RESEARCH AREAS

RESEARCH FACILITIES

Capabilities

The basic energy conversion steps of charge photogeneration, separation, and recombination link research themes and principal investigators (PIs) across the ANSER Center and provide exciting opportunities for cross-fertilization. By leveraging the expertise of individual PIs, the ANSER Center hopes to create synergistic and emergent advances in solar energy research and technology.

Synthesis and Fabrication

Precisely creating the complex materials architectures needed to achieve efficient solar energy conversion requires new approaches to self-assembly and directed fabrication. Projects include:

• Molecular assembly (PIs: Tiede, Wasielewski, Yu, Stupp, Firestone, Hanson, Lewis, Marks, and Rajh)
• Interfacial fabrication (PIs: Chang, Elam, Pellin, and Marks)
• Catalysis (PI: Marks)
• Solid state synthesis (PIs: Poeppelmeier, and Kanatzidis)
• Organic opto-electronic materials synthesis (PIs: Yu, Stupp, and Marks)
• Nanowire/nanoparticle fabrication (PIs: Wiederrecht, Odom, and Wang)

Characterization

To understand these phenomena, experimental research probes for elucidating nanoscale structure and dynamics are essential for all solar energy conversion processes. Projects include:

• X-ray and neutron diffraction (PIs: Poeppelmeier, Kanatzidis, Yu, Marks, Pellin, and Chang)
• Electron microscopy (Argonne Electron Microscopy ANSER Center)
• Small/wide angle x-ray scattering (PIs: Tiede and Wang)
• Steady-state x-ray absorption spectroscopy and surface x-ray absorption (PI: Chen)
• Grazing angle x-ray absorption, scattering, and diffraction (PI: Firestone)
• FET and TOF carrier mobility measurements (PI: Yu and Marks)
• Near field optical microscopy (PI: Wiederrecht)
• Laser-initiated time-resolved x-ray absorption spectroscopy and ultrafast optical spectroscopy (PI: Chen)
• Ultrafast transient absorbance and emission techniques with high spatial resolution (PIs: Wiederrecht and Wasielewski)
• Photo-modulated impedance (PI: Hupp)
• Multi-frequency electron paramagnetic resonance (PIs: Wasielewski, Utschig, and Rajh)

Theory/Modeling

Theory provides another fundamental overarching link for the ANSER Center, providing all the research areas with guiding principles, simulations, suggested new materials, interpretations of experiments, and provocative ideas. Projects include:

• Quantum chemistry of molecular structures (PIs: Ratner and Curtiss)
• Electronic structure of itinerant bands (PI: Freeman)
• Computational electrodynamics (PI: Schatz and Seideman)
• Molecular dynamics (PI: Curtiss and Ratner)

Facilities & Resources

Facilities

Beyond the extensive facilities available in laboratories of ANSER Center members, the participating institutions below bring substantial collateral resources that strengthen ANSER Center programs.

• The Argonne Advanced Photon Source (APS): a third-generation synchrotron hard x-ray source providing unprecedented brilliance and photon flux for state-of-the-art time-resolved structural characterization

• The Northwestern Materials Research Science and Engineering Center
• The Nanoscale Science and Engineering Center
• The Northwestern Integrated Molecular Structure Education and Research Center (IMSERC)
• The Northwestern Atomic- and Nanoscale Characterization and Experimental Center (NUANCE): electron microscopy, scanning probe microscopy, and nanoscale fabrication
• The Argonne Center for Nanoscale Materials (CNM): a DOE user facility providing state-of-the-art nanofabrication and characterization capabilities
• Institute for Environmental Catalysis
• National Center for Learning and Teaching in Nanoscale Science and Engineering (NCLT): an outreach program to the science education community; participants include Argonne, Michigan, UIC, UIUC, Purdue, Morehouse, Alabama A&M, Fisk, and U. of Texas at El Paso as primary partners

Resources

• Multilayer deposition by molecular beam epitaxy (MBE) at CNM
• Metal organic chemical vapor deposition (MOCVD) and atomic layer deposition (ALD) at Northwestern and Argonne
• X-ray nanoprobe: a major new facility at CNM that focuses high intensity x-rays to <30 nm, allowing the local structure and spectroscopy of nanoscale architectures to be examined in detail
• Spin Echo Resolved Grazing Incidence Scattering (SERGIS) at the Argonne Materials Science Division: a new approach to probing large-scale (1-20 nm) surface structures, providing 1000x greater sensitivity for membrane structural analysis

March 2009