovskites},
pubstate = {published},
tppubtype = {article}
}
We synthesize and characterize derivatives of the two-dimensional hybrid perovskite (2DHP) phenethylammonium lead iodide ((PEA)2PbI4) in which the para H on the cation is replaced with F, Cl, CH3, or Br. These substitutions increase the length of the cation but leave the cross-sectional area unchanged, resulting in structurally similar PbI42– frameworks with increasing interlayer spacing. Longer cations result in broader, blue-shifted excitonic absorption spectra with reduced or eliminated structure, indicating greater energetic disorder. Photoluminescence spectra are largely invariant and insensitive to cation length, suggesting polaron formation stabilizes a structural and electronic minimum. Temperature-dependent line width analysis reveals excitons couple to a vibration on the organic framework that is weakly sensitive to these cation substitutions, and Raman spectra and electronic structure calculations support the presence of such a cationic mode. Despite carriers being confined to the inorganic framework, the length of the organic cation alters the optical and electronic properties of 2DHPs.
2018
Straus, Daniel B.; Kagan, Cherie R.
Electrons, Excitons, and Phonons in Two-Dimensional Hybrid Perovskites: Connecting Structural, Optical, and Electronic Properties Journal Article
In: The Journal of Physical Chemistry Letters, vol. 9, no. 6, pp. 1434–1447, 2018.
@article{Straus2018,
title = {Electrons, Excitons, and Phonons in Two-Dimensional Hybrid Perovskites: Connecting Structural, Optical, and Electronic Properties},
author = {Daniel B. Straus and Cherie R. Kagan},
url = {https://pubs.acs.org/doi/10.1021/acs.jpclett.8b00201},
doi = {10.1021/acs.jpclett.8b00201},
year = {2018},
date = {2018-02-26},
journal = {The Journal of Physical Chemistry Letters},
volume = {9},
number = {6},
pages = {1434–1447},
abstract = {Two-dimensional (2D) hybrid perovskites are stoichiometric compounds consisting of alternating inorganic metal-halide sheets and organoammonium cationic layers. This materials class is widely tailorable in composition, structure, and dimensionality and is providing an intriguing playground for the solid-state chemistry and physics communities to uncover structure–property relationships. In this Perspective, we describe semiconducting 2D perovskites containing lead and tin halide inorganic frameworks. In these 2D perovskites, charges are typically confined to the inorganic framework because of strong quantum and dielectric confinement effects, and exciton binding energies are many times greater than kT at room temperature. We describe the role of the heavy atoms in the inorganic framework; the geometry and chemistry of organic cations; and the “softness” of the organic–inorganic lattice on the electronic structure and dynamics of electrons, excitons, and phonons that govern the physical properties of these materials.},
keywords = {2D-materials, exciton−phonon coupling, hybrid perovskite, perovskites},
pubstate = {published},
tppubtype = {article}
}
Two-dimensional (2D) hybrid perovskites are stoichiometric compounds consisting of alternating inorganic metal-halide sheets and organoammonium cationic layers. This materials class is widely tailorable in composition, structure, and dimensionality and is providing an intriguing playground for the solid-state chemistry and physics communities to uncover structure–property relationships. In this Perspective, we describe semiconducting 2D perovskites containing lead and tin halide inorganic frameworks. In these 2D perovskites, charges are typically confined to the inorganic framework because of strong quantum and dielectric confinement effects, and exciton binding energies are many times greater than kT at room temperature. We describe the role of the heavy atoms in the inorganic framework; the geometry and chemistry of organic cations; and the “softness” of the organic–inorganic lattice on the electronic structure and dynamics of electrons, excitons, and phonons that govern the physical properties of these materials.
