Experimental

What molecular properties give rise to a strong piezoelectric response?

  • By Burcu Ozden
  • 22 November 2017

In this study Geoffrey R. Hutchison and his colleagues tried to answer the question of " What molecular properties give rise to a strong piezoelectric response?"  To do so, they systematically probe the interplay among peptide chemical structure, folding propensity, and piezoelectric properties, uncovering in the process new insights into the origin of peptide electromechanical response. They have designed variety of peptides and peptoids and test the effect of molecular properties on piezoelectric response via serious measurements including ircular dichroism (CD), Polarization-modulated infrared reflection−absorption spectroscopy (PM-IRRAS), tomic force microscopy (AFM), piezo-force microscopy (PFM), and X-ray photoelectron spectroscopy (XPS) measurements. They showed backbone rigidity is an important determinant in peptide electromechanical responsiveness. 

New Era in Thermal Scanning Probe Lithography

  • By Burcu Ozden
  • 15 November 2017

Tevis Jacobs and his collaborators from IBM and SwissLitho were achieved sub-10 nanometer feature size in Silicon using thermal scanning probe lithography. In this work, they  the t-SPL parameters that influence high-resolution patterning on the transfer stack and demonstrate that sub-15 nm half-pitch resolution patterning and transfer by t-SPL are feasible. They found that the resolution in t-SPL is limited by the extent of the plastic zone in thermo-mechanical indentation on the pattern transfer stack because, at temperatures approaching the resist’s decomposition temperature, the line shape widens, reducing the achievable resolution. They achieved reliable transfer of patterned dense lines down to 14 nm half-pitch and in the best case 11 nm half-pitch. Furthermore, evidently they showed that an enhanced resolution below 10 nm half-pitch might be possible on a mechanically different transfer stack.

The Ability to Electrically Tune the Dimensionality of mesoscopic LAO/STO Channels

  • By Burcu Ozden
  • 27 October 2017

In this work, authors used conductive atomic force microscope (c-AFM) lithography in which the conduction is controlled by surface protons that are distributed on the LAO surface. They have created two conducting channel with varying witdhs as 10 and 200nm on a  LAO/STO heterostructures grown by pulsed-laser deposition. They designed the the devices in a way that two conducting channels connected in series with two leads and voltage probes. By using silver epoxy on the bottom of the STO substrate they created contacts for a back gate voltage. They investigated changes in the magnetotransport properties on the channels with different widths by varying back gate voltage and applied magnetic field. They measured the conductance for both narrow and wide channels and demonstarted the hysteresis of both channels with back gating. Saturation of the conductance at higher gate voltages was also shown. They were able to demonstrate dimensional crossover from 2d to 1D behavior with their magnetoconductance measurements.



New Technique for Measuring the Layer-Resolved Charge Density

  • By Burcu Ozden
  • 25 October 2017

Recently Benjamin M. Hunt and his colleagues developed a new technique for measuring the layer-resolved charge density, from which they can map layer polarization of the valley or spin quantum numbers in bilayer graphine and other two dimensional materials. In this study, they demonstrated direct measurement of valley and orbital levels in bilayer graphite. They have detected that the four valley and orbital components have different weights on the two layers of the bilayer. By using Hunt’s technique one can probe layer, valley, and spin polarization quantitatively in other atomic layered materials, including twisted bilayer graphene and both homobilayer and heterobilayer of transition metal dichalcogenide

 

Department of Mechanical Engineering, Carnegie Mellon University
Ph.D., Materials Science and Engineering, The University of Texas at Austin, 2012
Summary:

Our group studies the role of external electromagnetic fields, such as microwave and millimeter waves in accessing regions of the free energy/phase space diagram of a material, hitherto unavailable to conventional synthesis routes. Examples include structurally integrated ordered-disordered ceramic oxides and oxide-polymer composites with unexpected electronic and mechanical properties, adaptive oxides for resistive switching, supersaturated mixed oxide solid solutions with hierarchical structure. An additional benefit involves employing low temperatures for directly processing such materials on fibers and flexible, light-weight substrates for applications in sensing and energy harnessing, storage.

