CEEM Seminar: Darryl L. Smith-Noise Spectroscopy as a Probe of Condensed Matter Systems

Pump-probe techniques, which measure the response of a material to an external perturbation, are often used to study condensed matter systems. Generally, the magnitude of the measured response decreases with decreasing system size.  Therefore measurements based on pump-probe techniques can become difficult for nanometer-scale structures.  The fluctuation-dissipation theorem guarantees that the properties of a system can also be determined from its intrinsic fluctuations.

CEEM Seminar: Daniel Friedman-Multijunction Solar Cells for Concentrator Photovoltaics

The large-scale use of photovoltaics is becoming a reality, with more than 3 GW of solar cells produced worldwide in 2007. However, it is anticipated that on the order of 100 GW or more of solar cells will be called for within the next few years. For 100 GW of photovoltaic power, the conventional "flat-plate" approach would require ~500 km2 of cells, a daunting challenge. A significant part of the solution is likely to be "concentrator" photovoltaics using optics to focus large areas of light onto much smaller ultrahigh-efficiency solar cells.

CEEM Seminar: David Ginley-Interfacial Studies and Modification of Contacts Toward More Stable OPV Devices

Contacts are a key area for defining the performance and stability of OPV devices. We will discuss both new analytical studies on the stability and behavior of conventional and inverted contact geometries. We will present recent results on the use of thin oxide layers on InSnOx and ZnO contacts to improve performance and stability including TiO2, gradient doped ZnO and NiO. We will also present results on using time resolved microwave conductivity measurements (TRMC) to look at the inherent properties of the polymer and the bulk heterojunction.

Energy Leadership Lecture Series: William McDonough-Cradle to Cradle Design: Creating an Environmentally and Economically Intelligent Future

Recognized in 1999 as one of Time Magazine's "Heroes of the Planet," William McDonough is known throughout the world for his environmentally responsible architectural design. With his design firm William McDonough + Partners, Mr. McDonough has engaged in what Time calls "practical utopianism," providing economically and environmentally sound solutions for his clients. 

Brent Constantz-Sequestering CO2 in the Built Environment

Calera’s Carbon Capture and Conversion (CCC) technology with beneficial reuse has been called, “game-changing” by Carl Pope, Executive Director of the Sierra Club. Calera offers a solution to the scale of the carbon problem. By capturing carbon into the built environment, Calera provides a sound and cost-effective alternative to Geologic Sequestration and Terrestrial Sequestration.

Lon Bell-Thermoelectrics, potentially an important contributor to energy savings and greenhouse gas emission reductions

Thermoelectric devices are reversible solid state heat engines. If direct electric current is applied, they function as heat pumps, and can be configured as coolers, heaters and refrigerators. If the process is reversed, and a temperature differential is applied, electric power is produced. The promise is that solid state engines can eliminate two phase air conditioning systems and the green house gas emissions present AC systems produce. This has led to great interest in thermoelectric technology.

Kei May Lau-Hetero-epitaxy of III-V Compounds on Silicon Substrates by MOCVD for Device Applications

III-V compounds have established their niches in optoelectronic, high-frequency and high-speed device applications that cannot be matched by Si electronics. However, Si has been and will remain the workhorse in the semiconductor industry. To further improve the performance and extend the functionalities of Si-based electronics, the best approach is to combine these well-developed materials and related technologies. Our group has been investigating integration of III-V devices on a Si platform.

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