2014
“Designing High-Performance PbS and PbSe Nanocrystal Electronic Devices through Stepwise, Post-Synthesis, Colloidal Atomic Layer Deposition,” Soong Ju Oh, Nathaniel E. Berry, Ji-Hyuk Choi, E. Ashley Gaulding, Hangfei Lin, Taejong Paik, Benjamin. T. Diroll, Shin Muramoto, Christopher B. Murray, and Cherie R. Kagan NANO Letters, 14 (3) 1559-1566 (2014)
“Air-Stable, Nanostructured Electronic and Plasmonic Materials from Solution-Processable, Silver Nanocrystal Building Blocks,” Aaron T. Fafarman, Sung-Hoon Hong, Soong Ju Oh, Humeyra Caglayan, Xingchen Ye, Benjamin T. Diroll, Nader Engheta, Christopher B. Murray, and Cherie R. Kagan ACS NANO, 8 (3) 2746-2754 (2014)
“Solution-Processed Phase-Change VO2 Metamaterials from Colloidal Vanadium Oxide (VOx) Nanocrystals,” Taejong Paik, Sung-Hoon Hong, E. Ashley Gaulding, Humeyra Caglayan, Thomas R. Gordon, Nader Engheta, Cherie R. Kagan, and Christopher B. Murray ACS NANO, 8 (1) 797-806 (2014)
2013
“Solution-Based Stoichiometric Control over Charge Transport in Nanocrystalline CdSe Devices,” David K. Kim, Aaron T. Fafarman, Benjamin T. Diroll, Silvia H Chan, Thomas R. Gordon, Christopher B. Murray, and Cherie R. Kagan ACS NANO, 7 (10) 8760-8770 (2013)
“Crystallographic anisotropy of the resistivity size effect in single crystal tungsten nanowires,” Dooho Choi, Matthew Moneck, Xuan Liu, Soong Ju Oh, Cherie R. Kagan, Kevin R. Coffey, & Katayun Barmak Scientific Reports, 3 (2591) 1-4 (2013)
“In-situ Repair of High-Performance, Flexible Nanocrystal Electronics for Large-Area Fabrication and Operation in Air,” Ji-Hyuk Choi, Soong Ju Oh, Yuming Lai, David K. Kim, Tianshuo Zhao, Aaron T. Fafarman, Benjamin T. Diroll, Christopher B. Murray, and Cherie R. Kagan ACS Nano, 7 (9) 8275-8283 (2013)
“Near-Infrared Metatronic Nanocircuits by Design,” Humeyra Caglayan*, Sung-Hoon Hong*, Brian Edwards, Cherie R. Kagan, and Nader Engheta Physical Review Letters, 111 073904 (2013)
* Indicates equal contribution
“Plasmonic Enhancement of Nanophosphor Upconversion Luminescence in Au Nanohole Arrays,” Marjan Saboktakin, Xingchen Ye, Uday K. Chettiar, Nader Engheta , Christopher B. Murray, and Cherie R. Kagan ACS Nano, 7 (8) 7186-7192 (2013)
“Competition of shape and interaction patchiness for self-assembling nanoplates,” Xingchen Ye, Jun Chen, Michael Engel, Jaime A. Millan, Wenbin Li, Liang Qi, Guozhong Xing, Joshua E. Collins, Cherie R. Kagan, Ju Li, Sharon C. Glotzer & Christopher B. Murray Nature Chemistry, 5 466-473 (2013)
“Stoichiometric Control of Lead Chalcogenide Nanocrystal Solids to Enhance Their Electronic and Optoelectronic Device Performance,” Soong Ju Oh, Nathaniel E. Berry, Ji-Hyuk Choi, E. Ashley Gaulding, Taejong Paik, Sung-Hoon Hong, Christopher B. Murray, and Cherie R. Kagan ACS Nano, 7 (3) 2413-2421 (2013)
“Engineering Catalytic Contacts and Thermal Stability: Gold/Iron Oxide Binary Nanocrystal Superlattices for CO Oxidation,” Yijin Kang, Xingchen Ye, Jun Chen, Liang Qi, Rosa E. Diaz, Vicky Doan-Nguyen, Guozhong Xing, Cherie R. Kagan, Ju Li, Raymond J. Gorte, Eric A. Stach, and Christopher B. Murray JACS, 135 4 1499-1505 (2013)
“Bistable Magnetoresistance Switching in Exchange-Coupled CoFe2O4-Fe3O4 Binary Nanocrystal Superlattices by Self-Assembly and Thermal Annealing,” Jun Chen, Xingchen Ye, Soong Ju Oh, James M. Kikkawa, Cherie R. Kagan, and Christopher B. Murray ACS Nano, 7(2) 1478-1486 (2013)