We have extensive experience in the synthesis of inorganic and organic thin films using solution based sol-gel/microwave-assisted synthesis and chemical vapor deposition (CVD) polymerization. We carry out microscopic, spectroscopic and analytical characterization of thin films, as well micro/nano-fabrication processes for building and testing of photovoltaic, battery, and sensing devices.

Selected Publications: 
  1. “Unlocking the structure of mixed amorphous-crystalline ceramic oxide films synthesized under low temperature electromagnetic excitation,” N. Nakamura, M. W. Terban, S. J. L. Billinge, B. Reeja-Jayan, Journal of Materials Chemistry A (2017) (in press). 
  2. “Regression Design for Low-Temperature Microwave-Assisted Crystallization of Ceramic Thin Films”, N. Nakamura, J. Seepaul, J. Kadane, B. Reeja-Jayan, Applied Stochastic Models in Business and Industry, 33, 314 (2017).
  3. “Microwave-assisted Low Temperature Thin Film Growth in Solution”, B. Reeja-Jayan, K. L. Harrison, K. Yang, Chih-Liang Wang, A. Yilmaz, and A. Manthiram, Scientific Reports, 2, 1003 (2012). 
  4. “Organic Passivation of Silicon Through Multifunctional Polymeric Interfaces”, M. L. Castillo, A. Ugur, H. Sojoudi, N. Nakamura, Z. Liu, F. Lin, R. E. Brandt, T. Buonassisia, B. Reeja-Jayan, K. K. Gleason, Solar Energy Materials and Solar Cells, 160, 470 (2017).
  5. “A Group of Cyclic Siloxane and Silazane Polymer Films as Nanoscale Electrolytes for Microbattery Architectures”, B. Reeja-Jayan, N. Chen, J. Lau, J. A. Kattirtzi, P. Moni, A. Liu, I. G. Miller, R. Kayser, A. P. Willard, B. Dunn, and K. K. Gleason,  Macromolecules, 48, 5222 ( 2015).
Most Cited Publications: 
  1. "Carbon-coated high capacity layered Li[Li0.2Mn0.54Ni0.13Co0.13]O2 cathodes ,"Jun Liu, Qiongyu Wang, B. Reeja-Jayan, Arumugam Manthiram, Electrochemistry Communications,12, 750 (2010)
  2. "Controlling the Growth and Luminescence Properties of Well-Faceted ZnO Nanorods," E. De la Rosa, S. Sepu´lveda-Guzman, B. Reeja-Jayan, A. Torres, P. Salas, N. Elizondo, and M. Jose Yacaman, J. Phys. Chem. C ,111, 8489 (2017)
  3. "Conductive Surface Modification with Aluminum of High Capacity Layered Li[Li0.2Mn0.54Ni0.13Co0.13]O2 Cathodes," Jun Liu, B. Reeja-Jayan, and Arumugam Manthiram, J. Phys. Chem. C,114, 9528 (2010)
  4. "Synthesis of assembled ZnO structures by precipitation method in aqueous media,"S.Sepulveda-GuzmanB.Reeja-JayanE.de la RosaA.Torres-Castro,V.Gonzalez-Gonzalez, M.Jose-YacamanMaterials Chemistry and Physics, 15, 172 (2009)
  5. "Structural Characterization and Luminescence of Porous Single Crystalline ZnO Nanodisks with Sponge-like Morphology," B. Reeja-Jayan, E. De la Rosa, S. Sepulveda-Guzman, R. A. Rodriguez, and M. Jose Yacaman, J. Phys. Chem. C,112, 240 (2008)
Recent Publications: 
  1. “Organic Passivation of Silicon Through Multifunctional Polymeric Interfaces”, M. L. Castillo, A. Ugur, H. Sojoudi, N. Nakamura, Z. Liu, F. Lin, R. E. Brandt, T. Buonassisia, B. Reeja-Jayan, K. K. Gleason, Solar Energy Materials and Solar Cells, 160, 470 (2017).
  2. “Unlocking the structure of mixed amorphous-crystalline ceramic oxide films synthesized under low temperature electromagnetic excitation,” N. Nakamura, M. W. Terban, S. J. L. Billinge, B. Reeja-Jayan, Journal of Materials Chemistry A (2017) (in press). 
  3. “Regression Design for Low-Temperature Microwave-Assisted Crystallization of Ceramic Thin Films”, N. Nakamura, J. Seepaul, J. Kadane, B. Reeja-Jayan, Applied Stochastic Models in Business and Industry, 33, 314 (2017).
  4. “A Group of Cyclic Siloxane and Silazane Polymer Films as Nanoscale Electrolytes for Microbattery Architectures”, B. Reeja-Jayan, N. Chen, J. Lau, J. A. Kattirtzi, P. Moni, A. Liu, I. G. Miller, R. Kayser, A. P. Willard, B. Dunn, and K. K. Gleason,  Macromolecules, 48, 5222 ( 2015).
Phone: 
Websites: 
Personal | Department
Department of Chemical Engineering, Carnegie Mellon University
Ph.D., Chemistry, University of California, Berkeley, 1985
Summary:

Professor Gellman's group uses experimental methods to study processes occurring on surfaces such as the bonding of molecules to metal surfaces, surface structure, reaction kinetics, catalysis, friction, and lubrication.  The use of surface science methods to create and study well-defined surfaces allows Professor Gellman's group to investigate surface chemistry relevant to these processes at the most fundamental level.

Professor Gellman’s group has pioneered the study of enantioselective surface chemistry on naturally chiral metal surfaces.  These surfaces are high Miller index planes that lack mirror symmetry and therefore exist as two enantiomorphs.  Recent work using D- and L-tartaric acid adsorbed on several Cu(hkl)R&S surfaces has demonstrated that one can achieve enormously high enantiospecific reaction rates via autocatalytic surface explosion mechanisms. Other work has used 13C isotopically labelled L-aspartic acid to monitor directly the enantioselective separation of DL-aspartic acid on Cu(3,1,17)R&S surfaces.  This work generates insight into some of the fundamental phenomena that lead to enantioselective adsorption and catalysis on chiral surfaces.

Recent work in Professor Gellman’s laboratory has focussed effort on the development of instrumentation and methods for high throughput study of surface phenomena.  Study of the surface science of multicomponent materials such as alloys is complicated by the fact that one needs to prepare, characterize and study many samples of varying composition.  Gellman’s group has worked to overcome this bottleneck by developing tools for the preparation of Composition Spread Alloy Films.  These are alloy films that have composition gradients parallel to their surfaces such that a 1x1 cm2 sample contains all possible compositions of a ternary alloy, AxByC1-x-y with x = 0 -> 1, y = 0 -> 1-x.  Spatially resolved materials and surface characterization methods (SEM, EDX, EBSD, XPS, UPS, LEIS, etc.) can then be used to map and study composition dependent phenomena such as surface segregation, catalysis, dewetting, and oxidation across the entire alloy composition space.

Another body of recent work exploits the use of spherically curved single crystal surfaces to conduct high throughput studies of structure sensitive surface chemistry that span surface orientations continuously.  This circumvents the need for study of many single crystals exposing surfaces of a single crystallographic orientation.  Surface Structure Spread Single Crystals expose a distribution of different surface orientations spanning a continuous region of the stereographic projection of all possible surface orientations.  Spatially resolved surface analysis methods such as STM, XPS and UPS can be used to study problems in surface structure, surface physics and structure sensitive surface chemistry

