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- Phone:
- 607-255-9617
- Mon - Tues:
- 8:00 am - 4:30 pm
- Wed - Thurs:
- 8:00 am - 4:30 am
- Fri:
- 8:00 am - 4:30 pm
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Faculty/Underg
Commencement 2009Updated about 5 months ago
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Events
1 upcoming eventSee All
- Nanocrystal Solids: A Modular ...
140 Bard Hall
Thursday, November 12 at 4:30pm
Cornell Materials Science & Engineering
Professor Dmitri Talapin
University of Chicago
Colloidal nanocrystals are considered promising building blocks for electronic and optoelectronic devices. Potentially, they can combine the advantages of crystalline inorganic semiconductors with sizetunable electronic structure and inexpensive solution-based device fabrica...tion. Nanoparticles of different metals, semiconductors and magnetic materials can self-assemble from colloidal solutions into long range ordered periodic structures (superlattices). Combining two types of nanoparticles yields binary nanoparticle superlattices (BNSLs) exhibiting very rich phase diagrams with a multitude of close-packed and non-closepacked phases. Through a series of systematic studies of self-assembly phenomena in single- and multicomponent nanoparticle assemblies we demonstrate that observed structural diversity is a result of the intricate interplay of entropy-driven crystallization with isotropic and anisotropic interparticle interactions, such as van der Waals, Coulombic and dipolar forces.
The electronic properties of nanocrystal solids are determined by concentration of mobile carriers and electronic communication between individual nanocrystals. We developed several approaches to electronic doping of nanocrystal solids based on the formation of inter- and intra-nanocrystal charge transfer complexes. For example, hydrazine molecules adsorbed at the nanocrystal surface behave as n-type charge-transfer dopant whereas Au-PbS core-shell nanocrystals show stable p-type doping due to electron transfer from PbS shell into the Au core. The bulky and insulating nature of conventional organic capping ligands typically results in poor electronic coupling in the nanocrystal solids. To address this problem we demonstrated that molecular metal chalcogenide complexes can serve as versatile ligands for a broad range of colloidal nanocrystals. This new class of nanocrystal colloids provides a set of advantages such as all-inorganic design, small (<0.5 nm) interparticle spacing, easy thermal ligand-to-semiconductor conversion, and diverse compositional tunability for both nanocrystal and ligand constituents. As the model systems, we show electron mobility of ~1.5 cm2/Vs in arrays of CdSe nanocrystals and very high (~200 S/cm) conductivity in 5 nm gold nanocrystal solids capped with [Sn2S6]4- Zintl ions.Read More
University of Chicago
Colloidal nanocrystals are considered promising building blocks for electronic and optoelectronic devices. Potentially, they can combine the advantages of crystalline inorganic semiconductors with sizetunable electronic structure and inexpensive solution-based device fabrica...tion. Nanoparticles of different metals, semiconductors and magnetic materials can self-assemble from colloidal solutions into long range ordered periodic structures (superlattices). Combining two types of nanoparticles yields binary nanoparticle superlattices (BNSLs) exhibiting very rich phase diagrams with a multitude of close-packed and non-closepacked phases. Through a series of systematic studies of self-assembly phenomena in single- and multicomponent nanoparticle assemblies we demonstrate that observed structural diversity is a result of the intricate interplay of entropy-driven crystallization with isotropic and anisotropic interparticle interactions, such as van der Waals, Coulombic and dipolar forces.
The electronic properties of nanocrystal solids are determined by concentration of mobile carriers and electronic communication between individual nanocrystals. We developed several approaches to electronic doping of nanocrystal solids based on the formation of inter- and intra-nanocrystal charge transfer complexes. For example, hydrazine molecules adsorbed at the nanocrystal surface behave as n-type charge-transfer dopant whereas Au-PbS core-shell nanocrystals show stable p-type doping due to electron transfer from PbS shell into the Au core. The bulky and insulating nature of conventional organic capping ligands typically results in poor electronic coupling in the nanocrystal solids. To address this problem we demonstrated that molecular metal chalcogenide complexes can serve as versatile ligands for a broad range of colloidal nanocrystals. This new class of nanocrystal colloids provides a set of advantages such as all-inorganic design, small (<0.5 nm) interparticle spacing, easy thermal ligand-to-semiconductor conversion, and diverse compositional tunability for both nanocrystal and ligand constituents. As the model systems, we show electron mobility of ~1.5 cm2/Vs in arrays of CdSe nanocrystals and very high (~200 S/cm) conductivity in 5 nm gold nanocrystal solids capped with [Sn2S6]4- Zintl ions.Read More
Time:4:30PM Thursday, November 12th
Location:140 Bard Hall
Cornell Materials Science & Engineering Faculty and Students teamed up to bowl and share some pizza at Helen Newman Lanes on 10/16/09
Cornell Materials Science & Engineering
On Friday, Oct. 16 from 6 to 8:45 PM, there is going to be an MS&E faculty/undergrad bowling event at Helen Newman.