“Chemically Tailored Dielectric-to-Metal Transition for the Design of Metamaterials from Nanoimprinted Colloidal Nanocrystals,” Aaron T. Fafarman*, Sung-Hoon Hong*, Humeyra Caglayan, Xingchen Ye, Benjamin T. Diroll, Taejong Paik, Nader Engheta, Christopher B. Murray & Cherie R. Kagan Nano Letters, 13 (2) 350-357 (2013)
*=Equal Contributors
2012
“Flexible and low-voltage integrated circuits constructed from high-performance nanocrystal transistors,” David K. Kim*, Yuming Lai*, Benjamin T. Diroll, Christopher B. Murray & Cherie R. Kagan Nature Communications, 3 (1216) 1-6 (2012)
*=Equal Contributors
“The State of Nanoparticle-Based Nanoscience and Biotechnology: Progress, Promises, and Challenges,” Beatriz Pelaz, Sarah Jaber, Dorleta Jimenez de Aberasturi, Verena Wulf, Takuzo Aida, Jesus M. de la Fuente, Jochen Feldmann, Hermann E. Gaub, Lee Josephson, Cherie R. Kagan, Nicholas A. Kotov, Luis M. Liz-Marzan, Hedi Mattoussi, Paul Mulvaney, Christopher B. Murray, Andrey L. Rogach, Paul S. Weiss, Itamar Willner, and Wolfgang J. Parak, ACS Nano, 6 (10) 8468-8483 (2012)
“Metal Enhanced Upconversion Luminescence Tunable through Metal Nanoparticle-Nanophosphor Separation,” Marjan Saboktakin, Xingchen Ye, Soong Ju Oh, Sung-Hoon Hong, Aaron T. Fafarman, Uday K. Chettiar, Nader Engheta, Christopher B. Murray, and Cherie R. Kagan, ACS Nano, 6 (10) 8758-8766 (2012)
“Bandlike Transport in Strongly Coupled and Doped Quantum Dot Solids: A Route to High-Performance Thin-Film Electronics,” Ji-Hyuk Choi, Aaron T. Fafarman, Soong Ju Oh, Dong-Kyun Ko, David K. Kim, Benjamin T. Diroll, Shin Muramoto, J. Greg Gillen, Christopher B. Murray, and Cherie R. Kagan, Nano Letters, 12 (5) 2631-2638 (2012)
“Remote Doping and Schottky Barrier Formation in Strongly Quantum Confined Single PbSe Nanowire Field-Effect Transistors,” Soong Ju Oh, David K. Kim, and Cherie. R. Kagan, ACS Nano, 6 (5) 4328-4334 (2012)
“Wrinkles and deep folds as photonic structures in photovoltaics,” Jong Bok Kim, Pilnam Kim, Nicolas C. Pgard, Soong Ju Oh, Cherie R. Kagan, Jason W. Fleischer, Howard A. Stone and Yueh-Lin Loo, Nature Photonics, 6 327-332 (2012)
“An Improved Size-Tunable Synthesis of Monodisperse Gold Nanorods through the Use of Aromatic Additives,” Xingchen Ye, Linghua Jin, Humeyra Caglayan, Jun Chen, Guozhong Xing, Chen Zheng, Vicky Doan-Nguyen, Yijin Kang, Nader Engheta, Cherie R. Kagan, and Christopher B. Murray, ACS Nano, 6 2804-2817 (2012)
“Molecular Monolayers as Semiconducting Channels in Field Effect Transistors,” Cherie R. Kagan, Topics in Current Chemistry, 312 213-237, (2012)
2011
“Flexible, Low-Voltage, and Low-Hysteresis PbSe Nanowire Field-Effect Transistors,” David K. Kim, Yuming Lai, Tarun R. Vemulkar, and Cherie R. Kagan, ACS Nano, 5 (12) 10074-10083, (2011)
“Thiocyanate-capped PbS nanocubes: ambipolar transport enables quantum dot-based circuits on a flexible substrate,” Weon-kyu Koh , Sangameshwar R Saudari , Aaron T. Fafarman , Cherie R. Kagan , and Christopher B. Murray, Nano Letters, 11 (11) 4764-4767, (2011)
“Near-Infrared Absorption of Monodisperse Silver Telluride (Ag2Te) Nanocrystals and Photoconductive Response of Their Self-Assembled Superlattices,” Yu-Wen Liu, Dong-Kyun Ko, Soong Ju Oh, Thomas R. Gordon, Vicky Doan-Nguyen, Taejong Paik, Yijin Kang, Xingchen Ye, Linghua Jin, Cherie R. Kagan, and Christopher B. Murray, ACS Chemistry of Materials, 23 (21) 4657-4659, (2011)