Selected Publications: 
  • "The Adsorption of Chiral Alcohols on "Chiral" Metal Surfaces," C.F. McFadden, P.S. Cremer, A.J. Gellman,  Langmuir, 12(10), 2483 (1996) 
  • “Polymers at Interfaces: Using Atom Transfer Radical Polymerization in the Controlled Growth of Homopolymers and Block Copolymers from Silicon Surfaces in the Absence of Untethered Sacrificial Initiator,' K. Matyjaszewski, P.J. Miller, N. Shukla, B. Immaraporn, A.J. Gellman, B.B. Luokala, T.M. Siclovan, G. Kickelbick, T. Vallant, H. Hoffmann, T. Pakula,  Macromolecules 32 (26), 8716 (1999) 
  • “Kinetics and Energetics of Oligomer Desorption from Surfaces,” K.R. Paserba, A.J. GellmanPhys. Rev. Lett.86(19), 4338 (2001) 
  • “Effects of Conformational Isomerism on the Desorption Kinetics of n-Alkanes from Graphite,” K.R. Paserba, A.J. Gellman, J. Chem. Phys. 115(14), 6737 (2001) 
  • “Enantioselective Separation on a Naturally Chiral Surface,”J. Horvath, P. Kamakoti, A. Koritnik, D.S. Sholl, A.J. GellmanJ. Amer. Chem. Soc. 126(45), 14988 (2004)
  • “The Real Structure of Naturally Chiral Cu{643},”A.E. Baber, A.J. Gellman, D.S. Sholl, E.C.H. Sykes, J. Phys. Chem. C  112(30), 11086 (2008)
Recent Publications: 
  1. “Enantiomeric Separations of Chiral Pharmaceuticals using Chirally Modified Tetrahexahedral Au Nanoparticles,” N. Shukla, D. Yang, A.J. GellmanSurface Science, 648, 29, (2016)
  2. “Xe Adsorption Site Distributions on Pt(111), Pt(221) and Pt(531),” A.J. Gellman, L.D. Baker, B.S. Holsclaw, Surface Science 646, 83 (2016)
  3. “Thermal interface conductance across metal alloy-dielectric interfaces,” J.P. Freedman, X. Yu, R.F. Davis, A.J. Gellman, J.A. Malen, Physical Review - B 93, 035309 (2016),
  4. “An Atomic-scale Picture of the Composition, Decay and Oxidation of 2D Radioactive Films,” A. Pronschinske, P. Pedevilla, B. Coughlin, C.J. Murphy, F.R. Lucci, M.A. Payne, A.J. Gellman, A. Michaelides, E.C.H. Sykes, ACS Nano 10, 2152 (2016)  
  5. “Editorial: Special issue dedicated to Gabor Somorjai’s 80th birthday,” A.J. Gellman, R.M. Rioux, P.C. Stair,  Surface Science 648, 1, (2016)
Phone: 
 | Department
Department of Chemical and Petroleum Engineering, University of Pittsburgh
Ph.D., Physics, Cornell University, 1993
Summary:

Surface Reactions (oxidation, catalysis) and Electron Microscopy (in situ)

Dealing with oxidation is a major societal priority, yet oxidation also presents a fascinating challenge in thin film growth.  Classical theories of oxidation were based mostly on thermogravimetric analysis (TGA) that only measures weight change, not structural changes.  Hence, classical theories assume a uniform film growth, yet it is well known that oxides do not develop as uniform films.  Recent developments of in situ experimental tools permit visualization of the dynamic processes at the nanoscale.  Yang’s research group uses in situ ultra-high vacuum transmission electron microscopy (UHV-TEM) to improve the fundamental understanding of oxidation; figure 1 are bright field images of Cu and Cu-5%Ni thin films during oxidation at P(O2) 10-4 Torr in situ, where oxide islands are seen to nucleate and grow and their shapes depend sensitively on temperature.  Heteroepitaxial concepts, based on surface diffusion, strain and structural evolution, describe surprisingly well these initial oxidation stages.