It’s a lot of fun, as those who participated last year can attest. Family members are welcome--we will distribute children and spouses through the faculty teams.
There is a sign-up poster at the entrance to... Bard for students and faculty to sign up their teams, or students and faculty can email me their team rosters.
Team formation is at 6 PM for students without a team, bowling starts around 6:15, pizza is served around 7:15. There is no cost.
Prizes will be awarded for every level of performance.
If you don't have a team to play on, that is okay! Show up at 6 PM and we can match individual students to teams.
We look forward to seeing you there!
Questions?
Contact: Melissa Totman
mlt39@cornell.edu or 1.607.255.4135Read More
It’s a lot of fun, as those who participated last year can attest. Family members are welcome--we will distribute children and spouses through the faculty teams.
There is a sign-up poster at the entrance to... Bard for students and faculty to sign up their teams, or students and faculty can email me their team rosters.
Team formation is at 6 PM for students without a team, bowling starts around 6:15, pizza is served around 7:15. There is no cost.
Prizes will be awarded for every level of performance.
If you don't have a team to play on, that is okay! Show up at 6 PM and we can match individual students to teams.
We look forward to seeing you there!
Questions?
Contact: Melissa Totman
mlt39@cornell.edu or 1.607.255.4135Read More
Time:6:00PM Friday, October 16th
Location:Helen Newman Lanes, Cornell University
Cornell Materials Science & Engineering
Professor John A. Marohn
Chemistry and Chemical Biology
Cornell University
What's going on down there? Insights into fundamental processes in organic electronic materials and devices from electric force microscopy.
Fabricating circuits and solar cells by solution-processing readily available organic compounds is a potentia...lly revolutionary concept. Given the meager understanding of organic semiconductor materials, however, development of organic devices proceeds largely by trial and error. While tremendous effort is being expended to mass-produce organic devices, almost no attention has been devoted to developing a microscopic understanding of fundamental processes in organic semiconductors. To accelerate development, we need a better microscopic understanding.
We use electric force microscopy to make local measurements of electrostatic potential and capacitance in working organic devices. Measurements take place with devices in vacuum or in nitrogen, and in some cases over a large temperature range and under variable-wavelength irradiation. The resulting data has allowed us to address long-standing puzzles related to ion motion, metal-to-organic charge injection, and charge trapping in organic semiconductor materials. Case studies involving both small-molecule and polymeric semiconductors will be presented.
The ability to characterize organic material at nanometer spatial resolution with chemical specificity lags far behind the ability to synthesize new materials and make devices. I will briefly present my group's work to develop scanned-probe approaches to detecting magnetic resonance and electric field fluctuations at nanoscale resolution.Read More
Chemistry and Chemical Biology
Cornell University
What's going on down there? Insights into fundamental processes in organic electronic materials and devices from electric force microscopy.
Fabricating circuits and solar cells by solution-processing readily available organic compounds is a potentia...lly revolutionary concept. Given the meager understanding of organic semiconductor materials, however, development of organic devices proceeds largely by trial and error. While tremendous effort is being expended to mass-produce organic devices, almost no attention has been devoted to developing a microscopic understanding of fundamental processes in organic semiconductors. To accelerate development, we need a better microscopic understanding.
We use electric force microscopy to make local measurements of electrostatic potential and capacitance in working organic devices. Measurements take place with devices in vacuum or in nitrogen, and in some cases over a large temperature range and under variable-wavelength irradiation. The resulting data has allowed us to address long-standing puzzles related to ion motion, metal-to-organic charge injection, and charge trapping in organic semiconductor materials. Case studies involving both small-molecule and polymeric semiconductors will be presented.
The ability to characterize organic material at nanometer spatial resolution with chemical specificity lags far behind the ability to synthesize new materials and make devices. I will briefly present my group's work to develop scanned-probe approaches to detecting magnetic resonance and electric field fluctuations at nanoscale resolution.Read More
The Solar Decathlon will be held on the Mall in Washington, D.C. this month...