“Diketopyrrolopyrrole-based p-bridged Donor-Acceptor Polymer for Photovoltaic Applications,” Wenting Li, Taegweon Lee, Soong Ju Oh, and Cherie R. Kagan, ACS Applied Materials and Interfaces, 3 (10) 3874-3883 (2011)
“Flexible Organic Electronics for Use in Neural Sensing,” Hank Bink*, Yuming Lai*, Sangamweshwar Rao Saudari, Brian Helfer, Jonathan Viventi, Jan Van der Spiegel, Brian Litt, Cherie Kagan, IEEE EMBC 2011 5400-5403 (2011)
* = Equal Contributors
“Thiocyanate Capped Nanocrystal Colloids: A Vibrational Reporter of Surface Chemistry and a Solution-based Route to Enhanced Coupling in Nanocrystal Solids,” Aaron T. Fafarman, Weon-kyu Koh, Benjamin T. Diroll, David K. Kim, Dong-Kyun Ko, Soong Ju Oh, Xingchen Ye, Vicky Doan-Nguyen, Michael R. Crump, Danielle C. Reifsnyder, Christopher B. Murray, and Cherie R. Kagan, Journal of the American Chemical Society, 133 (39), 15753-15761, (2011)
“Ambipolar and Unipolar PbSe Nanowire Field-Effect Transistors,” David K. Kim, Tarun R. Vemulkar, Soong-Ju Oh, Weon-kyu Koh, Christopher B. Murray and Cherie R. Kagan, ACS Nano, 5 (4), 3230-3236, (2011)
“Multiscale Periodic Assembly of Striped Nanocrystal Superlattice Films on a Liquid Surface,” Angang Dong, Jun Chen, Soong Ju Oh, Weon-kyu Koh, Faxian Xiu, Xingchen Ye, Dong-Kyun Ko, Kang L. Wang, Cherie R. Kagan, and Christopher B. Murray, Nano Letters, 11 (2), 841-846, (2011)
2010
“Comparison of the Energy-level Alignment of Thiolate- and Carbodithiolate-Bound Self-Assembled Monolayers on Gold,” Philip Schulz, Christopher D. Zangmeister, Yi-Lei Zhao, Paul R. Frail, Sangameshwar R. Saudari, Carlos A. Gonzalez, Cherie R. Kagan, Matthias Wuttig, and Roger D. van Zee, Journal of Physical Chemistry C, 114 (48), 20843-20851, (2010)
“Device Configurations for Ambipolar Transport in Flexible, Pentacene Transistors,” Sangameshwar Rao Saudari, Yu Jen Lin, Yuming Lai and Cherie R. Kagan, Advanced Materials, 44, 5063-5068, (2010)
“Small-Molecule Thiophene-C60 Dyads As Compatibilizers in Inverted Polymer Solar Cells,” Jong Bok Kim, Kathryn Allen, Soong Ju Oh, Stephanie Lee, Michael F. Toney, Youn Sang Kim, Cherie R. Kagan, Colin Nuckolls, and Yueh-Lin Loo, Chemistry of Materials, 22 (20), pp 5762-5773 (2010)
2009
“Ambipolar transport in solution-deposited pentacene transistors enhanced by molecular engineering of device contacts,” Sangameshwar Rao Saudari, Paul R. Frail, Cherie R. Kagan , Appl. Phys. Lett, 95, 023301 (2009)
2007
“Chemically Assisted Directed Assembly of Carbon Nanotubes for the Fabrication of Large-Scale Device Arrays,” G. S. Tulevski, J. Hannon, A. Afzali, Z. Chen, Ph. Avouris, C. R. Kagan, J. American Chemical Society, 129 (39), 11964 (2007)
“Alignment, Electronic Properties, Doping, and On-Chip Growth of Colloidal PbSe Nanowires,” D. V. Talapin, C. T. Black, C. R. Kagan, E. V. Shevchenko, A. Afzali, C. B. Murray, J. Phys. Chem. C, 111 (35), 13244 (2007)
“Synergistic Effects in Binary Nanocrystal Superlattices: Enhanced p-Type Conductivity in Self-Assembled PbTe/Ag2Te Thin Films,” J. J. Urban, D. V. Talapin, E. V. Shevchenko, C. R. Kagan, C. B. Murray, Nature Materials, 6 (2), 115 (2007).