Most Cited Publications: 
  1. “Shape-dependent catalytic properties of Pt nanoparticles,” Simon Mostafa, Farzad Behafarid, Jason R. Croy, Luis K. Ono, Long Li, Judith C. Yang, Anatoly I. Frenkel, and Beatriz Roldan Cuenya, Journal of the American Chemical Society, 132(44), 15714 (2010)
  2. "Formation of Quasi-One-Dimensional Cu2O Structures by in situOxidation of Cu(100)," Guangwen Zhou and Judith C. Yang, Phys. Rev. Lett. 89, 106101, (2002)
  3. “Sub-nanometer Au monolayer-protected clusters exhibiting molecule-like electronic behavior: quantitative high-angle annular dark-field scanning transmission electron microscopy and electrochemical characterization of clusters with precise atomic stoichiometry,” Laurent D. Menard, Shang-Peng Gao, Huiping Xu, Ray D. Twesten, Amanda S. Harper, Yang Song, Gangli Wang, Alicia D. Douglas, Judith C. Yang, Anatoly I. Frenkel, Ralph G. Nuzzo, and Royce W. Murray, J. Phys. Chem. B 110, 12874 (2006)
  4. "Preparation of TiO2-supported Au nanoparticle catalysts from a Au13 cluster precursor: Ligand removal using ozone exposure versus a rapid thermal treatment,"Laurent D. MenardFengting XuRalph G. NuzzoJudith C.YangJournal of Catalysis 243, 64 (2006)
  5. "Temperature effect on the Cu2O oxide morphology created by oxidation of Cu(0 0 1) as investigated by in situ UHV TEM," Guangwen Zhou, Judith C Yang, Applied Surface Science, 210, 165 (2003)
Recent Publications: 
  1. "Dislocation nucleation facilitated by atomic segregation," Lianfeng Zou, Chaoming Yang, Yinkai Lei, Dmitri Zakharov, Jörg M. K. Wiezorek, Dong Su, Qiyue Yin, Jonathan Li, Zhenyu Liu, Eric A. Stach, Judith C. Yang, Liang Qi, Guofeng Wang and Guangwen Zhou, Nature Metarials (2017)
  2. "Enhanced Carbon Dioxide Electroreduction to Carbon Monoxide over Defect-Rich Plasma-Activated Silver Catalysts" Hemma Mistry, Yong-Wook Choi, Alexander Bagger, Fabian Scholten, Cecile S. Bonifacio, Ilya Sinev, Nuria J. Divins, Ioannis Zegkinoglou, Hyo Sang Jeon, Kim Kisslinger, Eric A. Stach, Judith C. Yang, Jan Rossmeisl, and Beatriz Roldan Cuenya, Angew Chem, 38, 1521 (2017)
  3. "Atomically Precise Gold Nanoclusters Accelerate Hydrogen Evolution over MoS2 Nanosheets: The Dual Interfacial Effect", Shuo Zhao, Renxi Jin, Yongbo Song, Hui Zhang, Stephen D. House, Judith C. Yang, and Rongchao Jin, Small, 1613 (2017)
  4. "High-throughput, semi-automated quantitative STEM mass measurement of supported metal nanoparticles using a conventional TEM/STEM", Stephen D. Housea, Yuxiang Chenb, Rongchao Jinb, Judith C. Yang, Ultramicroscopy, 182, 145 (2017)
  5. "Comparison of Spinel and Monoclinic Crystal Structures of γ-Al2O3 for Simulation of Electron Energy Loss Spectra," Henry O. Ayoola, Cecile S. Bonifacio, Qing Zhu, Dong Su, Joshua Kas, John J. Rehr, Eric A. Stach , Wissam A. Saidi , and Judith C. Yang Microscopy and Microanalysis 23, 2020 (2017)
Websites: 
Personnal | Department
Department of Electrical and Computer Engineering, University of Pittsburgh
Ph.D., Electrical Engineering, University of Illinois at Urbana-Champaign, 2014
Summary:

In today’s big-data era, trillions of sensors will connect every aspect of our lives to the Internet, constantly producing and processing an overwhelming amount of data. Xiong is looking for novel materials for energy-efficient transistor and memory solutions with on-chip thermal management and 3D integration.