Cornell Materials Science & Engineering
Prof. Teri W. Odom
Northwestern University
Surface plasmons are responsible for a variety of phenomena including nanoscale optical focusing, negative refraction, and surface enhanced Raman scattering. Their characteristic evanescent electromagnetic fields offer numerous opportunities for sub-diffraction imaging, optical ...cloaking, and labelfree molecular sensing. The selection of materials for applications, however, has been traditionally limited to the noble metals Au and Ag because there has been no side-by-side comparison of other materials. This talk will describe our recent progress on manipulating surface plasmons from ultraviolet to near-infrared wavelengths using plasmonic crystals made from 2D nanopyramidal arrays. A library of plasmon resonances was constructed in the form of dispersion diagrams for a series of unconventional and new composite plasmonic materials. These resonances could be tuned by controlling both intrinsic factors (unit cell shape, materials type) as well as extrinsic factors (excitation conditions, dielectric environment). Finally, we will discuss prospects for generating plasmonic crystals with reduced lattice symmetries as a means to achieve broadband coupling.Read More
Northwestern University
Surface plasmons are responsible for a variety of phenomena including nanoscale optical focusing, negative refraction, and surface enhanced Raman scattering. Their characteristic evanescent electromagnetic fields offer numerous opportunities for sub-diffraction imaging, optical ...cloaking, and labelfree molecular sensing. The selection of materials for applications, however, has been traditionally limited to the noble metals Au and Ag because there has been no side-by-side comparison of other materials. This talk will describe our recent progress on manipulating surface plasmons from ultraviolet to near-infrared wavelengths using plasmonic crystals made from 2D nanopyramidal arrays. A library of plasmon resonances was constructed in the form of dispersion diagrams for a series of unconventional and new composite plasmonic materials. These resonances could be tuned by controlling both intrinsic factors (unit cell shape, materials type) as well as extrinsic factors (excitation conditions, dielectric environment). Finally, we will discuss prospects for generating plasmonic crystals with reduced lattice symmetries as a means to achieve broadband coupling.Read More
Time:4:30PM Thursday, October 8th
Location:Bard 140
Cornell Materials Science & Engineering
Prof. Michael Smith,
Biomedical Engineering,
Boston University
Cells in vivo are often embedded within a fibrous material termed the extracellular matrix that regulates many cellular processes, including stem cell differentiation and cancer progression. Understanding the functions of extracellular matrices has enormous ...potential for the betterment of human health. However, matrix protein function is often investigated in a context that is not physiological, for example as an adsorbed monolayer on the surface of a Petri dish. Increasing evidence suggests that the native, fibrillar structures have different, and in many cases more dynamic, properties than the individual molecules. This talk will present multidisciplinary efforts which purpose to characterize the properties of fibronectin fibers, a highly extensible fiber present within the extracellular matrix during development and wound healing that displays a number of binding sites for cell adhesion molecules and soluble signaling molecules. First, spectroscopic tools were used to demonstrate that cell traction forces stretch fibronectin fibers and that this mechanical extension is mediated by alterations in molecular conformation. Next, a novel cell-free assay was developed for the generation of fibronectin fibers that could be probed both mechanically and biochemically. This tool was used to demonstrate that fibronectin’s mechanical properties vary markedly as the fibers are stretched and furthermore that mechanical strain alters fibronectin adhesivity for soluble binding partners. These data indicate that the function of fibronectin fibers can be mechanically actuated.
Read More
Biomedical Engineering,
Boston University
Cells in vivo are often embedded within a fibrous material termed the extracellular matrix that regulates many cellular processes, including stem cell differentiation and cancer progression. Understanding the functions of extracellular matrices has enormous ...potential for the betterment of human health. However, matrix protein function is often investigated in a context that is not physiological, for example as an adsorbed monolayer on the surface of a Petri dish. Increasing evidence suggests that the native, fibrillar structures have different, and in many cases more dynamic, properties than the individual molecules. This talk will present multidisciplinary efforts which purpose to characterize the properties of fibronectin fibers, a highly extensible fiber present within the extracellular matrix during development and wound healing that displays a number of binding sites for cell adhesion molecules and soluble signaling molecules. First, spectroscopic tools were used to demonstrate that cell traction forces stretch fibronectin fibers and that this mechanical extension is mediated by alterations in molecular conformation. Next, a novel cell-free assay was developed for the generation of fibronectin fibers that could be probed both mechanically and biochemically. This tool was used to demonstrate that fibronectin’s mechanical properties vary markedly as the fibers are stretched and furthermore that mechanical strain alters fibronectin adhesivity for soluble binding partners. These data indicate that the function of fibronectin fibers can be mechanically actuated.