“Molecular Assemblies: Briding the Gap to Form Molecular Junctions,” C. R. Kagan, C. Lin, in Multifunctional Conducting Molecular Materials, eds. G. Saito, F. Wudl, R. C. Haddon, K. Tanigaki, T. Enoki, H. E. Katz, M. Maesato, Royal Society of Chemistry, London 306, 248, (2007).
2006
“The Role of Chemical Contacts in Molecular Conductance,” N. D. Lang, C. R. Kagan, Nano Letters, 6, 2955 (2006).
“Enforced One-Dimensional Photoconductivity in Core-Cladding Hexabenzocorenenes,” Y. S. Cohen, S. Xiao, C. Nuckolls, C. R. Kagan, Nano Letters, 6, 2838 (2006).
“Organic and Organic-Inorganic Hybrid Molecular Devices,” Proceedings of the 12th International Micromachine/Nanotech Symposium, 31 (2006).
“Device Scaling in Sub-100 nm Pentacene FETs,” G. S. Tulevski, A. Afzali, T. O Graham, C. Nuckolls, C. R. Kagan, Applied Physics Letters, 89, 183101 (2006).
“Chemical Complementarity in the Contacts for Nanoscale Organic Field-Effect Transistors,” G. S. Tulevski, Q. Miao, A. Afzali, T. O. Graham, C. R. Kagan, C. Nuckolls, Journal of the American Chemical Society, 128, 1788 (2006).
2005
“Self-assembly and Oligomerization of Alkyne-Terminated Molecules on Metal and Oxide Surfaces,” L. Vyklicky, A. Afzali, C. R. Kagan, Langmuir, 21, 11574 (2005).
“Operational and Environmental Stability of Pentacene Thin Film Transistors,” C. R. Kagan, A. Afzali, T. O. Graham, Applied Physics Letters, 86, 193505 (2005).
“N-Sulfinylcarbamate-Pentacene Adduct; a Novel Pentacene Precursor Soluble in Alcohols,” A. Afzali, C. R. Kagan, G. Traub, Synthetic Metals, 155, 490 (2005).
“Electrostatic Field and Partial Fermi Level Pinning at the Pentacene-SiO2 Interface,” L. Chen, R. Ludeke, X. Cui, A. G. Schrott, C. R. Kagan, L. E. Brus, Journal of Physical Chemistry B, 109, 1834 (2005).
2004
“Molecular Transport Junctions: An Introduction,” C. R. Kagan, M. A. Ratner, MRS Bulletin, edited by C. R. Kagan, M. A. Ratner, 29, 376 (2004).
“Direct Assembly of Organic Semiconductors on Gate Oxides,” G. S. Tulevski, Q. Miao, M. Fukuto, R. Abram, B. Ocko, R. Pindak, C. R. Kagan, C. Nuckolls, Journal of the American Chemical Society, 126, 15048 (2004).
“Understanding the Molecular Transistor,” P. Solomon, C. R. Kagan in Future Trends in Microelectronics: The Nano, the Giga, and the Ultra, edited by S. Luryi, J. Xu, A. Zaslavsky, Wiley, NY (2004), p.168.
2003
“Evaluations and Considerations for Self-Assembled Monolayer Field-Effect Transistors,” C. R. Kagan, A. Afzali, R. Martel, L. M. Gignac, P. M. Solomon, A. Schrott, B. Ek, Nano Letters, 3, 119 (2003).
“Layer-by-Layer Growth of Metal-Metal Bonded Supramolecular Thin Films and Its Use in the Fabrication of Lateral Nanoscale Devices,” C. Lin and C. R. Kagan, Journal of the American Chemical Society, 125, 336 (2003).
“Organic-Inorganic Thin Film Transistors,” D. B. Mitzi, C. R. Kagan in Thin Film Transistors, edited by C. R. Kagan, P. S. Andry, Marcell-Dekker, NY, (2003), p. 475.
