Materials Day Agenda 2009

Within the Solar Industry the drive to guaranteeing long term performance of PV systems has led to a growing interest in products with improved energy efficiency. This has been driven by defined energy purchases as described in power purchase agreements. In the past, the performance metric for solar systems was based on STC performance or rated power alone. More and more, PV systems especially at the utility scale need to determine the competitiveness of their energy generation cost with that of other sources. In determining the total levelized cost of electricity (LCOE), system design aspects such as component reliability, power plant capacity factor, depreciation benefit, etc, will affect the overall cost of electricity. However, the single most important driver for the performance of any system is its energy production when deployed in a real world scenario. This talk describes the approach BP Solar has taken to maximize the energy output from their products by tailoring module electrical, optical, and thermal properties. By reducing series resistance losses, reducing light reflection from the glass surface, and improving heat flow through the module back, energy production of the assembly package has been increased by 7%. As a result, the impact of these improvements on the total lifetime energy yield and on the total efficiency of the product is very significant.

Heat transfer and energy conversion phenomena at nanoscale can differ significantly from that in macroscale.  In this talk, I will start with a general discussion of nanoscale heat transfer and energy conversion processes, followed by a few examples of developing better heat transfer and energy conversion materials exploiting nanoscale effects.  The first example will be how nanostructures can be exploited to reduce the thermal conductivity of materials for more efficient thermoelectric energy conversion.  In an opposite example, I will discuss how we engineer heat conduction to turn polymers from poor thermal conductors to highly thermally conductive materials.  I will conclude by introducing our newly established DOE Solid-State Solar Thermal Energy Conversion Center (S³TEC Center).

Continuing development of high-power white InGaN LEDs is enabling never before possible applications in displays and illumination.  Adoption of white LEDs in solid-state lighting applications is increasingly driven by social and environmental forces, where the long operating life, high efficiency, and absence of lead and mercury of the most advanced LEDs are very attractive.  While precise requirements vary by application, the key goals continue to be to generate maximum flux per package with high wall-plug efficiency, excellent reliability, and flexible packaging and optics at a competitive cost.  Progress in each key goal is increasingly dependent on sophisticated materials development, both in continuous evolutionary improvement and in the conception of novel new materials solutions.

In this presentation, I will describe a few key technologies deployed in LUXEON products from Philips Lumileds and discuss examples of epitaxy challenges and opportunities on the path toward ubiquitous application of solid-state white lighting.

Conventional electronic devices can be difficult to manufacture; their constituent materials require very high levels of order and achieving such low entropy in a semiconductor requires expensive and energy intensive fabrication. For example, the energy payback time for a crystalline silicon solar cell is on the order of 2 years, and at current manufacturing growth rates, it is expected to take at least 20 years to produce enough silicon-based solar cells to make a significant impact on the world energy supply. Similarly, epitaxial growth constraints are likely to limit solid state lighting sources to a small fraction of the overall demand for lighting.

There is an alternate approach that is more suitable for large scale production. In the new Energy Focused Research Center (EFRC) for Excitonics, we address materials with only short-range order. Such nanostructured materials are compositions of nano-engineered elements such as organic molecules, polymers, or quantum dots and wires, in films bound together by weak van der Waals bonds. These materials are characterized by excitons that are localized within the ordered nanostructures. Excitons provide a unique means to transport energy and convert between photons and electrons. Due to localization of excitons, the optical properties of the films are relatively immune to longer-range structural defects and disorder in the bulk. And in contrast with the painstaking growth requirements of conventional semiconductors, weak van der Waals bonds allow excitonic materials to be readily deposited on a variety of materials at room temperature. We address two grand challenges in excitonics: (1) to understand, control and exploit exciton transport, and (2) to understand and exploit the energy conversion processes between excitons and electrons, and excitons and photons.

For the past decade, much excitement has been generated within the field of nano-ionics, given the expectation that decreasing dimensions could lead to breakthroughs in energy conversion and storage technologies. While nanostructured electrodes have been implemented with much success in Li-ion battery technologies, the impact of nano-ionic materials on fuel cell technology remains less clear.  The fundamentals of nano-ionics are introduced, with a view towards practical implications for the functioning of solid electrolytes and electrodes.  Important phenomena such as ionic conduction, device degradation, and surface reactions are discussed with respect to the increasing role of space charge and strain effects in these small scale devices.  Implications for future research and development relating to intermediate-temperature and micro Solid Oxide Fuel Cells will be addressed.

The need for novel materials is the technological Achilles Heel of our strategy to address the energy and climate problem facing the world. The large-scale deployment of photovoltaics, photosynthesis, storage of electricity, thermoelectrics, or reversible fuel catalysis cannot be realized with current materials technologies. The "Materials Genome" project, started at MIT, has as its objective to use high-throughput first principles computations on an unparalleled scale to discover new materials for energy technologies.  I will show how several key problems such as crystal structure prediction and accuracy limitations of standard Density Functional Theory methods have been overcome to perform reliable, large scale materials searching.

I will show successful examples of high-throughput calculations in the field of lithium batteries and radiation detectors and discuss our developments in other fields.

A123Systems has developed a new generation of Li-ion batteries based on a novel nanophosphate chemistry.  The resulting batteries give unprecedented levels of power, safety and life, and are currently being used in a number of portable power, automotive, and grid applications.  The development and capability of this new class of batteries will be reviewed.  Following on the technical review, the current challenges facing battery developers will be presented and discussed in the context of the rapidly growing transportation and energy markets.

Venture capital plays a crucial role in moving innovation from laboratories into the marketplace; yet, it tends to be misunderstood in many research environments. In this talk, we will attempt to explain the basic tenets of venture capital, why it is useful, and what venture capitalists look for in an investment. We will also address the impact of the financial crisis on the venture industry, as well as the increasingly important role of “Cleantech” in venture capital at large. In addition, we will provide some general advice, based on our own experience, to materials science companies looking to commercialize their technology.

The recent financial meltdown in the US questions our understanding on several dimensions. First, what does it truly mean to have a sustainable financial sector? The US was by far the most developed and best regulated market on earth, yet it went through this massive failure. Financial crisis have been happening regularly throughout the last 800 years in many countries. The issue of sustainability is not a trivial one.
Second, what are the relationships between this financial crisis and asset and commodity prices prior to the collapse? We tend to assume that markets are independent and/or isolated.  This crisis has shown this is rarely the case. How do we deal with contagion? How can we measure it and can it be prevented?
Finally, the crisis indicates that our strategies toward improving standards of living in the world are severely flawed.  In financial markets, we tend to believe improvements in one area lead to improvements in the world.  These issues will be discussed and with relatively simple examples we will highlight why this is the wrong approach.