Specifically, Xiong is working on:

  • building wafer-scale energy-efficient 2D transistors, tackling challenges in synthesis, assembly and optimization;
  • characterizing nanoscale thermal transport in 2D materials, maximizing thermoelectric efficiency through heterogeneous stacking and intercalations for energy harvesting and developing on-chip thermal solutions;
  • achieving 3D integration of novel low-power memory (resistive and phase change memory) with logic, building energy-efficient flexible memory devices and exploring alternative memory structure with intercalation in layered 2D materials.
Most Cited Publications: 
  1. "Low-Power Switching of Phase-Change Materials with Carbon Nanotube Electrodes," Feng Xiong, Albert D. Liao, David Estrada, Eric Pop, Science 332, 568 (2011)
  2. "Ballistic to diffusive crossover of heat flow in graphene ribbons," Myung-Ho Bae, Zuanyi Li, Zlatan Aksamija, Pierre N Martin, Feng Xiong, Zhun-Yong Ong, Irena Knezevic & Eric Pop Nature Communications 4, 1734 (2013)
  3. "Using nanoscale thermocapillary flows to create arrays of purely semiconducting single-walled carbon nanotubes," Sung Hun Jin, Simon N. Dunham, Jizhou Song, Xu Xie, Ji-hun Kim, Chaofeng Lu, Ahmad Islam, Frank Du, Jaeseong Kim, Johnny Felts, Yuhang Li, Feng Xiong, Muhammad A. Wahab, Monisha Menon, Eugene Cho, Kyle L. Grosse, Dong Joon Lee, Ha Uk Chung, Eric Pop, Muhammad A. Alam, William P. King, Yonggang Huang & John A. Rogers, Nature Nanotechnology 8, 347 (2013)
  4. "Thermal dissipation and variability in electrical breakdown of carbon nanotube devices," Albert Liao, Rouholla Alizadegan, Zhun-Yong Ong, Sumit Dutta, Feng Xiong, K. Jimmy Hsia, and Eric Pop, Phys. Rev. B 82, 205406 (2010)
  5. "Phase change materials and phase change memory," Simone Raoux, Feng Xiong, Matthias Wuttig, Eric Pop, MRS Bulletin 39, 703 (2014)
Recent Publications: 
  1. "Energy Dissipation in Monolayer MoS2 Electronics," Eilam Yalon, Connor J. McClellan, Kirby K. H. Smithe, Miguel Muñoz Rojo, Runjie Lily Xu, Saurabh V. Suryavanshi, Alex J. Gabourie, Christopher M. Neumann, Feng Xiong, Amir Barati Farimani, and Eric Pop, Nano Lett., Article ASAP
  2. "SANTA: Self-aligned nanotrench ablation via Joule heating for probing sub-20 nm devices," Feng Xiong, Sanchit Deshmukh, Sungduk Hong, Yuan Dai, Ashkan Behnam, Feifei Lian, Eric Pop, Nano Research 9, 2950 (2016)
  3. "Lateral and Vertical Two-Dimensional Layered Topological Insulator Heterostructures" Yanbin Li, Jinsong Zhang, Guangyuan Zheng, Yongming Sun, Seung Sae Hong, Feng Xiong, Shuang Wang, Hye Ryoung Lee, and Yi Cui, ACS Nano 9, 10916 (2015)
  4. "Nanoscale phase change memory with graphene ribbon electrodes" Ashkan Behnam, Feng Xiong, Andrea Cappelli, Ning C. Wang, Enrique A. Carrion, Sungduk Hong, Yuan Dai, Austin S. Lyons, Edmond K. Chow, Enrico Piccinini, Carlo Jacoboni and Eric Pop, Appl. Phys. Lett. 107, 123508 (2015)
  5. "Li Intercalation in MoS2: In Situ Observation of Its Dynamics and Tuning Optical and Electrical Properties," Feng Xiong, Haotian Wang, Xiaoge Liu, Jie Sun, Mark Brongersma, Eric Pop, and Yi Cui, Nano Lett. 15, 6777 (2015)
Websites: 
Personal | Department
Department of Physics and Astronomy, University of Pittsburgh
Ph.D., Physics, University of Pittsburgh, 2011
Summary:

Owing to the recent development of material growth methods including the pulsed laser deposition (PLD) and molecular beam epitaxy (MBE), atomically sharp interfaces between materials become available. At these interfaces, the electron-electron interaction is greatly enhanced, leading to novel phases including metal-insulator transition,  superconductivity, magnetism and spin-orbit interaction.