Read More
Time:4:30PM Thursday, October 1st
Location:Bard 140
Cornell Materials Science & Engineering
Prof. Craig J. Fennie
Applied & Engineering Physics
Cornell University
The discovery of materials displaying novel properties is the driving force behind continued scientific progress across many disciplines. Due to their highly tunable ground states, structurally and chemically complex oxides are a promising class of mat...erials in which to realize new emergent phenomena that could not only challenge our current understanding of condensed matter but also provide real solutions for technological advances in for example the energy sciences and electronics. The traditional exploratory route to identify new phenomena, however, is quite demanding, as there are an enormous number of possible materials that have yet to be identified. Additionally, recent advances in synthesis techniques facilitate tailoring and enhancing the properties of complex materials at the atomic scale, greatly extending the design variables. In this talk I will discuss two examples of our recent work on the rational design of and subsequent experimental discovery of complex oxide materials rarely found in nature ñ ferromagnetic-ferroelectric oxides in which a spontaneous magnetism not only coexists with but also is strongly coupled to a spontaneous electric polarization. I will show how we combine microscopic models, symmetry principles, and crystal chemistry to develop a general set of chemically and physically intuitive mechanisms and design rules. We then use first-principles computational techniques such as density-functional theory to screen potential realizations of these rationalized design criteria; first-principles density-functional methods recently have proved a powerful tool for studying the properties of complex materials at the level of atoms and electrons, without the need for empirical input. I will argue that contrary to its historic role, theory should be the first step in the discovery of new phenomena as it provides a natural starting point for synthesis of truly unprecedented materials.Read More
Applied & Engineering Physics
Cornell University
The discovery of materials displaying novel properties is the driving force behind continued scientific progress across many disciplines. Due to their highly tunable ground states, structurally and chemically complex oxides are a promising class of mat...erials in which to realize new emergent phenomena that could not only challenge our current understanding of condensed matter but also provide real solutions for technological advances in for example the energy sciences and electronics. The traditional exploratory route to identify new phenomena, however, is quite demanding, as there are an enormous number of possible materials that have yet to be identified. Additionally, recent advances in synthesis techniques facilitate tailoring and enhancing the properties of complex materials at the atomic scale, greatly extending the design variables. In this talk I will discuss two examples of our recent work on the rational design of and subsequent experimental discovery of complex oxide materials rarely found in nature ñ ferromagnetic-ferroelectric oxides in which a spontaneous magnetism not only coexists with but also is strongly coupled to a spontaneous electric polarization. I will show how we combine microscopic models, symmetry principles, and crystal chemistry to develop a general set of chemically and physically intuitive mechanisms and design rules. We then use first-principles computational techniques such as density-functional theory to screen potential realizations of these rationalized design criteria; first-principles density-functional methods recently have proved a powerful tool for studying the properties of complex materials at the level of atoms and electrons, without the need for empirical input. I will argue that contrary to its historic role, theory should be the first step in the discovery of new phenomena as it provides a natural starting point for synthesis of truly unprecedented materials.Read More
Closing the loop: from models in the computer to real materials in the lab
Time:4:30PM Thursday, September 24th
Location:Bard 140
Cornell Materials Science & Engineering Prof. Richard Robinson to be featured on "The Secret Life of Scientists"
Source: mse.cornell.edu
Cornell's Department of Materials Science and Engineering offers degree programs for both undergraduate and graduate students, accredited by the Accreditation Board for Engineering and Technology.
Cornell Materials Science & Engineering
Powerful molecular design criteria are emerging for the formation of nanocomposites containing multiple functionalities. In particular, several examples are discussed in which the self-assembly of block-type polymers was combined with functional oxides using a simple "one-pot" procedure. The spatial arrangement of eac...h component and thus functionality was tuned by varying the polymer architecture. Furthermore, such materials design strategies can be based on inexpensive and mass produced reagents to facilitate translation to industrial scale production. These multifunctional materials may provide scalable solutions for global problems including energy generation, storage, and conversion devices.Read More
Mr. Morgan Stefik, Wiesner group
Time:4:30PM Thursday, September 10th
Location:Bard 140