“Charge Transport on the Nanoscale,” D. Adams, L. Brus, C. E. D. Chidsey, S. Creager, C. Creutz, C. R. Kagan, P. Kamat, M. Lieberman, S. Lindsay, R. A. Marcus, R. M. Metzger, M. E. Michel-Beyerle, J. R. Miller, M. D. Newton, D. R. Rolison, O. Sankey, K. S. Schanze, J. Yardley, X. Zhu, Journal of Physical Chemistry B, 107, 6668 (2003).
2002
“An efficient synthesis of symmetrical oligothiophenes: Synthesis and transport properties of a soluble sexithiophene derivative,” A. Afzali, T. L. Breen, C. R. Kagan, Chemistry of Materials, 14(4), 1742 (2002) .
2001
“Patterning Organic-Inorganic Thin-Film Transistors Using Microcontact Printed Templates,” C. R. Kagan, T. L Breen, L. L. Kosbar, Applied Physics Letters 79 (21), 3536 (2001).
“Organic-Inorganic Electronics,” D. B. Mitzi, K. Chondroudis, C. R. Kagan, IBM Journal of Research and Development, 45, 29 (2001).
“Colloidal Synthesis of Nanocrystals and Nanocrystal Superlattices,” C. B. Murray, S. Sun, W. Gaschler, H. Doyle, T. Betley, C. R. Kagan, IBM Journal of Research and Development, 45, 47 (2001).
2000
“Synthesis and Characterization of Monodisperse Nanocrystals and Close Packed Nanocrystal Assemblies,” C. B. Murray, C. R. Kagan, M. G. Bawendi, Annual Review of Materials Science 30, 545, (2000).
“Photoconductivity in CdSe Quantum Dot Solids,” C. A. Leatherdale, C. R. Kagan, N. Y. Morgan, S. A. Empedocles, M. A. Kastner, and M. G. Bawendi, Physical Review B, 62, 2669 (2000).
1999
“Organic-Inorganic Hybrid Materials as Semiconducting Channels in Thin-Film Field-Effect Transistors,” C. R. Kagan, D. B. Mitzi, C. D. Dimitrakopoulos, Science, 286, 945 (1999).
“Design, Structure, and Optical Properties of Organic-Inorganic Perovskites Containing an Oligothiophene Chromophore,” David B. Mitzi, Konstantinos Chondroudis, Cherie R. Kagan, Inorganic Chemistry 38, 6246 (1999).
“Charge Generation and Transport in CdSe Semiconductor Quantum Dot Solids,” C. A. Leatherdale, N. Y. Morgan, C. R. Kagan, S. A. Empedocles, M. G. Bawendi, M. A. Kastner, MRS Proceedings 571, 191 (1999).
1998
“Submicron Confocal Raman Imaging of Holograms in Multicomponent Photopolymers,” C. R. Kagan, T. D. Harris, A. L. Harris, and M. L. Schilling, Journal of Chemical Physics, 108, 6892 (1998).
1996
“Long Range Resonance Transfer of Electronic Excitations in Close Packed CdSe Quantum Dot Solids,” C. R. Kagan, C. B. Murray, and M. G. Bawendi, Physical Review B, 54, 8633 (1996).
“Electronic Energy Transfer in CdSe Quantum Dot Solids,” C. R. Kagan, C. B. Murray, M. Nirmal, M. G. Bawendi, Physical Review Letters, 76, 1517 (1996).
1995
“Self Organization of CdSe Nanocrystallites into Three Dimensional Quantum Dot Superlattices,” C. B. Murray, C. R. Kagan, and M. G. Bawendi, Science, 270, 1335 (1995).
“Synthesis, Structural Characterization, and Optical Spectroscopy of Close Packed CdSe Nanocrystallites,” C. R. Kagan, C. B. Murray, M. G. Bawendi, MRS Proceedings, 358, 219 (1995).
1993
“Solution Precipitation of CdSe Quantum Dots,” C. R. Kagan, M. J. Cima, MRS Proceedings, 283, 841 (1993).
1992
“Ion-Exchange Reactions of Potassium Brannerite, K0.8(V0.8Mo1.2)O6,” Peter K. Davies and Cherie R. Kagan, Solid State Ionics, 53-56, 546-552 (1992).
Books and Journals Edited
“Molecular Transport Junctions,” edited by C. R. Kagan, M. A. Ratner, MRS Bulletin, Materials Research Society, PA, (2004).
“Thin Film Transistors,” edited by C. R. Kagan, P. S. Andry, Marcell-Dekker, NY, (2003).