A notable example is the (001) LaAlO3/SrTiO3 (LAO/STO) interface, where a polar discontinuity drives electronic interface reconstruction and leads to a 2D electron liquid (2DEL) at the interface. The interface conductivity is critically dependent on the LAO thickness. Below a critical thickness 4 unit cell the interface is insulating, otherwise the interface is conducting.

Since the discovery of the 2DEL in 2004[1], intense interests have been casted on this area.  Up to now, the knowledge on this interface is growing rapidly, and so do the debates. The 2DEL is gate tunable, with a critical LAO thickness dependence[2]. The interface is superconducting, an inherent property of STO[3, 4]. More interestingly, it has a similar superconducting phase diagram as the high-Tc superconductor. Although both LAO and STO are non-magnetic, the interface is magnetic[5, 6].  More interestingly, magnetism and superconductivity can co-exist[7-9]. Owing to the inversion symmetric breaking, the interface has strong tunable spin-orbit interaction[10, 11]. Provided all these interesting phases, we invented the conductive-AFM lithography method that allows us to fabricate nanostructures on demand, effectively programing all these properties into nanoscale. Indeed, it is fun to watch all these properties interplay at nanoscale.

  1. A. Ohtomo, and H. Y. Hwang, Nature 427, 423 (2004).
  2. S. Thiel et al., Science 313, 1942 (2006).
  3. N. Reyren et al., Science 317, 1196 (2007).
  4. A. D. Caviglia et al., Nature 456, 624 (2008).
  5. A. Brinkman et al., Nat Mater 6, 493 (2007).
  6. Ariando et al., Nature communications 2, 188 (2011).
  7. J. A. Bert et al., Nat Phys 7, 767 (2011).
  8. D. A. Dikin et al., Physical Review Letters 107 (2011).
  9. L. Li et al., Nat Phys advance on (2011).
  10. A. D. Caviglia et al., Physical Review Letters 104, 126803 (2010).
  11. M. Ben Shalom et al., Physical Review Letters 104, 126802 (2010).
Selected Publications: 
  • "Electron pairing without superconductivity," Guanglei Cheng, Michelle Tomczyk, Shicheng Lu, Josh P. Veazey, Mengchen Huang, Patrick Irvin, Sangwoo Ryu, Hyungwoo Lee, Chang-Beom, Eom, C. Steve Hellberg, Jeremy Levy, Nature 521,196 (2015)
  • "Writing and Low-Temperature Characterization of Oxide Nanostructures," Akash Levy, Feng Bi, Mengchen Huang, Shicheng Lu, Michelle Tomczyk, Guanglei Cheng, Patrick Irvin, Jeremy Levy, J. Vis. Exp. 89, e51886 (2014)
  • "Anomalous Transport in Sketched Oxide Nanostructures," Guanglei Cheng, Josh Veazey, Patrick Irvin, Cheng Cen, Daniel Bogorin, Feng Bi, Mengchen Huang, Chung-Wung Bark, Sangwoo Ryu, Kwang-Hwan Cho, Chang-Beom Eom and Jeremy Levy, Physcial Review X, 3, 011021 (2013)
Department of Chemistry, University of Pittsburgh
Ph.D., Physical Chemistry, University of Wisconsin-Madison, 2013
Summary:

In the Laaser Lab, we are interested in developing a physical understanding of how changes at the molecular level translate to the macroscopic properties of responsive polymeric materials. For example, how does a change in charge spacing affect the interactions between charged polymers, and at what point do the polymers stop behaving like isolated chains in solution and start behaving like part of a bulk material? How do orientational changes in single polymer chains propagate through a material to achieve macroscopic ordering? And how do polymeric networks transduce force, to achieve things like mechanochemical responses?

We explore these questions by a number of optical and spectroscopic methods, such as light scattering and Raman and infrared spectroscopy, along with classical materials characterization methods like rheology and electron microscopy. Together, these methods allow us to develop new understanding of the structure and dynamic properties of responsive polymeric materials, and offer students the opportunity to gain broad experience in both physical chemistry and polymer science.

Most Cited Publications: 
  1. "Adding a dimension to the infrared spectra of interfaces using heterodyne detected 2D sum-frequency generation (HD 2D SFG) spectroscopy," Wei Xiong, Jennifer E. Laaser, Randy D. Mehlenbacher, and Martin T. Zanni, PNAS 108, 20902 (2011)
  2. "Transient 2D IR Spectroscopy of Charge Injection in Dye-Sensitized Nanocrystalline Thin Films," Wei Xiong, Jennifer E. Laaser, Peerasak Paoprasert, Ryan A. Franking, Robert J. Hamers, Padma Gopalanand Martin T. Zanni, J. Am. Chem. Soc. 131,18040 (2009)
  3. "Time-Domain SFG Spectroscopy Using Mid-IR Pulse Shaping: Practical and Intrinsic Advantages," Jennifer E. Laaser, Wei Xiong, and Martin T. Zanni, J. Phys. Chem. B 115, 2536 (2011)
  4. "Two-Dimensional Sum-Frequency Generation Reveals Structure and Dynamics of a Surface-Bound Peptide," Jennifer E. Laaser, David R. Skoff, Jia-Jung Ho, Yongho Joo, Arnaldo L. Serrano, Jay D. Steinkruger, Padma Gopalan, Samuel H. Gellman, and Martin T. Zanni, J. Am. Chem. Soc. 136, 95 (2014)
  5. "Bridge-Dependent Interfacial Electron Transfer from Rhenium−Bipyridine Complexes to TiO2 Nanocrystalline Thin Films," Peerasak Paoprasert, Jennifer E. Laaser, Wei Xiong, Ryan A. Franking, Robert J. Hamers, Martin T. Zanni, J. R. Schmidt and Padma Gopalan, J. Phys. Chem. C 114, 9898 (2010)
Recent Publications: 
  1. "Equilibration of Micelle–Polyelectrolyte Complexes: Mechanistic Differences between Static and Annealed Charge Distributions," Jennifer E. Laaser, Michael McGovern, Yaming Jiang, Elise Lohmann, Theresa M. Reineke, David C. Morse, Kevin D. Dorfman, and Timothy P. Lodge, J. Phys. Chem. B, 121, 4631 (2017)
  2. "Architecture-Dependent Stabilization of Polyelectrolyte Complexes between Polyanions and Cationic Triblock Terpolymer Micelles," Jennifer E. Laaser, Elise Lohmann, Yaming Jiang, Theresa M. Reineke, and Timothy P. Lodge, Macromolecules 49, 6644 (2016)
  3. "Tuning Cationic Block Copolymer Micelle Size by pH and Ionic Strength," Dustin Sprouse, Yaming Jiang, Jennifer E. Laaser, Timothy P. Lodge, and Theresa M. Reineke, Biomacromolecules 17, 2849 (2016)
  4. "Interpolyelectrolyte Complexes of Polycationic Micelles and Linear Polyanions: Structural Stability and Temporal Evolution," Jennifer E. Laaser, Yaming Jiang, Shannon R. Petersen, Theresa M. Reineke, and Timothy P. Lodge, J. Phys. Chem. B 119, 15919 (2015)
  5. "Probing Site-Specific Structural Information of Peptides at Model Membrane Interface In Situ," Bei Ding, Afra Panahi, Jia-Jung Ho, Jennifer E. Laaser, Charles L. BrooksIII, Martin T. Zanni, and Zhan Chen, J. Am. Chem. Soc. 137, 10190 (2015)

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